vbgambini Posted April 17, 2016 Share Posted April 17, 2016 Wussup guys Im having an issue with my brakes. Ive been searching but cannot seem to find what I am looking for. Sorry if its a little long. Not sure if I posted in the right section. Help needed! I have a 1978 280z. Went to take it out for a little drive around the block just to get it running and making sure everything still works. When I pulled out of the driveway when a few feet and my brakes were almost non existent. The pedal became very hard to push and barely stopping the car even when going 10mph. So I decided after researching that the master cylinder is probably going bad and mostly the brake booster needs to be replaced (Seemed like still original parts) So I ordered a new master cylinder and brake booster from Black Dragon. Disassembled all the old parts. Mostly took out the brake booster, and left the master cylinder for now since it is still full of liquid. Received my parts from black dragon this weekend. Here are my issues. Black Dragon part numbers #64-162-Z brake booster #64-103 Master Cylinder 1. The old nuts that went on the old master to booster, 3 of them fit but the top one. The nut cant even be screwed in. It looks like they sent me a bad part. Threads on the stud looked stripped. And even at an angle. But all other 3 nuts screwed in. 2. The new master I received has only 2 stud holes when the old master had 4 is that normal? So I said what the hell I will try and make it work. Ill just use the two vertical studs. So I just test fitted the new parts together out of the car, the master cylinder had to be wiggled in since the stud wasnt straight, and now when it slid in, theres a gap between the master and the brake booster. I dont recall there being some sort of spacer on the old master. I even tried the new master with the old booster, slid in perfect but still a gap. 3. New brake booster looks significantly larger than OEM, Measured the rectangular indentation that fits in the firewall on the new one and the old one. The new one is larger. Will it even fit in my car? Just frustrated because I wanted to get this done over the weekend and even ordered SS lines from MSA. And wanted to get it back on the road. Please if anyone can help me. Thanks. Quote Link to comment Share on other sites More sharing options...
Pillar Posted April 17, 2016 Share Posted April 17, 2016 (edited) There is supposed to be a spacer that goes between the MC and booster. It is an aluminum spacer with 4 holes (two of witch match up with the MC bolt holes. People often do not realize this spacer is a separate piece from the MC because both are aluminum and they often get 'fused' together a bit after decades of sitting. If you still have your old MC, grab the mount and give it a good turn. Might help to tap it a bit with a hammer to brake up the 38 years of corrosion. You can also rest the center bore of the old MC on a piece of wood (MC standing straight up) and tap downward around the mounting plate with a hammer (not too hard though as you don't want to brake/bend the plate). If you no longer have the old one: These spacers are hard to come by, especially since so many people have returned their core MC with them still attached and they end up who knows where (probably the trash). Nobody that I know sells them, so you will likely need to find someone with a spare, or hit a junkyard and hope for the best. I had the same issue where the previous owner lost the spacer when he gutted the engine bay. Luckily I was able to find one at a local Z yard. The spacer is 10mm thick, so if you can find a 10mm thick piece of metal stock, you may be able to make one, or have a machine shop cut out the mounting holes and center bore. Good luck! Pillar Edited April 17, 2016 by Pillar Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 17, 2016 Author Share Posted April 17, 2016 (edited) Pillar Awesome tip. I still have my old master in the car, maybe I just didnt see it was fused to the MC. I hope it is still there. I dont remember anything falling off when taking it off the booster. It definitely was sitting flush when I was removing it. So I guess I got the right parts. Just have that issue with that partially stripped angled stud. But what about the rectangular indentation that goes into the firewall? The new booster is seemingly larger than the OEM one? One other question since you've helped me out so much so far lol. When bench bleeding the MC, first off is it really a necessity? Or can I just install it and bleed it on the car? If so, when I do it, I see there are 4 ports, 2 bleeder ports, and the ports on the bottom of the MC. Do I have to bleed all 4 ports or can I just through the 2 bleeder valves? thanks man. Edited April 17, 2016 by vbgambini Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 18, 2016 Share Posted April 18, 2016 Most of your questions are answered, with illustrations, in the Brake chapter of the FSM. People do get wrong parts from the reman companies though. Don't forget to adjust the booster rod to fit the MC. Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 18, 2016 Author Share Posted April 18, 2016 (edited) Most of your questions are answered, with illustrations, in the Brake chapter of the FSM. People do get wrong parts from the reman companies though. Don't forget to adjust the booster rod to fit the MC. I looked at the manual and it seems very general on the bleeding area. Just said through the bleeder valves. But that is in the car Im assuming. So I guess I just have to do it through those 2 when bench bleeding. I saw that the rod can be adjusted. Do I just turn it? How do you know when it is properly adjusted though? Edited April 18, 2016 by vbgambini Quote Link to comment Share on other sites More sharing options...
Miles Posted April 18, 2016 Share Posted April 18, 2016 (edited) I looked at the manual and it seems very general on the bleeding area. I saw that the rod can be adjusted. Do I just turn it? How do you know when it is properly adjusted though? answers are in the brake forum and the FSM or Haynes manual for your car. Also, you may want to take the car to a brake shop. Edited April 18, 2016 by Miles Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 18, 2016 Share Posted April 18, 2016 (edited) Factory Service Manual. Not Haynes or Chilton or other. Rod adjustment is in there too. Edit - didn't see Miles's Hai(y)nes comment. I prefer the factory book myself. Edited April 18, 2016 by NewZed Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 18, 2016 Author Share Posted April 18, 2016 (edited) I just looked at the FSM and it says when installing, just air bleed it first. Then when bleeding if spongy pedal to do it through the bleeders. Am I getting this wrong? Edited April 18, 2016 by vbgambini Quote Link to comment Share on other sites More sharing options...
