Best way to test a c3 vacuum reservoir tank

[Robert B.]

Is there a best way to test a 1972 BB vacuum tank reservoir for leaks? I am trying to eliminate the vac tank in my earch for a vac leak.

Thanks,

Rob

[Joe L.]

Re: Best way to test a c3 vacuum reservoir tank

Is there a best way to test a 1972 BB vacuum tank reservoir for leaks? I am trying to eliminate the vac tank in my earch for a vac leak.

Thanks,

Rob

Rob-----


Very, very easy. Remove all of the vacuum lines from the tank. TIGHTLY cap off one leaving two uncapped. Attach a vacuum gauge to one fittings. Apply vacuum to the other fitting with a Mityvac and tightly pinch off the line from the Mityvac to the tank when you've reached maximum vacuum. Then, observe if the tank will hold vacuum for a reasonable period of time.

You can also use just the Mityvac with it's attached vacuum gauge, but I have found the above procedure to work best.

[Robert B.]

Re: Best way to test a c3 vacuum reservoir tank

Joe,

I don't have a separate gauge. I have a mighty vac with a gauge. If I am understanding I can cap off two ports and pump vacuum to see if it holds? Is 10HG vacuum good? Thanks.

Rob

[Joe L.]

Re: Best way to test a c3 vacuum reservoir tank

Joe,

I don't have a separate gauge. I have a mighty vac with a gauge. If I am understanding I can cap off two ports and pump vacuum to see if it holds? Is 10HG vacuum good? Thanks.

Rob

Rob-----

I'd pump it down to 15-20" Hg. However, if it will pump down to and hold 10" Hg, that should be ok.

[Robert B.]

Re: Best way to test a c3 vacuum reservoir tank

Joe,

I pumped it to 10"HG overnight and it held. I used the center inlet and plugged the two outside holes. So I guess my tank is ok. Off to the relays and actuaters. Thanks for your help.

Rob

P.S. If I have a bad check valve off my intake vac line, could this cause an idle issue?

[Lawrence M.]

Re: Best way to test a c3 vacuum reservoir tank

Robert, I don't know if the check valve can cause an issue with idle. However, on my 1969 I had an idle issue and after confirming the headlight and wiper vaccum systems were ok the leak was tracked down to the power brake booster.

Larry

[Dave S.]

Re: Best way to test a c3 vacuum reservoir tank

Is there a best way to test a 1972 BB vacuum tank reservoir for leaks? I am trying to eliminate the vac tank in my earch for a vac leak.

Thanks,

Rob

Rob,

There is a troubleshooting Guide available for these systems.

[Jay G.]

Re: Best way to test a c3 vacuum reservoir tank

...If I have a bad check valve off my intake vac line, could this cause an idle issue?

Robert,

The check valve is only in the system to retain vacuum once the car has been shut off. There are many reasons why you would have an idle quality issue but if it is related to the vacuum system, it would be a leak in the system not the check valve.

Regards,

Jay

[Don W.]

Re: Best way to test a c3 vacuum reservoir tank

Here's the trouble shooting guide; I used it and found 3 items that needed to be replaced....Don

http://www.docrebuild.com/dr-r-web/A-TROUBLE.HTML

[Robert B.]

Re: Best way to test a c3 vacuum reservoir tank

Thanks - I will continue my vac leak search.

[Edward J.]

Re: Best way to test a c3 vacuum reservoir tank

Bob, Vaccum Leaks Are Not Always The Problem, But The First Thing To Check, I Would Take The Air Cleaner Off And Hold Hand Over Top Carb. Leaving A Small Gap Between Fingers If Idle Smooths Out, You Got A Lean Condition ,vaccum Leak Or Fuel Problem .start With Blocking Of One Hose At Time To Eliminate The Problem Of A Hose Leak. Disconnect Each Hose At The Soruce,all Hoses Are At The Intake Rear Or Carburator Base. A Piece Of Electrical Tape Will Work ,unless You A Diff. Size Plugs To Block Off. The Carb Base Gasket Is One Other Source Along With A Intake Manifold Gasket.carb Cleaner Woud Be Helpful Spary A Light Mist At Base Area Of Carb. And If Okay Spary The Intake Manifold At Base,idle Will Smooth Out When You Find Source. Be Careful Not To Go Crazy With Cleaner Its Flamable.

[Robert B.]

Re: Best way to test a c3 vacuum reservoir tank

Thanks - good thoughts. I am planning to try this on the weekend.

Rob