D17 Series 1 hydraulic pump question

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   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.

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DaveKamp Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Apr 2010 Location: LeClaire, Ia Points: 5747	Post Options Post Reply Quote DaveKamp Report Post Thanks(0) Quote Reply Topic: D17 Series 1 hydraulic pump question Posted: 04 Sep 2023 at 6:16pm
	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.
	Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.

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steve(ill) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 11 Sep 2009 Location: illinois Points: 80837	Post Options Post Reply Quote steve(ill) Report Post Thanks(0) Quote Reply Posted: 04 Sep 2023 at 7:22pm
	normal mode of failure is the hose to the cylinder... or could be the cylinder seal.. Either way, if you DONT MOVE THE LEVER, you should not be putting oil to the hose / cylinder and therefore no oil transfer ......... right ?
	Like them all, but love the "B"s.

DaveKamp Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Apr 2010 Location: LeClaire, Ia Points: 5747	Post Options Post Reply Quote DaveKamp Report Post Thanks(0) Quote Reply Posted: 04 Sep 2023 at 7:25pm
	Yeah, I got that part, I've watched a few disassembly videos. I've got SOME fluid in the reservoir, and the handle tied down. Will that be sufficient to keep the pump safe 'till I finish my digging and shop this piglet?
	Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 20399	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 04 Sep 2023 at 7:34pm
	Should be. Keep an eye on the oil level. Disconnect the line beside the seat and cap it for absolute fix.

DaveKamp Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Apr 2010 Location: LeClaire, Ia Points: 5747	Post Options Post Reply Quote DaveKamp Report Post Thanks(0) Quote Reply Posted: 04 Sep 2023 at 8:13pm
	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...
	Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.

DaveKamp Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Apr 2010 Location: LeClaire, Ia Points: 5747	Post Options Post Reply Quote DaveKamp Report Post Thanks(0) Quote Reply Posted: 11 hours 17 minutes ago at 10:11pm
	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?? Edited by DaveKamp - 10 hours 43 minutes ago at 10:45pm
	Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 20399	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 2 hours 57 minutes ago at 6:31am
	You can't get it wrong. If you stuff 6 gallons of Pooh in a 5 gallon pail it won't work out well. If you pack too much in that groove you won't get the ram back in. Some of us old guys are so used to throwing things away out of seal "kits" this would be nothing new. A "kit" just fits several different things and may have parts you don't need for your particular application. Make it like it was for decades.

DaveKamp Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Apr 2010 Location: LeClaire, Ia Points: 5747	Post Options Post Reply Quote DaveKamp Report Post Thanks(0) Quote Reply Posted: 1 hour 60 minutes ago at 7:28am
	Okay, thank you. The manual showes and says both backer rings and O ring, but there clearly isn't enough gap. My suspicion is that, mine being a very early D17, may have been somehow different, and they changed the design... i.e., they started production with just one backer, then decided to open up the groove for a second one, but the service manual doesn't reflect that. sometimes things like that happen...
	Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.