72 pl521 Brake Master Cylinder needed

[dross93ranger]

I cannot find a brake master cylinder for my 72 Datsun 521. This is thee

Last part I need in order to drive my truck. Where can I find one or does anyone have one?

[skunk]

rockauto has them for 24.75+shipping.

http://www.rockauto.com/catalog/x,carcode,1212332,parttype,1836

[banzai510(hainz)]

Buy 2 as I have gone thru 2 of them already

also shaft might have to be cut if their to long. i thread the hex nut on cut a 1/2 then unscrew hex nut to clean threads

[mklotz70]

Now would be the perfect time to upgrade the m/c to a dual reservoir for the safety of it. A '77 620 would have a dual res m/c for a drum/drum setup. :)

[68Datsun510]

Is there a how to on that, Mike??

[mklotz70]

There's some info out there, but it would take longer to read it than to actually do the mod. :)

 

Basically, you'll have to slot the holes on the new m/c slightly....elongate them toward the body of the m/c just a bit...to get them to slip over the firewall studs. You'll also need to open up the hole in the firewall just a bit too. This can be done with a round or half round file in a couple of minutes, or you can use a die grinder or dremel. Mounting the m/c is the easy part. You'll need to fabricate a pushrod because the new one will use a completely different style than the stock one. Here's a recent thread that should show you enough to make your own :)

 

http://community.ratsun.net/topic/30419-master-cyl-upgrade-push-rod-build-mklotz70/

 

 

I referenced the '77 620 m/c, but you'll find that it's bleeder valves are on the same side as the clutch m/c.....and it's a really tight fit. I typically opt for the '78 280zx m/c. The vavles are on the engine side, but the bore is bigger and it will take more leg to push the brake pedal. It's also a disc/drum m/c, but I know of a couple of guys that have put them on their drum/drum setup. In this thread....http://community.ratsun.net/topic/27500-disc-brake-mc-conversion-question/ ....yello620 makes a reference at one point that the drum/drum m/c from the earlier 280z is the same part number as the next model's disc/drum m/c.

 

 

I just did a bit of digging on Rockauto.com....looks like the '75 610 m/c has the valves on the eng side and a 3/4" bore. It was a disc/drum car. I think it would keep your leg effort minimal and work fine with drum/drum. I certainly not an expert on brakes, but my best guess is the disc m/c should still work okay with the drum setup. Hopefully, someone else will chime in and correct me if I'm wrong. Anyway..... if you decide to upgrade to disc brakes, you won't have to mess with the m/c again. :) Now would also be a good time to put in an adjustable proportioning valve in the rear circuit.

[mklotz70]

I just doubled checked on RA.....the '77 620 was actually a disc/drum setup.....you'd want the '76 620 if you want to go with a drum/drum m/c. The valves are tight, you you can cut the nipples off the bleeder valves for clearance, you just won't be able to put a hose on them....which you won't have room for anyway :)

[mklotz70]

I'd also recommend getting the brake light switch off another rig...ie 620.....and mount it on your brake pedal assy. It will activate your brake lights much faster than the pressure switch it uses currently.

 

This link should/may...take you to a folder in my photobucket with a couple of pics of the switch mount on my old NL and the differences between the pushrods.

 

http://s88.photobucket.com/albums/k162/mklotz70/NL320/Brakes/#!cpZZ3QQtppZZ24

 

 

Wiring in the new switch is easy. Couple of bullet connectors on new wire running to the new switch. The bullets will plug directly into the stock wiring on the firewall so you don't even have to modify the stock harness. :)

[mklotz70]

I just tried the link...you may have to switch pages...the pics I referred to are on the 3 page of that folder.

[dross93ranger]

Thanks guys! I just ordered a few parts, nice find.

[DanielC]

It is just a minor thing, but on a 521, the threads on the hydraulic parts are 3/8-24, and I believe that all the newer master cylinders you mentioned are a M10-1.0.