1990 Q45 Brake Pad R&R (BRAKE PADS WORN)

[tangalora]

I found plenty of locations for the vise grips to grab so that the dial gauge could begin to check runout.

Here is a shot of just one of those locations.

The main thing I learned was to not try to zero the dial gauge (every time I touched it, it moved on me). The trick I learned was to just rotate the brake rotor a few times to 'set' the dial gauge in a certain spot ... and then to judge the runout based on the distance moved plus or minus that point (total runout not to exceed 0.0028 inch).

[tangalora]

After almost 500 miles with the "Brake Pads Worn" message, I finally found time to do the rears.

The rear brakes (I didn't attempt to adjust the parking brake) were as simple (for the most part) as the front brakes (components being smaller & lighter too).

It threw me for a loop the fact the hardware kits was asymetrical for the rears (only pad & shim on the outboard side; compared with pad, insulator, shim, & cover on the outboard side.

Also, not being able to turn the steering wheel to point parts inward or outward made it much more difficult to break the lower caliper pin free, as my wrenches didn't fit easily (hint overcoming this obstacle to be explained later). Removing the brake sensor connector from the bracket bolted to the axle was also difficult for me (I simply 'mangled' the old connector until it gave up its grip).

Perhaps the hardest task to overcome was the opposite of the front brake conundrum. In the case of the front, Heath and I fretted over how to immobolize the rotor; however, in the case of the rears, the problem was how to free up the rotor (overcoming the friction of both the differential & leftover parking brake).

Interestingly, I solved this problem of leverage to rotate the rear rotors (to check rotor runout) using a claw-hook pry bar as shown in the photo below. The claw-hook pry bar gave me just enough leverage to slowly turn the rotors (with the parking brake off) to gage runout with the dial gauge flex-arm jig in place. Also note I belatedly hit upon the (what seems to be better) idea of turning the lug nuts backward ... flat side against the brittle cast steel rotor (to prevent cracking the rotors). I suspect this accomplishes what Dennis noted can be accomplished with a stack of washers (which I didn't have).

I hope the next person benefits from these hints.

[tangalora]

Quote » It threw me for a loop the fact the hardware kits was asymetrical for the rears (only pad & shim on the outboard side; compared with pad, insulator, shim, & cover on the outboard side. [/quote] Ooops. Typo. The inboard side has the greater number of parts. See the photo below for comparison. The old parts are at top; the new at the bottom.

Unfortunately, I just realized (as I was writing this) I may have put the inboard parts back wrong! I took careful note of the order when I removed them, which was definately

• rotor
• pad
• inner shim (large rubberized black steel plate, with bent tabs)
• shim insulator (small light non-metallic flat plate, no tabs)
• shim cover (smaller shiny steel plate, with bent tabs)
• piston (caliper)

.However, I just noticed in the factory shop manual, the hardware is listed in a different order

• rotor
• pad
• shim insulator
• inner shim
• shim cover
• piston

Two questions:Q1: Do you think it makes a difference (the reversal of shim & insulator)?Q2: Can you confirm the FSM is correct (insulator touches pad, not the shim)?

[tangalora]

Before I forget, and so that the next NICO do-it-yourselfer benefits from our efforts, here's the procedure I used to replace the rear brake pads & hardware:

Preparation:

• Assume "Brake Pads Worn" lights up on your Infiniti Q45 dashboard (mine is a 1990)
• Read the "Rear Disk Brake" section of the FSM (BR-21 to BR-30 in the 90 FSM)
• Read the dozen Internet articles previously posted on this thread.
• Place a chock in front & behind each front wheel (total of 4 chocks)
• Remove the BBS Infiniti marquee hubcap (if equipped) with a special BBS wrench
• Loosen the five 13/16 inch lug nuts on each rear wheel in a clockwise star pattern (1,3,5,2,4)
• Place a floor jack under the rear differential & jack the wheels about 1 inch off the ground
• Place 1 jack stand under each rear axle lower control arm & lower the Q45 onto the two jack stands
• Set the floor jack slightly touching the differential (for additional safety)
• Try to gently rock the car off the 2 jack stands (better now than later)
• The Q45 should not budge

