Hey Guys-

So my D17 Series 1's rear lift has ceased function, and the reservoir is low, I added a little bit, and it operated slightly, and the reservoir level fell, and the rearend level went up, so I got the typical blown hose or cylinder seal.

Which I'll make a 'winter project' of... but for the moment, I need it for other things.

The issue I forsee, however, is that the pump is a demand-control device which is mechanically unloaded when pump pressure hits the unloading limit.

In most contexts, this means that a pump that has insufficient source fluid will never reach unloading pressure, hence it will continue to TRY to pump, sans fluid, until there's nothing left of the pump.

I SUSPECT that this might be the case of the D17 Series 1's setup, and I do NOT wish to damage the pump, so what I've done is placed the lift lever in the full DOWN position, and added fluid to the reservoir, to keep that pump wet.

Is this a satisfactory action for the pump's actual operation, or is it unnecessary, or is it futile?  Will the pump burn up ANYWAY, or will it be fine regardless??

I'll be using it with the backhoe attachment for the next two months-or-so, which absolves need for the lift or high-pressure system, because the backhoe runs off PTO pump.

Ah... excellent... YES!  Thanks guys!

I'm gonna bearings/seals the finals, brakes, and rearend, as well as PTO shaft, seein's how I gotta get in there anyway.  Probably put a diverter/selector on the feed pipe as well, just for future options.  I don't know what it would be, but Murphy's Law says that if I don't, I'll wish I had someday...

Okay, so I FINALLY got around to shoppin' the D17.  Got the lift housing off the tail, and yes, the cylinder seal was blown.  The hydraulic line was clearly original, it looks like the inside of this thing has not seen daylight since it was built in '57.

I had my local hydraulics shop make me up a 5800psi hose, and I got the new cylinder packing...  but I found that once ONE of the backup rings is in place, and the O-ring is in place, there's simply NO ROOM left in that groove for a second backup ring.

I looked it up (page 79) of the Allis service manual, and it shows, and explains TWO backup rings, one O ring... it says put both backup rings, then the O ring in the middle.

And then I looked back at my original photos, because I recalled only ONE backup ring.

Yep, only one backup ring, on the inside of the cylinder side...

So this leads me to wonder:

Did they, perchance, build them with just one backer, and then change the design soon after to accomodate a second?

With both backer rings in, I've got a 0.086" gap.  The O-ring is 0.208" thick... That's 0.122 crush of an O-ring that feels to be about SHORE A 70 or so... way too hard to make that crush.

What am I missing here??

Okay, so total fail on my part here.  Last night, I was looking at it with cold hands and tired eyes.

Today, when I was getting ready to put it back together, I noticed a little change in the cylinder's color, so got in there with a pick (to clean off what appeared to be a little spot of corrosion...

And it turns out that there WAS a second ring, and it was darned-near impregnated INTO the cylinder.  I few minutes with the pick, followed by a sharp screwdriver blade, I got it to break loose... and it came out almost clean.

After scraping the residue out, it allowed me to put the whole stack in just fine.

Then I picked up the housing and slid it into place, while my buddy Mike got the cylinder halves started, and the hose threaded through the top... wiggle and bump, and it went in just dandy.

So, my apologies for the false alarm.  Between the old merc-vapor high-bay lamps (purple glow) and tired eyes, I totally wasted your time.  ;-)

I got the PTO shaft back in, but not before replacing the rear bearing and seal.  I actually pushed the old seal off, and found that the closest modern replacement (an SKF 13661... about $15) was just a tad thicker than just half the original's width, so I bought TWO.  I pressed the first one full depth (which offset the contact path by about 0.135"), then pushed the second one on, which put it's lip about flush with the cover... and on the areal of the shaft clear of splines.  I cleaned up the shaft good, polished it smooth, and slipped it in, then the cover, and snugged it down.  Looks good.

I'm draining ALL the sumps good, then refilling all.  Is it just me, or has the prices of lubricants gone up by 300% since four years ago??