Owen Posted May 22, 2001 Share Posted May 22, 2001 I put the APV inline on the front brakes, tell me I did this right...you'll kill me if you say I did it wrong cuz it was originally on the rear brake circuit! THX. Owen Quote Link to comment Share on other sites More sharing options...
jeromio Posted May 22, 2001 Share Posted May 22, 2001 It goes on the line to the rear brakes. You need to remove the stock prop valves too. You want full braking force on the fronts, less on the rear (weight transfers forward during braking). The prop valve reduces the amount of pressure going to the rear brakes. Quote Link to comment Share on other sites More sharing options...
Owen Posted May 22, 2001 Author Share Posted May 22, 2001 My understanding is the that prop valve is used to balance the pressure to front and rear. And that I want the fronts to lock just before the rears. If the fronts always braked full force, that would be rather dangerous as well as inefficient on a racing circuit wouldn't it? It would be too hard to control the car if it nosedived every single time. I forgot to ask but thanks for reminding me, do I need to plug the stock holes in the stock p-valve? owen Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted May 22, 2001 Share Posted May 22, 2001 To keep the fronts from locking you use less pressure on the pedal You want to reduce the pressure to the rear in order to prevent the lighter end from locking up too quickly. Pete - how did you remove the prop valve? Did you simply gut it? I'd intended to run the setup "as-is" before taking any steps to change the behaviour.... Do the stock brakes have a residual valve too? i noticed something in th eback that looked liek it might be such a thing but had never seen anyone mention it...Thanks! Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 22, 2001 Share Posted May 22, 2001 Jim, I'm going to start charging you a consulting fee - this is the 3rd question in 20 minutes . Just kidding! I just didn't use the stock prop valve. I used a couple of unions in the stock position, but you could just leave them out if you're doing new hard lines. The older 240's did have a valve back there instead of the one on the firewall, I think. [ May 21, 2001: Message edited by: pparaska ] Quote Link to comment Share on other sites More sharing options...
jeromio Posted May 22, 2001 Share Posted May 22, 2001 What BLKMGK said. If you're gonna use an adjustable valve, remove the old stock one(s) entirely. My 71 has a rear prop valve as well as what looks like one in the front. Could be a residual or perhaps an unconnected low pressure warning switch. I dunno. But with the front and rear ZX brakes, I've left it all as is. I have my expensive adjustable valve sitting in the rear tool bin (not connected to anything). When I re-did my brakes, I went ahead and bled the whole system and then took it for a drive. Everything seemed to be balanced just fine. I do plan on installing it at some point. Currently the fronts lock up first, which is good, but the rears probably aren't getting enough pressure. Drum cylinders have way less fluid in them than calipers. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted May 22, 2001 Share Posted May 22, 2001 Pete, you can tell I'm getting close® then huh? I think for starters I'll leave it all alone and see how it brakes. I WILL take a close look at the rear to see what's there and report anything "weird". On the Mustang's tewy simply have you "gut" the stock valve by disassembling it - not sure that can be done on the Zs though. I'll have a look see... Quote Link to comment Share on other sites More sharing options...
Owen Posted May 22, 2001 Author Share Posted May 22, 2001 Hmm, can't judge from the posts whether I did it wrong or not. I do know there is a brake line "block" on the firewall above the tunnel. And a rear brake line thing on the rear above the differential. Don't know which one is the prop valve now... Well, I'm not gonna pull the engine and trans just to do this unless it is a major safety issue, haven't even started the car yet If it is, I'm gonna run the brake lines through the ****pit... Owen Quote Link to comment Share on other sites More sharing options...
Ruben Posted May 22, 2001 Share Posted May 22, 2001 Pete, I'm sure you're right. My mistake, the manual I have includes the '73 240Z as having it in the rear. Must be up to '72 since mine is in the rear and it's a '72. Ruben Quote Link to comment Share on other sites More sharing options...
Drax240z Posted May 23, 2001 Share Posted May 23, 2001 My 72 & my 73 had them on the firewall. Both cars were made in september of 72, even though one is a 72 and one is a 73. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted May 23, 2001 Share Posted May 23, 2001 Can it be "gutted" or must it be removed? The only one I'm familier with is on an American car, I'm not sure where mine is on the Z - it's a '72. On the American car you could unscrew a nut looking thing to get inside it, removing everything inside allowed you to bypass it altogether. Can that be done? Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 23, 2001 Share Posted May 23, 2001 Mine's a 9/72 "73" also. Yeah, you could gut it, but I had two couplers handy and it was easy to mount them with rubber insulated clamps with the OE bolt for the prop valve. Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 23, 2001 Share Posted May 23, 2001 Heh, the software didn't seem to like that word "kockpit" starting with a "c" On my 73 240Z, the thing on the firewall near the tunnel opening is the prop valve. At the rear of the 73 is a simple T block or splitter, no restriction that I could see. Quote Link to comment Share on other sites More sharing options...
Ruben Posted May 23, 2001 Share Posted May 23, 2001 Owen, You definitely have it wrong. It does not matter where you physically put the APV, however it must be installed in line with the rear brakes. As Jeromio and others mentioned you need full pressure in the fronts and have the rears adjustable. On the street and most racing situations you want the fronts to lock-up first. The proportioning valve on a 240Z is in the rear toward the passenger side above the diff. Ruben '72 240Z Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 23, 2001 Share Posted May 23, 2001 quote: Originally posted by Ruben: The proportioning valve on a 240Z is in the rear toward the passenger side above the diff. Ruben '72 240Z That's not completely true. I have a 73 240Z that has the prop valve on the firewall near the tunnel opening. I believe the earlier 240Z had it near the diff. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted May 23, 2001 Share Posted May 23, 2001 I think your thinking of the distribution block, with the warning light sensor. On my '72 240 it's above the rear end and is made of copper and is about 1" square. There is a plug at the top, unscrew that, and I think there is a spring in there with some sort of plunger thing. Take all that out, and put the plug back in. Quote Link to comment Share on other sites More sharing options...
Owen Posted May 24, 2001 Author Share Posted May 24, 2001 How exactly do you gut it? Haven't looked at it but doesn't the stock valve have both the front and rear lines going into and out of it? If you remove it, what do you do with the front line? Join it with a brass fitting? Thanks, there's more to this than I thought... Owen Quote Link to comment Share on other sites More sharing options...
Owen Posted June 2, 2001 Author Share Posted June 2, 2001 Gotta reply from Wilwood about which brake line to use. Their answer, as usual, was high ambiguous...they told me that if the rear tires are large, then I should put the valve on the front lines. That's it. What the hell is wrong with these people? How large is large? Or are they talking large brakes? I simply don't have the time to call them but I guess I'm gonna have to. Owen Quote Link to comment Share on other sites More sharing options...
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