Dissassemble:

• Open the hood & remove the brake master cylinder reservoir cap
• Note: Do not top off the brake master cylinder reservoir with DOT 3 brake fluid (less is better for now)
• Place an old towel around the brake master cylinder to soak up overflow
• Mark each wheel with chalk (Rear Left = RL, Rear Right = RR) so that you don't mix them up upon replacement.
• Do the right rear side of the Q45 first
• Remove the five right wheel lug nuts & place them in a suitable parts bin
• Locate the brake sensor twist fitted directly into the back of the right rear inboard brake pad
• [Optional] Disconnect the inboard pad brake sensor connector at the pad by pushing in & twisting counter-clockwise
• Remove the 14mm lower caliper cylinder body pin bolt
• Note: There is no need to remove the upper caliper cylinder body pin bolt at this time
• Swing the brake caliper cylinder body upward free of the brake rotor & secure to the frame to prevent hose damage
• Place a disc brake piston spreading tool in the caliper cylinder body piston cup
• Twist the handle of the spreader to push the piston back flush into the caliper cylinder body
• Check the brake master cylinder fluid level (which will rise due to the spreading of the piston)
• Pop off the outboard side shim
• Pop off the outboard side brake pad
• Inspect this outer pad for scoring or for uneven wear for diagnostic purposes
• Note the 1990 Q45 FSM wear limit is listed as 0.079 inches or 2mm (from an original 0.394 inches or 10.0mm)
• Note: OEM rear pads do NOT have a center groove cut in them to help determine wear
• Label the outer shim & pad (RRO === Right Rear Outboard side)
• Rubber band the used pad & outer shim, and place in your parts bin for reassembly hints
• Pop off the inboard side steel shim cover
• Pop off the inboard side rubberized inner shim
• Pop off the inboard side non-metallic shim insulator
• Pop off the inboard side right rear brake pad with embedded sensor socket
• With the pads out, remove the two pad retainers (bent steel canyon clips) from the caliper torque member
• Disconnect three butterfly-loop clips holding the brake sensor wire securely to respective holes in frame brackets
• Disconnect the (brown) brake sensor harness connector.from the brake sensor connector
• Remove the brake sensor connector from its bracket bolted on top of the rear axle.
• Note: This bracket (which holds multiple connectors) can remain bolted to the vehicle
• Remove the brake sensor harness connector & wires from the automobile.
• Again, inspect the brake pad for scoring, uneven wear, sensor condition, & other diagnostics
• Again mark the pad & hardware with chalk (RRI === Right Rear Inboard)
• Again, rubber band the set & place in your temporary parts bin

Inspect:

