791-6420 jack rebuild help

[GLHX]

When I put the jack down. You can see the fluid spills out.
‘it’s a quick pump Napa jack from 2004.
it doesn’t work like it used to and bleeds down after a few minutes under a car.
‘’I need help rebuilding it

 

[paulsomlo]

Is it overfilled? As far as bleeding down, most likely culprit is the main ram seal. Tear into it, then call Hydraulic Parts Supply in Sawyer KS at (620) 594-2247.

Searching on that model #, yields this and others: https://www.garagejournal.com/forum/threads/napa-3-5t-floor-jack-7916420-rebuild.382954/

 

[GLHX]

I think it’s that silver fitting in the bottle jack. It’s got a ball check valve and it’s not sealing. So it lets all the fluid out when the jack goes down.
‘’I did get a seal kit for it but it dint come with that piece.
‘’where can I get one of those replacement breather fittings?

 

[paulsomlo]

The silver fitting - you mean that hex shaped piece that's attached to the reservoir? There's a philips head screw offset from the center, not sure what that's about - you're saying there's a check ball as part of it?

You did check the fluid level for overfill, yes?

 

[Wamsutta]

SEAL KIT RS35SK

PARTS DRAWING

 

[GLHX]

The silver fitting - you mean that hex shaped piece that's attached to the reservoir? There's a philips head screw offset from the center, not sure what that's about - you're saying there's a check ball as part of it?

You did check the fluid level for overfill, yes?

yeah.
‘when I lower the jack. Fluid pours out of that little dot Next to the screw.
‘’I let the jack all the way down. Then filled it. It took 30+ pumps to make it work.

so then I jacked it all the way up and filled it. It took 20 pumps but it wouldn’t go down Because it was over full/
‘it slowly went down. Pouring fluid out of that little dot.

I needed to use it. so I let it down some and have to fill it before each use. I don’t let it drop all the way or the fluid goes out that hole.

it’s some kind of breather but I’ve not seen one like that and I can’t find a replacement. That dot looks like some kind of check valve.
you can see it in the other side of the fitting, but you can’t get access to it. It’s like the ball valve is made into the breather.

I don’t know if it will let me do videos. It would explain it better.

 

[GLHX]

SEAL KIT RS35SK

PARTS DRAWING

I got a kit from hydraulic parts supply.

I’ve never been in one of these before but I’m mechanically inclined so I wasn’t too worried about it. I might have to send it to them And have them fix it.

I know that check valve is leaking fluid from the reservoir

 

[GLHX]

the picture series shows the fluid pouring out of that fitting. When I lower the jack at all.

 

[paulsomlo]

If you filled it with the jack all the way up, then it's over filled - it needs to be done with the jack all the way down. When you fill it, the level of the fluid should be even with the top of the cylinder that's visible inside the reservoir. When you get the fluid level correct, you should probably try bleeding the air out of it; open the release valve and pump the handle 10 times. Also, see the screenshot I attached from the manual - it's possible that philips head screw needs to loosen.

 

[Wamsutta]

I got a kit from hydraulic parts supply.

I’ve never been in one of these before but I’m mechanically inclined so I wasn’t too worried about it. I might have to send it to them And have them fix it.

I know that check valve is leaking fluid from the reservoir

If you go into it, you might as well install the whole kit. That drawing I posted will make it easy.

 

[GLHX]

If you filled it with the jack all the way up, then it's over filled - it needs to be done with the jack all the way down. When you fill it, the level of the fluid should be even with the top of the cylinder that's visible inside the reservoir. When you get the fluid level correct, you should probably try bleeding the air out of it; open the release valve and pump the handle 10 times. Also, see the screenshot I attached from the manual - it's possible that philips head screw needs to loosen.

I filled it up both ways.
‘while it was all the way down., and all the way up.
‘it leaks fluid out so fast that i was able to experiment with it like that.

filling it up all the way down. It acted like there was barely any fluid. Even with bleeding it. It wouldn’t go to the top of its run.

filling it while it was up gave me some help. It only took 20 and it would go all the way up. But because it was over full. It would not go all the way down.

so I ended up doing it in the middle, so I could use it.

the problem is when it is all the way down and I fill it and bleed it. The jack doesn’t work well at all.

the bleed valve in the picture you posted wasnt on my jack when it was new, it’s never been messed with.
mine is the one in the picture I posted. It looks like it’s some automatic device. It does have a cap with 4 air holes that goes on top of that. It doesn’t have a screw to turn. The manual shows that it does. I think that’s an upgrade of some sort. I can’t find a replacement like that one either.

it’s like the problem is a little of both. It needs to be rebuilt and the breather check ball is bad.

it looks a lot like the second picture. But it’s built into a threaded breather

 

[Hiball]

Ok, The Reservoir is only so Big, As others have stated fill the reservoir with the lift arm down/piston retracted to where the oil just rests above the cylinder when peering thru the hole. Do Not Reinstall the Breather.


Next, Bleed the jack by pumping the handle with the Release in the Release position, this will purge the circuit between the reservoir and valve system.

Stop.

Recheck the oil, Add as Needed, as the Air you have displaced from the Valve circuits has been replaced with Oil, which has now lowered the reservoir level and can prevent your jack from making full extension and pumping air into the system, requiring further bleeding.

Turn the handle to the Lift position and cycle the jack “Off load” to full height and let it down. If it operates, reinstall the breather and call it good.

If you fill the reservoir at Rest, Middle and at full height there is No where for the Oil from the cylinder to go when you lower the jack. It appears your breather is missing a Cap at Min, Not a big deal but they aren’t designed to move oil, only Air so severely overfilling the jack might have caused some parts to leave the general area when pressurized oil was returned to the Reservoir.