74 620 break questions

[Eagle_Adam]

Ok not only am i new to Datsun's but this is my first truck with drum breaks so go easy on the newbie . I finally got my new 620 running!!!!!!!!!!!! YES!!! but now that i have driven it for the first time i now know that the breaks are not nearly as responsive as i would like them to be. The pedal goes almost all the way to the floor before the truck comes to a stop. I have taken my wheels off and adjusted the star wheels on the inside of each corner. Man was i happy to find out none of the star wheels were frozen. My first question is how many times do you normally need to advance the star wheel? My fronts only seemed to need to be advanced 3 or 4 clicks until i could hear the shoes lightly "scrape" the drums. The rears never seemed to "scrape" no matter how many times i advanced the star wheel. I stopped after 7 or 8 advancements it didn't feel right. Also are there any dead give aways that my breaks need to be replaced? Any other pointers or advice would be welcomed. Thanx for all the help guys.

[datzenmike]

To adjust the brakes turn the star wheel downward while spinning wheel by hand until resistance is felt. Pump brake several times to center the shoes and check for change and adjust again if necessary.

[mklotz70]

factory manuals at www.olddatsuns.com on the tech page.

 

If someone worked on them before and swapped the adjusters left to right, they will loosen instead of tighten.

 

On top of what Mike said....once you've gotten each side to feel about the same, test drive it, as the brakes just start to engage, you may feel a pull to one side or the other. You either want to loosen up the side it pulls to or tighten the opposite side. We're talking one click. That should help with eliminating the pull.

 

Since you still have the single resevoir system, you'll want the backs to be adjusted the same as the fronts. If they are looser, you'll have to push the pedal further. Basically, they all work off the same fluid and pressure....so they should all pretty much engage about the same time. The front and back brake setups are different to help with front to rear bias, but if you want more control, you can add an adjustable proportioning valve. Better to upgrade to a dual res m/c...better still....upgrade to discs :)

[datzenmike]

Mike I think all 620s had vacuum boosted tandem master cylinders.

[Eagle_Adam]

i started looking into dics's then i saw the price and then i realized that i need to be realistic right now damn responsibility sux. Is there such thing as turning the star wheels too far? and im gunna try to spin the rear star wheels in the opposite direction too.

[mklotz70]

I'm sure you're right Mike.....620's are simply parts trucks for me, so I don't pay too much attention to them :) lol

 

Adam...you can probably look inside the adjuster hole and see if after 5-6 turns, you have more or less spacing between the star wheel and the adjuster body. Yes, you can go too far and the brakes will drag and grab. Unless they drag enough to get really hot, then it will feel like constant brake fade.

 

 

On adobe, this is page 314 from the factory manual.