• Inspect the right rear caliper cylinder body single piston cup & rubber boot
• Look for scoring, rust, wear, foreign material, or other potential damage (as per the FSM)
• Mark the rotor & a lug bolt with chalk BEFORE any next steps (you'll see why later)
• Check each face of the brake rotor visually for scoring, roughness, cracks, chips, etc.
• Note that scoring, objectively, can be over 50 thousands of an inch (the thickness of a dime) & still be acceptable
• Some articles suggest scoring be subjectively checked with a ball-point pen (see if the pen leaves gaps)
• Other articles suggest using your fingernail (seeing if your fingernail catches)
• No scoring limit seems to be listed in the 1990 Infiniti Factory Shop Manual (FSM)
• With the caliper cylinder body out of the way, use a micrometer to check the brake rotor thickness in multiple places
• Measure clockwise, at least, starting at the marked lug nut moving clockwise & write down the measurements as you go.
• When finished, check the deviation between each measurement
• Note this rotor thickness variation limit is not listed in the '90 FSM (see articles instead)
• In my case, the rear rotor was 0.347 inches to 0.348 inches in thickness ('90 FSM minimum of 0.315 inches or 8 mm)
• Double-check that the rear parking brake is set in the driver c0ckpit
• Reverse at least two opposing lug nuts (or suitable flat-sided 12mm x 1.25mm/mm steel nuts)
• Torque those two (or all five) reversed lug nuts to about 60 pound feet
• Note: the parking brake will prevent the rear rotors from rotating as you torque down the reversed lug nuts
• Clamp a flexible dial gauge jig vise-grip (see tool references previous in this thread) to any convenient point
• Position the pin-type dial gauge against the rotor at about the center of where the pad meets the steel
• In the driver c0ckpit, release the parking brake
• Place a claw-type 12-inch pry bar across two lug nuts, with the claw cradling one of the lug nuts
• Spin the brake rotor (with the claw-type pry bar at about one revolution per 20 seconds) to 'seat' the dial gauge
• Do not try too hard to zero the dial gauge; just let it settle down as you turn the rear rotor
• As you spin the brake rotor, take note of the TOTAL runout ('90 FSM limit is 0.0028 inches or 0.07 mm)
• If the limit is too high, you'll need to re-index (rotate the brake rotor) to check again
• Note the rear brake caliper cylinder body is EASILY removed
• Merely pull inboard gently on the caliper cylinder body such that the upper pin slides out of its rubber-booted slot
• Note: You do not need to remove the upper pin from the caliper cylinder body; nor any brake hoses from any brackets
• To reindex, you may wish to remove the brake rotor
• To remove the brake rotor, you must also remove the brake caliper torque member (wrapped around the rotor)
• Remove the two 17 mm bolts to holding the caliper torque member to the rear brake rotor
• Bang lightly on the brake rotor with a rubber mallet to loosen the brake rotor from the wheel hub
• If necessary screw two threaded bolts (8 mm x 1.25 threads/mm) in each of the two holes provided for this purpose
• Turn the rotors on a lathe, if desired taking care not to exceed the minimum thickness (8 mm or 0.315 inches).

Repeat (for the left rear brake assembly):

• Servicing the left-rear brake assembly is the same except there is no brake sensor on the left rear brake pads

Replace:

• Clean the wheel hub of any dirt, rust, or debris (if the rear rotor was removed)
• Replace brake rotor on the wheel hub (if the rear rotor was removed)
• Replace caliper torque member (if the rear rotor was removed)
• Connect the new brake sensor connector to its bracket left bolted on top of the rear axle.
• Connect the (brown) brake sensor harness connector.to the brake sensor connector
• Connect three butterfly-loop clips to hold the brake sensor wire securely to respective holes in frame brackets
• Replace the two pad retainers (bent steel canyon clips) on the caliper torque member
• Clip the cotton end off a common cotton swab & dip it into your grease packet
• Lightly grease the surface of each new pad retainer pad contact area clipped to the caliper torque member
• Take note that there are more parts on the inboard side than on the outboard side
• Replace the inboard side brake pad with embedded sensor socket
• Replace the inboard side non-metallic shim insulator
• Replace the inboard side rubberized inner shim
• Replace the inboard side steel shim cover
• Replace the outboard brake pad
• Replace the outboard steel shim cover
• With a toilet-paper wrapper (not the TP, but, the wrapping paper around it), clean the two caliper cylinder body pins
• Lightly grease the two (now clean & shiny) caliper cylinder body pins
• Remove the disc-brake-spreader from the caliper cylinder body
• Swing the brake caliper cylinder body downward back into position
• Replace the 14mm lower caliper cylinder body pin bolt
• Reconnect the inboard pad brake sensor connector at the pad by pushing in & twisting clockwise

Repeat (for the left rear brake assembly):

• Servicing the left-rear brake assembly is the same except there is no brake sensor on the left rear brake pads

Reassemble:

• Flush & bleed the rear brakes (if desired) with DOT3 fluid
• Replace both rear wheels
• Hand tighten the five 13/16 inch lug nuts on each rear wheel in a clockwise star pattern (1,3,5,2,4)
• Check the underside of the car for any left-over tools, towels, grease packs, and kittens who have found a safe haven
• After both wheels have been hand tightened, jack the car up slightly in order to remove the jack stands
• Lower the Q45 as gently as possible as the tires settle back onto the ground
• Torque the five 13/16 inch lug nuts on each rear wheel in a clockwise star pattern (1,3,5,2,4) to 60 pound feet
• Remove and stow away the floor jack, jack stands, and front wheel chocks
• Replace the BBS hubcap (if equipped) on the aluminium wheels and twist clockwise to make sure it clicks in place
• Start the engine & make a note of the status of the "Brake Pads Worn" dash indicator
• Remove the parking brake & take your Q45 for a test drive around the block
• Perform the high-speed 25 mile burnishing procedure as noted in the police related previously referenced articles
• Report back to NICO your status & what you've learned so that others benefit

tangalora

[tangalora]

Since I didn't get any NICO answer to the reversed "Shim Insulator" question, I'm gonna dissassemble the rears today and reassemble in the (proper?) order as noted on page BR-22 in the 1990 FSM.

