Someone posted a thread a while back about when their 4Runner is put in drive it'll sit there until you give it some gas, then with a "thump" it'll break free. Mine has been doing this lately, although I now believe it's NOT transmission related, but rather a rear brake sticking. Has anyone seen this before? I've no way to really confirm which brake or why it'd stick like this.

Sometimes in traffic if I press the brake pedal hard I can then release the pedal and the 4Runner will sit there as if the parking brake is on. Once some gas is applied it'll break free and roll forward. Sometimes the "thump" is subtle, other times it's quite loud.

Any thoughts?

 

take the brake covers off and see if its leaking axle oil\grease... when the seals go out they tent to mess with the rear brakes

 

If you have not already smelled the gear oil, give a whiff around the rear wheels and check the inside of the wheel and around the brakes for grease/gear oil. You should see it or smell it if that is the issue. You can do this without taking anything apart, which is good.

If you do not find anything out of the ordinary, you are going to have to take it apart. If you do find something, you are going to have to take it apart.

 

As said above, gear oil leaking from an axle seal. This will make the brake shoes sticky. If it is the seal/oil you must replace the brake shoes, not just clean them.

That is my vote.

 

Actually I just fixed that very same problem with my truck this weekend...when i pulled the drums off there was alot of sticky black powder which was causing the thump problem. To fix, I got my inner oil seals from napa at about 7 bux each, had the drums turned and put new shoes on, all is well now. let me know if you need any help along the way.

 

Thanks.. I've got a new set of shoes sitting @ home. What/where are the inner axle seals? Are these the ones that you need to pull the axles to replace? I've the Haynes manual at home, but just not sure of what required for the inner axle seals. I don't see any fluid coating my drums on the inside when doing a visual inspection. I do know that these are the original brakes (50k miles on 2000 4WD). I guess being 7 years old I'll just change the shoes out regardless.

Thanks for the info.. if you have any other info regarding the seal replacement I'd appreciate it. Is there anything else (seal or otherwise) that should be replaced when the rear drums are off and the hubs are exposed?

 

I just followed the writeup in the tech section for the inner seals and the haynes for the shoe replacement.

some tips: freeze the seals so that they help to go in, also, I had to use a little bit of gear lube on the outside to help it in, you'll probably want to pick up 3 seals since you might mess up and bend the first one learning how to do it......to drive the seals in, you can rent a seal driving kit from autozone, its very important to use the driver that is exactly as big as the seal, anything smaller will warp it, and go easy hitting it in, tap it once or twice before taking a look at it to see how its going in

some things to do a couple days before you begin is to get some penetrating spray and with the stick attached to the nozzle, spray inside the black bellcrank housing sleeve, its on the back of the drum....you'll also want to ask your friends if they have a micrometer/measuring caliper 12 inches long, i had to pick one up at harbor freight for 45 bux(hopefully, i can return it tho), you'll need it for final adjustments of the star wheel, the drum has to sit about .02inch away from the shoes, turning the star wheel from behind with a screwdriver was too big a pain in the arse

here's some more info about adjusting the bellcrank

http://www.mediafire.com/?agzljmotnli

 

If you use the adjusting tool (spoon tool??) it is not any harder than most vehicles to adjust them out.

 

Update..

Extended warranty on my 4Runner is still active so the four rear axle seals AND bearings are being replaced under warranty. I already had a set of OEM shoes lying around so all it's going to cost is $50 for the deductible and $50 to install the new shoes.

They're also replacing my trans filter for $60, and refilling, they didn't recommend a flush for this particular transmission.

That should be the end of the rear end thump.