Floor jack not lifting like it used to

I have a MotoMaster Heavy-duty Service Jack, model no. 09-1047-6. It is sold as "Speedy Lift" because with one stroke, it contacts the chassis. I recently had a leak coming from one of the gears that controls the lock and release. I removed the gear and replaced the o-ring, but at the same time I removed 3 other screws with o-rings to inspect them as well as the release valve bolt. Re-assembled, and it wouldn't lift a load. I bled the system and topped up the fluid, and then it started working again BUT instead of lifting right to the chassis it now only lifts about 1/8" on each full crank. I dumped the fluid, refilled with fresh fluid, bled the system according to the manual, played with the adjustment screws and no difference. It will lift the load, hold the load, but just isn't working the way its supposed to. Any suggestions?

 

That's a tough one from a distance. I don't know about that particular jack, but it sounds like you have a double stroke type of pump on it. The high volume stroke gets it to the chassis and the reduction in the pump lifts the load.

This isn't from first hand knowledge on the jack, but I suspect you have air in the system, which you have already deduced, I'm sure. If you didn't have any check balls fall out when you had removed the screws/gears for oil ring replacement I would give the bleeding another shot.

Assuming all the screws were on the same face of the jack cannister - Stand the jack up so that face is pointed up and support it. Remove all the screws you had taken out and using your jack fluid bottle force fluid through the fill port and out the screw holes. Don't force it through too fast to prevent blowing a check ball out. You may have to work the jack handle to move the fluid through. I suspect you'll get an air bubble out.

If your fill port isn't on the same face, fill through one of those accessible.

That's the best advice I can give on the subject. We may have some jack people on this forum that can jump in with some other information.

Hope this helps,

Bob

 

What would these check balls look like?

I may try that idea and see if I can get fluid to run through one of the three screw holes, except this thing is extremely heavy and I may have trouble suspending it as the screws are near the handle.

 

The check balls are just little ball bearing looking affairs. Sometimes they are backed by springs sometimes they are gravity seated. I'm not saying they are even where you removed the screws, but it's a good idea to watch for them.

You would definitely see something like those for flow checking devices to hold the load up. Your release for letting the load down would probably be through a different fluid path back to the reservoir.

Hope this helps,

Bob

 

I'll give it a try when it warms up a bit. Thanks for the tips, hate to throw it away when it probably just needs another 30 minutes of tinkering.

 

marbobj, I took it apart again, tipped it vertical with the fill plug out and 3 screws out. Two ball bearings came out, didn't see from where but judging by where they landed they came from the fill plug. I put them both in the fill plug and refilled, bled, lots of air came out like you said, but now it does not work at all. I'm guessing I put the ball bearings back in the wrong spot? Probably near impossible to get them out now, lol.