Datsun 521 rear wheel cylinders

[glorydime]

seriously just now I realized the stamp on the side is from a 620, I'm an idiot. Thank you I am going to order tonight and get on the road in a day or so!!!!!! if anyone is looking for 521 brakes, and notice a T101 on the side of the cylinder its a 620. 

[jacimo98]

Could you possibly be getting the service adjustment wheel confused with a wheel cylinder?

[521Symmonds]

Well this thread explains why I can lock up my rear brakes on command on my 521. I got 620 rear brake cylinders. I'm going to revive this thread with a question.

My 521 rear right side brake is sticking to halfway whenever I drive forward. I will get a grinding sound like my brake shoes are barely touching the drums and I get a soft brake petal. So far I had flushed the brakes, checked all of the lines and found no leaks, checked the cylinders with no leaks, and bled the system with no issues. I go in reverse and it stops with no issues, it just happens going forward. Does it sound like a bad rear cylinder?

[datzenmike]

Trucks are light on the rear and the brakes work better with a load on them. There is a slight tendency for the body weight to shift forward under severe braking. This added weight on the front wheels increases the traction and prevents lock ups but at the same time reduces the weight and the traction on the rears and can cause lock up.

 

As 80% of your stopping power is done by the front wheels, be sure they are adjusted to spec so that you needn't overly apply the brakes when stopping. If you force the rears to work harder they will lock up.

 

Raise the wheels off the ground and turn them by hand. They should spin easily. If not, one or both may be dragging. The adjustment may be too tight and on the rears, the hand brake may be adjusted too tight. Loosen the hand brake and then adjust the wheel cylinders till they just barely rub. Pump the brakes several times between any adjustments to center the wheel cylinder and shoes. Now adjust the hand brake, but not too tight.

 

It's also possible the retaining clips and springs are broken or missing, the shoes on backwards or a foreign object like a stone is caught in there.

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