Beware of the shop-vac trick when changing hydraulic filters...

[old and tired]

What keeps the shop-vac from sucking fluid out of the fill opening?? Never heard of doing this. How do you know that your shop vac is perfectly balanced to pull a vacuum on top of the oil reservoir yet not so powerful as to suck fluid out?

Air space between the level of oil and the opening of the filler hole, I just put the hose up to the opening, I did not secure it or make a tight seal (at all)... just a little positive pressure.

Worked like it should have the second time around...

So, it was a new shop vac and was the first time using it... still not a good excuss

 

[CH4Ohio]

Air space between the level of oil and the opening of the filler hole, I just put the hose up to the opening, I did not secure it or make a tight seal (at all)... just a little positive pressure.

Worked like it should have the second time around...

So, it was a new shop vac and was the first time using it... still not a good excuss

Got it. Thanks. I kinda doubt that this procedure is included in any of the Workshop Manuals . . . But thanks for explaining it to me.

Plugging the vents and being sure the oil is cold probably has a more predictable outcome.

 

[KubotaToy]

I have used the "shop vac trick" many times on several different tractors with no problems. I actually saw this being used in a JD tractor repair shop back 25 years ago and asked the mechanic what he was doing and he explained the process, been using it ever since when I just need to swap filters.

I am sure "plugging" the vent will slow the drain of fluid also. To each their own...

 

[CH4Ohio]

I have used the "shop vac trick" many times on several different tractors with no problems. I actually saw this being used in a JD tractor repair shop back 25 years ago and asked the mechanic what he was doing and he explained the process, been using it ever since when I just need to swap filters.

I am sure "plugging" the vent will slow the drain of fluid also. To each their own...

Interesting. I keep thinking it would suck hydraulic fluid out. Kinda like the waste-water pump-out on a boat that uses a vacuum with a long hose to attach to a fitting on the deck to pump out the waste-tank. On those you need to be sure you have something open to keep from collapsing the tank (though I really don't think that's it any more powerful than my shop-vac). In that example, there's also a large air-space above the liquid prior to connecting the hose, but the suction evacuates the air and then the liquid below it.

Thanks for the additional info.

 

[oosik]

I changed the hydraulic oil/filters on my M6040 at 50 hours. I used the tried/true method - pull the plug and drain it. Yes - it probably takes longer but it's 100%.
I use my shop vac for sucking up sawdust, etc.

 

[Captain Dirty]

When I used the shop vac trick I used a short length of 1" diameter clear tubing between the fill hole and shop vac and had an assistant to control the vacuum by separating the vac nozzle from the tubing if it pulled fluid into the tubing. I heard gurgling when I broke the seal on the filters; no fluid entered the tube.

 

[nyone]

I removed a filter off a machine once, a Case W20 loader. I had to get down in the front of the machine right next to the filter. I twisted and twisted that filter loose until the 20psi behind the filter blew the gasket out right past my belly. I had to wait until it was all empty before I could get out and clean up the mess. It took 20 bags of speedy dry to clean that up.

 

[KubotaToy]

I keep thinking it would suck hydraulic fluid out.

Well, I do not stick the hose end into the tank space or near the oil but I just set it in the opening and either use a shop towel to wedge it, tape it in place or use my assistant if she is available. On my tractors, the oil is a good 8" below the fill ports and I've had the vac hooked up for 15-20 min when I had a problem with a filter and never sucked anything into the shop vac.

Hey to those who drain the oil every filter change (or at least part of it by way of the filter change), more power to ya as we all can do it different and still be correct in that we changed the filter when required, I just hate cleaning up the mess.

 

[cwbyeng1300]

Interesting. I keep thinking it would suck hydraulic fluid out. Kinda like the waste-water pump-out on a boat that uses a vacuum with a long hose to attach to a fitting on the deck to pump out the waste-tank. On those you need to be sure you have something open to keep from collapsing the tank (though I really don't think that's it any more powerful than my shop-vac). In that example, there's also a large air-space above the liquid prior to connecting the hose, but the suction evacuates the air and then the liquid below it.

Thanks for the additional info.

That deck fitting has a tube that goes to the bottom of the waste tank into the fluid. As long as the vacuum hose doesn't reach the liquid it only pulls a vacuum on the tank. Only oil that will go into the vacuum tank is maybe some mist droplets caused by the agitation.

 

[pmsmechanic]

I used this method once to change a leaking fitting on the bottom of a diesel fuel tank. The tank was about 3/4 full and I only lost a few drops. It worked awesome!

Absolutly do NOT try this on a gasoline tank as chances are very good that the electric motor will ignite the gasoline. If you insist on trying it have lots of insurance including on yourself.