Guest Mike Posted July 6, 2006 Share Posted July 6, 2006 The brake booster in my 260Z is bad. I found reference to a replacement for a 240Z and am assuming the same will work for a 260. The post I found recommended one for 1981 280ZX because it's a direct bolt-in replacement. Is this correct? Quote Link to comment Share on other sites More sharing options...
Ed260Z Posted July 6, 2006 Share Posted July 6, 2006 Not sure about the 81 ZX booster, but the any 74-78 booster is the correct one to go with. Quote Link to comment Share on other sites More sharing options...
BrianV8Z Posted July 6, 2006 Share Posted July 6, 2006 I have the 80ZX booster on my 280Z. It is larger than the stock 280 booster so I think you would have clearance problems if you have a 4 or 5 speed. Brian Quote Link to comment Share on other sites More sharing options...
zcarnut Posted July 7, 2006 Share Posted July 7, 2006 I have the 80ZX booster on my 280Z. It is larger than the stock 280 booster so I think you would have clearance problems if you have a 4 or 5 speed. No. I use the ZX brake booster on my early 260Z with a five speed manual transmission. No clearance problems with regard to the clutch master cylinder. The ZX boosters do have the same bolt pattern as the ‘74-‘78 Z cars. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 7, 2006 Share Posted July 7, 2006 Not sure about the 81 ZX booster, but the any 74-78 booster is the correct one to go with. Thanks Ed260Z. I'm a bit confused now because I'm getting different info from different sources. I spoke to a mechanic today who said I should just have this one rebuilt... no compatibiliy issues are possible. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 7, 2006 Share Posted July 7, 2006 I have the 80ZX booster on my 280Z. It is larger than the stock 280 booster so I think you would have clearance problems if you have a 4 or 5 speed. Brian I have an automatic tranny so there is plenty of room. It's a bolt pattern, linkage, and angle issue. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 7, 2006 Share Posted July 7, 2006 No. I use the ZX brake booster on my 260Z with a five speed manual transmission. No clearance problems with regard to the clutch master cylinder. The ZX boosters do have the same bolt pattern as the ‘74-‘78 Z cars. The '74 cars are in a transitional phase for SOME PARTS the early 74's were 240Z compatible while the late 74's were 280Z compatible. I don't yet know whether mine is an early or late model. From what I understand, the brake boosters didn't change through '78 and the '81 ZX can be a replacement... but I don't know. I'M SO CONFYOOOOZED. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted July 7, 2006 Share Posted July 7, 2006 No. I use the ZX brake booster on my 260Z with a five speed manual transmission. No clearance problems with regard to the clutch master cylinder. The ZX boosters do have the same bolt pattern as the ‘74-‘78 Z cars. I think he just said he has a ZX booster on his 260. Sounds like it will work fine. Quote Link to comment Share on other sites More sharing options...
Mike C Posted July 7, 2006 Share Posted July 7, 2006 73-78 have the same booster. 72 does not. I put a 73-78 replacement booster in my 72. Had to redrill the firewall for the 4 studs. It works great, but... you have to loosen it and move it around to get the clutch master cylinder out. Quote Link to comment Share on other sites More sharing options...
spotfitz Posted July 7, 2006 Share Posted July 7, 2006 It's been afew years since I replaced the booster in my early '74 but I recall having to flip the zx booster over for it to work because of the offset of the push rod. I recall needing to use the zx vacuum line or having to cut the existing one though, but don't quote me on that. Other then that it was a bolt on afair. I have heard that using the larger zx 2+2 booster causing problems with the clutch master cylinder though. This ofcourse being hearsay I'll have to take some pics this afternoon. It's one of very few things bolted back in the engine bay. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 7, 2006 Share Posted July 7, 2006 73-78 have the same booster. 72 does not. I put a 73-78 replacement booster in my 72. Had to redrill the firewall for the 4 studs. It works great, but... you have to loosen it and move it around to get the clutch master cylinder out. Thanks for the info Mike C. I'll be sure to post my results. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 7, 2006 Share Posted July 7, 2006 It's been afew years since I replaced the booster in my early '74 but I recall having to flip the zx booster over for it to work because of the offset of the push rod. I recall needing to use the zx vacuum line or having to cut the existing one though' date=' but don't quote me on that. Other then that it was a bolt on afair. I have heard that using the larger zx 2+2 booster causing problems with the clutch master cylinder though. This ofcourse being hearsayI'll have to take some pics this afternoon. It's one of very few things bolted back in the engine bay.[/quote'] I'm looking for a simple bolt-in deal. The easier the better. Since I'm running a 700R4, the larger diameter booster is fine. The larger one bolts straight in to any 74... early or late? Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 7, 2006 Share Posted July 7, 2006 I had the larger diameter booster on my 76 with 5spd trans and I hated it. The bigger booster made my brakes hard to modulate. The pedel was very easy to push and the brakes hit very hard. I went back to the smaller booster and love it. However, if you are running a big cam with low manifold vacuum, it could be a good thing. