69sroadster Posted September 15, 2011 Share Posted September 15, 2011 For those brake experts, I've researched on here and am looking for confirmation of the following: 1979 280zx has 3/16" brake lines with 10mm x1 tube nuts To use a Wilwood proportioning valve I would need an adapter for the lines like this from BrakeQuip BQ50 3/8" x 24NF M10 x 1 I would also need to plug the stock zx prop valve rear output or at least route it back on to itself so the right front still works normally. Quote Link to comment Share on other sites More sharing options...
beermanpete Posted September 15, 2011 Share Posted September 15, 2011 We just finished installing a Wilwood proportioning valve in our '73 240Z. The brake lines are 3/16" with M10 x 1.0 threads. We used the Wilwood supplied adapters for the SAE threads. We removed the original prop. valve entirely and replaced it with a union for the right-front brake line. For the rear we used store-bought pre-flared steel lines to go into the cabin through the firewall and back. To handle the metric vs. SAE threads we bought one pre-flared line with the SAE threads and the others have the metric threads. We cut off one end of the SAE line and one end from one of the metric lines and swapped the nuts. We re-flared the lines and voila. Quote Link to comment Share on other sites More sharing options...
rossman Posted September 15, 2011 Share Posted September 15, 2011 (edited) Dave @ AZC recommends leaving the stock proportioning valve so you end up with both the stock and Wilwood valves. Not saying you have too just FYI. Since I have an AN flaring tool I flared the 3/16 tubing and used AN to NPT adapters to the valve. Edited September 15, 2011 by rossman Quote Link to comment Share on other sites More sharing options...
beermanpete Posted September 16, 2011 Share Posted September 16, 2011 Dave @ AZC recommends leaving the stock proportioning valve so you end up with both the stock and Wilwood valves. Not saying you have too just FYI. Since I have an AN flaring tool I flared the 3/16 tubing and used AN to NPT adapters to the valve. Why leave the original prop. valve? It is just another part to go bad. In my case, it is already bad. Did you use an inverse flare with the AN fittings? I have not seen the 2 used together. Quote Link to comment Share on other sites More sharing options...
rossman Posted September 16, 2011 Share Posted September 16, 2011 (edited) Only because his instructions said to leave it. I didn't put too much thought into it. Mine is still good and I don't remember seeing many people complaining about them going bad. I'm curious how yours failed. The Wilwood valve that I purchased from AZC has NPT threaded holes in it. I purchased AN to NPT adapters and flared the stock tubing. Edited September 16, 2011 by rossman Quote Link to comment Share on other sites More sharing options...
69sroadster Posted September 16, 2011 Author Share Posted September 16, 2011 Beermanpete, Great ideas about using the metric and SAE line like that. I also thought about just getting rid of the stock proportioning valve and running the front brake lines together like you mentioned. Either way the rear will be directly from the master cylinder and through the Wilwood to the back. Also thanks for the info that the WW adj PV comes with metric adapters. Would leaving the front brakes through the stock proportioning valve help with kneeling etc based on a non-constant or linear effect it might still have on those only? Quote Link to comment Share on other sites More sharing options...
rossman Posted September 16, 2011 Share Posted September 16, 2011 Would leaving the front brakes through the stock proportioning valve help with kneeling etc based on a non-constant or linear effect it might still have on those only? The stock brakes do not go thru a proportioning valve. Never install a proportioning valve on the front brakes. Quote Link to comment Share on other sites More sharing options...
beermanpete Posted September 16, 2011 Share Posted September 16, 2011 Beermanpete, Great ideas about using the metric and SAE line like that. I also thought about just getting rid of the stock proportioning valve and running the front brake lines together like you mentioned. Either way the rear will be directly from the master cylinder and through the Wilwood to the back. Also thanks for the info that the WW adj PV comes with metric adapters. Would leaving the front brakes through the stock proportioning valve help with kneeling etc based on a non-constant or linear effect it might still have on those only? The Wilwood prop. valve comes with NPT to SAE threaded inverse flare adapters (at least ours did). Our car is a '73 and the original prop. valve has a connection with the front brakes. It is not just a pass-through. There is some interaction between the front and rear brake systems. I doubt you could leave it in with the rear brakes disconnected from it. The "kneeling" would not be affected by the prop valves. Brake induced dive is controlled by the struts, springs, suspension design, and such. Our OE prop. valve seems to be preventing any significant rear brake pressure. We used up several front pad sets and the rear shoes hardly look bedded in. It is very stable during hard braking as result, but to the detriment of braking power. We have the new prop. valve installed but have yet to drive the car, so we don't actually have proof the problem was the prop. valve (yet). Quote Link to comment Share on other sites More sharing options...
beermanpete Posted September 19, 2011 Share Posted September 19, 2011 (edited) We got our brakes finished today, finally. After battling a low brake pedal and assorted weirdness we checked the reaction disk and it was out of place. After we got that corrected the brakes work great. Hooray. The original problem was the proportioning valve. Now the rear brakes work as they should. The adjustment allows the bias to be set for early lock-up at either end, neutral, what ever you want. Edited September 19, 2011 by beermanpete Quote Link to comment Share on other sites More sharing options...
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