master cyl wont release

[poorbiker]

Jack K, everything checks out ok on master cyl but while checking I took another look at bore and your right its more a fine finish honing than a mirror finish, didnt dawn on me before about the finish. I guess it could be a combination of over honing and improper finish. I have installed sleeves on out of spec star hubs with great success but never a wheel cyl. I suppose using marine brass or bearing brass would simplify the hole thing.
Any pointers you would like to share, all info is good info except from attorneys..................

[poorbiker]

Yes the marine brass is a combination of a few different alloys including bronze, I have also heard it called bearing brass. And yes you can tell quickly while machining which you have.

Yes there are check valves in the kits, good thought but I have correct internal components installed though I did have to double check.....

Rear cylinder is working fine, its a pressure bind, releasing pressure at brake line fitting at master cyl relieves pressure, temporally though......

Hate to install an aftermarket master on my buddies bike but may have to temporally until I can attempt a repair on the oem cyl. I am going to have to buy a small bore inside micrometer though......

[poorbiker]

Is the bore .755 ? A tad over 3/4"

[Jack K]

poor biker,

It's been more than a decade since I did the install on the master cylinder sleeve but as I remember it was a pretty simple job. I did this for a cousin and he came to me because he knew I had a lathe. He supplied the sleeve and the old Wagner cylinder. Where he got the sleeve I can't remember, if I ever knew.

The sleeve was about half to two-thirds the length of the bore. I simply used this measurement for the depth to bore and, of course, used the OD of the sleeve for the ID of the bore less a thou or maybe a little less. Then put a little green loctite on and pressed it in. The hardest part was getting it set up in the 4 jaw chuck, I just don't use one often enough to be good and quick with it.

[rousseau]

does your "modified brake pedal setup " have a return spring? The small spring inside the master cylinder is not adequate enough to support the weight of a pedal.

[poorbiker]

Rousseau, ya it does. Turned out it was the honing someone had done to it prior to my buddy buying it. Bore is to rough. Installed an after market for now, all better.
Intend on looking at machining a sleeve for the oem. I have a few oem master cyl to play with, all have bore issues and were removed from service but I never threw them away.

[flathead tom]

check the brake hose they colapse inside works like a 1 way valve when hose gets old lets fluid in but not flowing back had this on my bike accell makes a hose when I bought mine !!!!!

[55tmm]

I agree w/flathead tom,I had the same problem with my brakes, it was the brake hose!

[duffeycycles]

or the steel line plugged

[36 knuck man]

Hose too on my 78 sporty, all three are blocked, Larry

[poorbiker]

well I forgot to post fix, someone suggested I check the plunger, its a fixed type, non adjustable. Well it turned out from my pedal and plunger rod were to tight, holding the piston open just enough that when hot, fluid, wasnt releasing, made an adjustment on plunger rod length on my lathe and all good now. It wasnt much I took off, didnt think it would have made that much diff live a learn, especially when custom or no oem stuff is installed. thnx for all the replies.