Hawk HPS Pads Installed...some noise

[BadMojo]

So, I just installed some new Hawk HPS pads and Brembo OE replacement rotors (no slots, no cross-drilling).

I replaced the old shims with new OE ones and used some anti-squeal compound.

I followed Hawk's bedding procedure as well.

I find that I'm getting an occasional squeal from what I think are my front brakes. It's not constant, and appears to go away once the pads have been warmed up a bit.

Is this normal with a slightly more aggressive pad than stock? If it's just the case of a trade-off of a higher performance pad, then I'm OK with it. Just want to make sure there's no problems.

Pedal feel is fine and all traces of pulsation I had with the old pads/rotors have gone away.

My only concern is that I did not use the replacement shims on the Hawk pads since the Hawk ones appeared to have a shim already on the pad. I put some anti-squeal between the Hawk shim and the shim cover and called it a day.

I haven't been able to really test this setup to its fullest because I need to replace a bad rear caliper and do brake lines, fluid and new pads/rotors in the rear.

Thoughts?

[Exar-Kun]

yeah, fix the rear caliper stuff first, then see if its still squeaking..

if so..I reccomend three steps for fixing squaling high performance brake systems:1.get2.over3. it

higher-temp tolerant pads dont tollerate lower temps as well, and thusly squeak..so you gain a bit of heat resistance/tollerance and stability..but get the occasional cold brake pad squeal...so what?

-chet

[BadMojo]

if so..I reccomend three steps for fixing squaling high performance brake systems:1.get2.over3. it

I can definitely do that. I figured it was a normal condition of a higher performance pad. Just wanted some confirmation. I'll drown out the squeals with my new BRM exhaust when I get it.

Thanks, Chet!

[toptechracing]

If it's just a slight squeek on application I would pull the pads back out and put a 45 degree chamfer on the lead and trailing edges of the pad.

[BadMojo]

If it's just a slight squeek on application I would pull the pads back out and put a 45 degree chamfer on the lead and trailing edges of the pad.

Other than quieting the pads down, would there be any benefit to this? The noise itself doesn't bother me, as long as everything else looks OK.

[toptechracing]

yeah it is mostly for noise. The more aggresive pad will squeel a little so you probably don't have an issue. I use the Blues on the rear of my racecar and it squeels like a lound pig on application..

[Def]

HPS are pretty docile pads - they shouldn't squeak from what I've seen and from driving a few cars with them.

Did you bed the pads in correctly? 5 stops 30-5mph, moderate pedal pressure, 10 mins of driving without using the brakes much, 5 stops 60-5mph, moderate pedal, drive for 10 minutes without using the brakes much then park it for a few hours. Should be good to go after that.

You need to transfer a layer of friction material to the disc - bedding them in will do this.

Other than that, make sure your calipers are put together correctly - things like missing clips or anti-rattle pins will cause some noise.

[BadMojo]

Yup. I followed the bedding procedure per Hawk's instructions. I'll put some more anti-squeal junk on there while I'm doing my brake lines and I'll double check the shims (also new).

The pads tend to squeak a little bit on application when cold. If I'm doing highway driving and go to make a stop from high speed, they'll let out a little squeak.

[Grant@tirerack]

Another source of noise can be from old spring clips/hardware. It's always a good idea to replace all of the little hardware pieces. They are exposed to a lot of heat and may not work as well to keep the pads in place when you are not using the brakes.

[BadMojo]

Another source of noise can be from old spring clips/hardware. It's always a good idea to replace all of the little hardware pieces. They are exposed to a lot of heat and may not work as well to keep the pads in place when you are not using the brakes.

Grant,

I was going to ask Hawk this, but perhaps you can help me.

I did replace all my hardware with new OE stuff. The only part I didn't replace on the front was the shim that goes between the pad and the shim cover.

On my old OE pads, the shim was a separate piece. On the Hawk pads, it appears that there was already a shim of the same thickness attached to the pad, so I didn't use my new OE shim (just the new OE shim cover)...perhaps that was my error.

The squeaking occurs briefly on application of brakes and mostly on lighter taps on the pedal as opposed to a moderate to hard stop. The squealing itself doesn't bother me, per se, I just want to make sure I installed the pads correctly.

[BadMojo]

Anyone else have any thoughts on the shim issue mentioned above?

[skatanic28]

i just threw the pads on how they came in the box, and put some of that brake goo on the back of the pads. i dont get any squeel, but ive heard of other people saying the hps can be noisy...

[BadMojo]

i just threw the pads on how they came in the box, and put some of that brake goo on the back of the pads. i dont get any squeel, but ive heard of other people saying the hps can be noisy...

I'm gonna go with extra brake goo (lol) and if that doesn't stop the squeal, then screw it...I give up.

I don't see how the OE shims will fit over the shims attached to pads themselves. I'll just put more brake goo between the metal shim attached to the pad and the shim cover.

Hopefully my new exhaust will drown out any brake noise.

