Ok, I've got a pretty big problem that I think that I have diagnosed, but I need to be sure. Once I am sure - what do I do? Here's the story:

My brakes have been poor for a while, and needed to be replaced. This weekend I put new rotors and pads on, and set about bleeding the whole system. I started at the right rear, and kept getting air bubbles. The fluid was coming out like soda - even when the new clean fluid started to come out! I was confused so I tried the left rear - same thing. No matter how much fluid I used, or which bleeding nipple I tried, I got clean fluid that was full of air.

I finally took a good look at the Master Cylinder Resevoir while the brakes were being pumped, and the fluid was foaming in the resevoir! If we pumped the brakes a bunch of times and then stopped, we could hear "PFFFFFFFTTTTT" noises and see bubbling in the resevoir..........
So I'm thinking that the seals in the Master Cylinder are finished - Anyone think any different?

That being said - What do I do? Do I buy a whole new MC? do I get a rebuild kit and just replace the seals? Do I get a reman MC? or do I go to a scrap yard and pick up a used one?

Anyone have any hints or tips for a MC repair/replacement?

Thanks for all the help!

 

It sounds like somethings not tight or not getting a good seal. I would guess that it's leaking break fluid whereever that pfffftt is coming from. That would be a good place to start.

 

Yeah, that'd be the MC! I'm not loosing a drop of fluid either. It just seems to create a bunch of foam in the resevoir, and then pump a bit of it through the lines.

Does this sound like a failure of the MC seals?

 

Has anyone ever seen this?

 

Mine leaks like a bitch.

Maybe it's a really small hole that's sucking air in?

Not sure what you could use to test for a small leak, because you don't want **** getting in your brake lines.

 

i just replaced mine cuz it was leaking, now the new one leaks in the same place, fortunatley the brakes still work perfect, just drip a little at the seal for the reservoir at the mc an the front

 

Get some zip-ties and strap down the reservoir.
That will stop the leak at the O-ring & keep it from sucking air.
(tip borrowed from Rxse7en)

 

my 2 seals were leaking too, right now i have my reservior off and have bought new seals. My engine bay below the brake system was a mess from it leaking. I'll let you know if I have any problems tonight when I re-intall and bleed.

 

i guees it isn't that uncommon, i will try the zip tie thing right now actually. good call

 

The seals are really pretty cheap. Typically less than $25 for the whole rebuild kit. Unless the reservoir is damaged, just do a quick rebuild. No fancy tools are needed at all.

The Zip tie method is almost as expensive as just replacing the reservoir seals since the reservoir seals are only like a buck or two each. Plus the Zip tie method is really only a temporary fix.

 

The above is right on..
I should have said - "cheap temporary fix."

 

Just FYI, brake fluid will screw up anything it touches. Mine ended up leaking on a few wires and caused a short. It makes its easiest meal of your paint.

 

brought back from the dead...... Im leaking break fluid pretty bad... its not the MC, i replaced that.. its not from the booster. . . and had a friedn pump the brake with the resivor cap off . .no foaming or sounds of any kind... soft mushy pedal... and only leaks like a freaking faucet when I DONT drive it.. when I do drive it it leaks a lot slower... I am sooo confused?!?!?