Farm Equipment - Ac d17 series 3 lift arms down speed

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Ac d17 series 3 lift arms down speed

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Category: Allis Chalmers
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=208826
Printed Date: 28 Dec 2025 at 12:50pm
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Topic: Ac d17 series 3 lift arms down speed

Posted By: Vwcountry
Subject: Ac d17 series 3 lift arms down speed
Date Posted: 07 Nov 2025 at 4:36pm

The lift arms work just fine but when you let them down you can’t do it slowly it comes down like a hammer. Is this normal thanks

Replies:

Posted By: DrAllis
Date Posted: 07 Nov 2025 at 5:52pm

I guess, yes. What exactly are you doing that causes you to complain?? A "rate-of-drop" valve could be installed in-line to adjust oil return to the sump while not affecting raise speed.

Posted By: Clay
Date Posted: 07 Nov 2025 at 6:07pm

On the left hand side sheet is a one inch hole for the lowering adjustment.

This is the LIFT_LOWER Lever Linkage adjustment knob.

Turning the knob to the to the right increases the lowering adjustment. Turning it to the left slows the lowering adjustment.

I have a series II D-17. Not sure if it applies to other series.

Posted By: DrAllis
Date Posted: 07 Nov 2025 at 6:16pm

That adjustment screw only works when using the Traction Booster system, like on a mounted plow. If you've ever plowed, the plow still drops like a brick at the end of the field. That speed drop adjustment screw keeps the hand lever at the top of the bottom window and meters the return oil when the TBoost system is releasing the lift pressure. Early model D-17's did not have this, and the performance of the weight transfer system was lacking. So,this feature had to be created and works well if it is adjusted correctly. EDIT: I've never tried this but maybe it could work. If you screw that speed adjustment screw "in" (clockwise) as far as it will go, maybe the lift/lower lever stroke would be altered enough to where the hold valve plunger releases up higher into the mid-range of the levers stroke. Then, your hand could better control drop speed. Try it.

Posted By: Clay
Date Posted: 07 Nov 2025 at 9:05pm

I pulled out my operators manual and Dr Allis is right. It works with the traction booster.

Page 37 in my OPERATING INSTRUCTIONS.

ADJUSTMENT(LIFT-LOWER Lever Linkage)

Effective on tractors D17 - 17846 and up, with the 1" hole in the left hand side sheet.

1. Place the TRACTION BOOSTER hand lever at bottom of quadrant.

2. With engine running, move the LIFT-LOWER lever to the lift position and unload pump. At this time pressure will be indicated on the TRACTION BOOSTER gauge.

3. Carefully lower the LIFT-LOWER lever until you feel the lever contact with the hold position valve plunger. Without releasing the pressure indicated on the TRACTION BOOSTER gauge, turn the lowering control adjusting nut (located through hole in left hand side sheet below fuel tank) counterclockwise until the LIFT-LOWER lever latches in the lower window on quadrant. Now turn the adjusting nut clockwise until the gauge pressure drops.

Posted By: HudCo
Date Posted: 08 Nov 2025 at 4:36pm

so how well will it work when their is 1/8 of an inch of slop in every conection from the snap coupler bell to the pump and quadrant wich equals about a third of the quadrat before the tail end of it reacts

Posted By: DrAllis
Date Posted: 08 Nov 2025 at 5:14pm

Probably not as good as if there weren't any sloppiness in the linkage. From the snap-coupler bell area not a problem but from the hand lever down inside the torque housing would cause some issues, yes.

Posted By: Vwcountry
Date Posted: 09 Nov 2025 at 9:07am

After further investigation, I’ve noticed this only happens if the lift is raised all the way up. Anything less than all the way up you can raise it slow. You can let it down slow but once you go all the way up then it is much harder to get it to release to go down then it drops like a concrete block.

Posted By: DrAllis
Date Posted: 09 Nov 2025 at 10:59am

You didn't say what you are doing when you experience this. When raising anything, once the lift arms or implements are fully up/raised, you are supposed to place the Lift/Lower lever out of the raise window and into the middle of the quadrant. If you leave the Lift/Lower lever locked in the raise window, the hydraulic pump is hammering itself to maximum pressure of 3400-3700 psi. Now, in order to get the load to lower, you have to open the hold valve ball off its seat with 3400-3700 psi of pressure against it. Placing the Lift/Lower lever in the middle of the quadrant first, will slowly allow the lift pressure to slowly dissipate and then the hold valve ball is much easier to open for easier lowering control. Again, what task are you performing ???????