I can't wait to get new rear calipers installed (thanks, Alan) and get the SPL Stainless lines and Hawk Pads on the rear, along with the ATE Super Blue fluid.

***Skatanic, did you re-use your OE hardware? Did you put a shim or a shim cover on the existing pads, or when you say you just put them on did you throw out all your old hardware?

[skatanic28]

I'm gonna go with extra brake goo (lol) and if that doesn't stop the squeal, then screw it...I give up.

i swear sometimes i think im still 5 years old

I can't wait to get new rear calipers installed (thanks, Alan) and get the SPL Stainless lines and Hawk Pads on the rear, along with the ATE Super Blue fluid.

that is my exact setup, and it kicks ***. they just wont fade given my driving style, and the pedal feel is sooo much better than stock.

***Skatanic, did you re-use your OE hardware? Did you put a shim or a shim cover on the existing pads, or when you say you just put them on did you throw out all your old hardware?

i tossed all the old hardware. the pads already had the shims on them, so i just put em right onto the retaining clips. i seriously used a ton of that stuff though, i can still see the red now.

good luck and let me know how it works out for ya.

[s13sr20chris]

hawk hps front and rear, cleaned and lubed caliper slides, new caliper slide boots, new oe front rotors, turned rear rotors, no goo, no shims

i have abs(no worky) so i have slightly bigger front calipers and rotors(too much front brake bias)

no noise, no fade(on the street), and hard pedal

[BadMojo]

hawk hps front and rear, cleaned and lubed caliper slides, new caliper slide boots, new oe front rotors, turned rear rotors, no goo, no shims

i have abs(no worky) so i have slightly bigger front calipers and rotors(too much front brake bias)

no noise, no fade(on the street), and hard pedal

So, you actually replaced the dust seals on the calipers and cleaned them (the calipers)? Did you clean the calipers with brake fluid and then lube them with some of that caliper lube stuff that Permatex makes?

[s13sr20chris]

So, you actually replaced the dust seals on the calipers and cleaned them (the calipers)? Did you clean the calipers with brake fluid and then lube them with some of that caliper lube stuff that Permatex makes?

i replaced the rubber boots that fit over the caliper slides on the caliper bracket(aka torque member). the old ones were torn and the slides were sticking. i cleaned the slides(aka pins) and lubed them with nissan "pbc grease". the pbc stands for lead and copper. less than one liter bottle costs like $60. i have it at work for that dealership quality brake job(read warranty only )i did not disassemble the calipers themselves at this time. they work good and i dont feel like spending the $30 on a set of seals.

[skatanic28]

i took off the boots and cleaned and lubed the slide pins as well, but with just ordinary lithium grease.

[BadMojo]

i took off the boots and cleaned and lubed the slide pins as well, but with just ordinary lithium grease.

Thanks, man...I can definitely do that. My boots were in good shape, but I can lube up the slide pins. I've got some lithium grease in the garage.

s13sr20chris:

In the absence of Nissan's outrageously priced goop, would you recommend the lithium grease or is there another product that's readily available that I should use.

Thanks, guys.

[s13sr20chris]

heck nissan does not even use that stuff for caliper slides. i just used it for the heck of it. any good moly type grease would be my first pick. i imagine lithium grease would be fine too. a lot of wheel bearing greases are "high temp" type and designed for brake applications.

[Grant@tirerack]

Sorry, I didn't catch the shim question earler. The Hawk pads come with the shims installed already. No need to reuse the factory shims.

[Q45tech]

Interesting study shows how oem match rotor design [number shape of internal cooling fins] with grades [hardness] of gray cost iron and a particular pad material to reduce the noise brakes make.

Mix and match pads and rotors can never be as quiet as oem unless you are plan lucky. The oem shims are tuned for factory pads and factory rotors.......other than the added insulative function they may help or hurt noise at different temperatures.

What were the old oem pads -U90, -U91 [FE temp rated] or -U93 series [FF temp rated]..................what are Hawk HPS friction temp rating?

http://www.sae.org/events/bce/tutorial-ihm.pdf

Everything you need to know to redesign your shims to fit non oem pads.http://www.epcorp.com/NR/rdonl...S.pdf

Lots of engineering work required to select a pad and shim set and rotor design for quietness.

All in all the -U93 oem ceramic semimetallic pad combo works best till you exceed 600F.

The Axxis Metal Masters work up to 750F ............noiser when coldThe Axxis Ultimates are good till 900F...........noisier still especially cold

[BadMojo]

Point well taken, Q45tech. I actually did read quite a bit of what you linked to before my brain started to hurt.

I don't know the friction temp rating on the HPS pads, but they have a reputation as a fairly mild aftermarket street pad. They wouldn't stand up to heavy track use. Hawk only seems to post the numbers for their full blown race pads.

I'm not real concerned about NVH stuff...I just want to make sure my install was done correctly. Since I'm going to be doing more brake work soon, I'll lube up the slide pins and use some more anti-squeal compound.

So far, the new rotors and pads *feel* great. No problems with cold stops, either, which is always nice for a street pad.