oinojo Posted November 21, 2006 Share Posted November 21, 2006 Hey guys, ive been having this problem since i installed my N42 head (schneider stage 4 cam). When ever i would brake, my pedal would sometimes be very stiff and very hard to stop. I have 88' toyota 4x4's up front with the stock drums in the back. This setup has worked wonderfully up until this point. I have been searching some old treads and have come up on a possibility that my master cylinder maybe failing. Any suggestions would be helpful, thank you. - Jon Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted November 21, 2006 Share Posted November 21, 2006 yeah, i'd check the master cylinder and maybe swap it out for the zx BMC while you are at it. Also, I've heard that upgrading camshafts have to pull vacumm from somewhere and usually the 1st thing they pull it from is the BMC, but someone correct me if I'm wrong. Hopefully you get this fixed soon so you can bring the Z to the next meet! Good luck! Thanks for coming out regardless though. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted November 21, 2006 Share Posted November 21, 2006 It sounds like since the swap you are not getting any vacuum assist for your brakes. I have a similar cam to you in my N42 head, along with triple webers, and have no issues with enough vacuum for my brakes. I'd start looking at the hose that connects the brake booster to the intake manifold. Do you have any leaks? (If you did, I think you'd notice other issues with idle speed and driveability.) What about if you downshift so you're above say 2500 rpm while approaching a stop? Does that give you some brake assist? If so, then perhaps the check valve in the hose has failed. I'd start there before I swapped the MC. Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted November 21, 2006 Share Posted November 21, 2006 I have to agree w/ zmanco. Oh, and don't use a zx master with drums. Quote Link to comment Share on other sites More sharing options...
naviathan Posted November 21, 2006 Share Posted November 21, 2006 Sounds like a failing brake booster, not master cylinder. If the master cylinder were failing the pedal would be soft and difficult to stop. The booster helps make the pedal manageable. Check the vacuum lines as was stated by others. If that doesn't present an issue then pull the booster and check it out. Quote Link to comment Share on other sites More sharing options...
Oldestzguy Posted November 21, 2006 Share Posted November 21, 2006 If you have a radical cam, you might want to get a vacuum can and a few fittings (they look nice) at your local speed shop to "store" vacuum in for the power assisted brakes. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted November 21, 2006 Share Posted November 21, 2006 If the cam is the problem you may need to add an electric vacuum pump in addition to the vacuum can... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 21, 2006 Share Posted November 21, 2006 I don't think it's the cam. That "stage 4" is not that radical, it should be a Stage 2 in my opinion. I've got basically the same thing and haven't needed any auxiliary source of vacuum, and Zmanco said the same. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted November 21, 2006 Share Posted November 21, 2006 If the booster was weak or if you had a slight vacuum leak before the cam change, that small drop in vacuum could make a difference. Other factors come into play too, don't they? Size of carbs and compression perhaps? I don't really know... just throwing this out there. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 21, 2006 Share Posted November 21, 2006 Compression would, I suppose size of carbs would too. I had 8.5:1 compression with triple 44s and a similar cam and I didn't have trouble. It's possible for the cam to cause those kinds of problems, but I'd say that is probably not it in this case. Quote Link to comment Share on other sites More sharing options...
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