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D21- 3 point creeps up

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=202068
Printed Date: 07 Jul 2024 at 8:23am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com


Topic: D21- 3 point creeps up
Posted By: Acdiesel
Subject: D21- 3 point creeps up
Date Posted: 01 Jul 2024 at 11:11am
I bought this tractor not running. 
I have been doing a complete nut and bolt restoration on it. 
Rebuilt the engine, went throught every system and part, new seals bearings ETC.
I now have the tractor running and working out any bugs or leaks before I start to paint.

The Problem I have is when the engine is running around 3/4 throttle and higher the 3-point will start to raise. It does not matter what postion I have the control lever in, it has no effect on the 3-point till I throttle the engine back down.

I have taken the hydraulic spool valve assembly, manifold and traction booster valves apart-cleaned and resealed them. Everything looks okay, I must be missing something?

I have no linkage hooked to the traction booster valve, I have even removed the Traction Booster line and had it return to the sump and the 3- point still goes up on its own above 3/4 throttle. 

I have 1000 psi at idle and 2200 psi at full throttle.


Any help would be greatly appreciated.


I have tried to adjust everything on the hydraulic system and no change to the 3-Point 

I have an I&T shop Manal but it does not give the path of flow of the hydraulic system 








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D19 diesel,D17 diesel SER.3 D14 NF,D14 WF, D15 SER.II wf
D15 SER.2 DIESEL,D15 ser.II nf
D12 SER.I, D10 Ser.II
2-720'S

Gmc,caterpillar
I'm a pharmacist (farm assist) with a PHD (post hole digger)



Replies:
Posted By: DrAllis
Date Posted: 01 Jul 2024 at 11:40am
Explain 1,000 psi at an idle and 2,200 psi at full throttle. Is this measured at a remote coupler outlet and activating a remote lever ??   Pretty sure your problem is this:  normal backpressure in the hydraulic system with COLD hydraulic oil. By "cold" I mean less than 140 or 150 degrees F.  I just had my One-Seventy on a tractor ride over the weekend and when I ran at full throttle with warm hyd oil for 20 minutes the hitch was half-way or more up. This is a normal thing and a dirty or small hydraulic filter would make it worse.


Posted By: Acdiesel
Date Posted: 01 Jul 2024 at 12:08pm
Yes, That pressure is by activating the remote valve. with cold oil.

Everything is new: New filter and quality hyd. oil 

I even went as far as drilling the center hole on the Hydraulic filter housing a little larger to help the oil flow better.

I used air to do bench testing on this hydraulic system  and did notice that the port for the 3-point will build pressure if i restricted the flow on the return to sump line, that is what lead me to disassemble the filter housing and check to make sure the filter was not the issue and make sure that i did not put the by-pass in wrong.

Agco filter # 70239930 I have the NAPA interchange filter on there now #1049

Thanks, Dan 


-------------
D19 diesel,D17 diesel SER.3 D14 NF,D14 WF, D15 SER.II wf
D15 SER.2 DIESEL,D15 ser.II nf
D12 SER.I, D10 Ser.II
2-720'S

Gmc,caterpillar
I'm a pharmacist (farm assist) with a PHD (post hole digger)


Posted By: DrAllis
Date Posted: 01 Jul 2024 at 12:31pm
Everything is as it should be. The hitch won't lift anything, just itself.


Posted By: Acdiesel
Date Posted: 02 Jul 2024 at 10:55am
Thank's for your information!

-------------
D19 diesel,D17 diesel SER.3 D14 NF,D14 WF, D15 SER.II wf
D15 SER.2 DIESEL,D15 ser.II nf
D12 SER.I, D10 Ser.II
2-720'S

Gmc,caterpillar
I'm a pharmacist (farm assist) with a PHD (post hole digger)



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