Since I drove the previous rear pads for tens of thousands of miles with the brake "Shim Insulator" reversed with the "Inner Shim" w/o any known issues, I wonder what the purpose of the shim insulator is. I'm sure it's there for a reason.

Anyway, I always seem to have even more questions AFTER a job is done than before. Wierd.

For example, I had a problem with the rears similar to Heath's issue with the front. At first I could not spin the rear rotors by hand in order to check runout with a dial gauge. The friction, even with the parking brake off, was just too great (I guess it's coming from the differential hypoid gearing???)

Interestingly, I COULD spin the TIRE on the other side, which spun the brake rotor nicely w/o putting tilting pressure on the rotor under dial-gage test, but, I didn't have a helper handy to spin the other wheel while I checked runout on the rotor.

So, I used the claw pry bar on the upended lug nuts as shown in the photo below to overcome the friction (from the differential???).

My QUESTION: Q: How do YOU spin the rear wheels to check rotor runout?

tangalora

[Q451990]

Good question... I think I used a wrench or socket on the lug nut.

Heath

[tangalora]

Bearing in mind the Q45 rear brakes have both a "shim" and a "shim insulator" (in addition to a "shim cover), I looked up on the Internet what the purpose of the misplaced rear shim insulator might be.

I think most folks (if not all) intermingle the two.

An article, titled Replacing Disc Brake Pads (http://www.advanceautoparts.co....html) intimates the shim insulator might be for sound deadening.

This article titledReducing Brake Noise says "Improper insulating of pads from the caliper housing or caliper piston is the most common cause of disc brake noise. "

In the case of the Q45, the additional non-metallic rear "shim insulator" might be there to eliminate metal-to-metal contact between the blue-painted brake pad backing plate steel and the black rubberized metal "inner shim" (which is itself touching the shiny steel "shim cover" which is in contact with the steel caliper piston.

Another article, titled Selling Services (http://www.babcox.com/editorial/bf/bf120334.htm)also intimates the "shim" is to reduce noise (although that article doesn't discuss the shim vs the shim insulator purpose).

Another article actually equates the shim with the shim insulator (using them interchangably in the same sentence) http://www.motoringtv.com/archives/quak ... a.htmlNote: I wish it were as easy for me to interchange them.

Even the renown Bendix company mixes the two terms interchangably in the same press release as shown in http://www.bendixbrakes.com/pr/11052002_text.html

Perhaps the best Internet reference I found was the "Brake Manufacturers Council" report on Disk Brake Noise (http://www.brakecouncil.org/tips.htm)which also uses "shim" and "insulator" interchangably.

Perhaps most interesting of all was a sentence from that last reference stating "The new shim design utilizes a Nitrile Phenolic dampening layer sandwiched in between two thin wafers of steel. ". This quote seems to back up my earlier questioning of whether the factory shop manual is wrong in placing the non-metallic shim insulator against the pad metal itself, instead of placing the shim insulator between the thin metal shim and thin metal shim cover where I found it (on the existing calipers on the Q45 for the last 25 K miles).

[Q45tech]

I'm sure each brake design has different shim layouts.........what worries me is the shims haven't changed as the pad materials have changed............the acoustic engineering only gets done in the beginning while designing the car.

Impossible to measure rear runout without at helper to turn the other wheel, same with tighten front lugs nuts for measuring the help applies the brakes [other than your using wedge method].

0.002" is well within spec but it just means you are 0.002" closer to having to redo it again. What was the worst case runout position?

