F1 Caliper welding, answers needed.

[chips1953]

I have a front caliper that has been drilled to force the piston out. A cut down M6 bolt has been screwed into the hole to allow the caliper to be used again.
When I stripped the caliper down I found the tapped hole was not good. Can this be welded or can I drill and tap M8 from the inside, use a countersunk bolt, insert it from the inside, putting an M8 nut on the outside?
I'm worried the welding may damage the internals of the caliper bore and can't see any new or used on the net.

[Spitfire]

Hi, where has the hole been drilled ? I would guess that it is in the front face of the caliper if so there may not be much meat there and with the corrossive nature of brake fluid and the pressure in the system I would not be very happy going down the drill and re thread route.

I would definately go down the weld route if you want to save the existing caliper, but I am not an expert, I don't know if this could be done without distorting the caliper.

Keep looking for a second hand caliper they do come up on eBay, not so many for the CB750F1 as I found out when I wanted one but they do come up. The same applies to Brake pistons I had to fork out for an expensive stainless one from the US via eBay, as the F1 piston is a different size to all the K ones.

Cheers

Den

I put this together to check the compatablity of other CB750 brake parts

[chips1953]

Thanks for that Den..... 'll keep looking on Ebay.
Very useful list

[Bryanj]

Have you asked at Dave Silver?

[chips1953]

Well I rang D S yesterday after you mailed and they were still in the shop!!!!!
The system was down but they don't hold out much hope, so did a worldwide search on Ebay and came up with an item in Salt Lake City. 17 hours to go. I may scrap the other caliper then no will use it unless some on the site has a different idea.
Thanks once again.

[Spitfire]

Good luck with the caliper, it did take me two years to get one on eBay, now I have 4 saved searches which tell me if anything new comes up.

Cheers

Den

[Yoshi823]

It is normally the bleed nipple which shears off that causes the problems with these calipers.So there are probably a fair few old ones lurking about somewhere.

Pistons are easily sourced...stainless steel ones are recommended.I heard of someone who makes these to a drawing or from the original. I'll see if I can find the number/email address as he also renovates old and new calipers.

[SteveD CB500K0]

There's a guy on sohc4.net who makes phenolic pistons (he turns them down from automotive parts). They come highly recommended by our US cousins.

[Spitfire]

There is a caliper on eBay at the moment, well there was 2 days ago (todays Friday)

Cheers

Den