Caliper/master cylinder questions 1974 TX650

[wwitten]

OK have rebuilt the master cylinder that came stock on this bike with the correct rebuild kit. Replaced all rubber and steel lines put in new sender unit and bought a caliper from Mikes XS. Have tried to bleed this system as noted in the tech systems with no success. To check the master cylinder operation I attached a clear hose to the steel line going to the caliper, within a matter of moments can clear the air out of line and can get a 4-5" upright column of fluid when the master cylinder is operated. I would think this indicates master is functioning????? How can I tell if there is enough pressure?

So I took off the new caliper, broke it apart and eventually was able to get the pistons out with air, but they were stuck really hard. The inside of the housing showed some rust so I cleaned that out with brake fluid. Question is I know the pistons need to sit tight against the seals but when I install them even with brake fluid they are stuck damn near solid. Shouldn't there be some play so they can retract and engage with the increase/decrease in fluid pressure? They need to slide to some degree.

Could the seals be swollen from storage? Have them soaking them in fluid now.

Was ready to order a new master from Mikes, thinking I wasn't getting a fluid flow, but now I'm not sure how to truly diagnose/solve the real problem.

Thanks
Bill

 

[650Skull]

I have to rebuild the calipers on my TXA and the cost of rebuilding is more than the new calipers. Are these another of Mikes less than perfect reproductions..........

You don't make a lot of sense with your description, but if you are getting a squirt of fluid when you are operating the brake lever then your m/c sounds like it is operating. You won't be able to gauge the pressure till you get the caliper working.

If you had rust inside the caliper i would be taking pics and sending them to mikes asking for an explanation. Thought the seals would dry out if anything and should need a bit of lube, (brake fluid).

 

[cros36]

i have the repop MC and caliper from mikes on my 74. bled them like you bleed brakes and everything works great. sorry no help.

 

[wwitten]

Well I contacted Mikes and they are sending out a replacement caliper, hope this ones in better condition....