I have a 1986 4runner, SR22, manual. I recently bought the truck and I was hearing a rubbing noise periodically from the front right tire. Then I would hit a bump and the sounds would stop. I assumed it was the brake pads so I replaced them.

After installing the new pads, I pumped the brakes, and the brake pedal goes right to the floor. I can get some pressure, but it goes away almost immediately. My brake fluid is full and I don't see any leaks.

Do I have air in the line? It looks like I can get the air out at the master cylinder and there is a bolt behind the tire going straight up, is this for getting air out as well? I can't tell what that bolt is for. It looks like a 5/16 or 3/8 bolt. (Well, it looks like the metric equivalent)

When the truck is off the pedal works as if there is pressure, but when I hold the brake pedal down and start the truck, the pedal drops to the floor.

I have changed the brakes in other vehicles without issues, but they were newer.

 

I think you have a master cyclinder problem and you will also need to blled the lines. then if no good you might want to check your brake cyclinders

 

Thanks Mark. I have the Toyota Repair manual. It seems to have everything, but it isn't very clear on how to bleed the lines. I will work on it.

 

FIXED!!! I unscrewed the bleeder screw, pumped the brakes until I didn't hear sputtering, held the brake down with my tool box and tightened the screw.

 

kind of a wierd way of bleeding brakes here's the problem if you pump the pedal with the bleeder open you introduce more air into the system so while you got your pedal back you probably still have air in the system here's one that works well but for some reason you don't hear to much about when the pedals up the system is wide open from the reservoir on down just pump the pedal a couple times with all the bleeders closed then one at a time in order RR. LR. RF.LF. open them up and let gravity do the work it may take some time but it almost always works I've been a mechanic for 28yrs and can only remember a time or two when this didn't work some times I've had to repump the pedal between wheels but it usually just drips right out some caps seal really well so pop the reservoir cap off and keep it full because the weight of that fluid is whats pushing the fluid out of the bleeders this also works well for changing your fluid just siphon out the reservoir first and fill with new fluid then watch for clean fluid at the bleeders good luck buddy and enjoy working on your truck the sense of accomplishment from doing your own work is almost as good as the money you save I get $32.00 an hr on the job and the shop gets alot more but no one I know goes to a shop when you learn more you can help out your family and friends maybe even make a little side money like I used to do when I was younger

 

Thanks Allen, I will try that. The brakes have been working fine until yesterday I noticed some play in the pedal. I will try your technique this weekend.

I still have the rubbing/grinding noise. I went to a shop in Denver called Toyota Doctor and asked them about it. I have used them before when I rebuilt an engine. I got it rebuilt and they fine tuned it for me. Saved myself some money, even if I didn't get it exactly right. Anyway, they will diagnose it for $45-$90. One guy said there is a brass bushing that wears out, but I guess that is only in auto-locking hubs? Another guy said it sounds like the U-joint. They will drive it and, hopefully, figure out what the problem is. And, hopefully, I will be able to fix it.