rake light on

[pjm8047]

I was driving my rr yesterday and i stopped at a traffic light.i was holding the brake down and my brake light came on and engine ran rough but light went off when i let go of the brake.im not leaked brake fluid. Whats going in?

 

[tpodwdog]

master cylinder could possibly be on its way out! or a possible vacuum leak.... power brakes on that thing?

 

[72RoadrunnerGTX]

Light was tripped by the pressure differential switch in the combination valve. Vacuum leak alone would not account for the light. A seal failure in the master cylinder likely, or any hydraulic component seal failure will create a pressure difference between the front and rear circuits while the pedal is depressed, tripping the light as it was designed to do. A MC fluid leak into the booster would create a momentary rough idle symptom. Check your fluid level.

 

[Cranky]

At first, I thought this was about a farm implement . Fluid level is up where is should be in the MC? If not and you don't see any leaks, check under your carpet where it goes up the firewall just below where the MC bolts on.

 

[Revhendo]

I was going to say "too many leaves in the cowl".

Check your fluid levels. Check your wheel cylinders/calipers for leakage. Unbolt your master cylinder and look behind it for signs of leakage. 72RRGTX is correct, you have a pressure loss somewhere that is tripping the pressure dif switch. Start checking at the top and work your way down. A bad power booster won't trip the light, but it could be combined with a bad master that has leaked into the booster for too long.

 

[pjm8047]

Got 4 wheel drum brakes

 

[Cranky]

How far down does the pedal travel and is the MC level up?

 

[pjm8047]

Napa has a reman mc for $33.00. Probably buy that

 

[pjm8047]

How far down does the pedal travel and is the MC level up?

Didn't check fluid. Ill check it out Thursday or friday

 

[pjm8047]

might be a stupid but once i bench bleed the mc do i have to bleed all wheel clyinders?

 

[Ron 73]

I do, you can still get air in the system..

 

[pjm8047]

so i replaced the master cylinder and I found out that the master cylinder I had on there before was for a power brake system.Maybe thats why I had a tough time stopping the car but everything works fine now thanks guys