RDuff Posted October 13, 2020 Share Posted October 13, 2020 The general consensus is that if you change from the early master cylinder to a newer on, say from a 72, you need to reroute the hardlines because the front reservoir is moved to the back and vice versa. Today while just looking at things 240z I came across a build picture shows a Wilwood master that has the reservoirs reversed ,but is using the old routing.. The front goes to the front side of the brake light indicator and the back to the back. So my question is it really necessary to change the hardline routes if you go to a newer than early Z master cylinder? Or do only Wilwoods allow this? thanks, duff p.s. I am not really a newbie, my old user somehow got screwed up and unusable so I had to make a new one. Quote Link to comment Share on other sites More sharing options...
jhm Posted October 13, 2020 Share Posted October 13, 2020 Whatever MC you decide to use, you just need to ensure that your front brake lines are routed to the reservoir designated "Front", and the rear lines to the "Rear" reservoir. Up to you to pick the master that best meets all your overall needs for your build. If you switch to anything other than an original MC for your year, be mindful of the fact that the prop valve and electric safety fail switch may not work as intended. That may or may not be important to you. I hope this answers your questions; but if not, post again with more detail on your car and your goals for it. Quote Link to comment Share on other sites More sharing options...
RDuff Posted October 14, 2020 Author Share Posted October 14, 2020 I guess my question should have been why the switch of position on the master cylinder of the front and rear . The brake light indicator simply notes a change in pressure between front and rear. It shouldn’t matter which side of the indicator the lines going into it are, as long as the output side are correspondingly attached. The proportioning vale on the 71 Z is at the back of the Z just before the distribution block for the back brakes so I do not see how it would be affected. The reason for the for this topic this is one of the plugs on this rare master cylinder leaks and since I in stalled a NOS rebuild kit I am hoping to some day to find a replacement plug, in the meantime I would like to drive it without having to reroute the MC lines. Based on the photo I saw it seems you can use a newer MC using the current hardline. Quote Link to comment Share on other sites More sharing options...
Miles Posted October 14, 2020 Share Posted October 14, 2020 The 240z uses a tandem MC. It doesn't make any difference which line goes where. As far as the tanks go, the front circuit has a larger tank. Just switch position of the tanks. Quote Link to comment Share on other sites More sharing options...
jhm Posted October 14, 2020 Share Posted October 14, 2020 (edited) Yep...as long as the MC has constant bore, can swap the reservoirs so the larger tank services the front brakes, as Miles suggested. Couldn't tell from your OP if you were considering swapping in a Wilwood, or some other aftermarket, MC. Sounds like you're trying to maintain things as original as possible, IINM. Similar discussion on ClassicZCar: https://www.classiczcars.com/forums/topic/21826-brake-master-cylinder-240z/ Edited October 14, 2020 by jhm Quote Link to comment Share on other sites More sharing options...
RDuff Posted October 16, 2020 Author Share Posted October 16, 2020 Thanks guys. I have ordered a new master cylinder for a 72 and will reverse the reservoirs. I am still trying to find a replacement for the defective hardline connector for the original MC( see my post in parts wanted). Even though my Z is not completely original I would like to keep it as close as possible. Fifty years ago I bought my first Z. 45 years ago my new wife and I took it on a cross country trip. In1988 I bought my second Z, my current Z. Hoping to make some trips. It was a Scarab conversion. In a month I will be 75, with age my need for speed has lessened. I replaced the 327 ,4 speed with an 83 ZX motor and 5 speed. Installed SUs and did a ground up restore. HybridZ over the years has been a great source and help. So thanks again . Duff Quote Link to comment Share on other sites More sharing options...
Miles Posted October 16, 2020 Share Posted October 16, 2020 Your new MC will have the part you now need. So problem will go away. The threaded part of the "plug" has a standard thread. The part you are asking about is interchangeable for the the 240Z, 260, 280Z and up to the 1979 280ZX. Parts wanted: What you want to buy is an old 240Z, 260Z or 280z MC which will give you two plugs and cones. Quote Link to comment Share on other sites More sharing options...
RDuff Posted October 16, 2020 Author Share Posted October 16, 2020 I have bought and returned master cylinders because they are not interchangeable. My Z was built 2/71. Even though the dimensions of the “nut” are the same( take a 24 mm wrench) my older MC has a larger bore than the newer ones that the plug screws into. Quote Link to comment Share on other sites More sharing options...
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