ashersullivan88yota

Every once in a while my brakes will start dragging and locking up on the front and they over heat so I have to let them cool down anybody have ideas of what could be causing this?

wyoming9

iTrader: (1)

Calipers hanging up.

Master cylinder not allowing the calipers to release all the way.From one problem or another.

Have you worked on the Brakes??

ashersullivan88yota

Yes just replaced master cylinder and put right side caliper on a while back

wyoming9

iTrader: (1)

Brakes should always be balanced what you do to one side you always do to the other.

Did this problem start when the Master Cylinder was changed??

Was the Master Cylinder the same as the one you removed??

Did you check the Booster push rod was to the correct length if it was to long the calipers will not retract all the way.

Bottom line Brake fluid is not flowing out of the calipers or it is a mechanical problem.

Is it both front calipers or just one side?

884runner232

Replace your brake hose.

ashersullivan88yota

Both front drag I replaced one because I changed pads and the Pistons wouldn't press in

Terrys87

iTrader: (1)

I had the same thing to happen to me a few months ago. I had not done any brake work and the brakes just applied themselves. After going thru several checks, mine turned out to be the Brake Booster. Not saying this is your issue and was the first time I had ever dealt with anything like that. It seemed to do it at higher RPMs which makes sense to me as it would create a higher vacuum.

scope103

This happened to me on an S-10; the flex line to the wheel broke down internally, so that brake fluid would not come OUT of the caliper. In my case, it was easy to diagnose: I couldn't push the calipers back into the bore to get the new pads in.

You should also check the installation of the caliper pins. If one or both is bent (or installed wrong), the caliper won't slide correctly on the mount. This usually causes dragging on only one side of the rotor.

RJR

Can you elaborate on this a bit, scope? I have almost the exact problem you describe, where the inside pad on the driver's side has worn about 3x faster than the other three pads on the front. There's also a barely perceptible pull to the left when the brakes are applied lightly.

Are you saying that the pads (which are supposed to slide freely on the pins) get stuck on the pins in certain cases?

I'm just in the process of replacing the pads, and I was able to compress the pistons fully with no trouble.

Thx,

scope103

On my Dodge Conquest (Mitsubishi Starion), I somehow bent one of the pins, causing the pad on one side to not slide. On the Conquest, the pins were threaded about 8mm up near the hex-head to hold them in the caliper. On the Toyota, they have a flat head on one end and held with a cotter-like clip at the other.

Either way, if the pad can't slide (more or less) easily on the pin, it may hang up enough to wear it quickly.

RJR

That's good to know. I will definitely make sure things are sliding freely before I put it back together. I already ran the pins over the wire brush wheel to clean off accumulated rust and dirt, so that should help.

wyoming9

iTrader: (1)

When changing pads I always put new pins in.

Maybe your winter chemicals are not as bad out there.

Terrys87

iTrader: (1)

I too run the pins under a wire brush then I wipe the pins down with a rag with some WD-40 on them when installing them. Not sure how long it last but it helps to spin freely when installing the wire that acts like a clip. We dont have to deal with chemicals like in the Northeast, that stuff is bad.

I have rebuilt calipers and just replaced my front calipers today with remans on my 86. Seems like I only get about 5 years out of calipers any more. I have had the same issue one pad wearing more then the other in the past. In my opinion, the brake fluid is more corrosive then in the past. I had one truck for 19 years and never replaced or rebuilt a caliper on it.

I just scrapped a caliper today that I removed from a parts truck not long ago and the pistons were frozen and this isnt the first time I have seen frozen calipers. Anymore when I replace a clutch, you may as well as replace the slave cylinder as it will eventually fail on down the road and that is with a new Aisin slave cylinder. I am really thinking it is fluids that cause all the damage. I disassemble the old parts when done with them to see what causes issues. There is some nasty stuff in these things and I change fluids regularly as it is cheap enough to flush most systems.

Odin

I was about to ask about that. I've seen some pretty nasty looking fluid. The black stuff and debris I just flushed out of my master and slave YIKES. I imagine I'll have to replace them before too long.

RJR

My pins weren't really corroded; just surface rust and accumulated dirt. They cleaned up pretty well and work smoothly now. But, it's something I will certainly keep an eye on. Good stuff to know.

Colorado hasn't traditionally been as bad with the salt as the northeast, although my particular town seems very enamored of magnesium chloride these days. I usually try to hose out the underneath of my truck and the wheels and suspension fairly quickly after every storm. I'm not sure just how corrosive mag chloride is, but I don't like leaving it on my vehicle too long.

bswarm

You should be using brake assembly grease on the pins, sliders, and anywhere the calipers slide on the brackets. Same on drum brakes where the shoes contact the backing plates. It doesn't take much, a thin film of grease will help the pads wear evenly.

RJR

I thought about lubricants, but it seems like they would just attract dirt and eventually make the problem worse. The caliper area is a filthy environment, particularly when you drive as many dusty backroads as I do. The FSM mentions disk brake grease on the anti-squeal shims, but not on the pins.

Unlike the GM brakes I've worked on, the Toyota brakes do not have a sliding caliper, at least on my '94. Instead fluid is routed to pistons on both sides of the caliper to apply the pressure to the pads, so the only sliding involved is the pads on the pins. The holes in the pads are quite a lot larger than pins, so it seems unlikely that sticking would occur in most cases.

Odin

I do believe it mentions specific lube points in this FSM everyone talks about.

Terrys87

iTrader: (1)

I have rebuilt cali[pers and behind the pistons is some stuff that can build up behind them in a system that has been flushed in a long time.

Another thing I have done is to fill the brake lines at the Master Cylinder with PB Blaster and then use an air hose to blow the lines out with the lines disconnected at the brakes. That will blow out flakes of rust in the lines. Not sure how clean it gets them but has to help keep the fluid cleaner for a longer period of time. That gets alot of nasty stuff out.