Big Kahuna Posted February 26, 2004 Share Posted February 26, 2004 I have finally found the time to get my 240z back on the road. One dilema though. Yes, I search the archieves! I did new lines, toyota and 240sx calipers, and difffential valve. Everything appears to be right on the money except the master cylinder. I'm am not sure if I got the booster rod adjustment right. the manual does a poor job of explaining this. Can someone enlighten me. The m/c was used, is there way of determining if it is bad? or maybe the booster? Is the booster different on the zx vs z? I bench bled the MC prior to install, bled it again in the car, No air. Bled the calipers, No air. Yet pedel preasure is still weak. I am ready to give up and send it to a brake shop! Quote Link to comment Share on other sites More sharing options...
Tim240z Posted February 26, 2004 Share Posted February 26, 2004 Is the MC new? Are you getting good fluid pressure to the calipers when you bleed them? Quote Link to comment Share on other sites More sharing options...
Big Kahuna Posted February 26, 2004 Author Share Posted February 26, 2004 getting good fluid to the calipers. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted February 26, 2004 Share Posted February 26, 2004 The booster assists the driver in providing pressure to the calipers. A "weak" pedal to me describes lack of any real back pressure or feedback. If this is correct then the booster could be working fine (providing the assistance) but you would be having a problem with the fluid side of the system (perhaps the MC). If the booster was bad, and all other parts were working correctly, then the pedal pressure would be higher than "normal" for the same stopping power, which, in a way can feel like brake fade. One other thing to check if you've got all new (or rebuilt) parts is to make sure the in-line vacuum valve is looking in the correct direction. This one-way valve prevents air from going toward the booster, but allows air to pass from the booster to the engine (thus providing the vacuum necessary to operate). If it is reversed, it would prevent the evacuation of air from the booster diaphram. Quote Link to comment Share on other sites More sharing options...
Big Kahuna Posted February 26, 2004 Author Share Posted February 26, 2004 I think I have narrowed it down to the Master. I am going to go get another one, this time rebuilt. What is the apropriate way to adjust the booster push rod into the Master Cylinder? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 26, 2004 Share Posted February 26, 2004 You should have a little free play between the two. I think I set mine at about 1/8" free play. Also when I did mine a buddy and I made a new pushrod out of a bolt, because the stock rod was too short. We cut the bolt to the right length and ground the head off and made it smooth and round, and stuck a little grease in there so that it didn't wear the cup out. Jon Quote Link to comment Share on other sites More sharing options...
Guest Looking for apt in Alb Ny Posted February 27, 2004 Share Posted February 27, 2004 40 bucks rebuilt isnt bad to begin with. im doing this swap as well and I didnt play with the pushrod . Ill find out if i goofed anyhting up. Quote Link to comment Share on other sites More sharing options...
Big Kahuna Posted February 28, 2004 Author Share Posted February 28, 2004 Got the brakes working again. Had to go back with the original master. Not sure why but my booster would not work with the 15/16 280zx MC. Tried every thing including the bolt trick to lengthen pushrod. The booster pushrod was too short. Maybe I missed something but I could not get full travel in the master. I went to the manual as well as victoria british catalog and found that apparently there is a difference in boosters on early Z's(mine is a 71). If that differance effects this swap, Not sure! But after a weeks worth of trial and error, I'm guessing so. I have not given up though, after the turbo swap, I'm going to try again with a different booster. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 28, 2004 Share Posted February 28, 2004 Mine works with the early booster. Maybe you didn't make the rod long enough??? Jon Quote Link to comment Share on other sites More sharing options...
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