Contour Enthusiasts Group Archives Forums General Troubleshooting early signs of brake master cyl failure ?

Hi

4cyl 98 gl auto. What are the early signs of brake master cyl failure ?

I have a weird "thump" that i feel in the ball of my right foot as go from park to drive 1st thing in the am.

I think that I get a thump for the 1st few times I stop at stop signs.

After the car warms up a bit, there is no "thump".

Ideas ? Car didn't do this 20,000 miles ago.

Thanks,

jim

When a master cylinder fails, the pedal will sink to the floor when holding steady pressur on it. Early signs of failure are that it sinks slowly. Advanced cases the pedal sinks more rapidly.

It doesn't sound like what you are experiencing.

It sounds like you are feeling the change in load on the powertrain as the slack is taken up from engaging the transmission. It is more noticable when cold because the engine is idling faster and the trans fluid has not warmed up yet. It is probably a normal condition, but I can't really tell from long distance. If you are still concerned, have an expert start it cold for you and get their opinion.

Not a brake problem. I would check trans fluid level and also cv joints in the axles.
Bill D.
Does it do this when warmed up as you shift into reverse?

Signs of Master cylinder failure: you slam into the guy in front of you!

noise no longer there ?

I was in-accurate in the description of the noise/vibration. The vibration was on the heel of my foot via the floor pan as i shifted out of park.

Thanks for ideas....