e_racer1999 Posted July 21, 2004 Share Posted July 21, 2004 i already posted this in clazziczcars.com, i just want maximum exposure.. okay, i have been researching this for a few weeks and i want to know EVERYTHING before i begin. i've searched several forums and have recieved mixed answers. my big question is: if i have a 1972 240 and i am going to do the rear disc swap with the maxima brackets and rotors, calipers, and master cylinder (15/16) from a 1979 280zx, what is the story with the proportioning valve? a few sources say that they have used the 240 one, a few recommend the one from the 280zx, and a few say that you don't need one at all. the reason that the last one makes sense is that the front discs on the 240 are larger diameter than the 280zx ones, and hence the proportioning valve would seem overkill. anyway, if i do bypass the proportioning valve, how do i do it? P.S. sorry about this long azz multi-part question, i just want to know what everone thinks! -jason Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted July 21, 2004 Share Posted July 21, 2004 That's the same exact brake upgrade I did on my '73. Do yourself a favor and get an APV (Adjustable Proportioning Valve). You plumb it into the rear brake line. This way, there is no guessing and you can tune the brakes yourself. You can mount the APV anywhere you want, like on the firewall inside the engine bay, or even inside somewhere. Just as long as it plumb's into the brake line going to the rear wheels, somewhere between the master cylinder and the tee to both rear wheels. You can keep the stock proportioning valve if you like, but you must gut it (take the spring and stuff out) for the APV to work properly. Keeping the stock proportioning valve just lessens the amount of brake line work that you will have to do. If you want to clean it up, then just eliminate the stock proportioning valve and run new brake lines. Oh, and welcome to HybridZ! !M! Quote Link to comment Share on other sites More sharing options...
e_racer1999 Posted July 21, 2004 Author Share Posted July 21, 2004 thanks matt... what would the cost be on an APV? Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted July 21, 2004 Share Posted July 21, 2004 They are around $40 to $50 Quote Link to comment Share on other sites More sharing options...
Synlubes Posted July 21, 2004 Share Posted July 21, 2004 Mine is a Tilton small version. I mounted inside the car so ajustments could be made quik and easy. I removed the stock pro valve and did some basic brake line ajustments to get things hooked up. http://f1.pg.photos.yahoo.com/ph/valubes/detail?.dir=/7e99&.dnm=296d.jpg Quote Link to comment Share on other sites More sharing options...
e_racer1999 Posted July 22, 2004 Author Share Posted July 22, 2004 thanks! nice setup, too. Quote Link to comment Share on other sites More sharing options...
Ben Posted July 24, 2004 Share Posted July 24, 2004 When I had my car inspected it passed with a Willwood valve in the rear circuit, and no OEM valve. However the pedal travel was too excessive for my likeing, so I upgraded from the OEM 7/8 to a 1" MC. Pedal is firm, brakes are good, bias is good. I was going to go for the 15/16 MC, but there are no aftermarket suppliers of that part & OEM was $500AUD. All residual valves are removed. It pulled up about 1700N on the rears & 2300N on the fronts. For comparison, a semi-trailer bogey pulled 25000N a few minutes later!!!! This is with stock front discs with Hilux Calipers on the front & Skyline sliding calipers on the rear (simillar to 280ZX). Semi-metallic pads all round. Quote Link to comment Share on other sites More sharing options...
ecp48 Posted July 25, 2004 Share Posted July 25, 2004 Doug, Why did you run the brake line through the drivers compartment? Wouldn't it have been safer to just extend the valve stem (handle) into the driver's compartment. Where did you find the adapters, ie: metric brakeline to the proportioning valve? Thanks, ecp48/Ed Quote Link to comment Share on other sites More sharing options...
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