Power booster checking

Is there a way to check a booster on the bench? I have two off and I don’t want to install on truck and find it’s bad

Run a hose from the check valve to a vacuum source on a running engine. Depress the pushrod that links to the brake pedal. It should go in easily and return fully as well. You'll hear if there is a vacuum leak, and it most likely will not work either.

So no way of checking without hooking up to another engine?

sure a vacuum pump if you have one.
you have to apply vacuum to it to test.

IF I could get a long hose up to DC.. plenty of vacuum up there.

i have pulled a vacuum on more than one booster with a hand held vacuum pump. really doesn't take that long

I have a mighty vac, I’ll give it a try

I have a mighty vac, I’ll give it a try



You'll have arms like Popeye when you are able to pull that much vacuum with one of those.

let us know if it works. it did for me providing the booster doesn't have a large leak. Obviously with a smaller leak it will create a vacuum but not hold it. Do verify your hose connections / adapters are not the source of the leak. I normally pull the check valve from the booster, block it, pull a vacuum and verify that it holds. reinstall and pump away. Depending on the size of the booster and the pump will dictate how many pumps /long it will take

I checked one today, when I put a tapered adapter hose for the MV I found the grommet was cracked in many places. Now I need to find a bigger adapter to fit the metal hole. Should go by HF and get their vac pump.

i have a vacuum pump that i use for ac systems. it works good for a lot of applications, including testing brake boosters.
i have a ball valve on the hose, so when vacuum is applied according to the gauge, i close it.
if it holds, it's good. if not, it's repair time.
i also have a mity-vac and another hand operated vacuum pump. those DO make you get Popeye arms pumping a booster, even the small ones.