1974 620 Emergency Brake Does Not Allow Full Wheel Cyl Piston Compression

[Cardinal Grammeter]

I've been completely through the Emergency Brake cable system (EB) and it does not fully release the brake shoes so they can fully compress the wheel cylinder (WC) pistons. 

 

With the brakes and emergency brake both fully released, given the shoe return spring forces, the shoes are reacted by the EB Extension Link (EL) - not the WC pistons.   

 

I've never seen a system like this in American cars - they always have EB "clearance" so the EL is loose between the shoes.  Of course you can adjust up the EB so that clearance is minimized.

 

Eureka?  maybe:

But that clearance must be taken up and so wastes the limited available travel of the EB manual control.

 

Is that the design of the Datsun EB system?  - purposefully having the shoes on the EL so no actuation travel is wasted on EL clearance???

 

I wouldn't be surprised given the innovative, clever bell crank mechanism to handle the cable and sheath reactions.

 

Edited June 14, 2022 by Cardinal Grammeter