Bad brake master cylinder?

[55Test]

So a few days ago just as I was parking my 2000 Corolla in my yard, my brake pedal dropped to the floor. I didn't see any fluid leaks nor did the brake warning light come on. With the help of my dad I checked the brake system earlier today. No visible fluid leaks anywhere. We tried bleeding each brake and it seemed like there was very little fluid flow to the rear. No lines are leaking and nothing I can see is broken, so I was thinking maybe the master cylinder has gone bad. Is that possible? The car has 447210 kms on it.

 

[CT8]

Probable and with that many miles yes and a new M.C. would be a good idea anyway.

 

[BigD1]

Pump pedal to get some brake, and then holding the pedal down it starts dropping? Every time I have had this to happen over the years with no leaks, it was a bad master cylinder. I reckon they leak on the inside, but on one occasion I did have one seeping where it is bolted to the firewall.

 

[Trav]

No external leaks, its probably leaking into the booster. Time to pull it and investigate.

 

[55Test]

I pumped for 10 seconds and got no pressure, the pedal just goes to the floor with no resistance

 

[cb_13]

If the fluid is not disappearing it sounds like it's leaking past the seals internally inside the master cylinder. A new master cylinder is needed. Replacing as much brake fluid as possible at this time would be a good idea as well.

 

[sciphi]

Does the pedal sink when the engine is both off and on? If it only sinks with the engine running, it's probably a bad brake booster. Try it with the brake booster hooked up and unhooked.

 

[55Test]

Sinks with the engine on and off

 

[georgemiller]

Had the same symptoms on daughter's 2001 Camry. Brand new master cylinder 29.99 delivered to my house from Car Parts wholesale on Ebay. Works perfect.

 

[crazyoildude]

if there are no leaks anywhere you can see and you don't have to add brake fluid you can have air and contaminants in the line buy 3 pints of dot 3 brake fluid and power flush each wheel starting from the right rear.. You had very little fluid flow to the rear because they need to be bled really good.

 

[Trav]

Originally Posted By: Trav
No external leaks, its probably leaking into the booster. Time to pull it and investigate.


Sorry my bad reading, you did say the fluid was not going down. It sounds like a failed MC