[tangalora]

I just noticed this unanswered question: Quote »0.002" is well within spec but it just means you are 0.002" closer to having to redo it again. What was the worst case runout position?[/quote]Checking my service log file, I see 5 numbers (one for each lug bolt wedge measurement if I remember correctly) of 0.0015, 0.002, 0.0005, 0.0015, & 0.0002 for the rear left wheel. Strangely, I don't see any numbers for the rear right (it was a few weeks ago & it was cold outside; I hope I didn't forget to do it; I'm trying to remember; that's why I write this stuff down).

One problem I distinctly remember is that my claw-pry-bar method rear-rotor spin method tended to skew the results because it put edge-pressure (if I wasn't careful) on the dial gage stem. I would have preferred Dennis' suggestion of asking a helper to spin the attached wheel & tire assembly on the other side of the axle. This probably would have zero skew factor whereas my claw-hammer-wedge idea was lousy from that respect.

[tangalora]

Along the same vein of not having a helper handy so having to figure out a method to get the job done alone, I always seem to have to STAND on the lug wrench in order to loosen the lug nuts (or almost any nuts for that matter).

I wonder, is it just me, or do you too find you have to stand on the lug wrench to crack those nuts loose?

(I even find myself standing on the wrengh to tighten nuts, although I am sure you'll yell at me to use a long leveraged torque wrench instead).

[tangalora]

I think we solved the problem of the misplaced shim insulator!

On my way across the country (for the sixth time this year), I stopped by to visit the world famous NICO parts guy often praised here.

Joe didn't have the 1990 parts diagram for the rear brakes but he printed for me the 1995 setup which shows the "shim insulator" between the "inner shim" and the "shim cover" on the rear brakes.

From the photo below, you can see that page BR-22 of my 1990 Infiniti Q45 factory shop manual intimates otherwise. The 1990 FSM (apparently incorrectly) shows the "shim insulator" touching the metal of the inner brake pad.

Apparently the 1990 FSM is in err.

According to Joe's 1995 exploded diagram, the "shim insulator" belongs right where I found it and right where I subsequently put the new one.

Q: Does anyone have a 1991, 1992, 1993, or 1994 FSM who can confirm our presumption of this error?

[maxnix]

1994 Q45 FSM - No shim insulators shown for front pads. Shim insulator between shim cover and shim on inside rear only. No shim cover on outside of rear pads.

[tangalora]

Quote »1994 shim insulator between shim cover and shim on inside rear only[/quote]This 1994 evidence jives with the 1995 rear-brake exploded diagram that Joe at Infiniti of Scottsdale, AZ provided me (see attached photo) this week.

It may very well be that the 1990 factory shop manual is wrong. If so, it's our NICO duty to inform the users out there. (Does this kind of serious error go into a TSB?)

Since the 1994 & 1995 FSM shows the correct placement of the shim insulator, all we need is a report from the 1991, 1992, and 1993 owners to determine the breadth of the purported error.

QUESTION FOR 91,92,93 owners:Q: Where is your "shim insulator" depicted in your FSM?a) Rear inboard; sandwiched between the "shim" (touching the brake pad) and the "shim cover" (touching the caliper piston)?b) Rear inboard; touching the brake pad?

[DAEDALUS]

The '93 manual shows the same order of components as the '90 manual. I would assume things aren't correct in the '91 or '92 either. Not sure if I would call it a serious error...incorrect vehicle jack points is a serious one to me. Didn't the shim kit come with a little diagram on a piece of paper?

[tangalora]

Quote »Didn't the shim kit come with a little diagram on a piece of paper?[/quote]Nope. It just comes with a printed parts list.I just asked Joe if he adds anything to the kit and he replied he sends it to us just as he receives it (see photo below). He even took me to the back shelves where he pulls down the parts to show me the packages in that back room (I never saw so much soda under a staricase in my life).

Unfortunately, I'm beginning to suspect thousands of 1990 to 1993 Q45 rear brakes are reassembled incorrectly (if folks believe the canonical 90-93 factory shop manuals).

Q: Can anyone confirm whether this purported error also exists in the '91 & '92 FSM?

Q: Does anyone know if an incorrect brake hardware reassembly is dangerous?

[maxnix]

One of my front pad/shim combo was incorrectly done by the dealer.

