ezzzzzzz Posted September 23, 2006 Share Posted September 23, 2006 I'm having problems my rear disc brakes not working well so I'm in the process of replacing the possibly faulty MC and modded the NP-valve to fully separate the front and rear brakes into individual systems. (http://forums.hybridz.org/showthread.php?t=114918). I thought I'd try to install the larger S30 booster for less pedal effort at the same time since the brakes were much firmer than with the stock disc/drum setup. Several posts said it couldn't be done but it appeared no one had actually tried and failed. Since I had a spare 8.5" booster I thought I'd give it a go. First, the retaining bolts are spaced approximately 1" further apart on the horizonal but the vertical spread is identical at 2.75". It's really in metric but I used a basic tape measure. I did an eyeball alignment to mark the wider spaced holes to either side of the existing holes in the firewall. I then looked under the dash to ensure there was room for the nuts/washers for the new pattern. Next came the drilling. I drilled the holes in steps and then did a little bit of filing with a small round file to get slip fit of the booster. Oh yeah, I also had to slightly bend the brake and clutch lines to clear the booster. An application of sticky weatherstrip goop will seal the new booster from water leaks. The lip of the booster was lighty tapped in near the clutch MC but it may have cleared anyhow. There was ample room at the throttle bracket. I only wish I'd made a template for the holes to guide me. Damn my lack of patience! The attached photos tell the whole story. Quote Link to comment Share on other sites More sharing options...
Miles Posted September 23, 2006 Share Posted September 23, 2006 Will it make any difference in pedal feel? I am planning do the same thing. Miles Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted September 24, 2006 Author Share Posted September 24, 2006 It should improve the pedal feel making it feel more like a 280ZX with the front and rear brake upgrade in the 240Z. I'm thinking the overall diaphram area is nearly doubled which equates to a lot more assistance for the 3/4" stock MC and a stock feel with the 15/16" MC. Presently, the 15/16" is heavy and requires a lot of foot pressure using the smaller 240Z booster. Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted September 24, 2006 Author Share Posted September 24, 2006 I installed the bigger booster and a rebuilt MC this morning. My 10 y.o. girl helped me bleed the brakes (that's cool!). The brakes were upgraded to the 280ZX front calipers/300ZX vented rotors and 240SX rear calipers/300ZX non-vented rotors. The 280ZX NP-valve was modded to completely separate the front and rear systems. I took it for a spin and the brake performance is fantastic. It will come to a halt very fast. The pedal is still firm but not like before. My girlfriend could brake it without too much complaint. I'm pleased with the outcome. I'll have to drive it more to determine if a variable proportioning valve will be needed but I'm doubting it right now. Quote Link to comment Share on other sites More sharing options...
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