Miles Posted April 18, 2016 Share Posted April 18, 2016 I prefer the FSM also, but the Haynes Datsun 240Z, 260Z, and 280Z Manual does contain some answers to his questions such as how to adjust the MC push rod. There are many many write ups in the brake forum that explain or answer most of his questions. Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 18, 2016 Author Share Posted April 18, 2016 (edited) I found the adjustment on the push rod. Says no more than 10mm it has to protrude im guessing to where it is flat on the opening from the spacer or is it from the bottom of the bore where it comes out of? I get confused looking at these manuals. Just trying to find out what reference point am I measuring from. The flat part of the booster, the complete bottom of the hole, or the flat part of the spacer to the MC. Edited April 18, 2016 by vbgambini Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 18, 2016 Share Posted April 18, 2016 The flat part of the spacer. AKA the mating surface with the MC. Where the spacer and the MC meet, to the tip of the rod. Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 18, 2016 Author Share Posted April 18, 2016 Thanks for the help guys. I hope I still have that MC spacer. Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 18, 2016 Author Share Posted April 18, 2016 Ok. Had a few minutes to check the car again. I still do have the spacer. Like Pilar said it was fused to it but not a problem to break free. Tried to test fit the new booster. Seemed like it'll go right in, just having trouble pushing it through the firewall since the rubber is preventing me from being totally flush. Could I use grease to push it through the firewall hole? Its like a 1/4 of an inch from getting all the way through. Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 18, 2016 Author Share Posted April 18, 2016 (edited) Had a few minutes to check the car again. I still do have the spacer. Like Pilar said it was fused to it but not a problem to break free. Tried to test fit the new booster. Seemed like it'll go right in, just having trouble pushing it through the firewall since the rubber is preventing me from being totally flush. Could I use grease to push it through the firewall hole? Its like a 1/4 of an inch from getting all the way through. Now if I can only get the old nut to just screw in the top stud for the MC I should be golden. Any ideas? It screws in the other 3 just fine. I dont think its worth sending back and waiting for a new one when it only has to turn a few times. Maybe some washers? Edited April 18, 2016 by vbgambini Quote Link to comment Share on other sites More sharing options...
Miles Posted April 18, 2016 Share Posted April 18, 2016 (edited) Ok. Had a few minutes to check the car again. I still do have the spacer. Like Pilar said it was fused to it but not a problem to break free. Tried to test fit the new booster. Seemed like it'll go right in, just having trouble pushing it through the firewall since the rubber is preventing me from being totally flush. Could I use grease to push it through the firewall hole? Its like a 1/4 of an inch from getting all the way through. Post pictures of this problem. Now if I can only get the old nut to just screw in the top stud for the MC I should be golden. Any ideas? It screws in the other 3 just fine. I dont think its worth sending back and waiting for a new one when it only has to turn a few times. Maybe some washers? You can run a die with the correct thread pitch down the stud that you are having trouble starting a nut on. post pictures of the booster and the areas you are having trouble with. Edited April 18, 2016 by Miles Quote Link to comment Share on other sites More sharing options...
Pillar Posted April 18, 2016 Share Posted April 18, 2016 Glad you were able to find the spacer! By rubber, do you mean the cup/boot that goes around the input shaft at the firewall? As Miles stated, you can try running a die down the messed up threads to clean them up. However it may be hard to start the die if it is the very first few threads that are messed up. It then becomes imperative to start right at the right point Otherwise once it seats itself and you get to the good threads, it could potentially cross on them and re-cut them if it isnt just so. Still, worth a shot. Pillar Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 18, 2016 Author Share Posted April 18, 2016 Pillar Yes the rubber boot that goes around the shaft that connects to the brake pedal. It goes in but then like a 1/4 inch it decides to be tough to finally slide all the way through the firewall. Does it just need a little force or could I use some grease to push it in? Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 18, 2016 Share Posted April 18, 2016 A little lubricant like WD-40 and pulling it from the inside will probably do it. Pulling will make it smaller. Pushing makes it spread out. It's supposed to be a tight fit though, it's a seal. Make sure the hole doesn't have old sealant making things difficult also. You can make a crude thread chaser by filing a slot on the inside of a nut. And you can clean up damaged threads with a small file and some patience. Also, if you have extra thread and the damage is at the tip you could just grind the or file the bad portion down. Just make sure the part that does the clamping is in good shape. Quote Link to comment Share on other sites More sharing options...
vbgambini Posted April 19, 2016 Author Share Posted April 19, 2016 NewZed Sounds good man. Maybe I can start screwing it from inside and itll pull it in. ill give that a try the next time I can go work on the car. Thanks a lot for the help guys. Ill get back you guys when I get to it again. Thanks Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 19, 2016 Share Posted April 19, 2016 Be careful that you don't pull it completely off though. Pretty sure it's removable. You could probably remove it, insert it in the hole, then push the booster in to it. Just guessing. Quote Link to comment Share on other sites More sharing options...
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