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Thread: MC issue? Rear brakes locking up!

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Posts: 1-7 of 7
2008-01-15 03:26:44
#1
MC issue? Rear brakes locking up!
For years I had been having an increasingly mushy brake pedal. If I pump once, on the second pump the brake pedal become rock solid. Good sign of a bad master cylinder, no?

Back in August or so, I replaced my OEM MC with an NX MC from Rock Auto. It went in easily, and the proceeded to bleed the entire system in the order outlined by the FSM. Took it for a spin around the block, and it felt good. Until.

Until I was on the freeway and jammed on the brakes as I got cut off, when suddenly the right rear wheel locked up and the car veered to the right. I let off the brakes and veered right anyway into the next, clear lane. After that the brake pedal itself "engages" the brakes higher in the travel (i.e. there is less free play in the pedal), the pedal is stiffer, and the brakes feel ineffective (especially as the rears lock up first, causing a near loss of control).

After a couple seconds the brakes return to normal operation, provided I do not stab at the brakes.

It never did this before. I am assuming that since the only major change was the master cylinder (I also replaced the rear brakes with OEM pades, the front discs, and the front pads with Carbotechs), that the master cylinder is bad. I am just looking for other opinions.

Help?

I have gone back and re-bled all the lines again, and there is no air in the system.
Brake setup:
AD22VF up front
OEM B13 rear
NX MC
Crown SS braided lines
ABS-disabled
2008-01-15 03:28:29
#2
how many times did you bleed it ?

sometimes the smallest air pocket can be PIA.
2008-01-15 03:28:53
#3
Honestly, I lost count.
2008-01-15 03:31:42
#4
try swaping in a New MC.

No leaks?
2008-01-15 03:39:37
#5
Yea, a new MC was my next step. Just looking for a sanity check here. No leaks.
2008-02-13 20:29:15
#6
FYI, solved the problem.

I had Rock Auto send me a new MC, and I installed it. Problem solved. Now those Carbotechs are grabbing like I thought, and when i brake hard, the car goes straight instead of veering all over the place.
2008-03-29 00:54:11
#7
Originally Posted by NismoSER
FYI, solved the problem.

I had Rock Auto send me a new MC, and I installed it. Problem solved. Now those Carbotechs are grabbing like I thought, and when i brake hard, the car goes straight instead of veering all over the place.


oh lord..your car goes straight?....mine stays in the spot when i press the brakes jk

glad to see you solved the problem
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