SOLVED: Leaking brake fluid

Need some assistance folks. My 01 has been great so far, but one pain in the ass has been my driver side drum brake. I successfully replaced the wheel cylinder about 2 months ago when I noticed it was leaking, hadn’t had any issues until now. I thought maybe it was faulty so I went back, exchanged it for another one and installed. Brake fluid leak continued, so I went back two more times, complained and replaced it. I’m sitting here after 3 wheel cylinders with brake fluid still leaking around and behind the drum. Any ideas? I believe it’s coming from the screw-on portion from the brake line, but other than that I’m stuck.

 

Exchanged for another one? You gotta go OEM these days aftermarket parts are crap.

Your specific situation sounds like your not getting proper sealing between the brake line flare and the wheel cylinder nipple. Assuming you've seated it properly while tightening the flare nut on your failed attempts, I'd say you need to inspect the brake line flare. Best case, it's a piece of grit or rust stuck or embedded in the flare, worst case, the aftermarket nipple was not concentric and distorted your brake line when you tightened it down.

Keep us updated.

 

Also check the flare on the brake line real good for any hairline cracks.

 

One bad wheel cylinder: sure, it happens all the time. Two bad wheel cylinders: it's a fluke... but hey, anything's possible. Three bad wheel cylinders: the odds are against it.
You have a leak at the connection between two parts. You've replaced one of the parts 3 times and the connection still leaks. What's the next logical step?

 

Is it possible that the rear axle seal is leaking on that side? If you are seeing oil splashed around on the inside of the drum/back plate and not directly observing leaking brake fluid from the wheel cylinder, I would check it out closely. Very typical place to leak.

Buckaroo

 

Not OEM, but I believe the part itself isn’t the issue after 3 attempts. Agree with the confirmation that it’s most likely the brake line flare. I’m going to jack her up today and try and get this resolved. Do you recommend maybe putting some loctite or tape on the thread?

That’s my thought process, since odds aren’t against it being the wheel cylinder it only has two other points of entry/exit, the bleeder nipple or brake line valve. Mainly fishing for others who’ve had the same issue

Nope definitely not seals (thank god). Brake fluid reservoir continues dropping after being topped off.

 

Don't use loctite or tape on the fitting threads. It is a mechanical seal between the flare and the fitting - the threads do not provide the seal. The flare needs to be well formed, the mating surfaces need to be clean and the line/fitting need to be in alignment. Make sure the nut threads haven't been cross-threaded and it threads easily. You should not have to lean on it to tighten it but you may need to support the cylinder side with another wrench.

 

We’re it mine, while I’d look at the line and flare, I’d likely simply replace that line.

 

Agree, this is likely where you would end up.....

 

So was able to solve today... Rather coincidental, but my diff is indeed leaking through the seal on the same wheel where I replaced the cylinder before, AND I’m also losing brake from my master cylinder. Good news is I got a free master cylinder, swapped it out and issue gone. Bad-ish news, I’m going to have to get down and replace the seal on my diff within the next month or two

 

If I am understanding you correctly, that is the axle seal that I suggested in my first post. The gear oil from the diff floods the axle up to the wheels and seals that are on the axle at each wheel contain the oil. When they fail, you get gear oil splashed all over the inside of your brake drum. Very common problem. Due to that problem, I replaced rear axle seals & bearings on both sides on my 2000 T4R a number of years ago. You may be able to get away with just replacing the seals but many times, play in the bearings is what causes the seals to leak. Also, you will need to replace the brake shoes as they are loaded up with gear oil. If you just do the seals and the leak returns, you get to do the brakes shoes again. Depending on how long you were running with the rear diff low on fluid, you may end up replacing/rebuilding that as well. The noise will tell you. Glad you finally found the problem.

Buckaroo

 

Actually the leaking seal causes the wheel bearing to fail. The gear oil gets into the sealed wheel bearing and washes out the grease which causes the wheel bearing to fail. That's why the two should always be replaced together.

Also, make sure your axle vent is clear and working. A clogged vent is the main cause of the seals leaking. Now would also be a good time to modify the vent to a hose style if you haven't already done so.