drunkn munky Posted December 9, 2008 Report Share Posted December 9, 2008 Is there a way of pushing out the caliper pistons with the calipers off the bike and hose removed? Also if the pistons come all the way out do i have to replace the seals? Link to comment Share on other sites More sharing options...
sherwood Posted December 9, 2008 Report Share Posted December 9, 2008 If a piston has been popped out with air then I personally would replace the seals. +1 They won't cost a lot and might save your bacon one day! Also if you are using any sort of fluid to try and free them just smear a little brake fluid around the seals. The stuff that smells funny and stays on your skin for the next decade Link to comment Share on other sites More sharing options...
David W Posted December 9, 2008 Report Share Posted December 9, 2008 Another day, another tool I have to buy.... Link to comment Share on other sites More sharing options...
drunkn munky Posted December 9, 2008 Author Report Share Posted December 9, 2008 that tool would come in well handy, gunna have to get one. So i can just pull the pistons out a bit with this , clean them up, lube with a bit of brake fluid?? Link to comment Share on other sites More sharing options...
Mr.Pigdog Posted December 9, 2008 Report Share Posted December 9, 2008 Hello mate!I got one of them tools and it wont take much brutalness to be honest(see the crossover arm that tightens the internal grips-well see how its only braced on one side??it opens up if you screw the adjuster too hard:so a new arm that braces from both sides is an improvement.Also the adjuster itself is really quite thin and delicate-about M4 if memory serves me right).Anyways anyone who strips calipers will know-those pistons can be VERY seized in.I found a small draper thing for cars(its meant to open car brake pads apart)anyways it puts this thing to shame and is 1/4 of the cost.i shall now see if i can go find a link or pic or whatever,it looks like a cast set of scissors. Piston seals are normally about the £2/£3 mark i think each.if you gone to the hassle of splitting the caliper i would go the whole hog and treat it to some new ones. Link to comment Share on other sites More sharing options...
Mr.Pigdog Posted December 9, 2008 Report Share Posted December 9, 2008 http://cgi.ebay.co.uk/Sealey-Ak7112-Disc-B...A1%7C240%3A1318 Crikey-its doubled in price since i got mine!! Link to comment Share on other sites More sharing options...
David W Posted December 9, 2008 Report Share Posted December 9, 2008 If I had one of those tools I'd be more inclined to strip the calipers regularly, so they shouldn't get all seized up in the first place! Link to comment Share on other sites More sharing options...
Mr.Pigdog Posted December 9, 2008 Report Share Posted December 9, 2008 Good lord zakalwe!!!i spent too long getting things at trade!alot of the time i find if moneys an issue you can scrape the seals clean of the white corrosion that clings to them.The fluid seals usually last alot longer than the dust seals do-also try comparing them all to see any variations in size Link to comment Share on other sites More sharing options...
drunkn munky Posted December 9, 2008 Author Report Share Posted December 9, 2008 2 or 3 quid each! Where from? The reason I didn't want to replace the seals was because there silly money for replacements. Plus its not that the brakes are sticking its just that i got the track bike stripped down for a winter clean up and thought if do some preventive maintenance on the brakes. Its a nc35 by the way, if anyone knows of some cheap replacement seals feel free to let me know. And thanks for all the tool suggestions, didn't even know such a tool existed. Link to comment Share on other sites More sharing options...
Mr.Pigdog Posted December 9, 2008 Report Share Posted December 9, 2008 From my boss(who happens to own a bike shop)but keep it quiet as im not so sure he would be happy supplying parts at cost to the masses. Link to comment Share on other sites More sharing options...
lorenzo Posted December 9, 2008 Report Share Posted December 9, 2008 Wemoto do seals for a good bit less than a dealership, despite the ones I got last time from them actually being OE ones! As for pushing the pistons out, you can do it super cheaply, just using a finger and an 8mm spanner: I did a very rough bleed on my calipers the other day, from completely empty hoses and calipers etc, just by holding my finger over the end of the bleed nipple. Just have it about 3/4 of a turn open but with your finger pushing down on the hole, perhaps with the caliper up on your lap in an old washing up bowl or something, pump the lever 3 or 4 times, let your finger off as you do a squeeze in, then put it back over before you loose off the lever. It's not a perfcet way of doing it, and the brakes won't be good enough to use on the road, but it'll only take you 10 minutes to do 2 calipers like this, and it'll push the pistons out in a nice steady manner. Get a dirty great spanner to put down the middle of the caliper that you're not bleeding so the pistons don't move out in that one when you're doing the other. The real key thing to all of this is working out just how far you can take the pistons out before they pop out completely, but are far enough out so that you can remove them with a gentle little tug just for that final couple of mm. I've got a slim chunk of wood and a stack of old cardboard that I put in the middle of the caliper so I can get the pistons out most of the way and then will push against something to stop them still coming. Of course, if you didn't lend your nifty vacuum pump thingy to your mate about 9 months back so he could 'try it for a bit' then you wouldn't have to do these sorts of things, would you... (you know who you are) Link to comment Share on other sites More sharing options...
drunkn munky Posted December 9, 2008 Author Report Share Posted December 9, 2008 Really! Fancy sorting me out a front set for nc35 and a 94 rgv Link to comment Share on other sites More sharing options...
