99 Honda Hornet Caliper Strip Down + Rebuild.

[anthony_r6]

Hi Guys,

Need to strip and rebuild my calipers after my pistons kept sticking. I'm replacing the seals, and the pistons, but want to know what should be used to clean the inside of the calipers? I'm seeing "Brake System Cleaner" in the Haynes manual, but I can't find anything like that, just disc/chain cleaner.

Would WD40 be appropriate for cleaning the insides considering I'll be removing the seals anyway?

Also, no compressed air, so I am planning to use the hydraulic system to push them out, any idea how much of a mess I can expect this to make as I'm doing it? How easy do they pop out?

Should I take both calipers off at the same time, or do one then the other, then bleed?

Thanks!

Anthony
____________________
Ted : "Maybe he's agoraphobic."
Dougal : "Jack scared of fighting? I don't think so, Ted."

[SnowTigeress]

[DrDonnyBrago]

You can clean the insides with almost anything you want so long as you remove it all afterwards and it doesn't damage aluminium. You might struggle to remove all WD40 so I'd pass.

What I do is use fairy liquid in a bowl of hot water with a toothbrush. When I'm done I rinse it thoroughly with clean water and stick it in the oven on low heat to dry it out (all seals are out by this point, it is just a wet block of aluminium).

It doesn't need to make any mess at all if you know what you are doing. You can pump the pistons on one side out most of the way out, stick something in the caliper to stop them coming out any further then move to the other side and do the same. Empty the system by undoing the banjo or bleed nipple and pumping - hold it over a bowl or use a rag to catch spills.


Brake cleaner is used to remove oil/grease then evaporate quickly leaving the discs dry and clean. If I am not dismantling my brakes (i.e. cleaning them in situ) then I tend to use cheap stuff like paraffin to do most of the cleaning then just use brake cleaner to remove the paraffin afterwards. You can get brake cleaner in poundland, halfords or a motor factors.

[Frost]

Water will be just fine for cleaning provided you let things dry. Don't use abrasives like pastes or polish. I used to use a tiny electrical flat screw driver and an old tooth brush to clean mine.

As for getting the pistons out do it while they're still on the bike. Pump them all out as far as possible (topping up on fluid if needed) but not completely out. So jamming a bit of metal in there helps. If you're replacing the pistons you can always just grab them with mole grips / pliers and pull them out.

Replace the bleed nipples. They corrode and get brittle and the last thing you want is for one to snap our round off, so use a ring spanner or socket to undo them.

Remember to put copper grease on the pad backs and ordinary grease on the retaining pin.

[janner_10]

I did my rear caliper last weekend - It was a right royal pain in the ass - so allow a few hours.

One of the pistons was seized causing the rear brake to be permanently on slightly - hence why I did mine.

You may want to try and get your seized piston going again by removing the caliper from the bike, edging the piston out with the pedal and cleaning it with a toothbrush for instance - if that gets it going you have saved a bit of work.

If you want to change the pistons though then just split the caliper and pull the things out with molegrips - which is what I had to do as it was stuck in there solid.

I then soaked both halves in hot soapy water and gave them a scrubbing with the same toothbrush, rinsed thoroughly and dried on a radiator. A small screwdriver cleans the slots behind the seals very well and a small allen key can be used to clean the upper part of the slots. Mine were full of salt and crap.

However new set of pistons and seals and all is good - fuel consumption has got better also - now i'm not riding around with the rear brake on!!
____________________
Yamaha FZS600 (Now gone to heaven) > CBR600F4i (SOLD) > '99 YZF-R1

[anthony_r6]

[anthony_r6]

Okay guys.

I finally got around to removing the calipers from the bike and taking them apart. Three of the pistons came out with minimal effort, but the fourth one was jammed right in there, and I had to work it loose with some maul grips. Needless to say all the pistons were messed up.

The problem I'm having now is that I have scratched (at least I think it was me) the inside of the pot, where the pistons are housed. Is this gonna pose a problem? Can I sand them down or something?

Also, once I got the pistons out, I noticed there was a seal missing in all the pots, is the dust seal the first one? cause that wasn't present at all. No wonder they were caked in crap.
____________________
Ted : "Maybe he's agoraphobic."
Dougal : "Jack scared of fighting? I don't think so, Ted."

[DrDonnyBrago]

[anthony_r6]

[herulach]

Appreciate you've already done it, but I find a tyre inflator (electric) with a beachball nozzle and a cut in half brake hose useful for getting pistons out. If they're twin like that you won't get them all the way (use a spanner) but saves farting around pumping them out with the pedal.

Fasten the half hose to the caliper, stick the beach ball nozzle in, turn the compressor on. Bobs your uncle.
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YBR 125>FZS600

[Vincent]

[Vincent]

I may have one of these calipers you can have cheap, or, I think I have a set of decent pistons too. Chuck that one in the bin mate, it's fu**ed.

BTW, first caliper I ever stripped I shagged the pistons too, that's me, you and a few million other people
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Space Is Deep

[anthony_r6]

[Vincent]