Ok, here's the deal. I'm trying to help my boy out and fix my old Max. (I sold it to him 2 years ago, it's the one in my sig.)

He doesn't know much about cars and he let the rear brakes go pretty far. The rear driver side pad was metal to metal, so he took it to Midas and the qouted him $860 to have rear pads, rear rotors, one rear caliper and a new master cylinder.

I told him forget it and have the car towed to my house.
After tearing it apart, I changed the rear pads inspected the calipers and rotors replaced the master cylinder. Both calipers seemed un harmed and the pistons twisted back in without promblems. The rotors where brand new brembos, replaced 2 years ago by me. One looked fine, the other showed the metal to metal contact but doesn't look bad enough to replace. Plus the rotors that Autozone has for the Max are larger than stock and the calipers will not fit.

So, here's my problem. After everything has been replaced including the Master cylinder, the pedal is really mushy. When you began to brake while driving, the brakes will catch then the pedal will slowly drop to the floor. What's the problem?? Do I just need to keep bleeding the brakes? Or am I missing something? What other things, beside air in the lines could cause this.

Thanks for any help, sorry so long.

 

Inspect the calipers for leakage first,if none then try to bleed them more..

 

my car did that and it was the master cylinder,But first look for
any leaks and bleed a couple more times before buying one.
p.s. Dont buy a auto zone m/c they are junk.

 

That might be the problem. That's what I was posting above, I've already bought and Installed the Autozone Master Cylinder. And I've got the mushy pedal.

 

did you pump the master cylinder first?
they always recommend to bench bleed.

 

Just a dumb question. If you just did the rear brakes and master cylinder, you did bleed the fronts also? Perhaps you got air into the front lines changing the master cylinder.

 

Just start over and make sure that u have and extra can of brake fluid. Start with bleeding the master cylinder. Then make sure bleed the brake caliber which is farthest from the master cylinder which should be the back brake on the passenger side. Then precide to do the other back brake caliber, then the passenger front, then the last one. If it is still mushy most likely u didn't get all of the air out. Make sure don't be cheap with the brake fluid. Open the nipple a few times when the brake is pressed to make sure that u get all the air out. Make sure that u close the nipple securely when the brake is still held to the floor.

P.S. Make sure to let the person know who is pressing the brake to pump it a few times and u tell them when to hold it down and let up. That should minimize the chance of air getting back in.

Hope that helps. Let me know if u have any other problems.

 

Definately try bleeding them out some more. If the rear rotors are like mine (I have a 94) the rear rotors are from a 93. I had to get the 93 rotors they are smaller. Mushy usually equals air or a leak.

 

I am facing a similar problem, my pedal would sink on me, so i replaced the master cylinder with one from autozone.... it worked for a week but kept leaking fluid, so i got the dealer part from nissan, i had my mechanic install, brakes are excellent now, exept now fluid shoots out of part of the abs. I certainly dont wanna replace this thing, i know they are really expensive, does anyone have any suggestions?

 

rebuild or replace or let it leak.

Leaking is bad and dangerous so thats out.

Rebuilding is complicated and could be expensive

Replacing with a new piece is really expensive, or getting a used one isnt so bad, but could fail again.

You can also get rid of the ABS system and not have to worry about it as well...

Take your pick.

~Alex

 

I've been searching for a thread like this for two months! I'm having the same problem. I've replaced the master cylinder 3 times (carquest) and I'm still getting serious fade. Both wheel cylinders have been replaced (drums), all the brake lines (rubber) and the brake booster. The only thing I've read is to check the build date on your max for the master cylinder, cars built in 1990 have two different types of mc's one ranging from 1/90 to 9/90 then from 10/90 on. When ever I go to carquest they only show one mc for my car but the dealer had two. I'll try autopartswarehouse.com and see what they offer and report on how it turns out.

 

Some members have mentioned a problem with the steel brake lines corroding and leaking. Follow them under the car and check them for leaks.

 

just got off the web and phone with autoparts warehouse. they are showing two different master cylinder's like the dealer does but at a huge price difference 166 vs 280. i'm ordering today so good luck to me.

thanks 92 Max we cleaned then checked the lines for leaks and everything is air tight.

 

Hey that's cool you can spend more money buying it from them than some other place

 

I dont think the link in your sig could be any BIGGER

 

sometimes I'm as subtle as a 20 lb sledgehammer to your toes





that would be a nice sig quote

 

I finally found the problem! First thing was the master cylinder. BE SURE TO PURCHASE A NEW ONE. I went through 3 remans and all three leaked with fading pedal. After putting the new one on, there was no more fading pedal. I still have a small leak and slightly excessive pedal travel but tonight I will adjust the brake booster (also replaced). Hopefully this will take up the pedal slack and push the mc piston in far enough to stop the leak. (leak was from a loose line, i put thread sealer on it and tightend it back up, no more problems)