The Stovebolt Site Forums The Parking Lot Big Bolts 63 c60 hydraulic fluid leak

Hey y'all, after my truck sitting still for about 5 years I'm bringing it back to life. For the most part it's going ok,running and driving good, still got brake issues but I'm working thru that. I've worked the bed hoist a few times and it does ok, real slow though. I put new fluid in the resevoir and it did better but noticed a leak from the top of the piston down onto the frame. It leaks pretty bad and will require a new fill up each time I use the dump pretty much. Is fixing this a big deal ? It may just be a seal ? Any thoughts ?

Troy
1963 c60

Fluid should not be up there above the piston, air only. You'll probably need to remove the bed cylinder and get it rebuilt if possible. If all it needs is a new piston packing, not much of a problem- - - -if the cylinder is scored or rust-pitted, things get pretty $pendy in a hurry.

Edit: What weight of fluid are you using? A lot of the older dump trucks I've worked on used a very heavy hydraulic fluid, something about the thickness of 40 weight motor oil. If you're using something thin like EP-32 tractor hydraulic fluid, a seep leak will turn into a gusher.
Jerry

Hey Jerry, good to hear from you.... I did put in a aw-32... that stuff was pretty thin as I think about it I will buy a heavier grade and see what happens. I'll let you know. I'm looking forward to hearing from you sometime in the future about what we talked about

Thanks and blessings,

Troy

Have a conversation with someone at your local farmers' co-op about what type of fluid is available. Since the dump system has only one function, raising the loaded bed, heavy fluid shouldn't present a problem. Does your system have a reserve tank, or does it use the upper side of the cylinder as its storage section? Some of the more primitive systems simply store enough fluid above the cylinder piston to supply the pump as it raises the bed, while others have a frame-mounted reserve tank onboard.
Jerry

It has the reserve tank located under the bed and between
the frame rails.... It holds about 2-3 gallons I'd guess.

Thanks for helping

Troy

Can you identify the brand and type of the hoist? if it is a single cylinder (sounds like it is) and it lies horizontally when lowered it would be a twin arm underbody. All of them from the 30's onward used cast itron piston rings and were of low pressure design (1000 psi rated) and gear pumps which is why they would work with heavy weight oil but were not originally intended to. Hydraulic oil from that era was generally 5W and if it's heavier then someone unwitingly likely used motor oil in it. Not good but won't hurt it.

First thing is to check for air being pulled in thru a fitting or around the pump or cylinder. Trapped air will blow oil out at the smallest leak or largest leak whichever is closest to the compressed air. Oil returned to the reservoir will be foamy too. If it will hold in the raised position overnight then you can probably eliminate the broken piston ring possibility. Also check for leaking at the cylinder rod area. If thats a leak then it requires the rod packing to be replaced. It's simply a matter of elinination to locate the problem area. If the cylinder requires rebuilding and your not comfortable removing it from the hoist frame then by all means take it to a good equipment repair facility. Don't risk your life working under a raised body. If the cylinder head is welded on then you must have it machined off and rewelded.

I do not know whe the brand nor type of hoist I have but will investigate and get back soon. I will also leave it up overnight and see what happens. I believe it will hold as it's shown no sign of losing pressure in the system yet. I will also but some heavier fluid as Jerry has suggested and see what happens there as well..... I'll be getting back !

Thanks very much for your advice

Troy

I left the bed up all day today near full-tilt position and it didn't lose even 1/4 of an inch. It is holding tight. Does that mean the hoist and various components are pretty much ok ? This is even before I add the heavier fluid. It seems to be doing fine right now... I will add the heavier fluid and see if that leaks then get back.

Regards, Troy

If it has air trapped in the system just cycling the hoist should allow it to work itself out. I am not a proponent of using heavier oil which will not cure a leak. Run it many times first, 12-15 cycles, and see if it still leaks before changing the oil.

Ok, sounds like a plan ! Will do.

Thanks much, Troy