Series 3 rear brake cylinder operation

[jvsimmons]

Another dumb brake question: Pertains to 1983 Series 3, 88 with 10 inch rear drums with single dual piston brake cylinder Note that the rear shoe as designed does not have a top return spring. The question is are the rear brake cylinders designed only for left and right....in other words will a rear cylinder work for either left or right wheel? Ok, now for the dumb part. I needed to replace the rear brake cylinders....ordered them from RN. When I got them I took them out of the box and put them on the bench - ya, you got it - I didn't note which cylinder was for which side. So, I looked at the old ones still mounted and matched them up for the install with the brake line attachment on the rear side of the cylinder. After replacing both hard brake lines I was checking for leaks and had another person press the brake pedal ( drum on ). Had a leak on the left side. Took the drum off to inspect action of the pistons. Found that the rear piston moved out as one would expect but the front piston hardly moved the front shoe at all. This then leads to the next question - do the pistons move differentially ( one moves more than the other), thus that would lead to a left and right cylinder so that the piston that moved the most pushed on the front shoe . Could it be that I have the right side cylinder on the left side - since if I moved the cylinder now installed on the left to the right wheel then the piston that moved the most would be pushing on the front shoe? But that would mean that the brake line attaches to the front of the cylinder. Or have I got the cylinders mounted to the correct side and that maybe the left cylinder is defective? Or is this the way they are designed to work - rear shoe getting the most piston push?
Sorry but one dumb question lead to others. Input appreciated.

JIm

[roverp480]

The cylinders are only handed for the position of the bleed nipple and brake line fitting, internally they are the same. With the drum off the trailing shoe does not offer the same resistance as the leading one ( Due to the springs)so there will be a differential movement , but with the drum fitted the shoes movement is restrained by the drum and the pressure on each shoe is the same, as the pistons inside the cylinder have the same area. Where does the LH one leak, presumably from what you say its around the piston , not the connection from the line or breed nipple. Defective cylinder by the sound of it. Here in the UK there have been a number of reports of defective aftermarket wheel and master cylinders even to the extent of owners suggesting checking them internally before fitting

[jvsimmons]

Roverp480 - Thank you for the explanation. I am good now knowing that the install of the cylinders is correct and I don't have to do it all over. The leak was at the pipe connection to the cylinder - bought a better wrench and tightened the fitting. No leak. I will put the tire on and go for a test drive. Thanks again.