Rear Caliper - Helped Needed - Pictures of Issue - Stuck Piston

[Andy Smith FZS]

Ticking off my to do list for the MOT (Round 2)

Back caliper needs a new set of seals, I went for non OEM ones  (let the debate begin..)  :lol

My dad had taken one of the pistons out, fitted a new dust seal and tryed to refit the piston just to see if it made a difference I guess..  (sticky caliper - failed mot!)
Not sure why he didn't replace both seals but anyhoo.  Pistons stuck, tryed putting a g clamp on the other piston, plumbed it up back on the bike to try and work the bugger out.
No joy with this so I think there's a slight gap, although I didn't see brake fluid flying everywhere when pumping the brakes - brakes were bled properly.  I've added some pics of the offending piston in the caliper. 
Yam dealer will probably skin me a few quid so would like to avoid that if possible.  Dont want to rip the piston to pieces with a set of mole grips.  Plus you can't seem to be able to buy the piston on its own.  Bit of pain seeing how I've bought 2 packs of seals because I lost the first set.

Ps  I don't have a grease gun or an a decent air compressor. 


Pics show the piston isn't dead square. 
Any questions, any help please fire away.

[Dave48]

You could do what I did and split the caliper by undoing the 2 bolts on back. Don't lose the rubber washer that sits between the 2 halves & seals the fluid passageway. You can then blow pistons out with compressed air(cautiously) even if you have to ask the bike shop to do this. Then you can easily access grooves for seals to clean before fitting new seals-bit of red rubber grease helps when refitting pistons.

[Ian-man]

When I had a stuck piston I clamped the other piston and used an electric tyre inflator.  With the cone shaped air bed adaptor pushed into the cut end of an old brake pipe with the bleed nipple closed.

Sent from my HTC using tapatalk 4 beta

[clayt74]

:agree
No way that piston is going back in!!!!
Compressed air to blow it out from a friendly local workshop is ya best bet.
Good luck

[Andy Smith FZS]

Got my old brake lines in the garage so ill try the compressed air approach.  I'm sure there's a cheapo car charger style compressor in the garage.  Any ideas why the piston won't budge?  I know how the piston behaves in a working caliper as I just worked the front brakes abit because the bike sat for a year.  Pushing the pistons back in with my thumb.

Noticed a guys selling a fzs 600 caliper for 50 notes on fleabay and an fzs 1000 one too(different seller). Just thinking about all my options. 

Cheers for the advice so far.

[Fuzzy]

I have a fzs1000 rear caliper about to go in the for sale section - Let me know if you're interested.

[darrsi]

http://www.ebay.co.uk/itm/Yamaha-FZS-600...3ccfd6d9c5

[Dead Eye]

The OEM part no is 51L-W0057-00-00 which is the piston plus seals since they don't seem to do the piston separately but at £50~ I'm thinking you try and pull the bugger out!

[Ebme Geek]

If you are going to move that piston you seriously need to straighten it up first, maybe a flat bar in the slot (ref last pic) and use a screw driver to press in the lower edge, or split the caliper and with a suitable flat spacer squeese it gentley in a vice, but the bore may already be past it. Good luck !!!

[Enceladus]

how about splitting the caliper and using a mole grip (or similar) with some rubber (bike inner tube) as protection to get it out to refit it ?
Delboys Garage (Moonfleet41) did a great vid of a caliper stripdown and rebuild on youtube.
might be worth a go.

[Andy Smith FZS]

Thanks again for all the advice.

Split the caliper, stuck the side with the dodgy piston in the vice, used a latex glove to grip to prevent the mole grips marking the piston. 
Out comes the piston 1st try!  :lol Looks like I'll be sending the grease gun I ordered back (cant think of any other uses for me anyway)  Annoying seeing how I paid more for quick postage!

Turns out my dad had refitted the piston with just the fluid seal and left the dust deal out (not that made a difference - I think!)
After spending 15 mins trying to get the seal out, I noticed my dad hadn't cleaned the seal groove "properly"
I found loads of white/grey/green oxidized shite in the groove, scraped some out with nail without scratching anything important.
Currently sat in my vice horizontally, bleed nipple in and in a pool of general brake cleaner.  Will give it a good wash after and refit everything tomorrow when I'm back for work.
Work for Direct Line Group dealing with Motor Claims so any insurance advice needed gives a shout 

The seal was sticking out slighty which obviously caused the issue. Dont think we can blame non oem parts yet.
Might paint the caliper at some point, it was tatty before I took it off plus I've marked it from using the vice.
Is the o ring between the calipers just a small 1cm circular seal? (looks in good condition) I was expecting a single carb style gasket.

