Bad Brake Master Cylinder or Booster for my 1990 Q45?

[071990Q45]

Greetings,

I have been told that my master cylinder needs to be replaced by a mechanic who replaced all the v-belts the other day. He knew this because the car has no stopping power, the pedal goes to the floor (there is fluid in the resivoir), and there are signs of leakage where the MS contacts the brake booster.

I just wanted to run it by the club and see if anyone has any other thoughts on this. Is it the MS or the Booster. Will I need to replace both at the same time? I've already seen some posts regarding differences in master cylinders for different year Qs.

Also, does anyone have a master cylinder or A/C compressor for a 1990 Q45? (Cheap?)

Thanks!

Sam

[Q45tech]

The booster is just that a vacuum assisted pedal pressure multiplier!

Master cylinder leaks are a direct result of failure to change brake fluid at a reasonable interval...........letting it turn acidic from moisture and eating thru the seals. When the fluid changes color from perfectly sparkiling clear towards amber............don't buy the 99 cent per pint garbage it's already amber and degraded brand new.

Never seen a Q vacuum booster fail at least in 16.5 years.........not to say it cannot happen if owners abuse the system with enough vigor and try hard enough.

[maxnix]

Hey, welcome in to our club.

Do you have the FSM and TSB? You will need them.

Most information on mechanical procedures is in Infiniti Onine Mechanic. Try posting and searching there for these type of inquiries. Search first and you should find a well of information.
Modified by maxnix at 3:05 PM 6/13/2006

[071990Q45]

Well, just thought I would update this thread since I just got done installing the new (rebuilt Tokico/Nissan) master cylinder. Everything went smoothly, this was easier than I thought! Just be sure to "bench-bleed" the MS before installing it and connecting the two brake lines. Brakes feel good, not bad for a $66.00 MS from Autozone and $5 for brake fluid. To put it in perspective, my mechanic wanted $230 to get-r-done.

Now all I need to do is A/C compressor replacement, chain guides, and Bose amp replacement. Then I can finally enjoy this great car!

Let me know if I'm close: A/C compressor job - I'm guessing $400 (for a new one), Chain Guides ($1000-ish @ T3 or T1 I can't remember), and I already have the amp.

-Sam

[Q45tech]

Don't worry a 90 Q is a never ending adventure, by the time you get thru changing out worn components it will be time to start over.

But then again most drive fewer miles than I do.

[maxnix]

Man, I hope you bled the entire system and did not retain any of the expired brake fluid. If not, then do it tomorrow with some good DOT4 fluid.

[Jeff Williams]

Man, I hope you bled the entire system and did not retain any of the expired brake fluid. If not, then do it tomorrow with some good DOT4 fluid.

ABSOLUTELY! I went to DOT4 fluid and stainless steel hoses at the calipers. It was a huge difference.

I bought some ATE Super Blue fluid, and it was easy to tell when the old fluid was out. I flushed with some Auto Zone clear fluid first, then went to the blue. They also make some amber fluid, so when I do my next flush, I can go to amber fluid.

Don't try to keep brake fluid on the shelf. once the bottle is open use what you need, and toss the rest. Once the seal is broken, the fluid starts degrading.

Congrats on the self-repair, and welcome to NICO!

[elwesso]

Good deal, glad it was easy. Interestingly enough, ive heard of less failueres of the 94 MC than the 90-93 MC... Too bad you cant use the nabco MC from the 94 on the early ones.

[071990Q45]

I forgot I took some pics of the booster where the master cylinder had failed and leaked fluid. Just thought I would add them here.

For those who've never done this, don't make the same mistake I did. Buy or borrow the special tool to loosen the two brake lines from the MS. The FSM calls them "Flare Nut Torque Wrench". If you don't use them, you'll probably strip the nuts and have to use needle-nosed vise grips like I did. (live & learn)

Also, I was suprised that you can find OEM remanufactured master cylinders at your local Autozone - cheap. I've seen Tokico master cylinders for $150-160 on Ebay and other online vendors. Autozone had Tokico/Nissan reman. MS for $66. I was just suprised that they had the actual OEM part, I was expecting Beck/Arnley, Raybestos, or some other brand.

-Sam91 Q45