Aluminum floor jacks single pump vs. double pump

[orangebluegreen]

After trying the jack a few more times on my minivan I decided it was too much weight for the jack. It was making creaking sounds of pain under load, so it went back. Works great for lower weights though and you can't beat the maneuverability. I exchanged it for an over 100lb long frame that goes up 31" but that is a bit surprising effort wise also because it's only 2.5 ton and has a long lift arm. The height is good for getting jack stands in place and it's great for reaching tractor frames that are often too high for regular floor jacks. Not sure if I'm keeping it or not yet, would be great for changing mower deck blades.
Harbor Freight Tools - Quality Tools at the Lowest Prices was $149 in store.

Took my Craftsman 3 ton apart this weekend. The pump was leaking and I had avoided the job for years until it became unusable. Should have sooner, two bolts in the pump arm and then easy access to the pump, took 2 minutes to take apart. Pulled out the plunger and found some scoring. The seal didn't look too bad but it doesn't take much visible wear. Matched up the old seal at my local hardware store, 7/8x5/8x1/8 appeared closest. Took some 1500 grit wet\dry sandpaper to the plunger rod and did my best to smooth it. I should have started with a more coarse paper than moved up but didn't have any on hand and didn't want to change the diameter. Got it where it was nice and shiny but still had pitting, figured nothing to lose by trying it. So far even with remaining pitting on the plunger it is working without leaking though I assume the seal will wear faster with some pitting on the plunger. I've seen a lot of posts online that scrap these jacks because of leaks like mine and the entire pump is too expensive. The seal is very easy to replace and cost 50 cents or so. The ram piston was not leaking on mine, it's about 15+ yrs old btw. Also spent a couple hours cleaning and greasing the wheels, now it rolls easy and doesn't mark the finished floor.

This 3 ton Craftsman lifts my van with almost no effort whatsoever. If I keep the long frame is not certain yet.

 

[orangebluegreen]

A big part of your problem is that you bought a "rapid" floor jack. By this it means that the vehicle goes up fast with each pump. Ever watch NASCAR? Notice how the jackman throws his full body weight on the end of the handle to lift the car with only one pump?

Yes, love racing of all types. Old friend of mine owned an ARCA car (mid '90's) for a while that I worked on at Daytona but I wasn't the jack man. I've noticed the full body weight on the jacks for NASCAR also but figured they go up in one or two pumps so 6-7 should have been ok, but obviously not. Guess most of those jack men are pretty heavy or they have some design trickery. Not sure if their ratios are the same, perhaps they aren't going up very far because the suspensions may not drop down as much.

I found this 3 ton aluminum takes 16 pumps and that's close to my Craftsman 3 ton that takes 18 so it could be the three ton alum jacks are more like regular ones, they are about 60lbs. I had never counted until now. The long frame I just exchanged for takes more pumps than I had the patience to count and yet it still takes way more effort than my Craftsman 3 ton. I assume it's due to the loooooong lift arm and the leverage involved. Sure has a big looking piston in the pump and it's actually very easy to maneuver because the front wheels can be easily lifted by pushing down on the jack handle.
Craftsman has a 3 ton also but not sure if it's the same and how many strokes, if they weren't $300 I think one of these 3 ton aluminums would be my choice.
Torin Aluminum Race Jack 3-Ton, Model# T84030 | Rapid Lift + Race Jacks | Northern Tool + Equipment

Craftsman Professional 3 ton Aluminum Floor Jack - Model 50244 at Sears.com