Floor jack lowers too quickly

[t1snwrbrdr12]

Update…re-bled it and lost some fluid in the process, thought I was onto something. Jack worked seemingly normal on my Mazda. Today, used it on the odyssey (still being overly cautious to release it down onto stands as slow as possible) and it again slammed down. I was hoping being overfilled was the issue but not so sure anymore. May be a good excuse to get a long reach low profile harbor freight-y soon.

 

[xspeedy]

I think I might have the same Costco jack as you. What I find is that when the handle is tightened, it is hard to loosen and so when it does “give” it is does so with enough travel that the vehicle drops suddenly. I find I have to get up against the handle (in the vertical position) and with two hands right up near my neck, choke up on the thing and break the thing loose in a more controlled manner. That seems to do the trick. I tired lubricating everything to see if I could get that motion to be easier, but to no avail. Mine also sounds like it is slowly dropping with a load (makes popping sounds every so many seconds). I learned the trick to that is to fully raise the jack from a full down position and pump another couple dozen times after it is in the full up position (unloaded). I did that and it helped for a while, but started again. I’m going to replace the fluid and do a bleed.

 

[RYDMOTO]

Is there a needle valve that bleeds the oil to lower?
I would explore that maybe the needle valve needs replacing.
On my two aluminum floor jacks I don't quite have the dropping
issue, but I do have to have (when I can) have the pump pipe at
a 45 degree plus angle and grip with two hands and power turn it
slowly as previously stated. I have watched the gearing at the bottom
turn as I turn the handle and never gave it much thought until this
thread. There may be some slop in that gearing. Now I won't sleep
good till I look at it...lol

 

[t1snwrbrdr12]

I think I might have the same Costco jack as you. What I find is that when the handle is tightened, it is hard to loosen and so when it does “give” it is does so with enough travel that the vehicle drops suddenly. I find I have to get up against the handle (in the vertical position) and with two hands right up near my neck, choke up on the thing and break the thing loose in a more controlled manner. That seems to do the trick. I tired lubricating everything to see if I could get that motion to be easier, but to no avail. Mine also sounds like it is slowly dropping with a load (makes popping sounds every so many seconds). I learned the trick to that is to fully raise the jack from a full down position and pump another couple dozen times after it is in the full up position (unloaded). I did that and it helped for a while, but started again. I’m going to replace the fluid and do a bleed.

I don’t have any problem loosening it in a slow and controlled manner. In fact I’m extremely cautious after what’s been happening. I can slowly loosen it and watch the u joint turning ever so slowly (watching because I’m loosening it so slow I’m not even sure my hands turning it lefty loosey without being able to see that u joint turning). All the sudden out of nowhere it just slams, it never starts slowing lowering (with the weight of our van on it at least).

I used it recently after the re-bleeding on my Mazda and while I was still ultra cautious in lowering it, it lowered seemingly fine.

 

[ajchien]

Is there a needle valve that bleeds the oil to lower?
I would explore that maybe the needle valve needs replacing.
On my two aluminum floor jacks I don't quite have the dropping
issue, but I do have to have (when I can) have the pump pipe at
a 45 degree plus angle and grip with two hands and power turn it
slowly as previously stated. I have watched the gearing at the bottom
turn as I turn the handle and never gave it much thought until this
thread. There may be some slop in that gearing. Now I won't sleep
good till I look at it...lol

I’ve only seen the ball seat valves used as release valves rather than needle valves in these newer import jacks. True that the needle release valves offer better lowering control, but I’ve only seen them used in the older USA made and Taiwan made jacks.

@t1snwrbrdr12 Did you ever test the lowering of the jack with the reservoir fill plug left out? Another idea - If it’s not the vacuum generated, rather the handle control, I’ve also drilled a hole into the top of jack handles and stuck a foot long 1/4” bar through it making the handle a “T shaped bar”. Turning the handle using the T bar can offer more tactile control to open the release.

 

[t1snwrbrdr12]

I’ve only seen the ball seat valves used as release valves rather than needle valves in these newer import jacks. True that the needle release valves offer better lowering control, but I’ve only seen them used in the older USA made and Taiwan made jacks.

