Dragging Front Brake Caliper

[isby]

I have an intermittent dragging of (what sounds like) the front left caliper of my '84 3.2L. Sometimes it goes away when I tap the brakes, but increasingly it does not.

The caliper in question was replaced about 15 years (24,000 miles) ago. Based upon the records I have, there could have been a 10+ year period in there without any brake fluid flushes. I just did my 2-year brake flush and the problem persists.

Should I just move ahead with rebuilding the calipers or is there something else I should be thinking about before going down that road?

Thanks.

[pete3799]

Could be a brake line. Any record of them being replaced?
Jack up left front pump brakes. If they are dragging loosen the bleeder screw. if they free up it's most likely your brake line.

[isby]

Thanks Pete. All of the rubber brake hoses were replaced about 2 years (2500 miles) ago.

[Jdub]

If the hoses check out and this is happening over time I would guess that your caliper puck is moving into potentially corroded area of the bore due to natural wear of the brake pad?

For sure the rebuild of calipers and result is so very worth it. Think about doing an exchange if you are short on time. I prefer an overnight gravity bleed using four hoses open to air, then go with your method of bleeding. Good luck!

[isby]

Looks like I’m about to learn how to rebuild a caliper. My wife told me today that the car presents constant problems. I corrected her — it presents constant projects. And that’s the beauty of it.

[EC900]

I would do a thorough inspection and cleaning first.
If it’s been sitting, rust or other debris could be lodged between pad/rotor and if there’s no lip on the rotors, just replace the pads and lube the guides?
Had a friend who couldn’t figure out the intermittent screeching sound coming from his front brakes. Turned out to be a clothes hanger left behind by the mechanic used to hold the caliper was making contact to the either the cv or wheel.

[Otter74]

If you've eliminated everything else, then I'd rebuild it sooner rather than later. Years ago, my car went rather quickly from a sometimes-sticking LF caliper to, a couple of weeks later, the pedal going to the floor after the caliper froze and overheated the fluid. Exciting!

[Bill Douglas]

Before you start doing a rebuild try this.

Swing the caliper away from the rotor and squeeze the pistons back in with a G-clamp. Then put a bit of wood that is about the thtickness of your rotor in and step on the brakes. Do this a dozen times until the piston has loosened up and you can force it in by wiggling (twisting) the bit of wood.

Take the pins out that slide through the brake pads and wire brush the rust off. You can use a file too. Put a tiny bit of silicon grease on them and pout them back. Then refit the caliper. Check your fluid levels.

Then gor for a drive somewhere quiet without using the brakes then stop and put your fingers on the calipers to see that they are cold. If it's dragging it will be warm.

Good luck.

[porsche930dude]

What happens is rust and corrosion builds up in the 1/8" at the edge of the bore before it hits the seal. So its not a big deal to sand that off and fix it but to get in there it all has to come apart and then you find all the rubber is toast anyway.

[Ian Comerford]

Similar to Bill's suggestion above I would try exercising the pistons using this tool. Every winter I service my callipers in this way by removing the pads, pushing the pistons back in, fitting either the pads or a block of wood and pressing the brake pedal to move the pistons back out a couple of times each calliper. I rebuilt my callipers 14 years ago and have had no problems with dragging pistons using this simple service. You also get to have a good look around the brakes, suspension etc at the same time.
https://www.machinemart.co.uk/p/disc-brake-piston-spreader-0---65mm/

[Dpmulvan]

It’s a caliper not a jet engine, buy a few rebuild kits and do it. Quiet brakes and quiet time away from the wife.

[jlex]

The RF caliper on my '88 was dragging a few years ago and I was able to delay a rebuild by working the piston in and out of the bore. The temporary fix lasted only about a year. Just do the rebuild as it'll need it sooner or later. Haven't done the rear ones yet as they haven't been acting up (yet). Been delaying as I've read the rubber seals are a bit more difficult to deal with. Maybe this summer....

[Bill Douglas]

An old guy said to me years ago...

Drive backwards and slam the brakes on occasionally because the piston in the caliper needs some movement left to right, not just right to left.

My one dragging caliper has been fine ever since I did the working the piston in and out thing. Rubbers looked fine at the time too. I just wanted it working.

[emac911]

FWIW, I had issues with dragging brakes, but in my case the pedal was getting hard. All calipers and lines rebuilt/replaced. Lines flushed and bled. It turned out to be a bad master. There is a very small port in the master that allows fluid return, mine was clogged with gunk. Unusual master failure due to sitting for many years. Tell tale sign was opening the caliper bleeder would release the brake and all would be ok until I used the brakes several times.

Doesn't sound like your issue, but I thought I would include it just in case you run out of ideas.

[JSV798]

I've had success with working the pistons back and forth BUT if the dust seal is ripped you will need to rebuild. Not a difficult job except for getting the pistons out; I always ease them out while they are still on the car, not completely out otherwise you won't get the second one out.
On the other hand if the dust seals are OK and the pads are worn just change the pads as the pistons will then operate on a different area.
Roy