Stripping a rear caliper. FZR 600.

[D O G]

Reet, after trying to push the pistons back into their bores, failing, then being convinced to strip and rebuild the caliper, I have done so.

It is now in halves, bleed nipples were fine etc, but I cannot get the damn pistons out now. Any tips? I don't have an air line, but may be able to use one at a push. Is there any other tips?

Can I soak them in penetrating fluid to loosen them up, or will that knacker the seals?

Thanks people.

[mattgirv]

I wouldn't worry about the seals if you are rebuilding the caliper. Don't bother reusing them or you'll end up redoing it all again in a few months time. You can get seals for damn pennies.

As for getting the pistons out without air/pressure through the caliper, try clamping the caliper and using tyre levers hooked into the piston to pry them out. I used this method on a 2-pot caliper and only took me about 5 minutes.

I managed to do it fine without damaging the caliper or pistons. You can pick tyre levers up for a couple of quid in Halfords.

Oh and you could just take the piston seals off and then try using some sort of penetrating fluid? Just make sure you get it all off afterwards. You'll get it apart eventually and then you can just clean it properly anyway.
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Bikes: 1998 Honda VFR800Fi, 26,500 miles
1989 Honda CB-1, 38,000 miles

[Kickstart]

Hi

Seals are not pennies (and the seal between the caliper halves is not available from Yamaha). Probably at least £20 a caliper for original ones. And for those with Brembo calipers you will probably find replacement seals are not available.

Air line is best, but I would say to pump the pistons out as far as you can with the hydraulics before splitting the caliper. Should leave the pistons barely held in place.

You can then use some pliers with something around them to protect the pistons, but you stand a good chance of wrecking the pistons if you do this and they are at all stuck.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[mattgirv]

Yeah pennies was probably an underestimation. I paid £4 for a pair of seals and dust seals for my Nissin 2-pot caliper. Though not replacing them can be much more costly, my point was it was well worth doing if you are bothering to service your brakes.
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Bikes: 1998 Honda VFR800Fi, 26,500 miles
1989 Honda CB-1, 38,000 miles

[D O G]

[Kickstart]

[iooi]

Wemoto

£7.05 for a set of seals
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Just because my bike was A DIVVY, does not mean i am......

[Kickstart]

Hi

Yes, for pattern seals. Prices I mentioned were for OE seals.

Last time I rebuilt a caliper using non OE seals with pistons they would never bleed through (no leaks, etc, just as spongy as hell). Landed up having to get another pair of calipers.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[D O G]

Well I put it back together with the view of bleeding it, then using the footbrake to push the pistons out.

Turns out one of the bleed nipples is corroded, blocking the passage of fluid. Bugger. Iguess I will need a new bleed nipple at least. Most annoying.