Siezed screws

[Kiwi]

When i tried to disassemble the original master cylinder for the front brake, the screw heads sheared off.
I purchased another one on e-bay and this has the same problem.  Talking to the seller now to come up with a solution about him sending me product that is obviously messed up.

Anyway... any suggestions on how to remove the stuck bolts? I havent turned them really hard yet because i dont want to cause the same problem as my first master cylinder.

P.s.  Am i right in thinking that siezed screws are something that should be mentioned in an ebay auction?
here is the link for the auction
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=270411951873&viewitem=

[Brian Moffet]

One of mine was stripped when I tried to remove it.  I carefully drilled out the head so I could remove the cover, that gave me enough room to get vice-grips on the screw itself and remove it (a little pblaster may be required, but only after you try).  My problem was that the screw head was jammed enough to cause problems but the screw itself was able to be removed with no problems.

[h2olawyer]

On eBay, you run into a wide variety of item descriptions.  If you want to know a specific condition, you really need to ask about it to be sure.  I wouldn't be too hard on the seller unless he truly misrepresented it.  This is a fairly common problem on older motorcycle master cylinders.  From the content of his ad, he only claimed it was used and holds pressure.

The several master cylinders I've heard about on here with the same problem all were fixable using the same method Brian explains above.  You can get the stock screws from Yamaha or find some replacements in stainless @ any decent hardware store - which is really the better option.

H₂O

[Tiger]

 :) This has happened to me a couple of times and like Brian, I have drilled the heads off, removed the cover and extracted the "stump" with a set of vice grips...no problem. I replace these screws everytime I rebuild another Vision or work on other peoples Visions... 8)

The replacement screws that you require are M4.7 x 12mm flat head, philips drive...before you put them in use a wee smear of anti-seize, grease or even Vaseline to save having this "galling" problem again.

                8).......TIGER....... 8)

[Kiwi]

I can still get a little grip with a screwdriver, so i am soaking the whole thing in CLR over night, and it had WD40 on it all day today. 
If that doesn't do it i guess I'll drill out the top of the screws and go from there.

[Rick G]

I always  replace the screws as soon as I get a bike . I use socket head (allen) screws or lacking those , pan head  screws , rather than flat head . The sockets will allow  easy removal and even the pans wont seize , like a flat head.A little anti seize goes along way and is to be recommended.

[h2olawyer]

Go get some PB Blaster - it works much better than WD-40 (which is really good at displacing water, but not much else).  Even better are Liquid Wrench, Aero-Kroil and, according to a recent post, ATF mixed with acetone is the best for helping loosen rusty fasteners.

I don't think my can of WD-40 has even been touched since I got the PB Blaster.

Just a helpful hint.

H₂O

[Night Vision]

I can still get a little grip with a screwdriver, so i am soaking the whole thing in CLR over night, and it had WD40 on it all day today. 
If that doesn't do it i guess I'll drill out the top of the screws and go from there.

sounds like you stripped the top of the screw, did not break the head off?

if that's the case, try clamping down the top cover with a "c" clamp. this relieves some pressure from the rubber gasket and you night be able to get the screw out. 

[Kiwi]

i got them out.  I drilled the top of the screw out and then used some vice grips on the remainder.
Thanks for the help !