Brand new brake booster went out again!!

[SU'dCrazy280]

Well, many of you may have read my last post about my brake booster popping. Well, I purchased a new one from checker auto (a cardone) and put it in, and it worked great for a couple months, and all the sudden, (about 10 minutes ago) I was pulling into my driveway and coming to a stop when I heard a hissing noise when I hit the brakes, then my engine turned off because of an obvious vacuum leak in the booster. I am running an L28 bored .040 over, w/ flat top pistons, medium cam, and a little port and polish w/ the arizonazcar 4 barrel set up. Is my engine making too much vacuum for a stock booster?? The booster has a lifetime replacement so I'm not worried about that, but I just don't want it to keep happening because I have to travel over some pretty crazy mountain passes going back and forth for college. Is there a vacuum psi regulator I can put in-line on the vacuum hose between the intake and booster?? Anything helps, thanks

Mark T.

[kcelectronics]

I doubt that your mods have created a higher vacuum, (bigger cams usually do the reverse) But if you are using the engine to slow down on a steep down hill grade? Especially if you down shift first? This may be the cause of the problem, although the booster should be more than able to Handel this, I think may bee you were just unlucky, and the "New" booster may have been faulty?

[JMortensen]

No reason for downshifting to cause the booster to blow, nor should the engine vacuum cause it. kcelectronics is right that the bigger cam should mean less vacuum. I think you just got a bad booster. I'm going to move this thread to brakes/suspension/chassis where it belongs.

[Pop N Wood]

Another possiblity is some type of backfire causing the booster to overpressure. There is only so much vacuum you can pull, thus only so much damage that could possibly be done through "too much vacuum".

 

Do you still have the one way check valve in line to the booster? Maybe that needs to be replaced.

[Miles]

Mark

 

I bought two cardone boosters. Before I put them on the car I checked if there was a reaction disk. There was no reation disk in either booster. I am going to install original factory boosters on both of my 240s.

 

Miles

[SU'dCrazy280]

Well, I hope that it was just a bad booster, and I can't afford to get a factory one, so the replacement will be another cardone. But, could I put a psi regulator b/tw the intake and the booster just in case?? Or would this be a bad idea, cause I don't know if there is any other things that could be causing this, all I know is that it was a pretty distinctive hissing noise when she blew. I know that the booster only needs a small amount of vacuum to function, so any feed back would be great!! I need to get my Z back onto the road!!

[kcelectronics]

But, could I put a psi regulator b/tw the intake and the booster just in case?? Or would this be a bad idea, I know that the booster only needs a small amount of vacuum to function,

This is one area you don't want to mess with! There are millions of cars out there, and none of them have any sort of Vacuum "limiting" device, so you DON'T NEED ONE. And the more vacuum the better, I have a ford with a 351 and BIG cam and I need a Vacuum reservoir, just so my brakes will work continuously, the engine doesn't produce enough Vacuum at Idle (about 11" ) to provide enough boost for the brakes (It will stop but I need to really stand on the peddle), It really needs the engine to be used as a brake, so it will produce the higher vacuum needed (just lifting off the throttle while cruising is enough to raise the Vacuum. Level).