Rear Drum Brake 620 to 720 upgrade

[Figbuck]

I was all set up to change to discs all around, but circumstances out of my control have left me with the fronts done... but not the rears... and I have to drive two thousand miles in a couple weeks. The backs are toast and I have no parking brake either. It seems like such a wasted effort, but I need to get rolling again soon.

 

The guy who volunteered to help me on this has a plan. See what you think. Go to the P 'n P, get the rear backing plate and the E-brake stuff from a 720, then buy new wheel cylinders and put basically 720 drums on it.

 

It sucks to go through this, because eventually I will get rear discs done. But his argument is that both my 620 wheel cylinders leak, they are hard to get anymore, the 720s are easier to get and are bigger.

 

Maybe the same amount of effort gets you better brakes. Does that make sense?

[rsdaumer]

i just got wheel cylinders from autozone for 22 a piece for a 74.

[Radiant-Designer]

I got mine from advance auto, had them in stock which I was suprised since I live in New England and haven't seen another 620 here. You may just want to check around, seems a lot easier to me to replace those and bleed vs change everything and no unforseen issues.

 

But don't think that would be the issue for the e brake.

[Z-train]

Mixing brake systems isn't a good idea.Braking improvement with the 720 drums will be un-noticeable over the 620 drums.The diameter of the rear cylinders are matched to the front brakes & master cylinder.

[Radiant-Designer]

And they have them on eBay too.... And cheap wheel chicks or even a 2x4 for when you park just in case.... Especially if you plan on going disc soon.... Why make something over complicated?

 

 

77 is the year of my truck, if that helps at all, I did disc in the front and have everything to do the rear, just waiting till the spring when I can work on it.

[Figbuck]

So R-D you have all the stuff to do the rears... what brackets, hubs, how do you deal with the parking brake?

[yello620]

PM sent

[wayno]

So R-D you have all the stuff to do the rears... what brackets, hubs, how do you deal with the parking brake?

 

You can put just about any datsun/nissan rearend under your truck, the width will be the only issue, you can also use your existing park brakes, just put the 620 cables into the rearend you are going to use, I put 521 cables into a 1985 dually rearend that is in my 71 datsun 521, they work fine, just like a stock e-brake. Have you got this taken care of?