240zBoy Posted February 8, 2012 Share Posted February 8, 2012 (edited) I recently did the larger toyota brake swap from MSA to my newly JTR swapped 1972 240z and inspected one of the rear brake drums so maybe I did something. I bought the car unrunning though so I do not know if this normally happens. But when I let off the accelerator the car slows down way to fast and I really am not even able to coast. I have to slowly release pedal while decelerating to keep from lurching forward in my seat. I do need an allignment so that may be part of it and I didn't replace my rotors while doing the front brake swap so those both could be factors. Anybody had this issue or know what it could be? Edited February 8, 2012 by 240zBoy Quote Link to comment Share on other sites More sharing options...
rossman Posted February 8, 2012 Share Posted February 8, 2012 It's not normal. You probably have a stuck rear brake cylinder. If the rear drums are smoking hot after you drive a bit then you found the problem. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 8, 2012 Share Posted February 8, 2012 If you have a pyrometer you could take temps off of the brakes after driving and see if one is hot. Might be able to jack the car up and turn the wheels by hand and see if you can feel which one is stuck. Quote Link to comment Share on other sites More sharing options...
240zBoy Posted February 8, 2012 Author Share Posted February 8, 2012 I did have to replace one of the rear wheel cylinder because the bleeder valve snapped so maybe something is wrong in there. That won't be fun I hated being inside of that drum haha. But I will try that pyrometer and rotating the wheels before I go in there again. Maybe I just spoil myself and put disks all around Quote Link to comment Share on other sites More sharing options...
Miles Posted February 9, 2012 Share Posted February 9, 2012 (edited) Could be that the master cylinder (MC) push rod that goes between the booster and the MC is adjusted too far out. The factory setting per Haynes, is 0.138 in - 0.157in (3.5mm - 4.0mm) between the face of the mounting flange and the tip of the push rod. You do not have to remove the MC to make this adjustment. Just remove the MC mounting nuts and pull it forward to access the pushrod (7mm). Be carefull not to drop the reaction disk (small rubber disk between the booster and the push rod) inside the booster (see brake section for info on the reaction disk). If the pushrod is adjusted too far out, the MC piston can't return far enough to open the fluid return port in the MC and pressure will build up locking your brakes. First thing you should do before making the push rod adjustment is to relieve pressure in the brake system by opening the MC bleed screws (10mm). If the fluid is under pressure (indicating push rod is adjusted too long) fluid will spurt out when the bleeder is opened. This step will relieve the pressure and free up the brakes if the push rod is adjusted too long. Is your E-brake dragging? Did you adjust the rear shoes to tight? Edited February 9, 2012 by Miles Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 9, 2012 Share Posted February 9, 2012 What does it do if you shift in to neutral or hold the clutch pedal down? That will take engine-braking out of the picture. Quote Link to comment Share on other sites More sharing options...
240zBoy Posted February 9, 2012 Author Share Posted February 9, 2012 (edited) If I push the clutch in the car seems to not have the issue. Is there a way to fix this engine braking, it is a fresh rebuild so I do not want to be hurting it but I have heard multiple opinions on it being bad or good. Edited February 9, 2012 by 240zBoy Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 9, 2012 Share Posted February 9, 2012 Engine braking is totally normal. Quote Link to comment Share on other sites More sharing options...
240zBoy Posted February 9, 2012 Author Share Posted February 9, 2012 Alright good to know, now to get that allignment and finally enjoy the car. Thanks Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted February 9, 2012 Share Posted February 9, 2012 Disengage the clutch when you let off the throttle. Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted February 9, 2012 Share Posted February 9, 2012 Generally the higher your compression, the more engine braking. If is so severe that it begins to lock up the rear tires, learn to heel & toe downshift. It is a good skill regardless. Quote Link to comment Share on other sites More sharing options...
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