RearDrum Brakes Leak

I recently took a trip from Northern CA to the Sawtooth Mountains in Idaho with the girlfriend for a camping trip. During the adventure, while braking, I noticed that the vehicle would shake/shutter. Based on being a 4runner owner prior, I know that this typically is due to warped rotors. When I returned home, I climbed underneath the vehicle and observed oil around the driver side rear brake drum as you can see in the attached photo. I also noticed the parking brake indicator has been illuminated on the dash, even though it wasn’t set. Based on your guys’ experience, what is the likely issue causing this? I have little to no experience with drum brakes. I was going to get new rotors and pads, but I have a feeling this could also be some of the issue. Also, any recommendations for new rotors/pads would be appreciated also.

 

Sure looks like a rear axle seal leak to me.

Brake light can also come on if your brake fluid is low. If it is, it's worth investigating whether that's what's leaking on your tire. Could be either, based on the photos. My experience when you've got a wet drum and oil dripping on the tire is a rear axle seal leak. But if your brake light is also on, I'd sure want to investigate the possibility of a brake fluid leak at that rear drum.

I've always gone with OEM Toyota pads, but some people here have experimented with others. Most aftermarket pads aren't worth the effort. First, investigate the leak. If you put new pads on, but still have a leak, they'll just get soaked with oil and ruined.

 

Rear brakes on these are simple. The fluid is coming in that hard line to the wheel cylinder. If the line is in good shape, it could leak at the connection to the wheel cylinder, the wheel cylinder seals, or the bleeder screw. Replacing the wheel cylinder addresses all three. Then thoroughly clean the brake fluid out of the drum and replace the pads on both sides so they are even in wear. Replace drum if needed, OEM only here. Adjust the new brakes so that they drag ever so slightly when turning them off the ground. The brake light on the dash is due to low fluid in the reservoir. Refill the reservoir, or this is a good time to do a brake system fluid flush if it hasn't been done recently.

 

Okay. When I get home from work this evening I’ll climb underneath and see if something got knocked loose or cracked .

As for front brake rotors, do you recommend getting the rotors resurfaced or replace them. If so, what rotor/pad combo do you recommend. I’ve tried looking at different threads and there hasn’t been much consistency .

 

Brake rotors come thinner than they used to. Turning them only leads to warping sooner. Just buy new ones. Which brand is debatable. Can’t go wrong with OEM, but some of the performance brands have worked out well for people.

 

I'm going with wheel seals on this one.

Notice how the stain epicenter appears to be the axle tube itself, and it flows out from there. A quick swipe thru that muck and a whiff should tell you if it's gear oil or not. Gear oil (at least to me, while it's comforting) smells like shit. Not literal shit, but it's a dinstinct smell that clings to everything.

When was the last time you checked and/or replaced your differential breather on top of the pumpkin? That little round nubby thing, on top, toward the driver's side? It should spin freely and not be clogged. It should be replaced proactively at gear oil changes, or prob evry 60k-75k miles.

If that clogs up, and the diff can't expel hot gasses out, it'll typically blow out your wheel seals. it's the only logical place for the hot pressured air to go.

The skipping you're feeling is likely your drums/shoes not being able to get traction because they're coated in gear oil OR it's your ABS sensors sending bad signals to the ECU, and causing ABS to engage because the tone ring is covered in gunk from this mishap, or your wheel seal blew out chunks that are stuck in the tone ring, etc.

 

I’m sticking with brake fluid leak based on pics and symptoms

 

I can't dispute that, the leakage does seem to start up near the hard line. Sniff test should tell OP.

I mean, if his brake fluid level is below normal, that could say something too. But smell test is the winner.

 

Yeah only reason I even thought to mention brake fluid was the brake light being on. Otherwise I would have been certain it was an axle seal.

The suspense is killing me.

 

The only wheel cylinder leak I had was on a 52 Plymouth coupe. The fluid caused the friction material to swell and even the slightest brake application caused that rear wheel to lock. I remember being told I must replace the shoes but I was an impoverished student and cylinder rebuild kit plus a can of CRC brakleen fixed it right up.

