Rear drums leaking or just dirty?

[TejasRunner01]

Hey everyone,

I have been having intermittent rear brake lock ups when trying to move after being parked over night. One rear brake seems to "stick" and not let go. Usually the thing that fixes it is to reverse and then move forward again. My research as led me to believe the parking brake may be over tightened or the cable is binding; however, I adjusted them previously with the same problem still persisting ( and replaced one of the rear brake cylinders ).. still having the issue which gets much worse in the cold.

I took the drums off today.. they really aren't wet like you would expect due to an axle seal leak. Could the drums just be dirty or maybe just need turning? I do notice a slight stickyness on the pads.. this could be residue from when the brake cylinder I replaced had leaked. Also I have already replaced the diff breather in case you are wondering.

Your thoughts are welcome!

Thanks

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[SaulG]

"notice a slight stickyness on the pads.. this could be residue from when the brake cylinder I replaced had leaked "
Shoe goo looks like possible contamination..your last pic should be a few more degrees inward to see the axle seal..or pull ABS sens.
If you have it apart CLEAN it up and lightly scuff glaze off shoes, take it for a spin?

 

[Bad Luck]

Looks dirty/grimy to me but not a rear axle seal leak in my opinion. I'd also check your bell cranks to see if they are sticking. Mine were causing me to overheat one of my drums requiring replacement. Just a thought.

 

[TejasRunner01]

Thanks for your replies already.. so I cleaned it with brake cleaner, I'll do a light scuff before I put everything back together. Here are both axle seal. Covered with a nice coat of dust and perhaps the smallest bit of oil but it wasn't really "wet" until I blasted brake cleaner..

A new development, I peaked into both side rear drum cylinder dust boots.. milky liquid came out of both the passenger and driver's side.. I'm guessing that means both are compromised since it should be sealed completely when you look under the boots..

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[Bad Luck]

That's more of a dust boot than a seal. The axle seal we're referring to is in the axle housing inboard of the ABS sensor.

 

[BrianK14]

I don’t see evidence of a leaking axle seal. My vote is rusted and seized bell cranks.

 

[19963.4lsr5]

A new development, I peaked into both side rear drum cylinder dust boots.. milky liquid came out of both the passenger and driver's side.. I'm guessing that means both are compromised since it should be sealed completely when you look under the boots QUOTE]


Is not too out of the realm of possibilities that someone removed the brake shoes and gravity pushed a piston out of the wheel cylinder which would let brake fluid collect in between the dust seal and the dry side of the piston. I have a clamp I use to keep the pistons from pushing out of the wheel cylinder while I have the shoes removed.


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[TejasRunner01]

Hey everyone, thank you all for your posts! I ended up buying two new wheel cylinders and upgraded from the 15/16" bore that came with my rig because of the factory 15" wheels to the 1" bore that was equiped with the 16" wheels. I also realized how dry the contact points were between the hub and the shoes. After a good cleaning, greasing and wheel cylinder replacement we are back on the road. I'll update you if I have any issues!

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[MaineRunna]

The fibrous nature of the brake dust indicates to me that the brake shoes were contaminated with brake fluid when the wheel cylinder was leaking. Definitely will cause a grabby/ sticky brake especially when damp out or the brakes are cold. Clean the shoes with brake cleaner spray and sand them a a little. Sometimes I will take a torch and burn the gear oil or brake fluid out of the shoes. (carefully, you don't want to cook them.) Clean the drums out really well also. Make sure your e-brake bell cranks are not seized up as well. If not and cleaning the shoes and drums doesn't fix the problem, replace the shoes.

 

[PatrickStapler]

Rear Axle Seal Leak

This is what that looks like...

 

[TejasRunner01]

The fibrous nature of the brake dust indicates to me that the brake shoes were contaminated with brake fluid when the wheel cylinder was leaking. Definitely will cause a grabby/ sticky brake especially when damp out or the brakes are cold. Clean the shoes with brake cleaner spray and sand them a a little. Sometimes I will take a torch and burn the gear oil or brake fluid out of the shoes. (carefully, you don't want to cook them.) Clean the drums out really well also. Make sure your e-brake bell cranks are not seized up as well. If not and cleaning the shoes and drums doesn't fix the problem, replace the shoes.