Posted By: Vwcountry
Date Posted: 09 Nov 2025 at 6:06pm

All I am doing is maintenance that was neglected. I purchased the tractor about a month ago. I you asked what I was doing actually nothing just changing all fluids greasing all joints rebuild carb then I noticed even with nothing on lift arms if you raise all the way up max it seems to put the hydraulic under severe pressure and you have to really pull hard to get it to release. I am not leaving the lift control in raised position it just happens if it goes all the way up. Sorry if I didn’t explain it very well.

Posted By: Clay
Date Posted: 09 Nov 2025 at 7:27pm

Where is the traction booster lever positioned?

Posted By: DrAllis
Date Posted: 09 Nov 2025 at 7:36pm

He said "drops like a hammer". I assumed he meant the implement or lift arms dropped like a hammer. I guess not.............. I think Mr. VWcountry needs to actually connect an implement or hang a plow on the lift arms and operate the hydraulic system for a while and get the "feel" of what really happens.

Posted By: Vwcountry
Date Posted: 10 Nov 2025 at 9:11am

This tractor does not have a traction booster lever. It only has the lift control lever to the left of the steering wheel. That is all. And I have hooked implements to it. It lift them just fine. It’s the same way though if you raise all the way to the max height you have to pull the lift Lever very hard to get it to start to release then it drops like a hammer. But if you stop just before Max high, you can lower it very slowly and easy.

Posted By: DrAllis
Date Posted: 10 Nov 2025 at 9:33am

I've got a 1960 dealer sales book at home. I guess I've never seen any series 3 D-17 without a Traction Booster system on it. It was standard equipment. It may have been a delete item, but like I say, I've never seen one without. And, yours may not be a series 3 in actuality. Many older D-17's got a series 3 paint job and decals to look like a series 3. The 5 things that would designate it as a true series 3 would be fender mounted headlites, dry type air cleaner, belt driven power steering, oval muffler and band/disc brakes. Regardless, I can't help your complaint. I don't think there is anything wrong with your tractor. It just may not be what you think it should be when it comes to the operation of the Lift/Lower lever.

Posted By: Vwcountry
Date Posted: 10 Nov 2025 at 3:20pm

Sorry, I didn’t think I was complaining just asking but all five things that you mentioned about the tractor is exactly the way it is series 3, including the serial number on the tractor. But with only the single lift Lever to the left of the steering wheel, there is absolutely nothing to the right of the seat

Posted By: DrAllis
Date Posted: 10 Nov 2025 at 3:34pm

The Traction Booster lever sat on top of the Lift/Lower lever and utilized the notches on the quadrant. Does it have the snap-coupler bell underneath ??

Posted By: Vwcountry
Date Posted: 10 Nov 2025 at 4:47pm

No it only has the single lever for the lift unless someone modified it before me. The only levers on the entire tractor is lift. Throttle.Pto and belt pulley. I’m in the process of adding a single spool hydraulic for my hay bailer. Thanks for all the input

Posted By: DaveKamp
Date Posted: 10 Nov 2025 at 5:01pm

Hmmm... this is very peculiar.

I wonder if the 'delete' state of the traction booster system has somehow impacted the release valve... I don't recall if that is part of a spool, or if it's simply lifting up on a load-check ball... that'd take some other expert who knows how the traction-booster system operates... but it sounds like the TB functionality may be improperly locked-out.

Regardless, if you're gonna open up any hydraulic lines, you could install a check valve in line with the rear lift cylinder, and a bypass line AROUND it, with an adjustable restrictive orfice. When lifting, the bypass would allow flow out, as would the check valve, but when lowering, the check valve would stay closed, forcing return flow to pass through the restrictive orfice, thus giving you an adjustable max lowering rate. It would NOT prevent you from modulating the lowring to some LESSER part, if you can do so.

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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.

Posted By: Vwcountry
Date Posted: 12 Nov 2025 at 8:55am

That makes sense