Sticking Calipers

Ok, so my new-to-me 1988 ranger went on it's first road trip to my in-law's lake house about 60 miles away. About 40 miles out, the truck seemed to have no power, i stepped on the brakes and it pulled hard to one side - pulled over and both front wheels were so hot they made steam when I sprayed a little water on them. I know that the brake flex hoses can go bad and cause this - I finally got to the lake house, replaced both hoses and drove around some and everything seemed fine. Started home today and about 40 miles into the trip - same thing. I jacked both front wheels up and couldn't turn either of them. I was able to pry the calipers to the outsides where the piston went back in a little, and drove home without hitting the brakes. Any ideas? Also, are the two pins (metal over rubber) that hold the caliper on supposed to be super tight? I had to drive mine out with a hammer, but it seems that they wouldn't let the caliper move from side to side if they are that tight.

It's the little rubber boot that seals the piston inside the caliper, it gets hot and melts causing the piston to "stick" in the closed position... Go ahead and replace both of them with new ones, I've had this happen on every single RBV I've owned... So much so, two spare calipers made it into my roadkit... Simple fix, you can do both in 30 minutes including bleeding the brakes...

Thanks for the info.

Thanks a lot - I'll start looking for calipers. Replacing a couple of 20+ year old calipers seems like a no-brainer.

At $20 a pop I went ahead and got two extras and two bottles of brake fluid and added them to my roadkit... Haven't had to use them yet though (knock on wood)

Yeppers and get the calipers with the steel pistons in them instead phenolic(plastic as i call them)pistons...these plastic pistons tend to swell up when hot and causing a lockup.

Bruce said:

Yeppers and get the calipers with the steel pistons in them instead phenolic(plastic as i call them)pistons...these plastic pistons tend to swell up when hot and causing a lockup.

Click to expand...

I've never seen a phenolic piston in the calipers I get, but definitely stay away from that I'd say...

Check your wheel bearing!
My brake was grabbing and dragging and stuff like that after about 15-20 minutes driving. The inner wheel bearing was destroyed. I replaced everything, rotor, pads, bearings, but NOT the caliper. It's all fine now.
Just something to check on.

By the way, squash the end of the pin you try to drive out, they have little barbs that catch on the sides. You can even pull them out past that point with some jiggling, no hammer needed.

robertc1024 said:

Ok, so my new-to-me 1988 ranger went on it's first road trip to my in-law's lake house about 60 miles away. About 40 miles out, the truck seemed to have no power, i stepped on the brakes and it pulled hard to one side - pulled over and both front wheels were so hot they made steam when I sprayed a little water on them. I know that the brake flex hoses can go bad and cause this - I finally got to the lake house, replaced both hoses and drove around some and everything seemed fine. Started home today and about 40 miles into the trip - same thing. I jacked both front wheels up and couldn't turn either of them. I was able to pry the calipers to the outsides where the piston went back in a little, and drove home without hitting the brakes. Any ideas? Also, are the two pins (metal over rubber) that hold the caliper on supposed to be super tight? I had to drive mine out with a hammer, but it seems that they wouldn't let the caliper move from side to side if they are that tight.

Click to expand...

put some brake grease or something like that on em. they like to lock up. my 83 still has that problem(i jst havent fixed it yet)

wrecking-crew said:

put some brake grease or something like that on em. they like to lock up. my 83 still has that problem(i jst havent fixed it yet)

Click to expand...

Or you can spend $15 more and actually fix the problem

Good Idea Stuntman

I probably should have checked the inner bearings - already got the new calipers on. I did pop off the bearing covers and there was still ok looking grease that I could see on the outers. They did pass the sniff test - didn't smell like it was burned up. I'll take everything back apart and inspect/re-pack them. Thanks for the suggestion.

Bruce said:

Yeppers and get the calipers with the steel pistons in them instead phenolic(plastic as i call them)pistons...these plastic pistons tend to swell up when hot and causing a lockup.

Click to expand...

Phenolic pistons do not "swell" due to heat.

They also don't rust and cause the flaking hard-chrome to notch the seals either....

Do you guys make this shit up?

the usual cause for problems on the "split pin" caliper system is steering knuckle wear from previous operation with a warped brake rotor.

the inner pad oscillates back and forth and worries the brake piston up and down inside the caliper, the edge of the internal O-ring groove then notches
the side of the piston and the piston won't retract.

The thing is simply replacing the caliper won't fix the problem if the thrust notch in the steering knuckle is worn

this "thrust notch" is the square notch where the tab on the inner brake pad rides... if this becomes worn the rotation of the rotor can cam the pad into contact with the rotor and the brakes can't release cleanly and that causes all the symptoms of a stuck caliper....

Simply failing to grease the caliper slides can have a similar effect...

After much fighting with the '83-94 system I finally got royally pissed and switched to the 1995-97 brake system with the two piston calipers.

Other than a single seized caliper pin (after very nearly two years)
I only swapped out that first set of pads (installed in late August, '07)
the weekend before last... the pads still had some life in them, but I was driving to Indiana to tow a Ranger back here for a friend so he can work
on it... I needed the brakes to be perfect for a 700mile towing job.

It was then I discovered the seized caliper pin (which I had been unaware of)
and that took me only a few minutes to solve... by walking into my garage and grabbing a spare caliper bracket.

On the '95 brake system the caliper bracket is bolted to the steering knuckle
on the '83-94 system the bracket is a cast part of the knuckle...

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