drunkn munky Posted December 10, 2008 Author Report Share Posted December 10, 2008 Wemoto do seals for a good bit less than a dealership, despite the ones I got last time from them actually being OE ones! As for pushing the pistons out, you can do it super cheaply, just using a finger and an 8mm spanner: I did a very rough bleed on my calipers the other day, from completely empty hoses and calipers etc, just by holding my finger over the end of the bleed nipple. Just have it about 3/4 of a turn open but with your finger pushing down on the hole, perhaps with the caliper up on your lap in an old washing up bowl or something, pump the lever 3 or 4 times, let your finger off as you do a squeeze in, then put it back over before you loose off the lever. It's not a perfcet way of doing it, and the brakes won't be good enough to use on the road, but it'll only take you 10 minutes to do 2 calipers like this, and it'll push the pistons out in a nice steady manner. Get a dirty great spanner to put down the middle of the caliper that you're not bleeding so the pistons don't move out in that one when you're doing the other. The real key thing to all of this is working out just how far you can take the pistons out before they pop out completely, but are far enough out so that you can remove them with a gentle little tug just for that final couple of mm. I've got a slim chunk of wood and a stack of old cardboard that I put in the middle of the caliper so I can get the pistons out most of the way and then will push against something to stop them still coming. Of course, if you didn't lend your nifty vacuum pump thingy to your mate about 9 months back so he could 'try it for a bit' then you wouldn't have to do these sorts of things, would you... (you know who you are) Caliper are already off the bike and taken apart now so was looking for a solution without having to refit the lines but cheers anyway. Im confussed, how would a vacume pump push the pistons out? I now have the vacume pump back now if that was me you were refering to Link to comment Share on other sites More sharing options...
drunkn munky Posted December 10, 2008 Author Report Share Posted December 10, 2008 http://cgi.ebay.co.uk/Sealey-Ak7112-Disc-B...A1%7C240%3A1318 Crikey-its doubled in price since i got mine!! thanks but how would you use this to get the pistons out? Link to comment Share on other sites More sharing options...
Mr.Pigdog Posted December 10, 2008 Report Share Posted December 10, 2008 Ello,well you insert the end with the splayed edges into the hollow of each piston-then screw up the threaded part so that it grips the piston internally.should just be able to rotate and pull each piston out easy enough.If not i often insert a screwdriver straight through to give more leverage.Theyre indestructable so far and fit in most bikes pistons.Dont know what bike you have but some older brake pistons dont have a hollow in the middle so theyre no good for that.Believe me these work-i,ve spent many winters stripping cleaning and rebuilding peoples brake calipers.I hate it now. Link to comment Share on other sites More sharing options...
lorenzo Posted December 10, 2008 Report Share Posted December 10, 2008 I was referring to thefatman, who's had my pump since the summer, despite only wanting to try it for a day or two... The vacuum pump attaches to the bleed nipple on the caliper and will have your system bled up within about a minute. This way you can use brake fluid to pump your pistons out. Dead simple. Probably the best tool in my garage. Link to comment Share on other sites More sharing options...
drunkn munky Posted December 10, 2008 Author Report Share Posted December 10, 2008 I was referring to thefatman, who's had my pump since the summer, despite only wanting to try it for a day or two... The vacuum pump attaches to the bleed nipple on the caliper and will have your system bled up within about a minute. This way you can use brake fluid to pump your pistons out. Dead simple. Probably the best tool in my garage. Oh i see, i agree there dead handy, i always finish off bleeding with a few pumps of the lever the traditional way just to be sure theres a good solid feel. Link to comment Share on other sites More sharing options...
drunkn munky Posted December 10, 2008 Author Report Share Posted December 10, 2008 Ello,well you insert the end with the splayed edges into the hollow of each piston-then screw up the threaded part so that it grips the piston internally.should just be able to rotate and pull each piston out easy enough.If not i often insert a screwdriver straight through to give more leverage.Theyre indestructable so far and fit in most bikes pistons.Dont know what bike you have but some older brake pistons dont have a hollow in the middle so theyre no good for that.Believe me these work-i,ve spent many winters stripping cleaning and rebuilding peoples brake calipers.I hate it now. oh right, the picture is decieving as they look to big to get inside the pots, great tip. Cheers Link to comment Share on other sites More sharing options...
ronenige Posted December 11, 2008 Report Share Posted December 11, 2008 if you have really seized pistons i use a grease gun on the bleed nipple , if they are that stuck you will need new seals Link to comment Share on other sites More sharing options...
ronenige Posted December 13, 2008 Report Share Posted December 13, 2008 We have one of these at work , i just found out today , excellent bit of kit Link to comment Share on other sites More sharing options...
originalracingsnake Posted January 2, 2009 Report Share Posted January 2, 2009 We have one of these at work , i just found out today , excellent bit of kit How does that fit together then? Link to comment Share on other sites More sharing options...
sherwood Posted January 2, 2009 Report Share Posted January 2, 2009 Do those bits fit inside the piston and expand outwards to grip the piston and then pull it out from the caliper? Link to comment Share on other sites More sharing options...
Mr.Pigdog Posted January 2, 2009 Report Share Posted January 2, 2009 Yes you have a selection of inserts that expand-i have that same kit too-doesn't fit alll bikes i might warn(saying that it was a gas gas trials bike rear caliper that was the only one it didn't-silly small internal diameter). Link to comment Share on other sites More sharing options...
ronenige Posted January 2, 2009 Report Share Posted January 2, 2009 Yes you have a selection of inserts that expand-i have that same kit too-doesn't fit alll bikes i might warn(saying that it was a gas gas trials bike rear caliper that was the only one it didn't-silly small internal diameter). what he said Link to comment Share on other sites More sharing options...
alexp5 Posted January 2, 2009 Report Share Posted January 2, 2009 As above. I have a kit by Laser but Demon Tweeks list exactly the same kit, badged as 'Gunson', for about £50 more. Gotta love Demon Tweeks!!! Link to comment Share on other sites More sharing options...
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