Brake fluid leak - Toyota Nation Forum : Toyota Car and Truck Forums

Sarstan237 · 01-02-2005, 04:50 PM

I'm having a leak in my brake system and I've located it. The problem is which part is messed up, how do I fix it, and might this be the only reason why I don't have any brakes right now? So I went and got a new master cylinder for the brakes. I stuck it in, no problems or anything, save for I noticed there was no gasket. The old one had a gasket, but it looks very thin and I don't see precisely how it would be needed between the cylinder and the firewall. Anyway, I put it on, bled it already, but I still don't have any pressure worth mentioning. The leak is there, however. Between the firewall and the cylinder. Is something broken or defective there or do I really need a gasket? It never came with one in the kit, so I would figure it doesn't. Thanks in advance.

Sarstan

Insanity-74 · 01-02-2005, 05:13 PM

I would defo put in a replacement gasket.

Did you change both the internal and external master cylinder?

Are you sure you bled all the brakes correctly?

Have you checked the brake pipes for leaks?

Did you use the correct DOT brake fluid?

Have you tightened the bleed valves up without stripping the threads (easily done)

Are you sure you put the internal rubber seals/valves in the right way around in the master cylinder?

Sarstan237 · 01-02-2005, 05:28 PM

Taking another look at the thing, I noticed that the bar that pushed into the cylinder fromt he firewall is wobbling and moves about a good bit. I also noticed since trying to put in the fresh cylinder, that I get like a clicking when I try to push the brake petal as if there's a miss. I can't help but feel that's a big reason why I have no pressure. Any ideas?

I just have a master cylinder kit. Not sure entirely what that means for inner and outer...
I'm pretty sure it's bled correctly, but even if it wasn't, surely I would have some pressuer, right?
There are no leaks anywhere beside between the firewall and the cylinder. I'm sure of that one.
I am using the correct DOT fluid.
And the rubber tubes I put on correctly as well.

Insanity-74 · 01-02-2005, 05:39 PM

I wouldnt worry too much about the connecting bar wobbling about a bit as long as it is connected to the inside of the master cylinder correctly.

the "inner" part of the master cylinder is the sliding rod bit with the rubber seals on it that gives the system its pressure.

The "outer" bit is the outside bit that you can see in your engine bay, and obviously the bit that the internal rod slides in. The inside of the outer part (cylinder walls) can sometimes get scored by dirt and not enable a perfect seal. (if that makes sence)

If there is air in your system you will get no pressure, as air compresses easily. last time I bled brakes I used well over 1 liter of brake fluid to do all 4 corners of the car.

If you dont have one, purchase a brake bleed kit from an auto store, its a big help.

Sarstan237 · 01-02-2005, 05:52 PM

That's true. I never really considered the air would condence. I figured it was there and would have a more or less equal pressure to the fluid, silly me.

Okay, I'll see about bleeding more, but there's still that leak. I guess I'll see about some gasket or seal for that. THanks for the help.

CCTF · 01-03-2005, 10:31 AM

I wouldn't worry about the gasket. There shouldn't be any fluid at that point anyway. We just changed a master cylinder and didn't replace the gasket. No leaks. FYI we pushed two litres of fluid through the system in order to clean it out and get rid of air.

Insanity-74 · 01-03-2005, 10:56 AM

The absence of a gasket will alter tolerances on the brakes and after all, toyota wouldnt put one on if it wasnt needed. I would never remove anything from your brakes without either replacing it with the same or better, no matter how insignificant it may seem.

Sarstan237 · 01-04-2005, 04:57 AM

Well, either way I didn't put a gasket on. Found out the leak really just came from the damned resevoir not tighten up...
Anway, it's tightened onto the new one now and all I have to do is bleed out the thing better. At the time I can drive about fine and after a pump or two, the brakes are reasonable enough to get a good stop. Without a pump, I have to make sure it's to the floor for a good extra 20 feet or so. I just have to find a friend who'll pump the brake a few times and let me bleed it and won't let the brake out. Clearly that requires more talent than some of my friends have, heh.