Brake Fluid Leak?

[aric711]

Hello all, I'm relatively new to owning a 4Runner and very new to the forum. I have a 1993 4Runner with the 3.0 and auto tranny. I am leaking brake fluid somewhere around the master cylinder up front. I know that I refill the reservoir every week or two and that I fill it from the min line to the max line. So it's a pretty slow leak I guess. I have several questions surrounding that. First is, how do I tell exactly where the leak is? The fluid is clear and very hard to see, but I know I have fluid as high on the vehicle as the o-rings between the MC and reservoir. I first assumed they must be bad? After all the truck is 20 years old and I'm sure they've never been replaced. But, I'm concerned I'll replace those only to find out the MC itself is leaking somewhere. Is it possible for the MC to leak and fluid be higher than the leak itself? I know that defies gravity, but also know driving around, fluid gets in all kinds of places you would not think it could

Secondly, I'm a weekend warrior and have recently replaced the brakes, belts and a sensor that was bad on the tranny, myself. One of the reasons I bought a runner was to work on it myself (they seem easy to work on). I'm not real familiar with the MC and it's components. Does fluid normally go from the MC into the booster at all? I would not think so (thought that was mainly mechanical in nature) but want to know for sure. The fluid is definitely running down the MC, down the Booster and all the other parts of the truck on it's way to the ground. I've tried wiping it off so I can better tell where the leak is, but it's been so cold here lately and again with the fluid being clear its hard to tell.

I guess I could just use some advice. Do the o-rings go bad frequently, is that possibly what's bad? Are there any other things that regularly go bad that this could be? Sorry for the long post, but any help would be appreciated.

 

[KidVermicious]

Did you check all the fittings on the hard lines where they come into the MC?

 

[aric711]

Yes

The fittings do not appear to have any fluid on them and dont seem to be leaking at all.

I also forgot to mention that the leak existed before I replaced the brakes. (just for the record

It strictly looks like the fluid is leaking from the connection between the reservoir and MC. When you wiggle the reservoir, sometimes more fluid will come right out, other times it will leak out over time. Either way it does seem that is where the leak is coming from?

I guess I just wanted to make sure there is not somewhere else I should be checking also (like the fittings, which I did) :high5:

 

[KidVermicious]

When you wiggle the reservoir, sometimes more fluid will come right out, other times it will leak out over time. Either way it does seem that is where the leak is coming from?

So if it leaks right there when you wiggle it by hand, what do you think is going to happen when you wiggle it by driving around? I mean, if that's where it's leaking from I think that's probably where it's leaking from .

O rings are cheap, and you aren't going to hurt anything by replacing it.

 

[aric711]

Yeah

I know, I guess I just wanted a little reassurance because this is the first time I have "diagnosed" something like this, but it does seem pretty straightforward. I appreciate the confirmation and/or reality check.

I'll let you know how it works out after I replace the rings this weekend.

aric

 

[aric711]

Will I need to

bleed the brakes after taking the reservoir off and replacing the rings as long as I make sure the MC is topped off before reinstalling the reservoir? Seems like not, and I'd rather not if I dont have to, but just making sure?

 

[aric711]

Well got it done!

Was able to do the swap out of the rubber grommets on the brake fluid reservoir this past weekend. Doesn't leak at all now

I did, however, find another problem. Now I'm leaking from the top side of the tranny somewhere

Oh well, always some work to be done.

aric