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

dodge man · Sep 3, 2021

With my shop vac it’s not filtering if blowing and some dust does come out.

npalen · Sep 3, 2021

TBN is like a bunch of frat buddies comparing notes on things they pulled off in college!

Just kidding.

TMGT · Sep 3, 2021

dodge man said:
With my shop vac it’s not filtering if blowing and some dust does come out.

What kind of vac do you have? My Shop Vacs all create a negative pressure in the canister to create the vacuum so the discharge air is after the filter and should be clean. Provided the filter is actually functional.

Capngeo · Sep 3, 2021

old and tired said:
I drove my L2800 up on a block to make access a wee-bit easier, (off the ground and tilted) hooked up the shopvac and attached the hose to the filler hole in the back of the tractor. Loosen the filter then turned the shop vac on, had the new filter handy and ready to go... hoping to lose a drop or two; got the filter 3/4 off and There she BLOWS... I thought, I'm not in Yellowstone, why is there a hydraulic geyser. I'm trying to catch it in the bucket when I decided to screw the filter back on. (thank God it wasn't all the way off the threads).

Remember to hook the shop vac hose to the IN-take and not blow air into the filler hole!!!

My mom said I was "special"... I didn't know this is what she meant! Lost about a half gallon... It was one of those WTF moments...

Thanks for the morning chuckle! Sounds like something I'd have done

dodge man · Sep 3, 2021

I think you are correct now that I think about it you are correct.

TMGT said:
What kind of vac do you have? My Shop Vacs all create a negative pressure in the canister to create the vacuum so the discharge air is after the filter and should be clean. Provided the filter is actually functional.

DieselBound · Sep 3, 2021

pmsmechanic said:
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.

What is this "gasoline" that you speak of?

DieselBound · Sep 3, 2021

I used this for the first time recently and I DID end up with a bit of fluid in the vac, though not enough to not use this method again. No idea how I managed to do this, but note that it's apparently possible.

mikeAdams59 · Sep 3, 2021

Whenever I am replacing only the filter/s, I just catch whatever spills out in clean containers and run it through a fine mesh or filter cloth before pouring it back in. For some filter changes, when I think that the oil is still ok, I drain the oil completely into pails, filter it and reuse. I always use synthetic which has a long life and is expensive. This lets me feel and visually check the oil for contaminants.

jmc · Sep 3, 2021

dodge man said:
I think you are correct now that I think about it you are correct.

At first, I thought that the exhaust would be unfiltered too.

Looks like the canister is always under vacuum and the air velocity is high thru the intake port, due to its small opening. Then the air enters the canister, its velocity drops because of the larger opening, allowing the trash to fall down into the canister/out of the flow. Then the air accelerates as it hits the small exhaust opening near the top, is sucked thru the filter, (if any) and finally exits.