Rear Wheel Cylinder Link Size

[Rusty '86K20]

I am working through a brake job on my 86 K20 with 13" rear brakes (JB7 code). The rear brakes did not work when I bought the truck a few months ago. The wheel cylinders were bad, the lines were bad, and the master cylinder was leaking. Replaced the lines, wheel cylinders, shoes, hardware, and master cylinder. Bled out all the air and did a full fluid change in all lines. Still no back brakes. I think the wheel cylinder links (rods between the wheel cylinder and the brake shoes) are too small as they have 3/8" or so play between the shoe and the wheel cylinder when I seat them all the way in the wheel cylinder boot. I cannot verify if they are original or someone else's hack job. I would think there would be no free space or very little between the brake shoe and the cylinder link when installed. Any suggestions? I am having a hard time finding replacement links that rae specifically for chevy 13" drum brakes.

 

[Georgeb]

Please post up some pics.

 

[chengny]

I think the wheel cylinder links (rods between the wheel cylinder and the brake shoes) are too small as they have 3/8" or so play between the shoe and the wheel cylinder when I seat them all the way in the wheel cylinder boot.

There will be some degree of end play between the rods and wheel cylinder pistons upon initial assembly. When the return springs are installed, it will be somewhat reduced . Then, when you manually adjust the brakes using the starwheel, the gap will close even more.

The remaining clearance is supposed to go to zero - and stay that way - when the brakes are initially applied.

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If you feel that the last step isn't occurring, you might have to confirm that pistons are extending outward from the wheel cylinders when the brakes are applied. Pull one drum and then - while you stay by the wheel and watch the action - have an assistant gently apply the brakes. If he presses the pedal too hard/far, the whole assembly can fall apart and the piston can come right out of the cylinder.

Observe whether the rods move out, make contact with the notches in the shoes, overcome the springs and then begin to move the shoes outward.