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I am overhauling my brake system as I finish my complete rebuild and restoration of my FD. The brakes are one of the last things I need to complete.
I disassembled the calipers and sent them off to the powder coater. My issue is with the caliper piston. 3/4 of them are heavily pitted around the neck area. The sides that seal the pistons to the bore are good, but the top section is pretty nasty.
I have soaked them in purple power for 24 hours, brushed them with a plastic bristle brush, sprayed brakleen, and hit the top collar area lightly with a wire wheel on my drill taking extra caution not to touch the bottom mirror finish area.
How important is it to have a mirror finish above the bottom section and any tips on how to clean them up?
How important is it to have a mirror finish above the bottom section and any tips on how to clean them up?
It's not. That lip hold the dust boot and is not part of the piston that travels across the piston seals. It's only important that the lower section not be pitted which could either damage the seals or allow brake fluid to leak.
I would just hit it with a wire brush and spray it with some protectant.
Also make sure you don't brake apart your calipers. There's internal O-rings that can be hard to source (they are not part of the rebuild kit). i.e. like what this guy did...
I've got 2 of the pistons that have some heavy pitting on the lower seal section...looks like I need to find one for parts since they are out being powder coated right now.
It's not. That lip hold the dust boot and is not part of the piston that travels across the piston seals. It's only important that the lower section not be pitted which could either damage the seals or allow brake fluid to leak.
I would just hit it with a wire brush and spray it with some protectant.
Also make sure you don't brake apart your calipers. There's internal O-rings that can be hard to source (they are not part of the rebuild kit). i.e. like what this guy did...
My Atkins kit came with these O-rings. I even took mine completely apart and replaced them. Re-torqued to 52 lb-ft with blue thread locker. GTG. There is a thread around here somewhere that verifies that torque value, based on comparable Sumitomo Nissan model values and some fastener engineering.
I used a fresh rag and valve grinding compound for the piston seal area, and that same compound and Dremmel for that lip area. The Dremmel makes quick work of it, and, while not necessary, does make it an overall "complete" job.
Last edited by quichedem; Oct 8, 2016 at 04:15 PM.
i hate to sound like a "captain obvious" but i'll ask the question:
with the reman calipers being $45 each (+$50 core charge you get back) on RockAuto, why not just buy remans?
any remanufacturer will have QC and verify the pistons and seals are all working correctly via wet pressure test.
^this is for the front calipers, btw. the rears appear to be quite rare.
i hate to sound like a "captain obvious" but i'll ask the question:
with the reman calipers being $45 each (+$50 core charge you get back) on RockAuto, why not just buy remans?
any remanufacturer will have QC and verify the pistons and seals are all working correctly via wet pressure test.
^this is for the front calipers, btw. the rears appear to be quite rare.
Some of us just want to do it ourselves. I did a complete write-up for the rear calipers some months ago for the same DIY folks. The front set were a breeze compared to the rear calipers.
i hate to sound like a "captain obvious" but i'll ask the question:
with the reman calipers being $45 each (+$50 core charge you get back) on RockAuto, why not just buy remans?
any remanufacturer will have QC and verify the pistons and seals are all working correctly via wet pressure test.
^this is for the front calipers, btw. the rears appear to be quite rare.
l've done about everything myself, so this was just one more thing I wanted to learn/do. It's easier to powder coat with them completely disassembled too
I painted mine with the brush-on G2 kit. I painted the entire exterior of the calipers, and left the interior. I probably should have painted them before I rebuilt, but the spots I didn't paint will never be seen anyway.