 

I had an oil leak that soaked the clutch in my 1984 Dodge Charger. One day I pushed in the clutch and the clutch exploded. When we took it apart to fix it, there was nothing in the bell housing except the clutch fork and remnants of the throwout bearing. The brake pads will degrade with the brake fluid saturation. These trucks are very dependent on the rear brakes operating properly to get good braking. I would hate to lose that wheels braking due to failed pads and not be able to stop the truck. Hopefully OP has the means for proper repair.

 

You were just up in my area. Hope you weren't trying to get outside with the fire there.
Like others said, it could be axle seal or wheel cylinder. I would lean towards wheel cylinder since the brake light came on; which could indicate low brake fluid.
For pads/rotors, I would go with OEM or your own personal preference.

 

X2 for the axle seal.

 

Need a poll! Axle seal vs wheel cylinder leak

 

Too bad only the OP and mods can create polls!

 

The fitting from where the hard brake line goes into the drum was slightly loose. Definitely was able to get a wrench on it and tighten it up. Brake fluid was definitely low as well. Will that fix the issue, that’s to be determined….. thoughts?

 

I'll eat my words. Definitely brakes. Was the bleeder or brake line loose?

 

I think @KNABORES was right, and now I owe him a shot of good bourbon and a beer or something.

Meanwhile, thoughts.

Brake fluid is caustic. You really need to get a can of brake kleen and spray all that shit down, then probably follow up with some dish soap and water or degreaser or something. If not, all that shit is going to be rusting thru and paint peeling down the road. You may need to hit it with paint once you get it clean, rustoleum outdoor satin black will match factory nicely.

You may find you'll need to bleed. Have you noticed any change in braking, other than shudder? Is that gone now you've re-tightened the line?

I'd pop the wheel and drum off, myself, because I'm an anal SOB, to check interior stuff.

I'd also be curious to understand how/why that line got loose. Was there some event that tweaked or twisted the line?

 

The bleeder was tight. It was only loose (slightly), from where the brake line connects.

 

Appreciate it. Definitely going to take it for a test drive to the auto store to get more brake clean right now .

Quick update: Just drove to the auto store and did not notice any brake shuttering. Going to see how it does tomorrow on a quick trip deer hunting in the mountains and see.

 

How’d that happen? Someone mucking with your brake line? Ex perhaps.

 

I don't see brake shuddering going away just because you fixed a leak. If the leak caused the shuddering, it's from brake-fluid-soaked pads. Source of leak may have been fixed, but the issues it caused haven't been.

I've only had gear-oil-soaked pads, but the symptoms of that is very "grabby" brakes. You might even have a tire drag/skid on dirt roads. I never experienced shuddering. But like `shifty mentioned, brake fluid is a whole different thing than oil.

 

Oh, it will. A hairline seep in any hydraulic system will cause shudder.

Think about it. You apply pressure to the system by applying the brake, the pedal is boosting the fluid down the lines to jam the brakes. But there's the tiniest little crack that will allow a little sputter of fluid out, but it's such a small opening that it almost bubbles or spurts. With each spurt, a microrelease of pressure, and every little release of pressure, the brakes are going to release a bit. End result? It's going to feel like things are skipping. I assumed the skipping was due to contaminants on the shoes from gear oil. Clearly, the skipping was being caused by tiny little machine gun blasts of fluid skipping thru a hairline seam.

 

Huh. Yeah that logic makes sense.

Well, you're right we all owe knabores a beer.

 

We still need a pic with the drum off.

 

Yeah, I will get that when I can get around to it with my schedule. Luckily it’s not my only vehicle so when I get time to open it up I’ll be sure to update you guys

 

Update: Took the truck up to the mountains archery deer hunting yesterday, and there was no shuddering when braking coming down steep inclines. Maybe my front rotors weren’t warped after all. Thank you everyone for the help. When I get time I’ll end up pulling the drum apart.