MityVac not so mighty anymore

[dibbons]

I guess it needs a rebuild (model MV8000). I don't have a selector switch like the one in the video (and mine is plastic, not metal). Unfortunately, can't find the proper kit (MVM8901) in Mexico and USA suppliers won't ship.

I'll try disassembly and re-grease the seals and see what happens.

​

 

[dibbons]

Update: I disassemble, cleaned, and lubricated all the parts. I got it to "work" again except with my index finger over the main spigot tube: a) will only pump up to 25 (dial scale shows 0-30) and b) with my finger still firmly on the spigot, the dial immediately begins to drop (albeit very slowly).

It's still good for checking engine vacuum, but not suitable for checking leak down of vacuum diaphragms.

At the end of the posted video, the guy states his problem leak was a small o-ring/gasket he removed at the very end of disassembly (near the handle). When I took off that same part, I found no such ring/gasket. At first I thought it dropped off but I could not find it. Then I thought perhaps it had completely disintegrated. However, I don't find that part in the blow-up diagram in the instructions nor in the correct advertised repair kit.

 

[niceolddart]

I had one (Mighty Vac) that I bought a long, long time ago. Made of metal (Aluminum or pot metal) I lent it out & it came back broken. The new one I have is plastic. I wish I had my original one. Needless to say, I don't lend tools out too much anymore.

 

[toolmanmike]

I guess it needs a rebuild (model MV8000). I don't have a selector switch like the one in the video (and mine is plastic, not metal). Unfortunately, can't find the proper kit (MVM8901) in Mexico and USA suppliers won't ship.

I'll try disassembly and re-grease the seals and see what happens.

​

You bought the wrong one. The metal one is rebuildable. As far as I am concerned, the plastic one is a throw away.

 

[RustyRatRod]

Update: I disassemble, cleaned, and lubricated all the parts. I got it to "work" again except with my index finger over the main spigot tube: a) will only pump up to 25 (dial scale shows 0-30) and b) with my finger still firmly on the spigot, the dial immediately begins to drop (albeit very slowly).

It's still good for checking engine vacuum, but not suitable for checking leak down of vacuum diaphragms.

At the end of the posted video, the guy states his problem leak was a small o-ring/gasket he removed at the very end of disassembly (near the handle). When I took off that same part, I found no such ring/gasket. At first I thought it dropped off but I could not find it. Then I thought perhaps it had completely disintegrated. However, I don't find that part in the blow-up diagram in the instructions nor in the correct advertised repair kit.

View attachment 1716552082

25hg at sea level is all they are rated to pull, so it's doin good. To get much better, you need to go to outer space.