Anyone successfully repaired a stripped bleeder valve hole?

[CC2099]

The aluminum caliper's bleeder valve holes (There are 2 on the '79 850G) are stripped and I was thinking about getting a repair kit like this: http://www.jpcycles.com/product/240-797

The instruction manual says that I would need to leave 3mm (1/8") wall thickness but it looks to me like the wall is only 3mm thick with the current hole.

Anyone ever use one of these kits with success or should I just order a used caliper off eBay?

 

[Guest]

I would think new calipers would be cheap enough, one thing I would not want going through my mind as I brake hard into a corner i slightly overcooked is "hmm.....wonder how that cobbled caliper is holding up?". Just my .02. I betcha a parts wanted post might net you a caliper at a perty reasonable price.

 

[CC2099]

I ended up buying a caliper off eBay. $30 for the caliper $40 for shipping. Hopefully the bleeder valve holes aren't stripped on this one too. For anyone interested, here's a photo showing one of the bleeder valve holes expanded to 25/64" to fit the sleeve in the repair kit. The remaining wall is only about 1mm thick so it would probably be pierced if I tapped the hole. Before anyone asks, yes I drilled the hole straight. The small hole in the bottom is in the exact centre of the new hole. I just expanded the existing hole which must have been slightly off-centre to begin with. Hardly surprising for 1970's technology.

 

[CC2099]

The caliper from eBay arrived 2 days ago. The photos the seller took made it look like it was in pretty good condition but one of the pistons was seized and it was full of brown goo which I'm guessing was a mixture of old brake fluid, dissolved rubber & rust. I spent about an hour with a can of extra-strength brake cleaner, an air compressor and various blocks of wood to keep the non-seized piston in place while blowing compressed air through the bleeder valve hole. I filled the caliper with brake fluid and put the bleeder screws & banjo bolt back in and let it sit in the sun for about 30min. Diluted brown ooze came out. After a bit more brake cleaner and some more compressed air, the seized piston finally popped out. The pistons were in fairly bad condition with quite a few large pits but luckily the pistons from my original caliper were in good condition. I used 600 fine-grit sandpaper to remove as much rust as I could from the piston housing (I don't think the piston wouldn't normally make contact with the housing since the piston sits loosely in the housing without the seal in place). I also removed all the old seal material with a brass brush.

Here's a photo of the replacement caliper with new brake pads mounted. The eBay seller neglected to plug the banjo bolt hole so brake fluid stripped off quite a bit of the paint:


So far so good. The calipers are both moving freely and at the same time & most importantly, no leaks.

One thing I'm wondering about though is the brake shims.. I never had them on previously & so I had the shim springs in the centre facing out rather than how I've installed them in the photo where the shim springs on the outside facing in. The replacement caliper came with shims so I decided to use them. I'm not sure they have any effect on braking - at least I couldn't tell that they actually do anything.