Hydraulic Jack Assembly Question

[ScottNC]

What is supposed to seal a bottle /floor jack reservoir/tube to the valve body? It's a 70's Sears floor jack. It had been leaking for a while and using it to support half a tractor while the clutch was replaced finished it off. The reservoir tube to valve body is a metal to metal fit. There was not a seal or sealing compound between the two at tear down, so I left it that way. Tightening the crap out of the cap does not help. The seal kit I bought did not mention what or if there was supposed be something in there. I'm tempted to try plumbing packing - if it still exists.

 

[chvet73]

A picture would help. But it’s my guess that was a press fit originally. I’m not sure of the cure short of brazing or welding it in place.

 

[Jim.ME]

What is supposed to seal a bottle /floor jack reservoir/tube to the valve body? It's a 70's Sears floor jack. It had been leaking for a while and using it to support half a tractor while the clutch was replaced finished it off. The reservoir tube to valve body is a metal to metal fit. There was not a seal or sealing compound between the two at tear down, so I left it that way. Tightening the crap out of the cap does not help. The seal kit I bought did not mention what or if there was supposed be something in there. I'm tempted to try plumbing packing - if it still exists.

I take it the reservoir (outer barrel) threads into the base, as you say tightening didn't help. If this is the case, I expect the leaking oil is coming up through the threads. I would try using a good thread sealant on the threads of the barrel or Loctite 545 Thread sealant. Be sure to completely clean, de-oil, and dry all matings surfaces with any sealant you use. If you use the Loctite follow the instructions including cure time.

 

[Phill Tibbetts]

I have worked on hydraulic jacks and most bottle jacks are metal to metal fit with some type of gasket shellac applied during assembly. There is no pressure in the outer case as it is just a reservoir. The reason most leak is because someone has jacked something up that tipped over slightly crushing the outer shell on one side. If it is not too bad it can be put into a lathe an trued up so it will set flat on a smoth surface. I have fixed a lot of leaking reservoirs that way.

 

[Phill Tibbetts]

What is supposed to seal a bottle /floor jack reservoir/tube to the valve body? It's a 70's Sears floor jack. It had been leaking for a while and using it to support half a tractor while the clutch was replaced finished it off. The reservoir tube to valve body is a metal to metal fit. There was not a seal or sealing compound between the two at tear down, so I left it that way. Tightening the crap out of the cap does not help. The seal kit I bought did not mention what or if there was supposed be something in there. I'm tempted to try plumbing packing - if it still exists.

Is it a floor jack (the type on wheels like used to jack up a car) or bottle jack?

 

[Jaden]

On hydraulic bottle jacks, we usually used a small amount of Permatex #2.

 

[ScottNC]

It is a floor jack. The tube has plain, lathe turned ends - no threads. What I tightened is the top cap where the piston comes out. There is no damage to the tube, the area of the valve body where the tube sits is plain cast, I don't see how it ever sealed from new. The jack had a slight leak for decades, not enough to mess with, I just had to remember to park in on a piece of cardboard or it'd spot the floor. After using it to hold up the front half of a tractor instead of properly blocking it, it leaked about all the oil overnight - probably from a seal. Had it resealed but it never worked correctly and quickly developed another leak, bad enough I had to quit using it and left it in a transmission pan where in short order most of the oil leaked out. That's when I took it apart and found some jury-rigged seals had been substituted for the correct ones. I got it working, no leaks - I thought. Slowly oil started showing up around the tube/valve body junction and repeated attempts to correct it failed. Frustrated, I let the jack sit all summer until my ambition to fix it revived. I'll look into some sort of "glue" and give it another go next week, a good project as it's supposed to rain.

 

[Phill Tibbetts]

It is a floor jack. The tube has plain, lathe turned ends - no threads. What I tightened is the top cap where the piston comes out. There is no damage to the tube, the area of the valve body where the tube sits is plain cast, I don't see how it ever sealed from new. The jack had a slight leak for decades, not enough to mess with, I just had to remember to park in on a piece of cardboard or it'd spot the floor. After using it to hold up the front half of a tractor instead of properly blocking it, it leaked about all the oil overnight - probably from a seal. Had it resealed but it never worked correctly and quickly developed another leak, bad enough I had to quit using it and left it in a transmission pan where in short order most of the oil leaked out. That's when I took it apart and found some jury-rigged seals had been substituted for the correct ones. I got it working, no leaks - I thought. Slowly oil started showing up around the tube/valve body junction and repeated attempts to correct it failed. Frustrated, I let the jack sit all summer until my ambition to fix it revived. I'll look into some sort of "glue" and give it another go next week, a good project as it's supposed to rain.

Remove the outer tube and put it on a flat surface to make sure it is touching all the way around. Some permatex should seal it if it is.

 

[RedMF40]

I don’t know how to fix the jack but sellers are practically giving away the older and heavier floor jacks now that lighter models are available. I have two 2-1/2 ton jacks that a seller didn’t want to load up at the end of a tractor show. Ten bucks for the two of them and I’ve been using them regularly. They are definitely heavy.