HD6G injection pump problems
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=194917
Printed Date: 30 Oct 2025 at 9:11pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: HD6G injection pump problems
Posted By: IH Steve
Subject: HD6G injection pump problems
Date Posted: 01 May 2023 at 11:55am
| OK,so the transfer pump works but there is no fuel coming out of the injector lines. I turned the bleed screw loose, the one between the 4 lines on top of the pump,plenty of fuel coming out there but nothing out of the fittings where the injector lines go. Possibly a broken plunger in the pump? Is there any way to fix this? If not,does anybody know what kind of replacement pump would fit on? |
Replies:
Posted By: CAL(KS)
Date Posted: 01 May 2023 at 1:43pm
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hmm, hopefully the head isnt seized. those pumps are about impossible to rebuild because parts dont exist anymore ------------- Me -C,U,UC,WC,WD45,190XT,TL-12,145T,HD6G,HD16,HD20 Dad- WD, D17D, D19D, RT100A, 7020, 7080,7580, 2-8550's, 2-S77, HD15 |
Posted By: doctorcorey
Date Posted: 01 May 2023 at 9:36pm
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My last experience when I got my HD6G running (sitting for years), I loosened the injector line nuts, and nothing came out, just like for you, but shortly thereafter, the engine started. The fittings are so sealed that even with the nuts loose, no diesel will escape. Still that way after a hundred hours of running. Anyways, good luck. ------------- Semper Fi USMC 1958 HD6G, 1959 MF 203 loader, 1960 Case 420B Backhoe, MF 65 Tractor/Loader Diesel |
Posted By: IH Steve
Date Posted: 02 May 2023 at 7:33am
I actually turned the lines loose on top of the pump and pulled them off,still nothing 
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Posted By: doctorcorey
Date Posted: 02 May 2023 at 9:02am
------------- Semper Fi USMC 1958 HD6G, 1959 MF 203 loader, 1960 Case 420B Backhoe, MF 65 Tractor/Loader Diesel |
IH Steve wrote:Posted By: IH Steve
Date Posted: 02 May 2023 at 9:10am
| I tried removing the head,removed the 4 bolts and shut off valve cover,but it doesn't come off,seems to be caught on something |
Posted By: Ian Beale
Date Posted: 02 May 2023 at 6:08pm
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There is likely what looks like a stud with a hex head on the side of the head which has to come out to release the head. It has a square section O-ring on the end and that also has to come out - it might come with the stud but it might stick inside. Take care getting it out as IIRC it is also likely unobtanium And you have to remove the shaft assembly that links the governor rod to the spill valve - inside the shut off cover. Remembering slowly - There is a spring clip on the bottom of the head assembly that keeps the spill valve in place when replacing the head. If if has come off it will likely be in the bottom of the primary feed well. It does make replacing the head easier. |
Posted By: IH Steve
Date Posted: 03 May 2023 at 7:42am
| A stud with a hex head on the side of the pump head? I don't recall seeing one,or do you mean the one that holds the spring and valve thing in place? |
Posted By: IH Steve
Date Posted: 04 May 2023 at 7:25am
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I got it started and it runs the needle valve was stuck I took it out and cleaned it,started right up Thanks for the help everyone |
Posted By: CAL(KS)
Date Posted: 04 May 2023 at 7:39am
------------- Me -C,U,UC,WC,WD45,190XT,TL-12,145T,HD6G,HD16,HD20 Dad- WD, D17D, D19D, RT100A, 7020, 7080,7580, 2-8550's, 2-S77, HD15 |
Posted By: doctorcorey
Date Posted: 04 May 2023 at 10:55am
------------- Semper Fi USMC 1958 HD6G, 1959 MF 203 loader, 1960 Case 420B Backhoe, MF 65 Tractor/Loader Diesel |
Posted By: IH Steve
Date Posted: 04 May 2023 at 12:23pm
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I changed the filters before I tried to start it so it should be alright. Can't wait to start pushing dirt with it,still have to put the clutch back together. The parts should be coming this week Must be fun using these dozer loaders 
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