Old Calipers

[Rblackadar]

I was about to toss a set of old calipers out from my 4 speed when I decided to just take them apart for kicks and giggles. I soaked them in a derusting solution overnight and then preceded to take them apart. To my amazement, they cleaned up very nicely. I then removed all 4 bolts (scribing the mark of where they were positioned) and took the halves apart.The mating surfaces were clean revealing the original yellow zinc plating and the little rubber seal was in A1 condition.I had given up earlier on these things because I couldn't get the pistons out because the rings had hardened. So now that I had access to the piston, I took my vise grips/slide hammer combo and went to town on the darn thing (it took a while) When it finally came out, I then removed the seals to reveal a perfectly clean bore. The only thing that was rusted was the seal retainer ring that keeps the top seal in place. Now seeing this, I don't want to throw them out!!!! Do the front caliper repair sets have this retaining ring???? If so, I'll rebuild these bad boys myself. Also, I've heard that these things shouldn't be taken apart....eh..little too late for that now. But I was wondering if it's OK to reuse the same bolts in the same holes and tightening them to their original positions to where I scribed them. Finally, the other piston is stuck in the caliper and I can't get at it with the vise grips....should I put a new piston in on the other side and throw the caliper on and use the hydraulics of the car to force the old piston to move??? Thanks guys.

[Hasbeen]

I use air pressure to get stuck pistons out, & an old disc, & some
packing. The objective to avoid one piston comming out, while the
other was still well in the caliper.

This way you avoid using vice grips on the pistons, & can mostly
reuse them. Unlike the rear cylinders, I have never found any
corrosion in the calipers.

Hasbeen

[laskaboots]

I too have heard that they shouldnt be taken apart, but it sure makes them easier to rebuild, especially getting that dust seal installed. A few racing suppliers, Pegasus in Wisconsin for one, also sells the little rubber rings that fit between the two halves. Don't know what the actual torque needs to be on those bolts, but they're pretty big and I would think could take as much as any other hardned bolt that size.

[Rblackadar]

Actually, they came off pretty easy and were not too hard to put back on to their original scribed positions. These are the smaller 4 speed calipers and not the big brake ones.

[bmcecosse]

These calipers use the same rebuild kit as a Mini (that's Rover Mini, and NOT the BMW MINI!) - and yes the kit has the steel ring, and stainless pistons are available too if they are corroded.
I found a grease gun is the way to shift stuck calipers - just pump in grease and out they pop. Of course - you need to remove ALL the grease afterwards. As for the bolts - they are seemingly designed to stretch slightly beyond the 'yield' when tightened originally - I have in the past re-used them with a spot of Loctite on the threads and torque them right up to max figure for that size of bolt. Never had any problems !