fbekholden.com

Howdy folks,
Have a question regarding the HR rear cylinders which are for the disk setup. These are the smaller diameter ones with the flat bit pressing against the shoe rater than the forked thingy.
Are they supposed to have a spring between the pistons, pushing them apart? Like the bigger ones?
The reason I ask is mine tend to retreat back a mill or two when the pedal is not depressed. I think the rubber gasket does this when returning to it's natural shape. The brakes work fine, just there seems to be a fair amount of travel in the pedal. In case it's relevant, I'm running with the regular after market PBR master with the big 9'' booster, direct acting.

Sorry Richard - can't remember - and far too far away from home to get to my books.....
I have to ask - if you are running a direct acting 9" booster - does this not afford using standard HR wheel cylinders.

The smaller ones, as I understand it - and have fitted to mine - were for the disc brake single line servo system - to prevent the rear brakes locking up when applying the pedal. The smaller 9/16" rear cylinders reduced the amount of force.

With yours, I would expect you have a dual circuit system with a proportioning valve..... this should restrict the amount of pressure/force to the rear brakes.....
If this is the case, you might find you will "under" brake the rears....

frats,
Rosco

Close guess Ross, except no prop valve.

Thanks Richard,
I can honestly admit that I have not considered running the dual circuit without a proportioning valve.. I am guessing that your inclusion of the small bore rear wheel cylinders might be appropriate in such an application (no pun intended).

If you have a set of shoes to matcht these - do not EVER in your life-time - or that of you grandchildren's life-time - allow them to be swapped..... these backing plates are unique.... and you would be very well advised to keep a very taught leash on them..

frats,
Rosco

Problem solved. It appears the check valve in the outlet for the rear brakes was not checking. This little rubber doodad sits behind that brass cone in the outlet and (of course) allows fluid to flow out, but only back in under sufficient pressure (eg the return springs on the shoes). Once I took care of this, the pistons stayed out, nestled against the shoes. Massive thanks to Roger (Holdenman Restomotive) for his help.