Rear brakes work only on one side

2002 Tacoma TRD V6.

While I had the rear axle raised to adjust the parking brake, I noticed that my normal brakes (engaged by brake pedal) only engage on the driver's side, not the passenger. In other words, when I press the brake pedal, the driver's wheel stops spinning, the passenger doesn't change at all. Any idea what this could be? I pulled the rotor and don't see anything clearly awry.

 

Any chance you a have a bad axle seal? Gear oil leaking past the seal coats the drums and shoes and you have no braking action taking place. Its pretty common for the seals to leak.

You said you pulled the rotor, did you mean drum?

 

Bad axle seal would be my guess also. That is where I would look first

 

yes, i should have said drum, not rotor.

indeed, there was lots of oil/grease on the shoes and inside of the drum as well as other parts when I opened it up. you think the oil could be enough to completely stop the braking action? also, the parking brake still works.

 

If there is any liquid/grease inside the drum it can only come from the brake cylinder or the axle seal leaking. You could have a defective brake cylinder.

 

thanks for the info.

the liquid definitely looks like grease/oil, not brake fluid. I cleaned off the drum and brake shoes extremely well and re-installed the drum...the brake seemed to work slightly better but the wheel still spun. I then removed the drum and took a video (see below) while braking; the cylinder is definitely moving the shoes.

This certainly indicates it is the axle seal. I will prepare to replace it.

Questions: does differential oil really muck up the shoes so much that they can't stop the drum from spinning? does this mean i'll need to replace the brake shoes as well? ie, no way to clean them sufficiently?

looks like oem axle seal is part 90310-50006 from toyota. Any benefit to keep toyota oem part compared to aftermarket?

https://youtu.be/5JaEMvDyrQ4

 

Yep, it sure does.

The shoes are less than $20. Now you can properly adjust them as well.

 

Once brakes have oil on them they are ruined they basically absorb liquids so you can clean them all you want but you will never get the oil out of them.

 

Yep, you need new shoes, but I wouldn't replace them until you fix the axle seal. Definitely get the Toyota seal. If you end up replacing wheel bearings at the same time, make sure the seal sits on the retainer where it is supposed to. Toyota redesigned the seal and there is not a lot of room for error. Otherwise you will be replacing it again in 500 miles. Edit: A away to verify that you have a bad axle seal is to remove the abs sensor (or abs sensor hole cover) from the axle and look in the hole. If you see oil, your seal is bad.

 

like this? i assume the golden fluid is gear oil, meaning by axle seal has failed?

 

Yes that is correct. There should not be anything inside that tube right there except bare metal. The axle seal rides on the "retainer" that is on the inboard side of that tone ring (for abs). If you have a bad wheel bearing, it can cause the axle seal to fail. So it is usually a good idea to replace the bearing when replacing the axle seal, unless you know it's good.

 

so i removed the axle to replace the axle seal. unfortunately, when I was pulling the seal, i clumsily scratched the metal inside of the cylinder just outside of where the axle seal sits in a few spots. see pics.
just wondering if anyone knows whether this is problematic. you can feel the scratches with your finger; the worst is maybe 1 mm deep. i was thinking maybe smooth them down with a dremel? it's just not clear to me whether these locations will ever be in contact with anything else in axle/wheel assemble.

 

Those shouldn't pose any problems. There is only an o-ring at the end of the tube to keep dust out. I would just make sure there are no burrs and you shouldn't be fine.