1996 manual is the same as 1994 and 1995.__________________Brian1995 Q45 & Q45t & 2000 Q45

Discover the power of the button!

[Chingon]

so you guys are saying oem beats aftermarket? EBC, greenstuff, project mu, raybestos, hawk,etc..? Is this exclusive to the Q or the 300zx as well (or any car for that matter)?

while at it, how do you guys pop the pistons out of the calipers while they are out?

[DAEDALUS]

Some previous studies have been cited by Q45tech on the performance of OEM pads. Overall, probably the best mix of characteristics of any pad for anything near the price. Use compressed air to get the pistons out. Back before I had a compressor, I would have my gf carefully press the brake pedal till the piston was almost all the way out, then I'd clamp it and do the other one. When all were clamped, then I would disconnect the lines and remove the calipers. Kind of a pain if you're doing 4 pistons, or all 6. I only did one axle at a time.

[Chingon]

I wonder if nissan used the same compound for all their pads? I don't see why not....but then again, OEM are expensive as well.

[tangalora]

Anyone out there with a 1991 or 1992 Q45 factory shop manual?

Q: Would you confirm the location of the "shim insulator" in the rear brake exploded-parts diagram?

[#RealRiceGSR#]

I need you to update your e-mail adress, it is invalid, you can do so by using the user cp button at the top of the page; thanks.

[texasoil]

The shim insulator thread is much ado about nothing IMHO. It's 2 fold purpose is 1) dampen vibration, and 2 ) reduce heat conducted to the caliper piston. THEORETICALLY, it is slightly cooler between the shim and shim cover than directly against the pad backing and therefore should not get as hot and soften too much

[shadydolo]

I must agree with Q45tech on this and go with OEM pads. This car is a high end luxury (even older models) with very particular parts and how they work together. THe pads designed for this car were specifically tested for this car to handle its weight through different stopping habits. Things like that eg. brakes pads, belts, correct weight oil etc... OEM is your best bet for these items.

[tangalora]

For the record (to enhance this thread):http://nicoclub.com/zerothread?id=47476

1990 Q45 Brake Pad R&R (BRAKE PADS WORN)nicoclub.com/zerothread?id=47476

Here is an excerpt from a related brake thread (so others benefit):

Q: Why can't I see the photos in this thread?A: Dunno. The photos are in the thread as of November 2004.

Some people find they have to go to the "user cp" user control panel button at the top of the NICO web page and then click on the "reset forum cookies" button and then hit the button to go back to their profile and then find the article again and view it with the photos. Sometime they have to go through that process twice before the photos show up. I suspect it's something in the user preferences and cookies setup. If you really need the photos and you can't get them, you can post a request to anyone to mail you the 12-page PDF of this helpful brake thread which you can keep by your side to do your next Q45 brake job.

Q: If the previous owner replaced the brakes, why is "brakes worn" lit?A: Brakes wear differentially; maybe only one axle set was replaced.

Q: Day 1 I hear sound of brakes wearing out; day 2 "brakes worn" lights?A: These two events may not likely be related (except coincidentally).

The warning light remains for hundreds of miles before the friction material is actually worn off sufficient for metal-on-metal contact.

I've personally driven hundreds (I forget how many, maybe 500 as Dennis said) after the warning light lit and I still had plenty (relatively speaking) of friction material left. The pads do wear unevenly though, so, it's possible one side is touching the disk while the other side holds the sensor. Also, the sensors are only on one pad out of four for each axle, so, you could hear one side hit on day 1 and then wear out the other side (with the sensor) on day 2. Since my sensor was plastic about 10mm in diameter, I doubt you'd hear it contacting the disk.

Q: Is this something I can order parts for and fix in my garage?A: Absolutely. The brake thread shows all soft & hard tools needed.

Q: I need factory pads in order to have the sensor for replacement?A: Nope. Aftermarket pads come with splice'able sensors.

Use factory pads & parts (from Joe) for different reasons (please see thread). http://www.everythingnissan.com (www.everythingnissan.com).

Q: Are Q45 brakes any more difficult than a muscle car or Sentra?A: Yup. Easy. Proof you can do it is that even I can do it.

