Ed260Z Posted April 7, 2010 Share Posted April 7, 2010 Need some help with this one. I have a 74 260z with a 79 280zx brake master, SS braided flex lines, and 240sx rear disk conversion. I upgraded to the ZX M/C in preparation for larger front calipers, but have not done that yet. Here's my problem; the brake fluid is transferring from the front reservoir (rear brakes) to the rear(front brakes), and causing it to over flow. The rear brakes have been grabbing less, and less over the last 500 or so miles that I've driven it since the retro fit. What could be causing the fluid to transfer? Quote Link to comment Share on other sites More sharing options...
pat1 Posted April 7, 2010 Share Posted April 7, 2010 I would say the master cylinder is junk. The fluid is bypassing the seals in the master cylinder. Quote Link to comment Share on other sites More sharing options...
Ed260Z Posted April 7, 2010 Author Share Posted April 7, 2010 1 more note, during the install the M/C ran dry after I did the bench bleed. I redid the bleed in the car, but is it possible that I did it wrong, and that's what is causing this? Quote Link to comment Share on other sites More sharing options...
pat1 Posted April 7, 2010 Share Posted April 7, 2010 That would not cause the problem your having. You have a internal mafuction of the master cylinder. A seal or oring or a cup is damaged causing the internal leak in the M/C. Quote Link to comment Share on other sites More sharing options...
Ed260Z Posted April 7, 2010 Author Share Posted April 7, 2010 Thanks Pat1. Guess I'll be ordering another one Quote Link to comment Share on other sites More sharing options...
Nigel Posted April 7, 2010 Share Posted April 7, 2010 I see you've done a rear disk conversion. You didn't happen to install an adjustable proportioning valve did you? Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
Ed260Z Posted April 7, 2010 Author Share Posted April 7, 2010 I see you've done a rear disk conversion. You didn't happen to install an adjustable proportioning valve did you? Nigel '73 240ZT No haven't done that. From what I've read the fluid requirement for the 240SX Calipers is very close to the stock drums that were there. But if I ever put in a set of BIG brakes in the rear I will have to do that. Quote Link to comment Share on other sites More sharing options...
Nigel Posted April 7, 2010 Share Posted April 7, 2010 No haven't done that. From what I've read the fluid requirement for the 240SX Calipers is very close to the stock drums that were there. But if I ever put in a set of BIG brakes in the rear I will have to do that. Just checking, because if you follow some people's advice and gut the stock proportioning valve when you install the adjustable valve, you'll end up connecting the front and rear brake circuits together. You have to remove the stock valve entirely on '73 and later Z's. Nigel Quote Link to comment Share on other sites More sharing options...
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