Rear caliper dragging

[tobluforu]

Is there an easy fix to this, tricks, etc?? This is on my 72, M calipers.

[Grady Clay]

tobluforu,

The absolute first thing I would try is to remove one-pad-at-a-time and mechanically push each piston back.
If it successfully moves, cycle the piston by mechanically moving it ‘in’ and (carefully) using hydraulic pressure to move the piston ‘out’ against a worn-out pad or substitute.
Be very careful to not move the piston past normal operating range (worn pad) or out of the caliper.

If you can successfully cycle all four rear pistons, drive and observe brake function and any possible brake fluid leakage.
A good test for brake function is to have a long drive without using your brakes. Then use the brakes hard to stop from reasonably high speeds, using an IR thermometer to measure brake rotor temperature (both sides)through the spokes of the wheels and from the inside.
You must act quickly or the temperatures will equalize.
A low temperature indicates lack of braking function = stuck piston.


Here, we are talking about marginal functioning brakes.
We own 911s.
Our 911s have the world’s best brakes when functioning correctly.
I see no excuse for anything less than perfect function of the braking system.

Besides, it may save your life.

Best,
Grady

[James Brown]

calipers are easily enough to rebuild. this is a sign of corrosion/gunk keeping the pistons in the applied/un-retracred position. a weekend rebuilding them and 4 kits will vastly improve the braking to like new performance. see some of the caliper rebuild threads for great tech help. everyone has gone through this so just jump in

[midnight911]

this was just stupid me, but I should have done the basic first...check the tire pressure...

not porsche, but it was my BMW E30. E30 kept pulled to the right and front passenger side pads wearing quickly and unevenly. changed the wheel bearing, rebuilt calipers, replaced brake hoses, re-did alignment...still pulling to the right. so finally i went to the basics and checked the tire pressure. the pass front tire only had 10 psi. man, those low profile tires have stiff side walls. it doen't even show how low the pressure is. pumped the air in and fixed the slow puncture and the car now runs straight as republicans...I mean...as it should, and no more uneven and quick pad wear. the low pressure tire also wore very very quickly.

[Ronnie's.930]

Another possible cause of brake drag is a flex line that is degrading internally (not allowing the full release of hydraulic pressure). I know this from experience . . .

[RWebb]

Exactly. The hoses need to be replaced with new rubber hoses every 15 or 20 years at least.

How old are yours???

[tobluforu]

Mine are about 15 years old and ss. I just did a full flush and thought that maybe it was a emg brake shoe hanging up, but no such luck. Pads are Ferodo's. I rebuilt the fronts about 10 years ago.

[KNS]

I just had this problem last week with my daily driver, one caliper was rubbing a bit more than normal (I could actually smell the hot brakes).

I did what Grady suggested: I removed the pads and inserted some blocks of wood (so the pistons wouldn't extend too far). I then pushed the brake pedal and pushed the piston back in with a large screwdriver inserted between the blocks of wood. I did this over and over to excercise the piston in its bore.

It solved the problem.

[tobluforu]

I think I will give that a try.
Thanks