Brake problems

[4runnerfun]

Greetings. I am new member and I own a 89 4Runner 22RE with 180k original miles, and I started driving it regularly again for work (saves gas compared to my 3/4 ton work truck).
I noticed that the front brakes were runnuing hot and realized that the front brakes were not releasing. I jacked up the whole truck to inspect, and sure enough, the front wheels were really tight. The rears spun just fine.
I change the master (noticed a leak) along with new front pads, and that fixed it for about 100 miles or so, but it started up again. Has anyone else had this problem?
Can someone steer me in the right direction? Thanks in advance. Dave

 

[Mlachica]

It sounds like siezed pistons. I'm actually going through this on my 80. The pistons don't retract very well so the brakes get hot and prematurely warp. I decided to replace my rear calipers with OEM one's. For the front Toyota actually has a rebuild kit and I chose to do that instead of replacing the entire assembly. It's probably a good idea to flush the brake fluid if you haven't already done so.

All of these parts should be arriving this week along with new rotors and pads.

 

[keezer36]

Time was, we used to rebuild them. It's just a kit with a seal and dust boot. Take the caliper off, push the piston out with compressed air, remove the old boot and seal, hone the cylinder, blah, blah, blah.
I do believe you can get rebuilt calipers from you local parts store and turn in your old ones.
Do this soon. That piston is holding the inside brake pad against the rotor and wearing it down. Your gonna end up buying new pads again.


Do flush your brake fluid though. I do mine about 50k or when it starts looking a bit dark.
You can do this yourself with a plastic bottle with a bit of fluid in the bottom and a hose attached to the bleeder. Just don't let your master cylinder run down to the point your suckin' air, check about every ten pumps of the pedal.

 

[ntsqd]

The brake fluid has or had moisture in it. None of the normal components in a brake system would cause the corrosion that is causing the pistons to not fully retract. It is a sad state that the price of a rebuilt caliper usually makes it more cost effective to simply trade in your cores for rebuilts. That is, if your time is worth much to you. On some calipers the dust boot is extremely difficult to install without some sort of special tool.

One of the rarely known or followed (myself included in the latter) annual maintenance items is a total flushing of the brake system. The corrosion comes from the brake fluid's affinity for water. Moisture in the air gets pulled into the brake fluid where it eventually settles in the low points. Not only does this promote corrosion, it also lowers the fluid's boiling point.

Folks who are ultra concerned with brake fluid boiling point (road racers etc.) rarely buy the large bottles of brake fluid. It is more expensive in the small bottles, but you don't end up with an opened bottle sitting on the shelf gathering moisture either.

 

[Grim Reaper]

Shouldn't drag at all and I would be concerned that its bearing. If the hubs a locked it will feel like the brakes dragging as well. Other then those other possiblilites it is probably crud in the calipers.

Stock size tires or over sized? Oversize then upgrade. Hell upgrade anyway it doesn't cost much more if you are swapping parts.

The brakes on a 92 V6 is a direct bolt on and considerably more braking power. The rotors are thicker and the calipers have larger pistons. You may also need to swap on the master cylinder as it is a larger diameter. You will need to find a Reservoir at a junk yard or you can buy the masters with Reservoir from Marlin. http://www.marlincrawler.com/htm/brakes/mcylinder.htm

The rest f the parts I would get from Autozone or Advance or whatever big chain in your area.

Marlin lists that as a FJ80 masters but the V6 trucks also spec the same masters from 92 up.

Make sure to get new wheel seal and repack the bearings.

Unbolt the rear proportioning valve from the axle and zip tie it up to the floor.

The peddle will be firm do to the 4cly booster. A 90's V6 dual diaphragm booster is a bolt on. My wife doesn't seem to have issue with the firm peddle and she's 5ft 90lb.


This really has improved the brakes on my 86 that wears 33's. I can lock the 33's.

I have more info on the second page of this thread including some pictures showing just how much bigger the calipers are.
http://expeditionportal.com/forum/showthread.php?t=3033&page=2


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