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Post by Deleted on Mar 31, 2013 2:40:52 GMT 1
The brake calipers on my project 350lc are seized up solid!  I've been soaking them in WD40 for weeks, but still the buggers refuse to budge. Anyone got any bright ideas for shifting 'em? Cheers |
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Post by nige on Mar 31, 2013 7:24:32 GMT 1
Blew mine out with an air line. I left old pads in and a wedge between to stop pistons coming right out before both had budged. Then parted calipers and did one at time. Be warned if ya do this way cover piston as when they come out there a bit of force behind em.
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Post by andygasgas on Mar 31, 2013 8:03:44 GMT 1
I pumped mine out using a spare master cylinder as this pushes pistons out slowly used a soft wooden wedge in 1 caliper so pushed 1 side at a time
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Post by nige on Mar 31, 2013 8:26:34 GMT 1
Cylinder prob the safest way as mine did fly.
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Post by Denzil on Mar 31, 2013 8:39:21 GMT 1
I had the same problem and in the end I had to weld a bolt on the inside of the cylinder cups once the callipers were split obviously. As mine had not moved for in excess of 20 years they were stuck fast.
Took a bit of time but once all cleaned new seals and pistons and washers etc with fresh paint, lovely job.
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Post by Deleted on Mar 31, 2013 10:51:15 GMT 1
Thanks guys... Might try the airline first as I ain't got a complete master cylinder to hand. It may well go off like a giant air rifle though! lol The welded bolt could be a good solution.
Cheers.
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Post by Deleted on Mar 31, 2013 11:32:06 GMT 1
or use heat and pull the piston out
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Post by watchhislegs on Mar 31, 2013 12:03:59 GMT 1
if you're using an airline just wrap the caliper loosely in a blanket. it will stop the piston smashing your head open. still scares me every time I do it!
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Post by Deleted on Mar 31, 2013 12:25:44 GMT 1
if you're using an airline just wrap the caliper loosely in a blanket. it will stop the piston smashing your head open. still scares me every time I do it! It's the airline for sure now!  I reckon they may need a bit of heat though... they are well solid! |
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Post by nige on Mar 31, 2013 12:48:24 GMT 1
They do go with a bang had to hold the pressure on for what seemed a life time when did mine.
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Post by huggy76 on Mar 31, 2013 23:17:19 GMT 1
Use a grease gun to pump out the pistons, bit more controlled than an air line but unfortunately a bit more messy. Just need to see what size grease nipples you can find and then block off (using a bolt) either the banjo bolt or the bleed nipple.
Hope this helps
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Post by bare on Apr 2, 2013 5:06:10 GMT 1
Plug into your car's cigarette lighter type Air compressors are ideal for popping recalcitrant brake pistons. These can.. Unlike a real compressor, generate 200psi.
Few if any pistons resist for long at all :-).
again DO be Carefull there is a helluvalot of explosive energy released when they blow.. Any fingers in the path ..will... be chopped off.
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Post by muttsnuts on Apr 2, 2013 9:01:40 GMT 1
The brake calipers on my project 350lc are seized up solid! I've been soaking them in WD40 for weeks, but still the buggers refuse to budge. Anyone got any bright ideas for shifting 'em? Cheers WD40 is not a releasing agent/oil, it is a water dispersant oil, so is no good on siezed/stuck components, you need to use the proper pentrating oil, WD40 won't do squat with siezed/corroded items In respect of getting them out, air is a good way, if not a tad dangerous, grease pumping is a great way but messy, using an seperate master cylinder is a great way and the one I use, if that all fails then I drill and tap a hole in the piston base and then screw a set screw (bolt threaded over its entire length) into it and draw the piston out that way - normally something 8/10mm standard pitch is fine - of course the piston is scrap after that - but if its stuck that tight, is probably scrap anyway !  HTH |
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Post by Deleted on Apr 2, 2013 9:38:33 GMT 1
The brake calipers on my project 350lc are seized up solid! I've been soaking them in WD40 for weeks, but still the buggers refuse to budge. Anyone got any bright ideas for shifting 'em? Cheers WD40 is not a releasing agent/oil, it is a water dispersant oil, so is no good on siezed/stuck components, you need to use the proper pentrating oil, WD40 won't do squat with siezed/corroded items In respect of getting them out, air is a good way, if not a tad dangerous, grease pumping is a great way but messy, using an seperate master cylinder is a great way and the one I use, if that all fails then I drill and tap a hole in the piston base and then screw a set screw (bolt threaded over its entire length) into it and draw the piston out that way - normally something 8/10mm standard pitch is fine - of course the piston is scrap after that - but if its stuck that tight, is probably scrap anyway ! HTH WD sells itself as a penetrating/releasing oil... Either way, it hasn't worked this time, and neither has air, so I'm going to weld a piece of flat bar with a nut behind it to the cup and try and screw the bugger out. A combination of heat and brute force should shift them I hope. |
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Post by steven on Apr 2, 2013 9:59:48 GMT 1
I had one once that took about a month or more, soaking in a bucket of diesel, then blew out with an air line, but it did as has been mentioned, come out like a bullet and fly across the workshop, luckily not hitting anyone. I did have one once that would not pump out or blow out, even after soaking it for yonks in ....everything. The way I removed that one was to heat up the area around the piston with an oxy/acetylene cutting torch turned down low. My line of thinking was, to burn the rubber seal away, without overheating/melting the alloy caliper. It worked perfectly. After letting the whole thing cool down properly, I picked the caliper up, turned it upside down, and the piston fell out. Crude but effective steven. ps, i made this to push the new piston into the powder coated caliper, without marking the powder coating.     |
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Post by Deleted on Apr 2, 2013 10:22:31 GMT 1
I think they've been seized for years... the bike had been left in a leaky shed by all accounts. Heat is going to be the key.
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Post by Deleted on Apr 3, 2013 2:12:41 GMT 1
Job done... In the end I welded a bit of flat bar to the piston with some threaded sticking out through the opposite hole. Dropped a crush plate over the hole and screwed nut down the rod. Tightened the bugger up, and out they came. Thanks for the tips... I'd still like to see the air get one out! |
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Post by Deleted on Apr 3, 2013 6:12:42 GMT 1
got mine out with air, but i broke the seal with knocking it in a fraction to get the ball rolling, as bare said watch the fingers, i did it once before the rd and wasnt aware how it would go off, all i can say was holy shit then i started having flashbacks off what nearly happened, with the rd id knock it in a bit then blow it out a bit, this went on for 10 minutes a bit at a time, glad you got them out, they will look brand new when your finished, do you have a little sand blaster?
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Post by Deleted on Apr 3, 2013 8:25:19 GMT 1
No I don't, Ken... It's one of those things on the list. I've got that many little jobs that need doing it would worth the money just in saved time!
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Post by redfastlad on Apr 4, 2013 21:46:58 GMT 1
52 piece hammer set will probabley do it
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Post by JonW on Apr 8, 2013 9:14:36 GMT 1
Good to see you have it done. My advice... air never worked for me, I use hydraulic pressure from a spare front master cylinder. I also use penetrating oil and also very heat reluctant calipers with a heat gun. works even on calipers that people have tried other things on.
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phil38
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Post by phil38 on Apr 12, 2013 13:29:43 GMT 1
Combination of air-line & mole grips worked for me. Pistons needed replacing anyway so wasn't bother about wrecking them!
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I've been soaking them in WD40 for weeks, but still the buggers refuse to budge. Anyone got any bright ideas for shifting 'em?
