Slight oozing of brake fluid from the back of the rear Drums

Took my 04 Dakota in to have the new drums put on the back. Failed inspection at an earlier date for fluid leaking out of the right side drum. Mechanic put new drums on each side and noticed a tiny amount of fluid still oozing out. This morning I noticed both sides now oozing a tiny amount around the small rubber looking seal at the inside bottom of both drums. Anyone run into this before?

It sounds like your brake cylinders are leaking. Assuming they’re original (19 years old), it’s not surprising.

If they’ve been leaking, then your brake shoes should be replaced as well.


So this was the original issue and both cylinders were replaced along with everything else inside and the outer wheel hub. Posted a pic hopefully it uploaded

Depending on the fluid… either your new wheel cylinders are leaking or your axle seals are leaking. A feel and a sniff of the fluid leaking will tell a good mechanic which it is.


Yeah, if the wheel cylinders were replaced that’s either leftover old brake fluid or rear axle oil. Should be obvious which, once the drum is off. If it’s not, spray down the inside and outside with brake fluid cleaner, see where the fluid shows up first.

I trust my mechanic pretty well, is it possible to miss checking the axle seal? He noticed the slight oozing after replacing everything and I wonder what the chances would be that both new cylinders would be failing.

Okay for now I am just monitoring it and will take it back in Monday, do you know what oval shaped looking rubber piece is at the bottom center of the hub?

That’s the removable cover that provides access to the brake adjuster.

Appreciate the info, is that a possible source for break fluid to leak thru?

No, you can see the fluid is leaking down from above the rubber plug. Makes me think it’s the axle seal, but a look inside the brake drum would help.

Is the brake fluid full in the master cylinder?

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yes the fluid in the reservoir is full, before the drums were replaced I did have to add some maybe about 4 oz worth of fluid.

There is brake fluid on the tire from the brake bleeding process, how long ago was the work done? Rinse the brake backing plate, tires and wheels with a garden hose and see if the leakage continues.


The work was completed Wednesday afternoon. Immediately after test driving, mechanic noticed some fluid oozing out on the right side drum (which was the problem area). The left side drum was also done but only because you do both not just one. I noticed the left side had residue on it this morning.

It’s obvious the mechanic didn’t clean that area after bleeding the brakes, like @Nevada_545 said. So until it’s been cleaned we can’t know if there’s a leak.

For now I am just monitoring after each time I drive it. Monday I take it back in to be rechecked.

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Seems like a good plan. I’m thinking what you are seeing is the residual brake fluid & brake cleaner from the prior work. When I do that job myself as a diy’er I take time to clean all the residual fluids off the contaminated surfaces, but mechanics may not do that routinely, figuring it will clean itself. Suggest in the meantime to keep an eye on the brake fluid level in the engine compartment, and stop driving the vehicle and have it towed to the shop if it gets low.

If the leak is coming from the axle seal, the fluid level in the rear differential may be low. that level should be checked from time to time as a matter of routine maintenance, so suggest to ask your shop to double check. That job takes me less than 10 minutes on my own truck.

Thanks again for the info, if the axle seals end up being bad, is that an expensive fix? I haven’t come across that issue with trucks yet. I dont mind spending some more on it because the truck has done so well for me and this stuff doesn’t strike me as “get rid of it” repairs and more of wear and tear. Its gone on multi state trips several times a year, and the past 4 years of owning it, I’ve had a wheel bearing replaced, coolant flush, brake pads changed, transmission service and then of course this latest adventure but thats all. Going on 20 years I do not feel the need to be worried about the latest repairs.

Not crazy expensive, but get a couple of estimates, if that’s what it turns out to be. But we’re not there yet.

Did you get brand new drums or were the old ones resurfaced? If they were resurfaced, that could cause even new wheel cylinders to leak.

If the mechanic failed to adjust the brakes, right?