I have this pump on a Moroso vacuum pump, alternator bracket that initially didn't pull any vacuum, then started drawing vacuum after a few minutes. Then I go out a couple of days later and it doesn't want to pull vacuum again. I'm hoping one of you has a miracle quick fix. I looked at a YouTube video showing how to pull it apart but this one isn't budging. Any help appreciated.

Sounds like a stuck vain. I'd spray some brake cleaner in the inlet with it running.

Thanks, I'll try it.

Yeah like Denis said sounds like a stuck vane in the pump. You can try some brake clean in the inlet like he said but best bet is to take the pump apart and clean all the vanes and everything else. I do that about every other season and afterwards I can spin the pump by hand and can hear the vanes fling out, and it pulls vacuum right away on the engine.

Has anybody ever tried flushing one out with hot soapy water without disassembling it? Just curious.

flush with marvel mystery oil or brake clean, noneed to take apart unless concerned about veins.they can be somewhat inspected through ports

I had a weird problem one time with my pump. It's a Star but I don't think brand matters. Same issues as the op. I did pull it apart and found that the veins were sticking. It had some kind of black substance on the whole inside and brake clean, carb cleaner, naptha wouldn't even touch it. Believe it or not WD-40 took it right off. Only thing I could come up with was a reaction between the alcohol, water and Amsoil oil that I was running but I really have no for sure idea. I quit running Amsoil and never had that problem again. I have wanted to try the oil again just to rule out that it was the problem.

I had an old Mr. Gasket vacuum pump many years ago the I had to lightly sand the sides of the veins or they would stick. The slots in the rotor that the veins ride in were just a little bit tapered.

Just a couple of my experiences.

Curtis

Brake clean and WD-40. High humidity. May have to clean more often. Reg maint about 4 times a season. First indicators, slow to build or you have to rap it. Ever pull a VC off and see the white condensation, clean the pump also.

Thanks guys. Lot's of good ideas here and when I pull the motor at the end of the season, I will take it apart and clean it thoroughly.

X2 on the brakeclean & WD40. Do it more often if you only get moisture when you drain the puke tank. On my old car I had the fitting in a good spot in front of VC and zero-gap rings... I used to get almost all water out of the puke tank and hardly any oil sludge and I had the vaccumm pump seize up. My current car gets a bout a 50/50 mix of oil and water milkshake... seems to make the vacuum pump live longer.

Thanks for the info guys, it worked like a charm.