Andy

[Dave48]

Glad you got "offending" piston out. As you have discovered the grooves for seals must be spotless for seals to fit properly. The dust seals are the first line of defence for the piston seals & are "lipped" to form a close sliding fit against piston. Do yourself a favour and use a little red rubber brake grease on seals -it will make it much easier to fit pistons-failing that use clean brake fluid as "lubricant" for seals..
The small black washer is the seal between the caliper halves-just make sure it sits in recess before tightening bolts :eek

[bootz76]

or just send it to powerhouse automotive who will do it all for you they have have just totally refurbed mine including recoating it looks and works like new :b

[Andy Smith FZS]

bootz76 - How much did that cost?

Just had a shot at replacing the seals myself, cleaned the seal grooves abit more then attempted to fit them.  Was using silicon grease as lube but the main seal seems to stick out a touch too much, cant see any crud causing the problem.  When I was trying to put the dust deal in it just didnt want to play ball.  Out the packet, the inner section of the o ring (dust seal) has a groove around the middle section (is this normal?) couldn't see it fitting properly.  I put the piston back in the caliper with just the fluid seal in, making sure it was going in square.  It went in ok and was straight, but the seal seemed to be gripping it making it hard to get the piston back out.  I know there needs to be some friction, otherwise the piston would fall out. 

[Enceladus]

have a look at these m8
might help

https://www.youtube.com/watch?v=EDfNb_9YkcI
https://www.youtube.com/watch?v=DC_Id6rgP3g

he has loads of gread vids on there and some very handy (and cheap) tips and tricks.

[bandit]

Lubricate the seals lips & piston sides lightly with clean brake fluid,the fluid seal should sit flush make sure it's not damaged from the previous attempt.

[andybesy]

I'm a big fan of delboy's garage too - fantastic howto's.

One of his vids suggested seals need to in a particular way round?

Could that be the problem?

[ade the blade]

how about splitting the caliper and using a mole grip (or similar) with some rubber (bike inner tube) as protection to get it out to refit it ?
Delboys Garage (Moonfleet41) did a great vid of a caliper stripdown and rebuild on youtube.
might be worth a go.

ah..my matey Delboy. what a really decent and super- doooooper clever guy. been subscribed a while now .........ooops, back on topic, sorry !!

[Enceladus]

[quote author=Enceladus link=topic=8033.msg78824#msg78824 date=1369822513]
how about splitting the caliper and using a mole grip (or similar) with some rubber (bike inner tube) as protection to get it out to refit it ?
Delboys Garage (Moonfleet41) did a great vid of a caliper stripdown and rebuild on youtube.
might be worth a go.

ah..my matey Delboy. what a really decent and super- doooooper clever guy. been subscribed a while now .........ooops, back on topic, sorry !!
[/quote]
top bloke delboy. saved me loads of cash and given me the confidence to tackle lots of jobs myself
back to topic......
are the pistons corroded at all ?
might be why they are stiff ?

[Chris]

Must say I've watched all the delboy vids while on nights, great guy with sound advice and as others have said really gave me the confidence to tackle jobs that I would have needed help with before. Sensible and well thought out hints and tips.

On topic. I have just done my rear brakes with new seals. I split the caliper and was much easier to get new seals in with it split. the mechanical (fat) seal went in easily on mine and the dust seal was a right pain, it's so thin it flexes instead of snapping into the groove. My best advice is make sure the grooves are as clean as possible as even a tiny amount of white furry deposits will make the seal sit too pround. Once my pistons were in I pushed them all the way home making sure to keep them square in the bore. Once I had pushed them right in then they were pretty tight which I figured was a good thing and seems to be fine now it's back on the bike. will easily lock the rear wheel which is obviously more than enough power for a rear brake. I used red rubber grease while putting the pistons in and smeared some around the piston before pushing it home. I reused the seal between the caliper halfs as it was fine. Whilst bleeding the caliper I had a problem but I just bled to the end of the line and then tightened it up again and then bled the caliper which sorted it. sorry for the tomb to read! Hope that helps... 

Chris