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View Full Version : Front caliper rebuild - replace seals?


britaxcooper
26-03-13, 08:58 PM
The front calipers on my sv are pretty much knackered, I've bought a second hand pair off ebay which seemed the easiest option without having the bike off the road for too long. The new calipers look pretty clean but the pistons have road crap on as expected. If I take the pistons out and clean them up, providing the seals look okay I presume I can reuse them. My question is do I clean the pistons and refit with rubber grease or do I try remove the seals and clean the bodies too, or will this only knacker the seals?

svrich
26-03-13, 09:04 PM
If you're taking the pistons out you'd be best to clean the calipers out properly while you're there. Seals can be reused but they aren't too expensive to replace. As you don't know their history and how well they worked I'd go for a proper rebuild. And use red rubber grease on the seals when putting them back together.

andrewsmith
26-03-13, 09:12 PM
Redo the seal grooves when your doing a full strip. Takes 20 minutes with a dremmel and wire brush attachment.
Also pull the slides off and pull out the slide rubbers too, as they corrode on the inside. Then wash them with jizer or gunk to clean them up properly. If there is any minor imperfections on the pistons give them a quick once over with 1200 wet & dry using silicone grease

bellisan
26-03-13, 09:57 PM
Don't try too hard to reuse on the front brakes. I once got the dust seal caught between the piston and the caliper (don't know how, had not touched them in months), causing the pads to not retract properly, causing heating, and eventually seizing. Caused a nasty highside. Luckily was at the track.

rb8989
27-03-13, 08:42 PM
Don't try too hard to reuse on the front brakes. I once got the dust seal caught between the piston and the caliper (don't know how, had not touched them in months), causing the pads to not retract properly, causing heating, and eventually seizing. Caused a nasty highside. Luckily was at the track.

This is probably why some people opt for removing the dust seals completely for racing.

muzikill
27-03-13, 09:05 PM
Replace the seals. Dont be a knob with your life skinflint. For what they cost new :)

Whats wrong with the old calipers that made them useless? As long as the internals and the pots arent damaged if its just crud then a bit elbow grease does the trick.

Murley.
27-03-13, 10:08 PM
I've reused seals a couple of times. If they look alright and fit back in the caliper ok after they have been removed. Definitely worthwhile giving the seal grooves a damn good clean out. I use silicon grease to rebuild them along with silicon grease on the outer surface of the longer pin rubber. For the pins themselves I use synthetic grease.