How much vacuum leak is acceptable...?

[Calif240]

Hey guys... I've looked for this answer and can't find anything and am betting that everyone has an opinion, so I'm curious... I have a second generation Charger, so my engine drives vacuum for the brake booster, vacuum actuators for the headlights, and vacuum actuators for the A/C system. I just determined that I have a slight leak in my brake booster, and a slightly larger one in the "up" position on my headlights. My booster will hold vacuum on some tests and then others will bleed down from 15" at a rate of about 1" per 10 seconds, so it is not a major leak and intermittent. The headlights are a bit worse but only when "up".

My question is, knowing that any vacuum leak is inducing extra air to the back of my Holley (and lean conditions likely in the rear cylinders and rich up front), is there any vacuum leak that you would consider to be acceptable? Is it a requirement that the entire system hold vacuum at 15" for several minutes? What are your thoughts?

(FYI, all my lines and vacuum canister hold vacuum 100%).

Thanks,
Terry

[303 Mopar]

Any leak with vacuum for power brakes is nothing to mess with, zero in on where the leak is and fix/replace it.   

[Ghoste]

I would like to have zero leakage but with power brakes and the aforementioned headlight actuators I probably don't want to know what the bleed down rate is in my own car at a stop in the night.

[Calif240]

I'm betting very few chargers that have full vacuum systems have zero leakage in all actuator positions and all... That's not to say that it is ok, which is why I'm wondering if there is an acceptable amount... Just thinking... If you had to get new booster and all new actuators and lines for everything, Id bet you're talking $1500. Just to get actuators fixed are $200 each.

[A383Wing]

I'll take that bet with you...and you would loose...none of my cars have vacuum leaks...if they were supposed to leak, they would have made them this way from the factory.....a leak is a leak...get it fixed....also any leak will cause engine to run lean, possible burning the piston or valves

[WhiteOnGreen]

I had a small vacuum leak in the headlight canister and the engine strumble at part throttle, lean condition

[ws23rt]

When I first started my 69 hemi I had a large leak at one of the carbs. It was an unplugged port at the base of one of the carbs.
I drove the car around some before I found the leak and had no problem with my brake booster not working as it should.

So where the leak is has more to do with the brake booster operation (and headlight doors for that matter) than whether there is a leak or not.

And I agree with A383Wing. A leak is not intended in the design and they generally don't heal themselves.