Best vacuum for troubleshooting light system
 

I want to troubleshoot the vacuum system on my 75. Lights don't retract.
What is the best vacuum to buy?

https://shop.advanceautoparts.com/p/...+vacuum+tester

http://www.corvette-101.com/vacuum.htm

The hand vacuum pumps are all you need. Do not use a motorized vacuum pump of the sort used for HVAC as they are FAR too powerful and can damage the rubber diaphragms and other LOW PRESSURE vacuum components!

What about a vacuum cleaner? Lots of flow but less inches of vacuum.

Good luck making a leak-free connection from a vacuum cleaner to the system ;( Beyond that a vacuum cleaner is a high volume low pressure device. The vacuum system in your Corvette is low volume and low pressure. The difference between those systems is huge!

Mighty vac

I have a metal-bodied Mighty Vac, like the one pictured testing a heat riser valve (Amazon Link).

https://cimg6.ibsrv.net/gimg/www.cor...fb83472078.jpg

If your engine is operational, that is the best source for vacuum. The hand pumps and most mechanical pumps don't have the capacity of producing continuous vacuum level needed to diagnose these complete systems. The hand pumps are only good for detecting leakage in one [plugged-off] component at a time.