Need help with JI Case 310 power steering

Howdy, Folks!

Picked up a JI Case 310 TLB a couple weeks ago, and am close to having it sorted out well enough to start digging. Having a devil of a time with the power steering though, and could use some guidance. Kindly pardon any ignorance on my part, as I know little about tractors. I'm quite mechanically minded though, and have spent quite a lot of time wrenching on old British cars.

Anyway, the power steering is the type that has the G45056 cylinder along the front axle with an integrated spool valve, which is actuated by a link off the steering lever. This is fed from a G45055 pump mounted on the side with the intake/exhaust, with the G45054 remote reservoir. When the engine is running I'm getting a lot of foaming in the reservoir no matter how many times I purge the system, and seemingly a lot of fluid flow even with the spool valve on the cylinder centered. I'm also getting absolutely *no* power assist.

I've had the pump apart and it looks like it had been rebuilt sometime in the past, and clearance between the lobes of the ring and star-shaped piece in the pump (part A11024) looks to vary between 0.002" and 0.006". I haven't yet done a pressure test on it, so don't actually know if it builds any pressure. It will definitely move fluid though, and with the hose capped off it will stall the pump and the belt will slip (it's driven by double groove pulley on an alternator conversion).

I took the cylinder apart today to take a look at the spool valve, and have a new set of seals for it coming from Messick's on Wednesday.

At this point I'm kind of at a loss what to poke at, as I don't understand spool valves well enough to tell if that's the problem or the pump is. Any thoughts or advice?

Another thought I had is I think I saw mention in a thread here somewhere about the possibility of simply ditching the separate power steering pump and instead splicing it into the main hydraulics that run the loader and backhoe. I know for a fact that pump works, as both the loader and backhoe work just fine. Would cost a not small amount for fittings and new hoses, but compared to a pump rebuild for the separate pump it might be a better option.

Thanks!

-aric.

Good morning Aric - What's a TLB? I've a 310B backhoe loader unit, that's really useful on my farm. It, too, has power steering questions. It works but indifferntly. Kinda like the house cat, responds but not how you'd like. I do have a nice "pile" of Whitworth wrenchs and sockets from working on limey stuff too. Gathering dust though. Looking forward to a response on your questions.

What's a TLB?

Click to expand...

Sorry, thought I got that term here... Tractor / Loader / Backhoe.

If you're is a 310B, it's likely the same as mine but a year or two newer. I picked it up because I need to redo the 250' of French drain I hand-dug in November due to it ending up not being a surface water problem, and there's no way I'm hand digging it 5' deep, in January, in SE Pennsylvania. So far I've put 10 pounds of E7018 stick electrodes onto the backhoe to repair some really badly done "fixes" (cut out the whole mess of it and repaired it properly) and have redone both the fuel and ignition systems. Would be well on my way to digging were it not for it being impossible to steer with a full front bucket...

Anyway, I found a 1950's vintage US Army training video last night that explained power steering and spool valves, so I'm a bit further there. Looks like the flow I'm seeing with the valve centered is appropriate, so will poke at that further when the new seals arrive tomorrow.

Last night I did a bunch of drawfiling and stoning on the pump housing to get a better sealing surface, but that ended up dropping the depth of the bore for the gerotor a couple thou under the thickness of the gerotor and it would bind. So today I chucked the housing up in the lathe, faced the housing properly and then recut the bottom of the bore to allow 0.001" clearance for the gerotor. Total PITA since I don't have a suitably sized 4-jaw chuck and the bore is offcenter from the shaft, but got it done. Since I'm waiting on the spool valve seals and happen to have an appropriately-sized piece of ground rod, I'll be making a new pump shaft this afternoon. The original is horribly scored, so figure I may as well fix everything at this point. Guess that means I'll be pulling the pump shaft seal as well and trying to find a replacement... Ugh.

-aric.