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 7, 2006 Share Posted July 7, 2006 I had the larger diameter booster on my 76 with 5spd trans and I hated it. The bigger booster made my brakes hard to modulate. The pedel was very easy to push and the brakes hit very hard. I went back to the smaller booster and love it. However, if you are running a big cam with low manifold vacuum, it could be a good thing. The cam is a bit lopey, but a stock converter still functions okay. If it had any more lift it wouldn't though. I don't think vacuum will be an issue... at least not with the current cam. That said, I'll be switching to a solid roller cam soon with a bit more duration and this might lower the vaccum enough to affect the power brakes somewhat. I'll be installing the 4 piston calipers and the larger master cylinder too. Does this affect the feasability of using the larger booster given that more brake fluid will be displaced with the larger calipers? Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 7, 2006 Share Posted July 7, 2006 A lopy idle will reduce vacuum at idle which would warrant the use of a bigger diameter brake booster. The more overlap a cam has, the lower the vacuum. Plus the use of a larger diameter brake cylinder will require more pedal force to make enough line pressure. Looks like the larger diameter booster would be a good idea for your set-up. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 8, 2006 Share Posted July 8, 2006 A lopy idle will reduce vacuum at idle which would warrant the use of a bigger diameter brake booster. The more overlap a cam has' date=' the lower the vacuum. Plus the use of a larger diameter brake cylinder will require more pedal force to make enough line pressure. Looks like the larger diameter booster would be a good idea for your set-up.[/quote'] Thanks Pyro!!! Good news... maybe. Now all I need to know now is... Is the 1981 280ZX booster and master cylinder absolutely, definitely, positively, like fer-sher-fer-sher, without any doubts... a direct bolt-on replacement for ANY 260Z (early or late) with an automatic tranny??? Quote Link to comment Share on other sites More sharing options...
zcarnut Posted July 8, 2006 Share Posted July 8, 2006 ...Is the 1981 280ZX booster and master cylinder absolutely' date=' definitely, positively, like fer-sher-fer-sher, without any doubts... a direct bolt-on replacement for ANY 260Z (early or late) with an automatic tranny???[/quote'] As already mentioned, the ZX booster must be installed upside down, but that does not affect it's operation. I used the ZX vacuum hoses and cut them to fit. The ZX booster has a one inch thick aluminum spacer that is not needed. This results in the booster studs (that go through the firewall) being too long so they must be cut to length with a hack saw. The ZX master cylinder works with no mods needed at all. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 9, 2006 Share Posted July 9, 2006 As already mentioned' date=' the ZX booster must be installed upside down, but that does not affect it's operation. I used the ZX vacuum hoses and cut them to fit. The ZX booster has a one inch thick aluminum spacer that is not needed. This results in the booster studs (that go through the firewall) being too long so they must be cut to length with a hack saw. The ZX master cylinder works with no mods needed at all.[/quote'] Thanks zcarnut. I guess I have some studs to cut then, eh? I'll order the booster tomorow:mrgreen: Quote Link to comment Share on other sites More sharing options...
spotfitz Posted July 9, 2006 Share Posted July 9, 2006 Hmmm, I don't recall having to cut studs, as it didn't matter, but Mike... yes flip what ever size zx booster and use what ever size master you can get your hands on(preferable with Toy calipers, 15/16). Without the clutch master in the way all boosters from 70-83 will fit and all masters are interchangable. If you want, PM me. I know I promised pics, but I do have time tomorrow. I'll take what ever pics you need of a zx booster installed in a early '74 and I have a '77 and a '79(2+2) in the driveway for reference pics. I did have a '81(2+2) parts car, but had to give it away.. minus the 20 minute engine/tranny pull, ofcourse. JUST DO IT! Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted July 9, 2006 Share Posted July 9, 2006 Hmmm' date=' I don't recall having to cut studs, as it didn't matter, but Mike... yes flip what ever size zx booster and use what ever size master you can get your hands on(preferable with Toy calipers, 15/16). Without the clutch master in the way all boosters from 70-83 will fit and all masters are interchangable. If you want, PM me. I know I promised pics, but I do have time tomorrow. I'll take what ever pics you need of a zx booster installed in a early '74 and I have a '77 and a '79(2+2) in the driveway for reference pics. I did have a '81(2+2) parts car, but had to give it away.. minus the 20 minute engine/tranny pull, ofcourse. JUST DO IT![/quote'] Thanks for the info and offer of pics, spotfitz. If it's a straightforward install I think I'll be okay. But... just so I'll be better prepared, if you don't mind PM-ing me with a few, that would be great!! Maybe this is a good topic that could be permanently "stickied" with some pics?? If the studs don't need cutting, I won't... I'm lazy. I'm just very happy to have found a solution:-) BTW, what is the thing about dual master cylinders? Is that mainly for race use? Is this a difficult mod? I'll be upgrading the calipers to either the Toyota or the ZX and will probably buy a kit to make this fast and easy. I'm replacing the master cylinder with the larger 15/16 ZX version. Does anyone know which four piston caliper kit is the best deal? To everyone on this forum who responds to my stoopid questions... THANK YOU!!! I owe each of you an ice-cold beer Quote Link to comment Share on other sites More sharing options...
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