I am sick of brakes

[Dr. Pepper PhD.]

Ok as a header to this, when I bought my car the first thing I did was replace the front brake hoses and rebuild all four calipers. Followed by replacing the master cylinder.

Now, my master cylinder is leaking brake fluid and every time the brake is pressed I hear air leaking out of where the master cylinder attaches to the brake booster.

I took the master cylinder back on my lifetime warranty and got it replaced as I thought it was the problem. Forgot to switch over the rubber boot that goes around the neck of the master cylinder, and the new one didn't have one.

When I went back to get it they had already mailed it back and said that it wasn't a necessary part. So having gone through two master cylinders I am lead to believe that something is wrong with my brake booster. The brake fluid is leaking out of the same place the air is.

Any ideas?

 

[Rennat]

could you post a picture of where its leaking from the brake booster?

 

[Keros]

What type of brake fluid are you using?

 

[Dr. Pepper PhD.]

Well I got pissed off last night because air was leaking out of the bottom of where the master cylinder attaches to the brake booster and I couldn't bleed the brake line. But this morning the brake fluid level wasn't any lower than I left it last night so I am guessing the brake leaking stopped with the new master cylinder.

As it turns out I think the air in the bleeder hose was actually from not having the other end submerged in the brake fluid below. And I believe the air leaking is just because that boot is no longer there even though they told me that it was not a necessary boot and that no one carried it.

I'm getting ready to put the wheels back on and get it back on the ground so I will tell you in a bit if this is the case.

And DOT-3 brake fluid is what I am using.

As for the other question would it hurt anything to put a sealer bead of caulk along where the master cylinder meets the brake booster just so the air will stop leaking?

 

[limequat]

As for the other question would it hurt anything to put a sealer bead of caulk along where the master cylinder meets the brake booster just so the air will stop leaking?

Are you sure air is leaking? There should be no leakage there unless there is a defect in your booster.

 

[Dr. Pepper PhD.]

Okay I got everything figured out... The new master cylinder stopped the brake fluid leak, I couldn't bleed right because there was a hole in my bleeder hose next to the bleeder nipple, and the air was because I have no dust boot to go around the neck of the master cylinder so it "appears" it is leaking air when in fact it was just pushing the same air out and pulling it back in. Brakes are good again!!!

 

[cuel]

There should be a gasket between the master cylinder and booster, usually. LINK part # 47275. If you go back and follow the link to the booster, there's a part number for the boot, as well. You might want to make sure that the booster isn't full of brake fluid, as well. I've seen master cylinders leak into the boosters many times, and it usually winds up trashing the booster, which puts you at manual brakes until you get a new one.

 

[Dr. Pepper PhD.]

Yeah I checked the gasket it was good... So all that is left is the boot and instead of buying it i just sealed the master cylinder to the booster with some silicone... It probably isn't the best idea should it start leaking again... but I will deal with it should the day come.

 

[RiyadYar]

my gasket like that was ruined when i chaneged my booster so i just left it out ...should i get a new one from toyota? whats the purpose of it?

 

[tlo86]

just buy a new one

 

[product.sc]

id also buy a new one...

 

[annoyingrob]

There should never be any fluid in the area between the master cylinder and the brake booster. The gasket here is only necessary to keep dust and debris from getting inside. Silicone will work fine.

If you're leaking fluid between these two, that's "normal", as there's a drain punched into the bottom of the mating surface, to remove any fluid build-up should there be a leak in the master cylinder. If there's fluid leaking there, it means the main seal in your master cylinder is shot, and needs replacing.

Funny story, my celica had a leaky master cylinder. So much that it FILLED the brake booster with brake fluid. After I replaced the master cylinder, every time I would step on the brakes, the fluid in the brake booster would squeeze out. This would be why you're noticing leaks after you replaced the master cylinder. It'll go away after it squeezes out the fluid.