AC Forklift Hydraulics

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   I have an old AC forklift that has a problem with the tilt cylinders every time that I put a load on it and tilt it back it goes back down. I checked the cylinders and they don't seem to be leaking and they are non serviceable they are welded and don't have a screw out end. I also did change a line that was leaking on one side and the other side has a small leak I think. I also did change the fluid and does anyone know the capacity on these it has no dipstick I measured out 3.5 gallons and put the same amount in. I put ATF in it.

	This site is not affiliated with AGCO Inc., Duluth GA., Allis-Chalmers Co., Milwaukee, WI., or any surviving or related corporate entity. All trademarks remain the property of their respective owners. All information presented herein should be considered the result of an un-moderated public forum with no responsibility for its accuracy or usability assumed by the users and sponsors of this site or any corporate entity.
	The Forum	Parts and Services	Unofficial Allis Store	Tractor Shows	Serial Numbers	History

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Famous Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 01 Mar 2019 Location: Ventura Points: 6	Post Options Post Reply Quote Famous Report Post Thanks(0) Quote Reply Topic: AC Forklift Hydraulics Posted: 21 Mar 2019 at 1:36am
	I have an old AC forklift that has a problem with the tilt cylinders every time that I put a load on it and tilt it back it goes back down. I checked the cylinders and they don't seem to be leaking and they are non serviceable they are welded and don't have a screw out end. I also did change a line that was leaking on one side and the other side has a small leak I think. I also did change the fluid and does anyone know the capacity on these it has no dipstick I measured out 3.5 gallons and put the same amount in. I put ATF in it.

Sponsored Links

jaybmiller Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Location: Greensville,Ont Points: 24350	Post Options Post Reply Quote jaybmiller Report Post Thanks(0) Quote Reply Posted: 22 Mar 2019 at 6:16am
	If you mean when it tilts back,release leaver, it then tilts forward, I think the control valve has a small blockage or bad O-ring or ?? Something that isn't allowing the valve to fully close,so oil leaks internally. You don't say which model lift, but my FPD50 tank cap has a 'dip stick' attached to it. I'd say fillup yours to say 2" below where the stem and top of tank meet. you can try www.liberatedmanuals.com for a manual, 100s of them there. Jay
	3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water

Joe(TX) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 11 Sep 2009 Location: Weatherford. TX Points: 1682	Post Options Post Reply Quote Joe(TX) Report Post Thanks(0) Quote Reply Posted: 22 Mar 2019 at 5:32pm
	It's probably the cylinders leading at the piston seals. It seems to be the most common cause, at least all the forklifts and loaders I've had. Leaking o rings on the valve cannot cause the problem. They only control external leakage. There are no internal seals in the valve.
	1970 190XT, 1973 200, 1962 D-19 Diesel, 1979 7010, 1957 WD45, 1950 WD, 1961 D17, Speed Patrol, D14, All crop 66 big bin, 180 diesel, 1970 170 diesel, FP80 forklift. Gleaner A

Jim.ME Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 19 Nov 2016 Location: Maine Points: 958	Post Options Post Reply Quote Jim.ME Report Post Thanks(0) Quote Reply Posted: 22 Mar 2019 at 6:14pm
	You say you checked the cylinders and they don't seem to be leaking. How did you check them? Visually, as you didn't see a leak out of the cylinder at the rod? The piston packings could be leaking internally which you can't see. I don't know about those tilt cylinders but it doesn't seem that tilt cylinders would be non-serviceable (100% welded). Are you sure the gland on the rod end doesn't unscrew from inside the tube? If there is a bead of weld on that end I would wonder if someone had a problem and did that as a one time fix, for their use. How much slop in the valve? If the centering spring was bad the valve spool might not be in center, closed to both sides of the cylinders, when you let go of the handle. The model info and some photos might help.