Issue with Jack

[Beechbumm33]

I have a 3 1/2 ton napa jack #791-6425. The fluid level is topped off. The quick lift function works fine but once you put a load on it, it lifts very slow and eventually you only get a 1/4" of lift out of the handle. What seals go bad on these? Does anyone know how the valves work on these? This one has 4 valve holes and I cant find a description anywhere on how the should be adjusted.

Any help?? Thanks in advance!

 

[Hiball]

I have a 3 1/2 ton napa jack #791-6425. The fluid level is topped off. The quick lift function works fine but once you put a load on it, it lifts very slow and eventually you only get a 1/4" of lift out of the handle. What seals go bad on these? Does anyone know how the valves work on these? This one has 4 valve holes and I cant find a description anywhere on how the should be adjusted.

Any help?? Thanks in advance!

When a Hydraulic Jack start to fail, 99.9% of the time it’s a failed seal, the exception would be a jack that had been inverted or drained of oil and is air bound etc. It sounds like you jack possibly has weak pump seals, I would remove the fill plug and see if your jack operates a little more efficient. In regards to the valves, it’s always best to utilize factory settings, so before you start just randomly removing components or making adjustments it’s best to get the current setting by screwing them down to close while counting the revolutions.

 

[Beechbumm33]

Unfortunately, the valves have been messed with due to lack of knowledge on my part. On my jack, the fill plug is the breather. If I remove it and operate the jack, wont the fluid just spill out the fill hole?

 

[Hiball]

Unfortunately, the valves have been messed with due to lack of knowledge on my part. On my jack, the fill plug is the breather. If I remove it and operate the jack, wont the fluid just spill out the fill hole?

If your jack is spilling fluid out of the fill plug during operation, you have too much oil in the reservoir or heavy amounts of Air in the system. If your jack utilizes a Breather as a fill plug, disregard my earlier comment unless it’s not operating correctly. On second thought I’d probably pull it anyways and operate the jack. If it doesn’t get any better , It sounds like to me you need to night the bullet and put eyes on the seal components. If this is your next move, when you disassemble the valve components, keep everything in order for future reference.