While a Q45 brake job is relatively easy, there are a few tricks (such as imobilizing the front rotors and spnning the rear rotors to check runout) and FSM diagram booboos (like mis-splaced rear shims); so again, see the brake thread for the complete detail. That's why we wrote it.

Q: Should I replace the hardware?A: Do as qship96 says; get the hardware/grease kit from Joe.

In my situation, as the brake-thread photos show, my hardware kit was mangled beyond use. Using new hardware makes the job actually easier as the metal springs won't be warped hindering the new-pad insertion & motion.

Q: I usually just check over the rotors to insure that they are still smooth?A:Me too. I use my long fingernails and a dime as "precision" sensors.

In my humble opinion, far too many rotors are turned (see automobile articles in the thread backing up that supposition). Nothing wrong with turning rotors, mind you, except that most that are turned don't need to be turned. I think a groove can be 60 thousands before it needs to be put on a lathe (according to the referenced articles). That's thicker than a dime (if I remember correctly). Runout is a different story and should be checked with a dial gauge as shown in the articles.

Q: Won't the message clear itself once I change the pads?A: Yes. It will clear itself when you replace the sensor.The OEM sensor is much nicer than the Raybestos aftermarket sensor in that it's a complete wire that just plugs properly into the harness connector. The Raybestos aftermarket sensor splices into the wires and therefore may be error prone over time. Either way (I've done both), the message instantly clears itself up (unless you did the wrong axle, which happened to me as described in the brake thread).

Q: I can still use wood blocks and a c-clamp to push the piston back right?A: Why bother? Use a caliper spreader.When you remove the worn pads, the pistons will be all the way out. Push them back with a caliper spreader (I got mine at a local auto store for a few bucks). The caliper spreader (which remains in place while you do the brake job) keeps everything clean while you disturb all that brake dust & also prevents the kids from accidentally popping the pistons out by pumping the brakes when you go inside to bake some cookies or something.

Q: After we measure runout outside 0.0028 how do we correct it? A: Dennis explained it. We'd use thin shims behind the rotor.

However, I do understand your runout testing concerns. Here's my advice (for what it's worth). As Dennis mentioned (if I remember correctly), he checks runout and that takes him a long time. It took the longest time for me too. Here's a little secret. Most people, I think, do NOT check runout. So, you can do a pretty good job w/o that one test. Up to you, of course. It is better to check runout. But, I wonder if the local guys at Brakes-R-Us actually check runout? Does anyone have experience with this? Do the local brake shops take the time to check runout? Or do they just turn or replace rotors and consider the runout fine by default?

Q: Should I match the front/rear pads as Dennis suggests?A: Absolutely!

Notice Dennis' post above which says to match the pads. According to tests quoted in the brake thread, differences between stopping power were huge when there was a mismatch. Given that Joe sells pads at about the same price as aftermarket (in my case, anyway); and given Joe sells them cheaper that you can get the same pads for at the local dealership; and given Joe's OEM pads come with the correct sensor harness connector so there's no splicing needed; and given that you need Joe's hardware kit (if you can get it) anyway; and given that Joe's pads are to OEM specs (albeit perhaps not the original Q45 OEM specs), and given you still have hundreds of miles before a sensor trip turns into scraping metal (at least in my experience) ... blah, blah, bloah, I don't see any good rationale for NOT using Joe's OEM pads & hardware.

Q: How do I adjust the rear parking drum brakes?A: I never got that far so others will have to pitch in here.

The procedure for checking & adjusting the parking brake is on page BR-27 of the 1990 Q45 Factory Shop Manual (FSM), diagram SBR003B. A quick scan of that chapter reveals a shoe spreader (like all drum brakes) adjuster at the base of the drum and a front & rear parking-brake cable. There appear to be two length adjusters on each end of the rear cable (I didn't see any adjuster on the front cable, but, I may have missed it as the diagram is puny).

"]Q: If I don't get the OEM pads, is the pad wear sensor just unplugged?A: Dunno. Someone mentioned you might need to short the wires first.

DISCLAIMER: My only claim to any of the answers above is that I've read the FSM & done a brake job following NICO help every step of the way. I am NOT trained or qualified otherwise to answer any question above so take everything I suggest with a grain of salt.

