PETEW Posted June 21, 2009 Share Posted June 21, 2009 Hey guys, I am trying to diagnose a brake problem I am having. I have noticed with the 240 that the brakes have always felt wooden. I always thought it was because of the pads, or just old brakes. But after doing more analysis I think it something more than that. I have the vented toyota brakes up front and 280zx brakes in the back. I have a proportioning valve and all new fluid. I have been finding that my RPM's go up when I am sitting at a light, and my foot is on the brake. I thought the valve going to the intake was going bad and did some tests. It is working fine. I also checked for leaks in the hoses and can't find any. I am assuming that this must mean that the booster is going bad. I have also found that there is not a big difference when the valve was hooked up one way or the other. Again, to me this means the booster is not working, and I basically have no power brakes. Am I correct in my analysis, or could there be something else I am not thinking of. I just don't want to spend $120 for nothing. Thanks. Quote Link to comment Share on other sites More sharing options...
PETEW Posted June 22, 2009 Author Share Posted June 22, 2009 I remembered that the 280Z and the late 240Z booster should be the same so I used the one from my project 280. I pulled that one out cleaned it up put some semi gloss black on it (gotta make it look nice) and bolted it up a few hours latter. No more RPM rise. I will have to see if the bakes feel a little less wooden tomorrow. Tonight I am redoing the drivers seat so it is a little lower so I can get a helmet on to autocross this thing. Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted June 22, 2009 Share Posted June 22, 2009 Be sure you have the vacuum hose check valve in correctly. My brakes were also very hard for power assist. I found that the PO had installed that valve backwards. Once corrected it would lock the wheels up with relative ease. I also used a 280Z booster in my 71 240Z but it did require drilling a new mounting hole pattern in the firewall. Quote Link to comment Share on other sites More sharing options...
PETEW Posted June 22, 2009 Author Share Posted June 22, 2009 ezzzzzzzz, That is what I thought. I switched the valves both ways and no real improvement. The one way was a little better and made the RPM's rise when on the brake. I have since switched my booster and proud to announce that the brakes are now AWESOME. I don't know if Mike ever had properly working brakes, but these things are incredible now. I know I never had either Z work this well, so I am very happy. It only cost me some time, so that is the best part. Quote Link to comment Share on other sites More sharing options...
3ryce Posted September 10, 2014 Share Posted September 10, 2014 wait so petew did you have to redrill like ezzzzzz had to? Quote Link to comment Share on other sites More sharing options...
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