I joined up here with hopes you guys can help me figure out why this jack isn't working. It's a Matco AM200F 2-ton. When i got it i knew it needed rebuilding. So i ordered a rebuilding kit for it and got it all looking nice and new. However it's not working correctly. It lifts and lowers fine with no weight on it. However the pump plunger seal along with oil gets blown out whenever the jack has any weight on it. Not sure what's going on. Is anyone here familiar with these that can help. Thanks.
Matco floor jack... Need help
- Thread starter CoolKid
- Start date
rooster59
Well-known member
new U-seal? maybe in backwards? cracked? groove cleaned out? did a seal lip get folded back? that's what I would look at. open top of U goes toward pressure. nice jack
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rooster59
Well-known member
I assume the outside of the seal fits into a groove in the jack body, piston goes through the inside of the seal.
No groove.the seal is just an oil seal / wiper. It presses in and sits flush just like the original. Under the seal is a plastic split-washer and an o-ring. No pressure should be going against these parts unless something else is wrong. But i have no clue what it could be.
PWC Repair
Well-known member
Somewhere down in there is a spring loaded checkball. If it's rusted and stuck the fluid just shoots out the plunger like yours.
Here are pictures of the diagram that came with the rebuilding kit. Every single piece that i removed i replaced with new from the kit. A,B, and C all pertain to the pump block holes.
Attachments
PWC Repair
Well-known member
Is 5-11 stuck inside 5-5?
Yea. I replaced it when rebuilding.
Redraptor
Well-known member
I had a similar thing happen with mine. Different name but looks the same. I bought it 30 some years ago and it did come with a rebuild kit. It started leaking like that 20 years ago. Finally looked at it 2 months ago and replaced 8-2, 3, &4. Hasn't leaked a drop since. I think there's alot of side load when pumping and wears at the seals and maybe the push rod itself. I don't know how much pressure those seals see to push out fluid there but it sure is annoying.
I suspect a check valve somewhere isn't working and the pump is seeing cylinder pressure. When i get a chance I'll pull it apart again.
matt_i
Well-known member
#10 asm is the lowering needle valve. # 9 asm is a spring balance overpressure relief, the check appears to be in #6 asm, possibly one for leaving oil trapped behind the main raise piston and one to avoid pushing oil back into the supply reservoir on the pump stroke. . The screw does look like an adjuster rather than something to simply be bottomed out....
I agree this is likely the problem. If the check valve was working it wouldn’t push back to the pump. Usually found under a screw plug in the main pump casting.
paulsomlo
Well-known member
Umm... I think the pump always sees cylinder pressure on a downstroke.
I'll 2nd that emotion - it sounds like he's essentially pumping against a brick wall.