Replacing Caliper Seals on SV650

[bergj1986]

I need to replace the caliper seals on my 00 SV650 because one of the pistons on the right caliper doesn't move the same amount as the other one. I'm pretty sure it's the seals because after I attempt to clean the pistons with brake cleaner, the caliper works fine again for a little while.

My questions is, in order to remove the caliper pistons, I was thinking of removing the brake line and pulling the pistons out with the caliper on the bench. Is there another/better way to do this? This is my first time replacing caliper seals.

Thanks,
Josh

[BLACK SQUIRREL]

Dont know,

But I do have a st of First gen SV650 Calipers with stainless steel lines I would sell maybe

[gregp]

Remove the pads first (to avoid contaminating them with fluid), then remove the brake line. Then unbolt the caliper and do the rest on the bench. I used compressed air to pop my pucks out. Put a rag over the caliper when you do this.

[bergj1986]

I would def take the pads out and everything in order to get the pistons out. So I'll use the idea of using compressed air to pop the pistons out, replace the seals, then do I just push the new piston and seals assembly back into the caliper? It surprises me that theres nothing trying to hold the pistons in given the extreme forces theyre under.

[Kurlon]

Normally the pistons are restrained by the pads and rotor blocking their escape route. They aren't under extreme pressure though, just whatever pressure your hand can generate at the master, release and there should be a slight vacuum which draws them back in.

The seals are square section o-rings, which sit in grooves in the caliper body. Use a DULL pick to get them out without cutting, tearing, or puncturing them. Use a sharp pick to clean the seal recesses, paying particular attention to the inner and outer creases. Thats where debris and corrosion builds up and jams the seals and piston. Use brake cleaner to flush out any remaining dust, etc, blow dry thouroughly. There is brake specific grease you can use to lube the piston and seals for reassembly. Seals are set in first, then gently push the pistons back in place.

Be careful when using air to pop the pistons out... they will fire out of there like cannon shot if you're over zealous with the air...

[bergj1986]

I would imagine as long as I leave the pistons slightly out before removing the brake line, I should be able to remove them by hand once I have the caliper on the bench. So Kurlon, you're saying that the seals stay in the caliper in grooves? So I'll be removing the old seals, putting the new ones on the grooves, and then sliding the piston back in?

[Kurlon]

You'll need/want to use air/brake fluid to push them out, as they'll likely drag pretty hard. You DON'T want to get agressive and try using tools on them to remove them.

And yeah, the seals should stay in the groove in the caliper body when the pistons come out.

Brake Caliper Rebuild - Do-It-Yourself Instructions For Racers - Circle Track Magazine

That has a good write up with pics.

[bergj1986]

I can already see some pitting on my pistons, replace them? I would imagine if I can wetsand/scotch-brite them enough to where they're smooth, I should be ok? It looks like the pressure comes from the back of the piston (flat part) but I imagine the seals will seal the fluid out from the sides.

Thanks for the write up, VERY helpful!

[bergj1986]

Mongoose441, I sent your a PM about your calipers.