[Guest]

I have a major vacuum leak tried all the posted means to find but no luck.... can I block intake manifold where the carb sits and all vacuum takeoffs(power brakes,tranny,ect) then lossen all the push rods so valve all shut, then slowly and carefully feed it air and lissen for a leak if it comes out it must go in!!!! remarks welcome. ::

 

[Stroked66]

That's an interesting idea, but I doubt it's going to help you find the problem if you haven't already.

For instance: Say you do as you are suggesting and the vacuum leak involves the manifold gasket but is located UNDER the manifold. If you pressurize the intake, the air is going to bleed into the crank case and could end up burping through your pan gasket, or some other strange place, which wont help you locate the source of the leak.

Since you're already considering the trouble of removing the carb and other connections, why not remove the intake manifold as well, and replace the gaskets using a good gasket sealer and RTV sealant instead of the cork end gaskets. This way, you'll know it's not in the intake and can focus on external connections. It will also give you an opportunity to inspect the back side of the intake for cracks, which could also be the cause of a vacuum leak.

Good luck!

 

[manley]

Have you tried spraying carb cleaner or WD40 around gasket areas to help locate the leak? What carb are you using? Could it have a warped surface? If you end up pulling the intake, check all the mating surfaces to make sure they aren't warped.

 

[Aronj66]

I don't know how you check for leaks, but I use a small propane torch... Un lit, just spewing gas, run it along every hose seal and joint... When dod the leak start? did you make a change that caused the leak?