KlassicMotion Posted June 17, 2013 Report Share Posted June 17, 2013 I'm finally gearing up to lower my car.... I've got a set of 1982 280zx struts and brakes. I know the master cylinder I need is the 15/16" bore from a 1979-1981 280zx. My question is the brake line size. Did the 280zx use a different size hard brake line and soft brake line? Or more simply put; Do I need to swap my brake lines too? Quote Link to comment
hobbes_the_cat Posted June 17, 2013 Report Share Posted June 17, 2013 I am not sure if the lines diameter is the same or not (I think it is), but I used my stock 510 lines and everything is working fine. Quote Link to comment
Tristin Posted June 17, 2013 Report Share Posted June 17, 2013 I didnt notice a size difference when I did the swap, but I only eyeballed it. I just used the swap as an opportunity to switch the old cracking rubber lines to stainless. Quote Link to comment
KlassicMotion Posted June 17, 2013 Author Report Share Posted June 17, 2013 I didnt notice a size difference when I did the swap, but I only eyeballed it. I just used the swap as an opportunity to switch the old cracking rubber lines to stainless. Where did you get your stainless lines? Honestly, my car had been sitting for 12 years. I put a new master cylinder on and bled the brakes, and so for so good. I'm quite amazed there aren't any leaky seals yet. But the 280zx system I have, was good when I removed them, so hopefully I will have the same luck. Thanks guys Quote Link to comment
Tristin Posted June 17, 2013 Report Share Posted June 17, 2013 Had them made up at a local hose place. Just brought in my old line and they matched it up in stainless. Easy peasy mac and cheesy. Edit: Received your package today. Thanks again! Install tonight and test lights. I appreciate it :) Quote Link to comment
KlassicMotion Posted June 17, 2013 Author Report Share Posted June 17, 2013 Good deal. I hope it works for you. Quote Link to comment
Tristin Posted June 17, 2013 Report Share Posted June 17, 2013 Yeah lines were pretty cheap and they made them while I waiting. Quote Link to comment
datzenmike Posted June 17, 2013 Report Share Posted June 17, 2013 I just used 2001 Maxima rear disc flex lines on my '74 710 front struts. Same threads. Quote Link to comment
john510 Posted June 17, 2013 Report Share Posted June 17, 2013 Stock lines work,i think you want a 7/8 master cylinder ? someone correct me if im wrong. Quote Link to comment
datzenmike Posted June 17, 2013 Report Share Posted June 17, 2013 If running the monster zx calipers you really need the 15/16" master to move more fluid. The 7/8 will work and will produce more pressure with less effort than a 15/16" but the pedal will have to travel further to do this and may feel 'mushy'. If you do, get a vacuum booster to go with it. I have '84 Maxima goon struts and brakes on the front of my 710 and I used the Maxima 15/16" master also. The braking is superb. Quote Link to comment
KlassicMotion Posted June 18, 2013 Author Report Share Posted June 18, 2013 It looks like the Maxima 15/16 master is the same part number as the 79-81 280zx. Quote Link to comment
hobbes_the_cat Posted June 18, 2013 Report Share Posted June 18, 2013 I think the master cyl. size you need depends on if you are using rear discs or not. I used a 7/8 in my car with zx front brakes and stock rear drums and the pedal feel is perfect IMO. The 7/8 master was used in 280z's with drums in the back. If you are upgrading the rear to disc it would be appropriate to use the 15/16" master from the zx as the was a disc/disc car. I have heard of guys using a 15/16" master on a drum rear car and experiencing too hard of a pedal feel, like a brick. That is just what I have heard tho, once I tried the 7/8" in my car I was happy with it, so I never tried a 15/16". 1 Quote Link to comment
KlassicMotion Posted June 18, 2013 Author Report Share Posted June 18, 2013 Good info. I actually never thought of running stock drums on the rear. That would make the parking brake issue easier. How well does it brake? Does it nose dive? I just realized, with disc/disc, I will need to swap the proportioning valve too. These "easy" swaps always turn into bigger projects! No, it's not a big deal, but it's truning into a full weekend's worth of work. Quote Link to comment
Tristin Posted June 18, 2013 Report Share Posted June 18, 2013 My disc/drum setup brakes great... I would for sure upgrade to a 7/8th MC though. Ive got quite the soft pedal. I just havent gotten around to the swap yet. Functions great though. Quote Link to comment
hobbes_the_cat Posted June 18, 2013 Report Share Posted June 18, 2013 Braking feels fine to me, obvious improvement over stock. It doesn't nose dive excessively, and doesn't get loose on hard braking. All the guys who raced these back in the day ran stock drums in the rear... Quote Link to comment
