EvilRufusKay Posted July 18, 2003 Share Posted July 18, 2003 Has anyone ever had a problem with rpm raising when applying brakes? Is it a sign of a leaky booster? I moved the booster hose from the back of the carb port to the front port and the rpm raise was less but still occuring. Any ideas?? Quote Link to comment Share on other sites More sharing options...
Savage42 Posted July 19, 2003 Share Posted July 19, 2003 Has anyone ever had a problem with rpm raising when applying brakes? Is it a sign of a leaky booster? I moved the booster hose from the back of the carb port to the front port and the rpm raise was less but still occuring. Any ideas?? Yep, definitely a vaccuum leak. Many times, the booster will fill up with gas, too. Hope that helps. Quote Link to comment Share on other sites More sharing options...
Datsun660z Posted July 19, 2003 Share Posted July 19, 2003 Agree, sounds like a leak to me. But I just wanted to say I LOVE your avitar Quote Link to comment Share on other sites More sharing options...
timh Posted July 21, 2003 Share Posted July 21, 2003 I put a new (reman.) brake booster on recently and I still get an increase of about 100 rpm when I pump the brakes. Don't know. Might check the back flow valve first. Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted July 21, 2003 Author Share Posted July 21, 2003 I am not sure what a "back flow valve" is... please entertain my ignorance and fill me in. Thanks!! Quote Link to comment Share on other sites More sharing options...
timh Posted July 22, 2003 Share Posted July 22, 2003 Sorry, it's actually called the master vac check valve. On a 280z it's mounted on a bracket on the fire wall just above and right of the master vac and is inline with the vacuum line going from the manifold to the master vac. It should hold a vacuum on one side and flow air through the other. I assume a ZX has something similar. If you have a manual, the tests for the brake booster are easy to do if you have a vacuum gage and can cobble up a t-fitting to fit the vacuum lines. Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted July 22, 2003 Author Share Posted July 22, 2003 My vacum systm / canister has been bypassed. I only have vacum for the booster. Nothing eles on my motor requires vacum besides the vacum advance. Last night I diconnected the booster and plugged the carb ports. It ran much better and the brakes felt the same so I figure it must have a big leak. Do I need to drain the master cylinder to R&R the booster? Or can I sneak it out without that PITA! Quote Link to comment Share on other sites More sharing options...
timh Posted July 22, 2003 Share Posted July 22, 2003 I got my booster off without having to unhook the lines. Just be careful and watch for leaks. I keep soapy water near by. I think the check valve is there to prevent manifold gases from backing into the booster, as well as holding the vacuum. Quote Link to comment Share on other sites More sharing options...
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