Front Caliper Piston Service + Fluid Refill

[branny]

After a drop of the bike (99 SVS), the left hand caliper has been sticking. I have ridden it out and it comes good after a few minutes, but i do not want to risk a seize when i am riding.

I recently gave my back caliper a full service, split the caliper and regreased etc. It was actually a very rewarding job!

I want to do my front brakes now and wanted some advice on how similar it will be. Do i split the caliper in the same way?

Some other questions -
- I don't like the idea of bleeding the fluid dry, would it be best to service calipers then bleed new fluid through after? Or should i empty it out fully and fill up after? Just worried air bubbles will grow in the master cylinder.

- Depending on the answer to above, maybe i will do just the left hand side... problems here?

Basically, i can either do it myself or pay somebody £30+ to do it... i have fluid and grease, so i will do it myself providing it is not drastically different to the rear brake.

Any advice appreciated here guys!

[Mr Speirs]

I think if you are capable of doing the rear you will be capable of doing the front too. If it were me I wouldn't be comfortable just doing one id do them both at the same time, why not eh?
Not sure about the fluid question but again if it were me I would flush out the whole system and start from scratch.

[vzzzbuxt]

not that bad to be fair fella, just a few more pistons per calliper. personally if u cant afford the bike to be off the road longer than a weekend, buy a set of seals (wemoto personal choice) and split the front calipers, replace the seals and give all the pistons a polish/clean up and bleed new fluid through- the key to this is time/persistance its quite a simple task to do.

[yorkie_chris]

Or you could pay me £25 to do it :-D

Exactly the same as the rear in principle, except with it being a sliding caliper rather than opposed there's nothing to split.

Easy to do, get a G clamp, pump them out a bit at a time, using the G clamp to stop the other piston from moving. Get them bothe moving out equally if you know what I mean.
Reassemble as for the rear.

Do job right and do both sides. You can probably do both in 30mins.

[yorkie_chris]

not that bad to be fair fella, just a few more pistons per calliper.

Same number per caliper. But they are parallel rather than opposed.

[Mr Speirs]

YC if you were closer to me (geographically speaking) id take you up on that offer. I could do it on my own with the Haynes but would be more comfortable having a Pro showing me :)

[yorkie_chris]

I'm not a pro, just a tight amatuer! :-D

[arcdef]

why would a drop make them stick do you think???

[branny]

Exactly the same as the rear in principle, except with it being a sliding caliper rather than opposed there's nothing to split.

Easy to do, get a G clamp, pump them out a bit at a time, using the G clamp to stop the other piston from moving. Get them bothe moving out equally if you know what I mean.
Reassemble as for the rear.

Do job right and do both sides. You can probably do both in 30mins.

so, just to clarify... the caliper does not split? the middle paragraph makes it sound like i don't have to remove the pistons?

Do you have any advice on how to handle the fluid? Full drain?


why would a drop make them stick do you think???
i really don't know... but it seems that a slight knock on the caliper has caused it. If a re-grease does no good i will have to look more at warping.

[arcdef]

so, just to clarify... the caliper does not split? the middle paragraph makes it sound like i don't have to remove the pistons?

Do you have any advice on how to handle the fluid? Full drain?



no but you need to get the slider out and give that a clean/grease aswell, but yeah you can get the pistons out without taking the caliper apart

[vzzzbuxt]

Same number per caliper. But they are parallel rather than opposed.

:rolleyes:sorry brain in vfr400/nissin 4pot mode from the other weekend!!!

overall its more, but you know what i mean ;)

[yorkie_chris]

Branny, the caliper does not split. However you do need to remove the pistons to do a propa' job.

MY comment about pumping them out equally is to make life easy. If the pistons are at all siezed then there is not really any way to get the buggers out, so use the hydraulic system which suzuki have helpfully provided.
Obviously if you pump one out all the way, then there is no way to get the other out, so pump each one out a little at a time untill one of them starts to leak fluid around the seal, then you will probably be at a stage where the other piston is somewhere near, and will pull out by hand.

Then remove the seals, clean the grooves, grease and reassemble.

[branny]

ahh yes, of course! now i see what you mean.

thanks, i am going to tackle it on saturday morning... i think i just need some plastic tubing for the bleed. on the subject of the bleed, any preference on when to perform it? i think i will try to leave the fluid in the pipes until reassembly.

[yorkie_chris]

Might be a slight problem since you are about to open up 2 1 1/2 inch holes in the bottom of the system...

To keep the system partially wet, when you've popped the pistons out, use something to hold the lever back slightly, this should keep some fluid in most of the system due to its viscosity.

[branny]

true, i was considering undoing the brakeline to the caliper. sounds like tieing the lever back will do it then.

[yorkie_chris]

Undoing the brake line will just let the fluid pi$$ out anyway.

By cable tying the lever, you close the transfer port, stopping the contents of the reservoir from going all over floor/tyre/mudguard

[branny]

As per usual i seem to have made a right pigs ear out of this job.

i have ended up with both sets of pads removed, 3 pistons 3/4 way out and piston out with no fluid left in half the system.

I have totally removed one caliper but cannot for the life of me remove the 2nd piston. Are there any techniques people have used here???

As for the 2nd caliper... the pistons are unlikely to move from that one either... i am thinking it may be best to sort out the caliper i have off the bike and totally reassemble and put some fluid in, then deal with caliper 2.

In order to do that.... i need to remove my 2nd piston. Any ideas? If not, it may be a case of cleaning up one piston, refit it and put some fluid in... then pop the other. Will this work?

[arcdef]

this is exactly what i done and ordered a tool from sealey (google piston removal tool) turned out all i needed to do was re-bleed the system and use a clamp on the pistons moving out faster to allow the other to move if that makes sence??

[yorkie_chris]

Finish the caliper which is totally dissassembled. Get it back on the bike all done and dusted.

Then remove the dust seal from other caliper which you have got 1/2 apart. Pop the piston back in a little way, G clamp it. The you can build some pressure to get the stuck on out.

[branny]

problem is, i don't have a calper totally disassembled. I have 1 caliper with 1 piston stuck and 1 caliper with 2 pistons stuck.... i could do with tips on getting the final 5mm out! If i don't figure anything, i will just put the caliper back together and restart!

[yorkie_chris]

You got braided hose or normal?

[branny]

normal, it is a standard bike throughout.

[yorkie_chris]

Get something soft in the jaws of some grips and give the hose a bit of a squeeze

[branny]

Job done!

I used some of those ratchet plier things and a rag around the piston and just twisted it out.

cleaned out both calipers... wet and dried the pistons nice and smooth, greased up the seals and pistons, reassembled everything.

I needed some tubing for the bleed so went to halfords and all they had was a £5 kit thing, which seemed a rip off! Bought it anyway and to my surprise it actually made the bleed and fluid refill a piece of cake, it had a one way valve so you just had to pump the lever and fill the resi!

Took the bike for a 2 min run and the front brake is at least 10x more responsive! It's amazing how little you realise things need doing until you have done them!

Only thing is that i may have overfilled the resi slightly. When the bike is upright, the level is between max and min on both scales (never sure which scale is for which), but when on side stand it is over on one of the scales. I can't see that being an issue....


thanks for all the advice, it made the job a bit easier. I think it took me 2 hours... which isn't that bad going.




edit - it was interesting to see how much gunk had gathered in the lower caliper pot. also some gunk in the resevoir indicated it was certainly time for a service!