akira
New Member
Posts: 18
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Post by akira on Aug 11, 2011 14:29:46 GMT -5
Obviously with the bike having been under a bush for 5 years the front brake caliper is a little bit seized.
I've got a seal kit on the way off ebay so just need to get the pistons out......
Used a spare front reservoir & handle reconnected to the caliper in the garage, bleed it thoughly but there not shifting.
One thing that is different about these pistons to my other bike is the washer type rim welded into the top of the brake pistons ?
Q: Is there or has anyone fabricated a piston extractor tool to pull them out ?
I'm probably going to have to fabricate something, how i see it is a 10mm bolt hacksawed down the centre so that it can be wedged apart and with notches cut into bottom of the bolt so that it catches the washer lip as its wound out. Hopefully winding the piston out.
In the past i've used compressed air to get sticking pistons out but this caliper is a bit too far gone.
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cyril
Full Member
Posts: 58
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Post by cyril on Aug 12, 2011 5:38:21 GMT -5
Hi Akira.
Using an air line is dangerous!!!!
The gas compresses and acts like a huge spring (Storing the energy)
propelling the Piston at speed when it releases.
A work colleague recommends using a grease gun.
Modify a Banjo Bolt with a grease nipple.
The grease gun can reach pressures over 1,000 psi relatively safely.
And grease is relatively incompressible.
You will also need some kind of G clamp, to control the first eased piston..
sods law dictates that they will not release at the same time or rate.
when the pistons release, there will just be a splurge of grease from any trapped air.
Easier to control the piston release, than press one back in, to get the most seized one out.
Hope this is of help.
Best of luck Chris
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Post by Jake on Aug 12, 2011 8:58:31 GMT -5
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akira
New Member
Posts: 18
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Post by akira on Aug 12, 2011 14:17:12 GMT -5
Hello Chris just to clarify the "compressed air" issue
What I actually used was a high pressure stirrup type bicycle pump attached to the bleed nipple. Also with a rag bunched up to catch the piston as it comes out. They generally come out with a little splutter not the explosion that you see on the youtube example.
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akira
New Member
Posts: 18
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Post by akira on Aug 13, 2011 4:39:25 GMT -5
Well I've just made a caliper extractor tool out of some 12mm expander tube / bolt thingy i've just found in a box in my garage. Added another nut and 2" metal plate with a hole and a washer and hey presto a Caliper extractor tool costing exactly nothing.
Within 30 mins i'd pulled 6 pistons out of 3 very corroded revere front calipers (smug grin!). Can't believe how quickly I managed to put this extractor tool together, all the bits just seemed to be hanging around my garage. I've got alot of "stuff" (crap) in my garage. I think i'll be doing the lottery tonight !
Will try and post picture of this homemade extractor tool.
If any body wants one of the 12mm Expander / bolt thingy i've got about 10 of them in a box, god knows where they've come from I think my old man must have got them from a boot sale in the past.
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akira
New Member
Posts: 18
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Post by akira on Aug 13, 2011 8:58:37 GMT -5
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Post by Jake on Aug 14, 2011 3:01:57 GMT -5
This is the odd bolt that is so perfect for this task, I don't even know what this type of bolt is called ? Some form of bespoke "through bolt", any ideas ? Looks like a nifty idea....  So how does it work exactly...... I’m assuming that the 12mm ‘expander bolt’ expands inside the piston and you then haul the piston out with brute force?  Is that right? |
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akira
New Member
Posts: 18
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Post by akira on Aug 14, 2011 3:13:32 GMT -5
No brute force what so ever involved. Its all done by winding in and out the 2 nuts at the top and it just winds the piston out.
You tap the crossed tube into the piston then screw in the bolt and give the silver nut a few turns to push on the bullet shaped metal plug which expands inside the piston. Don't screw this in too much or you might not be able to get it out. Just enough turns to lock it against the piston.
You then start winding clockwise the brown nut against the grey backing plate and the piston winds out nice and smoothly.
I've got another 4 of the M12 cross cut tube and bullets if anybody is interested. You'll need to find a 2" M12 bolt / M12 nut / Backing plate and washer.
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Post by Jake on Aug 14, 2011 4:46:56 GMT -5
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akira
New Member
Posts: 18
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Post by akira on Aug 14, 2011 8:24:29 GMT -5
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cyril
Full Member
Posts: 58
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Post by cyril on Aug 20, 2011 16:25:13 GMT -5
Hi Akira.
Exhaultations and felicitations
Hats off to you.
Neat solution to a sticky problem
Chris
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akira
New Member
Posts: 18
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Post by akira on Aug 21, 2011 3:13:50 GMT -5
Cheers for the "tip of the hat" Chris I've been a regular poster on the sv650.org forum for the last fews years what with owning an SV but you don't get any thanks for your idea's / help on that site. But thats probably the difference between "bike polisher's" (SV owners) and bike riders that appreciate the Revere. I did a post about swapping out the rubbish rectifier on the older models for a £20 Honda rectifier (about 100+ models) and moving it to a more accessible location with greater air flow. All I got was negative comments. forums.sv650.org/showthread.php?t=158589Still refining the Caliper extractor. Found a machinist to make a collar adapter so that the tool will do the rear as well. Its 2 half shells that you drop into the caliper piston (cup) with 12mm hole drilled into it. The same scenario then applies, tap the anchor, lock it, and hopefully it should wind out the caliper. Andy |
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akira
New Member
Posts: 18
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Post by akira on Aug 27, 2011 5:12:26 GMT -5
Well I've got the website up for this tool, its still under development as is the tool. www.ex-caliper.co.uk - the "Easily Xtract Caliper" pistons tool (play on Excalibur as in Arthur & Sword-stuck-in-stone !) Still on the look out for a machinist to make the Aluminium collar for the rear piston ? |
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