Guest scca Posted August 6, 2001 Share Posted August 6, 2001 all zx use a 15/16 master, although the 82-3 are opposite mount and i doubt that those boosters will fit in a early car? best is to use a 75-8 Z booster and a 79-81 master.. IMO...... Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted August 7, 2001 Share Posted August 7, 2001 Mike, would that possibly hold true for my car with the Outlaws? I'm just a little nervous that I've got almost ZERO brake pressure right now with just the front brakes hooked up. I'm not going to panic until after the rears are done but right now I'm a little worried and am trying to plan what I might have to do. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 7, 2001 Share Posted August 7, 2001 Could you expand on that a bit? When you say zero brake pressure, what do you mean? Firm pedal, but no decel? Mushy Pedal, no decel? Quote Link to comment Share on other sites More sharing options...
jeromio Posted August 7, 2001 Author Share Posted August 7, 2001 For some inexplicable reason the breakage of my hood release was followed directly by the death of my vacuum booster. Manual brakes suck, lemme tell you. Odd that when I press the brake pedal, the idle goes up considerably. I guess that is a pretty beefy hose going to the booster - giant vacuum leak. Anyway, since I am replacing the booster, I'm thinking I may as well replace the MC as well. I have 82 280ZX NA calipers up front and 82 turbo calipers in back - should I just get the 280zx unit? IS the turbo or even 2+2 unit appreciably better? Thanks. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted August 7, 2001 Share Posted August 7, 2001 In my case I get really mushy pedal and no apparent pressure to the brakes. My rear lines are non-existant and there's NO fluid in the rear cup of th emaster. I have no doubt this accounts for some of the effects I'm seeing (ahem). The fronts will be bled further today just to make 100% sure there's no air in them. I get a decent amount of fluid through them when bleeding but the pedal goes right to the floor with only a little sensation at the very bottom. Capped up it's not much better, even with the motor running. Prior to swapping out everything the brakes were fine so I expect that switching to larger capacity calipers and having the open rear lines is the cause rather than any bad parts. Quote Link to comment Share on other sites More sharing options...
Mike C Posted August 7, 2001 Share Posted August 7, 2001 If you've worked with the stock Z brakes at all, having properly adjusted rears is paramount to a firm brake pedal. The master cylinder has a floating "plug" between the front and back that activates the brake circuit warning light if one side fails. That's probably where your pressure is going. Get the rear circuit completed and both ends properly bled then you'll know where you are at. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted August 7, 2001 Share Posted August 7, 2001 I have seen a couple of Z's with the 280zx brake booster. They had to be turned upside down to mount properly. I suppose it would have a size advantage, but asthetically, I prefer the smaller ones. You should be able to have the booster that you have rebuilt, unless you are concerned with down time on your Z. Mike Quote Link to comment Share on other sites More sharing options...
RPMS Posted August 7, 2001 Share Posted August 7, 2001 quote: Originally posted by Z-Gad: I have seen a couple of Z's with the 280zx brake booster. They had to be turned upside down to mount properly. Not so! I've got a 1979 280ZX booster and master cylinder, and they bolted right up with NO modifications. That doesn't mean that everything is well, though! My brakes are odd. The first inch of travel of the brake pedal does very little, although there is SOME slowing of the car. Then the next 1/2 inch grabs BIG time! It's almost like using pneumatic brakes, if you've ever had that pleasure. If you're careful, you can modulate smoothly. If you're not careful, you'd better hope that you've got your seatbelts on, because you're about to discover the unhappy limits of adhesion! I'm thinking that this will go away when I install the bigger Toyota calipers up front. Could this two-stage behavior be due to air hiding somewhere in the brake lines? Or do you think it's an issue of adjustment in the rears? Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted August 7, 2001 Share Posted August 7, 2001 Thanks, I feel MCUH better about not having pressure now - whew! I've done NOTHING to the brakes other than swapping in the disks. I figure I'll see how it goes without gutting the valve in the back and whatnot and only make changes as needed. I might have to replace it all mind you but I'll do it one step at a time. Thanks again, that's a load off of my mind and explains why Mike said o put lines on the rear and plug them. I think I'd rather wait for lines though (lol). A shame all of the aftermarket masters I've looked at are single and not double else maybe we could find something other than Nissan to replace this for more volume... Quote Link to comment Share on other sites More sharing options...
Drax240z Posted August 7, 2001 Share Posted August 7, 2001 Scott, if I remember correctly there is a pushrod that is adjustable between your brake pedal and booster. Sounds to me like you need to adjust this to be longer, so that it actuates the booster immediately. DrewZ set up the toyota 4x4 front setup on my car, and I must say it kicks serious ass for pedal feel. Rock hard, you sneeze on the pedal and you'll come to a stop. He said all he did was adjust that pushrod... Quote Link to comment Share on other sites More sharing options...
jeromio Posted August 8, 2001 Author Share Posted August 8, 2001 Okay, so I had to order the booster. I specified a 78 280Z unit. They listed 2 sizes (?) - I chose the smaller - 7.5 inch I believe. I also got an 82 280ZX MasterCylinder. So I tore everything apart tonight and the MC is just wrong. It looks similar, but it's got smaller reservoir fittings and the flange, which only has 2 mount holes, doesn't fit (the top and bottom have no holes and both hit the bolts on the booster). The old flange was a 2 piece thing and it also had "7/8" cast into the side. The new one just has some gibberish numbers/letters. Aargh. The booster is just too big. It looks like the bolts are all the same, but they must've slipped me the big one (ew, that sounded bad) instead of the correct, smaller one. It won't fit between the throttle linkage bracket and the clutch master. Aargh again. So, I'm presuming that this is just the typical chain store screw up - they gave me the wrong parts. Because that combo, 78 booster and 82 MC should work fine, right???? Quote Link to comment Share on other sites More sharing options...
Guest scca Posted August 8, 2001 Share Posted August 8, 2001 the 82 master wont fit a pre 82 booster not the parts store screw up --- YOURS 82-3 use horizontal mounts and pre 81 all the way to 1970 use a vertical one........................ you want a 79-81 master DONT order a later 81 or 82+ master it will not fit. Quote Link to comment Share on other sites More sharing options...
jeromio Posted August 8, 2001 Author Share Posted August 8, 2001 Oh great, and you had that info right there in your other post above - Doh! But the 78 booster should be good, right? So, they did screw that one up.... Quote Link to comment Share on other sites More sharing options...
RPMS Posted August 8, 2001 Share Posted August 8, 2001 quote: Originally posted by Drax240z: Scott, if I remember correctly there is a pushrod that is adjustable between your brake pedal and booster. Sounds to me like you need to adjust this to be longer, so that it actuates the booster immediately. Come to think of it, that sounds like it would produce EXACTLY the symptoms I'm experiencing. Dang, you're a fount of good information today! Quote Link to comment Share on other sites More sharing options...
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