Saving a Master Cylinder.

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kerryb

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I bought a GL1100 Aspy master cylinder with linked brake line fitting on Ebay. Paid an awful lot of money for it...and was very disappointed. The M/C was crusty, seized, and the ears of the circlip were broken off. I played with it for an hour or so and decided to risk cutting the circlip in half with a dremel cutoff wheel. This shouldn't harm the function when I'm done. Then how to get the stuck piston out without destroying the valve body? And then a brainstorm...(hope it doesn't turn out to be a light drizzle!)...I drilled and tapped the piston to accept a 1/4-20 threaded rod to make a slide hammer. A couple washers, a piece of pipe and presto, out comes the piston without damaging the bore.
I hope this helps someone else, cause these master cylinders are hard to find.
 

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[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=102129#p102129:27o1i6fj said:
Joep » Mon Nov 04, 2013 1:32 am[/url]":27o1i6fj]
as long as the drill and tap doesn't affect the piston actuation it should be a good fix..

I'm not sure how you mean that. The rebuild kit includes a new piston and circlip, the drilling needs to be down the center of the piston (I stopped when I hit the spring through the other end) There is a lot of room to drill through the center of the piston and not hit the wall of the bore. The old piston is now scrap.
 
[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=102133#p102133:oshldtgq said:
kerryb » Mon Nov 04, 2013 6:44 am[/url]":eek:shldtgq]
[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=102129#p102129:oshldtgq said:
Joep » Mon Nov 04, 2013 1:32 am[/url]":eek:shldtgq]
as long as the drill and tap doesn't affect the piston actuation it should be a good fix..

I'm not sure how you mean that. The rebuild kit includes a new piston and circlip, the drilling needs to be down the center of the piston (I stopped when I hit the spring through the other end) There is a lot of room to drill through the center of the piston and not hit the wall of the bore. The old piston is now scrap.

Haven't had to buy a replacement rebuild kit so wasn't aware it came with a new one... was thinking some might try cleaning it and reusing.. and with the push rod wasn't sure it wouldn't interfere with the workings of the matter..
 
I might have to do this on an '82 MC I have. I've removed stuck pistons by drilling and installing a self-tapping screw and pulling them out, but your idea of cutting threads and using a long rod as a slide hammer sounds much better. Now, where did I put that old master cylinder...???
 
[url=https://classicgoldwings.com/forum/viewtopic.php?p=189810#p189810:3t6u6ujz said:
chilidawg » Yesterday, 6:43 pm[/url]":3t6u6ujz]
Maybe someone in command, ought to make a sticky out of that!!
Just did :thanks:
 
I made a fitting with grease nipple on end that I just screw in piston brake line hole and then pump full of grease forcing piston out easily. Works every time
 
Same here i just pump full of grease to force piston out. If the bore is corroded i bore out bore on lathe.Then press in stainless steel bar (make bar.002 larger than bored hole) then install on lathe and rebore to original size problem solved permanently.
 
I had both my master cylinders stainless steel sleeved. Honda's standard cylinders are renown for being crap.
So if you don't fix the cylinder you are always going to have problems. I've been looking for another fuel tank for my 1100 and every tank I've looked at has paint peeled off in same location.... Rubbish rear master brake cylinder.
Fix with resleeving.. Ask your brake specialist about it. Lifetime guarantee on them.
 

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They're not as bad as Harley Davidson, when I got this 2002 road king with only 11 thousand miles on it, it needed a new front master cylinder where the rubber had worn out the metal body.

Now what kind of pig iron crap must they be made of to do that?!?!
 
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