Posts: 1
Threads: 1
Joined: Apr 2016
looking for hydeaulic floor jack design pdf
Posts: 6,843
Threads: 4
Joined: Mar 2015
hydeaulic floor jack design pdf
This is a 1 1/4 ton hydraulic floor jack my father passed on to me. He bought it new during the 1970s. It began to leak down a little a few months ago. The lift arm no longer rises when the handle is pumped up and down. (I was able to pull the lift arm up by hand and it settled slowly enough that I could make a photo with the arm partially raised.)
I checked to be sure it was adequately filled with fluid, but that was not the problem. A few months before this problem, there were bubbles coming up through the vents at the filler plug. At that time I raised the lift arm with the handle, released the jack's valve, and let the arm fall slowly several times to purge air from the system. Finally, one day, the lift arm would not rise at all. If filling with fluid and purging air from the system do not restore function, there is probably internal leakage, even though fluid is not leaking from the jack. From what I have read, forty years of service is a reasonable time for a hydraulic jack to operate before it needs a rebuild.
A word of caution: Rebuilding this jack presented several challenges that seemed almost insurmountable at the occurrence of each. Rebuilding this jack was much more difficult than simply replacing a few "O" rings, and it required more than the very few hours some say are required for rebuilding a jack. Further, I had to make several special tools to get the job done. If you want to attempt rebuilding a jack and you are not a member of Instructables, I would encourage you to pick a password and a screenname, and join. Doing that will allow you to download a PDF of this Instructable for printing, or to view at any time later on your computer, assuming you wish to consult what I have done as a guide.
When putting fluid into a jack never use anything other than hydraulic jack fluid. Do not use motor oil or brake fluid. Brake fluid makes the seals swell.