Brake Fluid Leak?

In a Facebook Tacoma group, a guy suggested that the problem could be caused by a clogged differential breather. My breather was definitely clogged. After cleaning the breather, do I still need to replace that axle seal? Obviously I will replace those shoes. Someone also suggested that I should replace that drum. Can I replace just one of them?

 

The drum should be fine. Pick up a can or three of Brakleen and spray liberally on your hardware and wipe clean. Make sure you put a drip pan below your brake to collect the gunk that will drip off. I would try to avoid getting any on the rubber boots but everything else should be good to go. You'll need to reapply some anti-seize on a few of the mating points on the shoes. You shouldn't need to replace the drums themselves unless they are heavily worn/grooved on the inner face. I do recommend replacing your brake shoes though but that's up to you. You'll need to calibrate your parking brake adjuster on the back of the brake (the little rubber plug and the metal gear, search for adjusting rear drums on this forum). As far as the axle seal, I've always gone with the general rule that it should be replaced if fluid seeps past it. The seal sits in a keyway and if it was subject to overpressure due to a clogged breather, it's a possibility that the seal was pushed out of that keyway. You won't be able to check until you pull the axle unfortunately. It's installed along with your wheel bearing to give you a general location. I dont have access to my docs since I'm not at home. Also, one last thing. Do not just copy what the other side of the vehicle has, it should be a mirror not a direct copy when you reinstall.

-J

 

Once fluid wicks past a seal, that's sort of the end of the seal. In some cases they will still leak, but much less than before. In other cases it'll keep leaking at the same rate.

But it should smell like gear oil - very distinct and very

Get another nose in there. Brake fluid barely smells like anything. Gear oil stinks from a distance. Be sure what leak you're dealing with (BTDTGTTS) first. In the Florida heat the gear oil will get even more "aromatic" and be obvious. The good news is whether it's a bad wheel cylinder or a bad seal both are pretty easy even for a first-timer. Take your time, pay attention, and you'll be fine. And if it's gear oil, might as well change out the rear diff fluid while you're at it (since you're gonna stink from the stuff anyway, embrace the suck!)

 

The diff breather was what caused mine to leak.
You can clean it up and see if the leak stops.
It depends on how bad the seal was pushed out.

I did NOT replace any brake components.
But my leak wasn’t as bad as your, I caught mine pretty quick.
I just soaked the shoes down with brake cleaner, took some 200 grit sand paper and “roughed” the shoe material up. Stuck it all back together and drove it 70k more miles.

Yours has been seeping/leaking for awhile. It’s almost grease at this point.
You can try to clean them up and top off the fluid. You might get lucky.

 

OK.... my sniffer doesn't work anymore. I remember what gear oil smells like but can't smell anything like that in there. My brakes have been mushy for quite a while. I bled my brakes after changing my front pads the other day and the brake fluid is so dirty it's actually black. The level wasn't low though, so that indicated to me that it's not leaking. A few years ago, I bottomed out in a deep muddy creek and was held up by a root for several hours. I didn't turn my engine off at the time to keep water from coming into the exhaust and I did change my gear oil after that. So, I could kinda fall into either category. Since it's not that difficult of a job and not too expensive, maybe I should change my axle seal, wheel cylinder, and brake shoes. (although the shoes seem to have meat on them). Also change gear oil and replace my brake fluid. Your thoughts?

 

I have to be honest, I’ve never seen an axle seal that caused differential to creep up around the wheel cylinder on the outside of the baking plate like yours. This is a situation where I’d have to be there and inspect it myself to give you an opinions.

The parts are cheap enough, yes.
The issue is, you’re taking the brake components off either way.
I’d hate to pull it all back apart if it was the axle seal.

Technically, if you are a hack like me.
You don’t have to pull all the brake companies off to do just the wheel cylinder.
But you should……


What I should do, and what I do, are two different things.

 

This is interesting. Looks like mine but not quite as bad. No solid answer there either. I think I'll do it all.

https://www.tacomaworld.com/threads/07-rear-drum-brake-leak.476933/

 

I can’t say that I blame you for wanting to do it all.

It’s not a particularly hard job. I just hate the smell of diff fluid, working in diff fluid, and hate drum brakes. If your shoes weren’t so coated in “what ever it is”, I’d be tempted to spray it down, top off the fluids and see where it originates from. But you have a pretty good leak there.

You said your diff breather was clogged. Which pushes me more towards telling you to do both the seal and cylinder.

Buy 3 cans of brake clean.
1 for pre cleaning before disassembly.
1 For the axle
1 to clean up afterward

Also, here is a tip. Jack up the side you are working a bit further.
That way when you pull the axle, the fluid flows down back into the differential.
There will be some residual fluid in the axle tube, it will drip out when you pull the axle.
Unless you have the side you’re working on up higher.


Good luck. You got this bud.
It’s not that hard, it’s just messy.

 

Thank you! Getting on it now.

 

Can you tell if that seal is bad by looking at it?

 

Not really, not on most.
However, mine did have prominent “bulge” at about the 4 o’clock position.
But that’s not typically, I could have been me that “bulged” it when removing the axle.
But I am still thinking it was the pressure that caused mine to push the seal out.

You definitely have a build up there. And it’s almost waxy.
Which isn’t what I see with brake fluid. But you’re there now.

Little more advice, clean up the area where the o-ring rides.
That’s your only defensive of water intrusion. I put some o-ring lube on mine just to help.
But mostly to make me feel better. If you don’t have any, no big deal. But definitely make sure the matting surface is clean where the o-ring sits.

 

The arrow is touching the o-ring.
Lots of guys forget about it.

 

Just go back from Toyota. That O-ring is hard to find. I'm putting all back together now. Next, opposite side shoes.

 

Is there a groove for the o-ring or does it set outside the rim?

 

I don’t remember there being one.
I believe the bearing assembly is beveled to accommodate for a “groove”.

I just put mine back in the same spot and sent it. Been fine since.

 

So, is there a difference in how you install the left and right rear brake shoes? I see plenty of videos showing the left and indicating a certain way for the drivers side but nothing I've found mentions the passenger side.

 

It’s the same for the both side.

 

You are awesome! Thank you for this!