510 and 280ZX master

[benzo]

Hi all

 

I have a 71 wagon and I have installed the Zx front brakes but was wondering about the master cylinder. my question is will the ZX master bolt right in? does it have the same mounting pattern? also will the difference in feel and performance from the stock 510 master be worth the replacement?

 

Thanks

 

Benzo

[thisismatt]

If you get a 79-81 (I believe those are the years), then yes it will bolt right up. The correct under/over pattern is found on those years and is easily recognizable by the dual reservoirs. The later model masters have a single reservoir and have a side-by-side bolt pattern that would require redrilling the plate for new bolts.

 

You may find the 15/16ths bore to be too large/stiff - others have. There are other options, though, or you can get a B210 booster to help out.

[Burabuda]

yeah i did that swap once, and used the zx master, but the pedal feel was all wrong so i switched to a 710 master and then it was all good

[240ADAM]

I just put a 15/16ths master on my 620. I havent driven it yet, I'll let you know how it feels.

[BarryA]

after bleeding and adjusting the rears there's way too much pedal travel (pedal nearly hits the floor). Since the pedal travel was ok with the original front brakes, I'm presuming that the larger HB calipers are overwhelming the capacity of the original 620 m/c.

 

Plan to pick up a 280ZX m/c and pressure bleeder tonight, and will report back on the change after swapping master cylinders.

[240ADAM]

I didnt notice much difference between the ZX and stock 620 MC, maybe a little more pressure required. With the new brakes it sure does stop better.

[Lozer]

sounds like someone ran out of fluid in the resivour and need to bleed the master.

[DAW]

Does the 620 have power brakes? If so, a common mishap is to drop the reaction disc into the booster during R&R of the master and this creates a lot of extra pedal travel. If this is it, pull the booster and recover the disc rolling around in it, epoxy it to the rod/piston where it is supposed to locate, and reassemble.

 

If no power brakes, disregard this post.

DAW

Edited December 11, 2008 by DAW
typo

[bonvo]

im wondering about this myself im having issues with my master and i figured might as well upgrade i was wondering if i have to bend any new lines my other question was answered about bolting up i already have power brakes so i dont think pedal feel will be much of an issue

[Jester]

The problem with going from a stock set of calippers to a set of D21's is the portion of the bore in the master that is used. The "old" brakes used only a portion of the throw in you master cylinder. When you switch to the "new" calippers, you will require a differant amount of brake pedal needed to stop the same rig. You are now pushing the rubber cups in your master into an area in the bore that they are not use to being used in.

Brake fluid being the nasty, rust enabler it is, corrodes the inside wall of your master cylinder bore. When you introduce the rubber cups to this portion, they go to crap in a hurry. Expect to replace your master soon if you don't do it now. Just hope it's not in a time of NEED that it desides to go south.

ALSO, keep this thought in your head the next time you are bleeding your brakes. Too much pedal throw will do the same thing.