Cleveland brake piston: O Ring groove dimensions

[IanLaw]

(Apologies for the odd“type” spacing in this post – I had to type it in my wordprogram and paste it here, because there seemed to be some kind ofglitch when I tried to type direct in the box on the forum page. Very weird!)




I have an old set ofCleveland brake callipers for my Boredom Fighter project and sincethey didn't have pistons with them, when I bought them, I have turnedsome new pistons on my lathe. The cylinders are believed to beCleveland part number 061-00601 and are 1.500”OD & about 0.5”deep.

I sized the O ring grooves using information fromvarious websites. The O rings are a good fit, but seem excessivelytight in the cylinders -too tight for me to risk pushing the pistonsfully home in the cylinders, in case I can't get 'em out!






Could anyone who hassome expertise with Cleveland brakes advise me exactly what thecorrect groove dimensions should be for my home made pistons?






I keep looking on e-bayfor suitable replacement pistons, but haven't had any luck so far.






Thanks!







Ian


(Apologies for the odd“type” spacing in this post – I had to type it in my wordprogram and paste it here, because there seemed to be some kind ofglitch when I tried to type direct in the box on the forum page.)

[WLIU]

Don't have the dimensions but the last time that I had mine apart it did take some force to pop the piston back in.

And to get it back out, plug one of the hydraulic line ports and put compressed air in the other. Hold your hand around the calipher so that the piston pops out against your palm. Don't let it go flying across the shop.

Best of luck,

Wes
N78PS

[martymayes]

Ian, Parker Hannifin Corporation publishes the "Parker O-Ring Handbook" (publication # ORD 5700) which has all the o-ring groove dimensions you'll ever need. I have cut many o-ring grooves with no problems. That publication is available online. Also version 28 or higher of the Machinery Handbook has o-ring groove size information.

I would not worry about getting the piston stuck in the brake caliper. A little shop air on the back side through the fluid fitting will remove the piston. Just be careful and treat it like a loaded gun.

[IanLaw]

Many thanks Wes & Marty and that gives me confidence to go ahead. I will double check the depth & width of the grooves with the Parker O Ring Handbook.
My copy of the Machinery Handbook was inherited from my late Dad. Just checked and it is the 10th (1941) edition -so is a little out of date!

Thank you again.

Ian