@t1snwrbrdr12 Did you ever test the lowering of the jack with the reservoir fill plug left out? Another idea - If it’s not the vacuum generated, rather the handle control, I’ve also drilled a hole into the top of jack handles and stuck a foot long 1/4” bar through it making the handle a “T shaped bar”. Turning the handle using the T bar can offer more tactile control to open the release.

I haven’t tried that. If it were to make it operate normally, what would the fix be?

I don’t think it’s a problem with my control of the release handle…I use jacks almost every day and don’t have this problem except with my personal home jack.

 

[ajchien]

I haven’t tried that. If it were to make it operate normally, what would the fix be?

I don’t think it’s a problem with my control of the release handle…I use jacks almost every day and don’t have this problem except with my personal home jack.

If leaving the fill plug out helps control the lowering of your jack, then either your reservoir is still overfilled or you could install a reservoir vent (aka hydraulic breather) in lieu of the fill plug. If the jack also lifts the load with fewer pumps at the same time, it also means that the seals on your pumps are worn out.

Hydraulic reservoirs should have vents rather than plugs sealing the system. When there is a plug sealing the reservoir, a vacuum develops in the reservoir. The amount of vacuum is increased if there is less starting air the reservoir (too much oil). The vacuum deteriorates the pump seals over time, and can also increase the rate of return of oil during release. A jack that has a vent will not build a vacuum in the reservoir, be “self-air bleeding” each time you use it, it will have pump seals that last longer (bc they’re not fighting against a vacuum), and be easier to control while lowering (no vacuum assisting the rate of return to the reservoir). Leaving the fill plug out, as a test, is essentially putting in a temporary (extra large sized) vent.

A jack that has a sealed plug does have some advantages. first, it won’t leak oil during shipping, when the boxes that jacks are shipped in can get turned various different ways, allowing oil to leak out of a vent. It also won’t allow air contaminants in, thus keeping the oil cleaner and needing less oil changes over time. IMHO, it also done to decrease the life of the pump seals so that people buy replacement jacks more often.

this YouTube video is not exactly how your jack works, but it is trying to demonstrate why a vent is put into hydraulic systems. Comparing the video to your jack, the lifting rod is usually much larger in your jack, so the oil level changes in the reservoir more. Also, instead of the vacuum stopping the lifting rod, in a jack, the lifting rod keeps moving creating more vacuum.

 

[The motor guy]

Always had this problem. Its like the handle was stuck at first and then no matter what it came down fast. I had a buddy that would keep vice grips on the handle of his floor jack. Dude was a pro at letting it down slowly

 

[D60]

My AC Hydraulics jack has a large D-handle. This gives you leverage with opposing hands to just crack the valve, and much more control as a result.

 

[FFWD]

I've had this fast dropping problem with my Powerbuilt jack since new.
https://www.princessauto.com/en/2-ton-xtra-low-profile-floor-jack/product/PA0008486698

I bought it ages ago, and at the time found a video online showing how to fix it, but I never got around to it and now can't find it any more. From what I remember, it had something to do with the release valve opening being square, and that as you turned the handle, the valve popped open, resulting in the sudden release. The video showed how to modify it so that the release was more gradual, but I can't remember what it as that they did.

 

[D60]

I've had this fast dropping problem with my Powerbuilt jack since new.
https://www.princessauto.com/en/2-ton-xtra-low-profile-floor-jack/product/PA0008486698

I bought it ages ago, and at the time found a video online showing how to fix it, but I never got around to it and now can't find it any more. From what I remember, it had something to do with the release valve opening being square, and that as you turned the handle, the valve popped open, resulting in the sudden release. The video showed how to modify it so that the release was more gradual, but I can't remember what it as that they did.

Funny you say that. Years ago I had two Powerbuilt 3T jacks. They were identical and both purchased from my local Checker (now O'Reilly).

One dropped quickly unless you barely cracked the valve. The other was far more predictable and easy to modulate.

I'm not sure what ever happened to those jacks.....I think I sold one and gave one away.

 

[The motor guy]

Funny you say that. Years ago I had two Powerbuilt 3T jacks. They were identical and both purchased from my local Checker (now O'Reilly).

One dropped quickly unless you barely cracked the valve. The other was far more predictable and easy to modulate.

I'm not sure what ever happened to those jacks.....I think I sold one and gave one away.

I have a buddy that leaves a vice grip on the handle for more control.