Laecaon Posted June 18, 2013 Report Share Posted June 18, 2013 If your stock MC is working fine (3/4") there is no need to swap, it pushed plenty of fluid, would lock up the brakes just fine way before I bottomed it out, felt great with good feedback. I now have a 7/8th MC and it was the worst decision. Pedal is way too stiff and feels numb, I couldnt imagine a 15/16th. The 7/8ths made it the stiffest pedal on my car, stiffer than the Clutch. What I would suggest, is the 13/16th out of the '79 620. No I am not complaining about how stiff it is, Im talking about the need to swap, and I would advise against it. Most talk about a squishy pedal, My guess is they need to do a full fluid flush, its amazing what that will do. Quote Link to comment
Tristin Posted June 18, 2013 Report Share Posted June 18, 2013 If your stock MC is working fine (3/4") there is no need to swap, it pushed plenty of fluid, would lock up the brakes just fine way before I bottomed it out, felt great with good feedback. I now have a 7/8th MC and it was the worst decision. Pedal is way too stiff and feels numb, I couldnt imagine a 15/16th. The 7/8ths made it the stiffest pedal on my car, stiffer than the Clutch. What I would suggest, is the 13/16th out of the '79 620. No I am not complaining about how stiff it is, Im talking about the need to swap, and I would advise against it. Most talk about a squishy pedal, My guess is they need to do a full fluid flush, its amazing what that will do. Youre the first person Ive ever seen complain about it being too stiff. Interesting. I know for me, when I switched to ZXs I did a full fluid flush, replaced the lines with stainless, and installed new pads. My brake pedal pressure is pretty soft. Ive never bottomed the pedal out before stopping, it works great... just way too soft. Quote Link to comment
Laecaon Posted June 18, 2013 Report Share Posted June 18, 2013 My pedal never moves more than 1/8th travel for normal driving, and a quartet for full lock up. Quote Link to comment
KlassicMotion Posted June 18, 2013 Author Report Share Posted June 18, 2013 I've got a new 3/4 on the stock brakes now. I did a fluid flush, no leaks, and it's a squishy pedal!? I didn't go any further than that because I new a swap was emminate. How about the proportioning valve? No one has mentioned they swapped that out. I had assumed the bigger discs, even if just up front, would need a diiferent proportioning valve. I did a drum to disc swap on an Bugeye Sprite once. That swap required a different MC and larger brake lines. That is why I asked about brake line swap. I had to be carefull when ordering wheel cylinders for my early Minis, because there aredifferent sizes between the years. The symptons of squishy pedal, stiff pedal, all sound like something isn't setup correctly. Wether it be pedal travel, or hydraulic volume and or pressure issues. Unless someone can tell me with certainty that there is no difference in the systems, (me, not having knowledge with hydraulic dynamics) I think the best route would be to put eveything 280zx on. From the MC, to line size, to proportioning valve, to front and rear brakes. I don't know how to figure out the differences in proportioning valves, maybe someone else does? I still have the lines from my 280zx, they're just in storage 3500 miles away.... I suppose if the stock 510 lines screw into the proportioning valve and MC, then they should be the same size.... Quote Link to comment
KlassicMotion Posted June 18, 2013 Author Report Share Posted June 18, 2013 My pedal never moves more than 1/8th travel for normal driving, and a quartet for full lock up. Sounds about right. But with non power brakes, your pedal should be firm. The difference would be with the firm pedal, whether or not it stops with reasonable application of pressure, or it if you have to really stand on it to get them to stop. Quote Link to comment
Laecaon Posted June 18, 2013 Report Share Posted June 18, 2013 I know zx soft lines screw into ZX hard lines. wait, unless you have rear disc, you don't want the zx MC... Quote Link to comment
Tristin Posted June 18, 2013 Report Share Posted June 18, 2013 Ive only seen people upgrade proportioning valves when going full discs. Quote Link to comment
KlassicMotion Posted June 18, 2013 Author Report Share Posted June 18, 2013 Yeah, that's what I was trying to say. Full 280zx disc swap front and rear, with PV and MC. I have to wonder if larger front calipers would require different PV. Quote Link to comment
KlassicMotion Posted June 18, 2013 Author Report Share Posted June 18, 2013 I know zx soft lines screw into ZX hard lines. wait, unless you have rear disc, you don't want the zx MC... Did you mean to put 510 somewhere in there? And why wouldn't you want the zx MC with zx rear disc? Was there a 510 rear disc option? Quote Link to comment
Laecaon Posted June 18, 2013 Report Share Posted June 18, 2013 Yes... "510 hardline" I hate typing on my phone. Quote Link to comment
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