Weird braking problem

gentb · 04-18-2001, 08:36 AM

91LX Conv AOD 5.0

Brakes are new all around. Sometimes the pedal is hard like I am having a booster/ vacuum problem. You can't hear any leak.
If the booster were going bad would heavy pedal pressure change the idle like it would in a carburated car? If so this is not the problem. I put on a new (rebuilt) master cylinder and it has changed the problem (made it better) but not eliminated it. I still think it is somehow related to vacuum. I had the problem before I changed engines but I am now running an E303 cam. Anybody had any vacuum problems at low idle with this cam? I know I'm rambling but I'm at wits end. Is there a vacumm resevoir (can) on this car somewhere?

91evilstang · 04-18-2001, 05:56 PM

The E303 cam is known for very low vacuum(In my neck of the woods)One of my friends has a kenne bell setup theirfore has a boost/vacuum gauge.According to the gauge he was running about 8 inches of vacuum at idle(not enough to run even a new brake booster.The problem was readly solved by changing cams.He put back in his stock one and the problem was solved.Ihave an F303 in my car and it operates very smoothly and has less idle lope than the E303 It also makes more power.

------------------
speed is money.How fast you want to go?

04-18-2001, 08:36 AM	#1
gentb Registered Member Join Date: Mar 2001 Location: Starr,SC Posts: 16	Weird braking problem 91LX Conv AOD 5.0 Brakes are new all around. Sometimes the pedal is hard like I am having a booster/ vacuum problem. You can't hear any leak. If the booster were going bad would heavy pedal pressure change the idle like it would in a carburated car? If so this is not the problem. I put on a new (rebuilt) master cylinder and it has changed the problem (made it better) but not eliminated it. I still think it is somehow related to vacuum. I had the problem before I changed engines but I am now running an E303 cam. Anybody had any vacuum problems at low idle with this cam? I know I'm rambling but I'm at wits end. Is there a vacumm resevoir (can) on this car somewhere?

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04-18-2001, 05:56 PM	#2
91evilstang Registered Member Join Date: Mar 2001 Location: lafayette IN USA Posts: 48	The E303 cam is known for very low vacuum(In my neck of the woods)One of my friends has a kenne bell setup theirfore has a boost/vacuum gauge.According to the gauge he was running about 8 inches of vacuum at idle(not enough to run even a new brake booster.The problem was readly solved by changing cams.He put back in his stock one and the problem was solved.Ihave an F303 in my car and it operates very smoothly and has less idle lope than the E303 It also makes more power. ------------------ speed is money.How fast you want to go?