screw broke off in clutch master cylinder reservoir

Hi everyone,

My restoration (to 'ride-able' condition) of my 82 Sabre is coming along nicely and I've nearly finished stripping the bike (leaving the engine on the frame). One of the first things I did was check the reservoirs of brake fluid in both brake and clutch reservoirs. As suspected, both were empty. At least the brake reservoir had a residue of brake fluid (and bleeding at the bottom resulted in some fluid). I intend to buy rebuild kits for both so I can repair them properly.

The clutch master cylinder has a major issue... I did manage to get the lid off though... after much trouble. The screw started turning, then all of a sudden the phillips slot stripped (it was quite bad already). I tried a number of things - make a new slot (failed) - extractor set (failed). I brought it to a friend's house (he's building a Virago bobber) and he couldn't get it out either. Final step was to drill out the remaining head and try vice grips on the stump. This failed too.

Is there anything else I can try? Is it possible to retap the screw hole? Should I start looking for another master clutch cylinder assembly?

Thanks for any advice,

Trent

 

Soak it down good and let it sit overnight with a penetrating oil: PB Blaster or some such. Then find a left-handed drill bit smaller than the bolt, it's very likely that the drill bit will catch slightly and back the bolt right out. If it doesn't then use an EZ Out to remove it. Be very careful with the EZ Out because if you break it you're basically screwed. They are extremely hard and cannot be easily removed. You're looking at galvanic corrosion between the aluminum reservoir and the bolt.

Just a thought: get a good stone and stone down the mating surface of the reservoir before you put everything back together. You'll be glad you did.

 

I would suggest a heat/torch after soaking in penetrating agent. Care full with heat though sight glass has a rubber seal around it.

 

A used master cylinder won't cost much...
sabre brake master | eBay

Next time you strip a head, try an Alden Grab-It.

 

Prices on eBay for a used clutch master assembly range from around $60 to $120 plus shipping. I can get a new one for $250 plus shipping. I thought I might be able to do better so I went to Joe's Motorcycle and ... found a used '82 VF750S clutch master assy for $40 in their yard. Score! I'll put some brake fluid in it tonight and soak the piston as it's seized right now. Between the two units I should be able (with a rebuild kit) fix everything and make it look nice.

Thanks for the advice - I'll try get the screw out later so I have a spare master clutch assy!

Trent