[Q45tech]

http://www.edccorp.com/products/brakedesign.html

In the middle of the site click on the graph to enlarge to see and study a typical pad vs. friction vs. temperture vs. speed curve

http://www.pagidusa.com/pagidracing/techinfo.htmltemp vs friction on various Pagid pads look at RS 4-2, RS 4-2-1, RS 4-4 as they at least go down to 100F

http://www.ward-engineering.co.uk/ebc.h ... o....s.htm

http://www.stoptech.com/axxis_pads/#ultimate $48 per front set.

[AlabamaDan]

Tangalora,

You'd ask how to break those lug nuts loose....I solved that problem. After much searching I found that the lug wrench provided by Infiniti in the trunk fits better than any of my 4-ways. Judging by your photos you concluded the same. The question is how to get any pressure with that little ackward tool. I took a 30 inch pipe and slide it over the handle as a sort of cheater bar and was able to get the power I needed. Hope this tip helps someone in the future.

[tangalora]

You'd ask how to break those lug nuts loose.... I took a 30 inch pipe and slide it over the handle as a sort of cheater bar

Following that lead, yesterday I picked up three 30 inch unthreaded pipe of an inside diameter of 1 1/4, 1 1/2, and 2 inches (as I just can't budge those nuts no matter how much I curse).

In addition, the store only had two different lengths of "breaker bar", so I picked up both - but they are considerably smaller than 30 inches.

What size (ID) "cheater" bar or breaker bar do most of you use?

[DAEDALUS]

I have a 4' steel pipe that just fits over the breaker bar you have there. A ratchet should not be used as a breaker bar--the mechanism is weak compared to everything else. The pipe is actually a pipe-bender handle that I picked up from Sears for maybe $20, can't remember.

[911/Q45]

I developed a close relationship with my 4 foot cheater pipe when I tightened the crank bolt.

[xmateo]

Since Dennis & Heath were so very right on the fuel pump & visor repairs (saving me a bundle!), I'm now putting myself totally in NICO's hands on my brakes (even though I know I can save dollars elsewhere - and - even though the unbiased Consumer Reports organization says otherwise - I'm gonna' trust you guys on this one too).

Frank amicably picked up the phone at http://www.everythingnissan.com (888-216-5328) and quickly took my order for:

• 1990 Infiniti Q45 Front Brake Pads (Part #41060-64U91) $64.49
• 1990 Infiniti Q45 Rear Brake Pads (Part #41060-66U85) $56.24
• Front Hardware Kit (Part #41080-60U27) $45.70
• Rear Hardware Kit (Part #44080-60U25) $45.70
• 3-day ground shipping (via Airborne Express) $10.46
• Total: $222.59 (sans rotors or caliper rebuild components, which may be needed, later)

EverythingNissan doesn't apparently sell tools (so I couldn't get the dial-gage holder for runout there), but, Frank kindly pulled the hardware kits off the shelf when I asked to confirm the contents and described its components (per axle) to me as

1. 4 x shims
2. 4 x backing plates
3. 8 x guides
4. 1 x brake grease[/list=1] Frank helped me understand that, apparently, those other mandatory replacement parts noted on page BR-18 of the '90 FSM are only needed if I were to rebuild the calipers (which makes sense). The only place we had any contention was on Dennis' comments above about the actual COMPOSITION of the friction material. We just weren't sure if the OEM U91/U85 pucks I just purchased were bona fide ceramic or just semi-metallic. Joe eventually got on the line (I appreciate him taking the time to talk to me, even though the order was already a fait accompli either way), saying he always thought the OEM replacement pads were semi-metallic, but, since he had the highest praise for you NICO guys, admitting humbly, "I've been corrected more than once by Dennis", we left it at asking you guys to confirm their true nature.
   
   This just pushed my brake-maintenance job by another weekend - but the good news is we'll get another weeks' worth of research added to the knowledge leve.
   
   Q: Can anyone confirm the true nature of the U91/U85 pads?

What is the hardware kit? Is this something that normally comes with the pads I buy from Tirerack? I am leaning toward buying OEM from EverythingInfiniti, but the price looks steap.