Caliper Piston Sizes
 

I'm lazy. Can someone tell me whether the caliper pistons on my front brakes are the same size as the pistons on my rear brakes? '83 SC. I think they are not the same size.

I've had a rear piston sticking/dragging. I have rebuild kits for the front but I think they won't fit the rear. Poop. Perhaps I have some old pads that are thicker and might help 'till the weekend. I hate to disassemble/clean/libe without a rebuild kit in my hand. I'm too slow to be doing projects twice.

Jim,

48 mm front, 38 mm rear

You could try pulling the rear pads out and slowly exercise the pistons out by pedal power ... and spray/brush down the pistons with Brakleen ... to buy yourself a bit of time until the kits arrive from Pelican! If/when the dust seals happen to pop off, you could even apply a bit of Dow Corning 111 to the sides of the exposed pistons after the cleaner dries out.

Okay, I've got pads that are thicker than the ones on the calipers. I'll probably try them. They are indeed smaller than the front ones, so I am pretty confident the pistons are also smaller.

The pistons seem to move okay in the bore, so I'm not sure why they're dragging. I'm open to any suggestions or wisecracks. The passenger side rotor has been hot.

I think I hear the voice of experience. Thanks, Warren. I think I might just spray, peel back some boots, lube some pistons with DC-111 and work them in and out a bit. Thanks again.

How old are the flex lines?

I had a problem with dragging pads. Based on what I read here and here I expected to find the flex line bores had swollen shut. Apparently they can close up such that fluid will not flow back from the caliper when the pedal is released.

In my case, it turned out the caliper seals had deformed (instead of a square cross-section, they were rhombus-shaped) and were not retracting the piston when the pedal was released. This was probably due to the combined effects of accumulated crud and sitting too long without being exercised.

Good luck.