Datsun Roadster Forum-311s.org

Scott,

They look identical, but the pistons are different sizes, the actuator rods are different, the 510 is metric, and the bolt spacing is different. All easy to overcome, but takes some time to complete...TR

I am on a budget, but safety is always first. $+50 does not sound bad. I am still curious on what parts need to be swapped for it to work.

Will this work? http://cgi.ebay.com/ebaymotors/ws/eBayI ... ename=WDVW

Also, Sam, How much do you want for it? And does it work?

Joaquin

I'm guessing that the used unit is your best option given a budget.

Pressing twice as hard for the same braking would eventually become a bother or make your right leg really strong! Given that, I would only consider a Z or 510 master if you were planning on converting to Volvo calipers in the future...

The one you found on eBay would require all of the modifications I listed previously and you would be pushing twice as hard...

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Well TR,

I guess I must be nuts because the brake master that is on the roadster right now is off a 71 510 I think I used the actuating rod off the worn out roadster master but otherwise it bolted right in. The brake lines threaded right in and sealed too. Uno, there has been discussion on other posts regarding folks just bolting in brake and clutch masters from the Z car, if memory serves, mixing metric and american thread sizes and those folks got away with it. Hmmmmmm, maybe if you don't know you can't do it, you can get away with it. I just measured the bolt spacing on the 510 and the Roadster and they sure seem the same to me. The 510 master on my Roadster works just dandy by the way with normal pedal pressure.

Scott

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Mark - I know it is counter intuitive, but the larger the master cylinder piston, the less pressure for a given amount of effort. Smaller master pistons give higher pressure and less volume of fluid movement for the same effort.

Scott - Maybe there is a difference I did not know of between early and late roadster masters or 510 and Z masters...I'll have to look into it and figure it out, unless someone knows? To mount the Z master on the 66, I had to open up the bolt holes a bit to fit the studs. I also had to open up the firewall for the master flange. I always thought Z and 510 masters were the same, but maybe not? A quick part number search away from that answer...

The standard tube nut will thread right into the metric bore, not recommended, but it appears to work!

I put it back together, and bench tested it, the piston for the front brakes seems to have alot of pressure, on the other hand the the one for the rear brakes only dripped liquid, and no pressure. When I installed it and bled the system, the rears only dripped liquid, no pressure in the rear, the fronts brake better than before now, but I still cant get the rears to work, I also looked inside with the brake drum off and the new clys. dont seem to move. I have new cylinders in the rear, and new brake lines all around, but the only thing I have not replace is the master. Is that really what I should point my finger at?

Joaquin

Maybe I need to look at my MC again. Everyone is talking about a 5/8" MC. I took a 3/4" MC off my 70. I put on the Z-car master using metric to standard adapters. The bolt holes lined right up. I figured that The 7/8 would only require 36% more force than the 3/4. Is my MC wrong, or did the later cars have a larger MC?

The brake masters on my 70 Roadster and 71 510 are 3/4 inch. The clutch masters are the same too and they are 5/8. This is fun. Posts up the whazoo. I like it. Confusion reigns.

Scott

Alright, I had to look at some references...

Roadster:

66 & early 67 has the single 7/8"
After that, the dual 3/4"
Clutches use 5/8"

510:

Early used a single 3/4"
Replaced by a dual 3/4"

240Z:

Dual 7/8"

So maybe the 510 unit is the closest match, the metric fittings probably the biggest hurdle? TR

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Given your info came from the Nissan manual, I'd trust that more than the write up I grabbed info from. I bet the author confused the early 1500's and 1600's like you mentioned... TR

I swapped a 510 m/c into my car (dual, 3/4") due to budget.
All you have to do is take your roadster brake line connections (the 1-1/8" large nuts on the bottom) off your old m/c, and install them on your new 510 m/c. If someone gets really picky, they could use their old reservoirs, as the 510 reservoir has the 'full' line, horizontal, not for our tilted application. I doubt that anyone would pick up on that small item considering all the other strange swapped stuff I have keeping my car going.
Joaquin, I have some bench bleeding tubes made up (made from a JY 521 pickup find) if you want to borrow them. Fergus O in HB

Since brakes are working good now(except rears), For sure in a week or so(before Solvang) I will have enough to get me a 510 one, and I will just swap the bottom bolts.

Fergus, Sure I would like to borrow the bleeding tubes, you should also come by again to see the car. Its been a while since you last saw it, now you got to see it running PM me.

Joaquin