Harbor Freight Motorcycle Lift Table Air/Hydraulic Conversion

Convert from manual action to air/ Hydraulic action on my Harbor Freight 1000lb. Motorcycle Lift Table

Harbor Freight makes a few different models here are the ones used in this video.

Model Numbers:

Motorcycle Lift Table # 69904

12-Ton Air/Hydraulic Jack # 99487

[martinhauk]

I have the Central Pneumatics motorcycle lift table from Harbor Freight that came with the air/ hydraulic jack. After about 12 years of frequent use, the pneumatic pump gave out and I manually pumped it up for about a year. For several years I had been toying with the idea of converting it to a hydraulic cylinder, similar to what's used in a log splitter. After about a year of hunting on line and through junk yards I came across a hydraulic pump unit for an automotive lift. I found a 2" cylinder with a 6" stroke that I thought would do the job. I fabricated a mount out of a 4" square steel tube (a little over kill there. 3" would have been quite adequate). That served as a cross member between the frame rails of the lift. I made a post out of 3 pieces of 5/16" X 2" bar stock sandwiched together and welded. I drilled one end to receive the clevis pin of the hydraulic cylinder. Then I centered and welded the post perpendicular to the square tube. The material for all the fabrication came from the local scrap yard. I had to weld the cross member onto the frame far enough forward for the rear lift arms to clear in the down position. That meant removing the rods for the pedals. The rod on the cylinder was much smaller than the ram on the old jack so I had to make a collar to thread on the end of the rod to make it fit into the cup on the V plate. The pivot rod for the V plate broke the center bolt twice so I drilled and tapped each end and bolted a fender washer to the ends to keep the rod in place. Once mounted and connected to the pump unit I rolled my 600# bike on the lift and hit the button to lift it. I found I had turned my lift into a catapult. It lifted the bike to the top in less than 2 seconds, and when it got to the top it jerked the whole assembly back about 4" along the floor. I had to slow it down. To do so I made a restrictor that I put in the fitting by the cylinder to restrict the rate of flow into the cylinder. I had to choke it down from 3/8" down to .025". That slowed the lift down to 8 seconds and kept it in place. The pump unit has a go switch to raise the lift and a lever to let it down by gravity. I installed a pedal switch on the opposite side of the lift so I can lift it from that side too. Since the cylinder has a 6" stroke and it only takes 4" to lift it all the way, I installed a stop switch to keep it from over extending. I put a 960# bike on the lift and it lifted it about a third of the way up and overloaded it and blew the breaker. I then installed a 2 1/2" cylinder which gave me plenty of force to lift a 1000# bike. I realize that this is a little more work and expense than the air/oil conversion done here, but I think it was well worth it.

The only down side is if the lift isn't all the way up, and I want to lift it higher, I have to let it down, either on to the safety bar or all the way down. This relieves the pressure on the hydraulics and allows the motor time to spool up again to lift it all the way.

[jeffjensen]

What A Great Idea. My Only Problem With This Concept Is That It Would Work In My New Home Theater. Was Going To Mount The Fully Motorized Theater Seats 💺 For 2 People To Sit On And To Sit Down And All Of A Sudden Your Seat Starts To Rise. Loud Noise That It Makes Is My Concern. Certainly There Must Be A Way To Make It Quite. Do You Have A Video Of The Same Thing Only In Hydraulic. My Vision Is To Find A Platform Such As Yours And It Rises And Lowers Total Quite. Awesome Video! Let me Know.

[mikebarcelona]

Excellent idea, how many ton capacity is that hydraulic jack ? And where can I get that foot pedal ? Thanks

[M.TTT.]

Nice, I might have to do this, the stock jack has a lot of trouble lifting 800+lbs.

[knighthawk]

I noticed some black paint at the base of the bottle jack, did you have to weld that baseplate on?

[marburgerkris]

Did you have to add extra fluid to the jack for it to work laying on its side? I’m doing the same conversion. The air over hydraulic jack I have is different than yours but is the exact same set up.

With the jack I have in the orientation like yours it will not lift like it is starving for oil.