Very informative! Thank you. I'll definitely follow that line of attack if I continue to have problems. I did not realize what the fibrous brake dust meant, now I do! I used brake cleaner on the shoes but I did not sand them.. I only lightly sanded the drums. Again, I'll post back if I have issues.


Also thank you for the picture of what a axle seal leak looks like! I definitely don't think I am having that issue .

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[Drcoffee]

It will take you 10 minutes to find out if the axle seal is leaking. Pop out the ABS sensor and look into the cavity. If there is any oil in there, the seals are blown. To me the brake slave cylinders are not leaking at all. They look dry.

A possible solution to leaking axle seals - Toyota 4Runner Forum - Largest 4Runner Forum

 

[Kanoe]

It will take you 10 minutes to find out if the axle seal is leaking. Pop out the ABS sensor and look into the cavity.

Literally, 10 minutes. I just crawl under and take a peek. No need to remove wheels or drop the spare. I can't believe people worry about this problem but are reluctant to just take a look for themselves.

If the ABS sensor is stuck, a gentle rotation cw/ccw rotation with a pair of slip joint pliers while gently lifting with a flat screwdriver will get it out with no stress. No muscle is needed on this part. Then put a little silicone grease on it when you put it back and it will continue to be easy to remove.

 

[TejasRunner01]

Literally, 10 minutes. I just crawl under and take a peek. No need to remove wheels or drop the spare. I can't believe people worry about this problem but are reluctant to just take a look for themselves.



If the ABS sensor is stuck, a gentle rotation cw/ccw rotation with a pair of slip joint pliers while gently lifting with a flat screwdriver will get it out with no stress. No muscle is needed on this part. Then put a little silicone grease on it when you put it back and it will continue to be easy to remove.

I nearly popped off the abs sensor but I read a few posts of people messing it up when taking it off.. I rested on maybe I shouldn't so I didn't even try lol. I figure you would find the oil all over the drum if that was the case anyways

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[Kanoe]

I figure you would find the oil all over the drum if that was the case anyways

Well, yes and no.

In my case I noticed the oil leak into the ABS cavity early. There was oil in the cavity, but none had migrated out to the brake area. So I was able to do the bearings and seals and Dr Coffee flip but my brakes and drums were still perfect and did not need to be replaced. So in a way, not checking could cost you a whole lot more.

 

[Drcoffee]

The mistake many make is replacing the bearings. If the seal leaks, the bearings will be floating in gear oil and well lubricated. Its when you fix the seal and the oil stops flowing that the bearing fails from being dry. Knowing what I know now, I would have just removed the bearing side cover and washed out the gear oil with brake cleaner, drain out the oil on the outer side of the bearing (drill a 1/8” hole in the dust seal and plug it when drained) and repacked the bearings with lithium grease before reassembling the axle with the reversed inner retainer. The cost would be about $25 a side. New seal, new retainer, lithium grease.

*Cut the old retainer off and heat the new retainer to install.

 

[BostonJon]

Having just rebuilt my rear brakes - shoes, Springs, bellcranks, etc - i then realized that my e-brake cable was binding and no longer siding property within the plastic sheathing. If your brakes are still binding, perhaps your cable is not retracting when you put down the lever. You noted this in your original post so don’t forget that it might be a possibility. Replacing the cable is a little tedious but not difficult.

 

[TejasRunner01]

Having just rebuilt my rear brakes - shoes, Springs, bellcranks, etc - i then realized that my e-brake cable was binding and no longer siding property within the plastic sheathing. If your brakes are still binding, perhaps your cable is not retracting when you put down the lever. You noted this in your original post so don’t forget that it might be a possibility. Replacing the cable is a little tedious but not difficult.

I will certainly check this out as well. Thank you for the post!

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[pentagrammaton]

It will take you 10 minutes to find out if the axle seal is leaking. Pop out the ABS sensor and look into the cavity. If there is any oil in there, the seals are blown. To me the brake slave cylinders are not leaking at all. They look dry.

A possible solution to leaking axle seals - Toyota 4Runner Forum - Largest 4Runner Forum

where exactly is the rear ABS sensor?

 

[Scramble]

where exactly is the rear ABS sensor?

right here.