Farm Equipment - D17 Hitch Bolt Size

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D17 Hitch Bolt Size

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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=189002
Printed Date: 16 Sep 2025 at 4:06pm
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Topic: D17 Hitch Bolt Size

Posted By: d17wd45
Subject: D17 Hitch Bolt Size
Date Posted: 20 Jun 2022 at 9:24am

D17 Series III - Needing to know the bolt size for the two bolts that holds the plate to the housing for connection of the drawbar. The plate has the PINS the drawbar slides on the tractor. Have attach a picture. Thanks for any help.

Replies:

Posted By: DrAllis
Date Posted: 20 Jun 2022 at 11:18am

I going to say they are 3/4" NC diameter by 2 1/2" long- grade 8 quality and use a hard flatwasher, not a lock washer. The length is a guess on my part but close. They need to be TIGHT or they will work loose.

Posted By: TramwayGuy
Date Posted: 20 Jun 2022 at 1:34pm

“….3/4" NC diameter by 2 1/2" long- grade 8 quality and use a hard flatwasher, not a lock washer. ”

Grade 8 is probably overkill, as the material you are screwing it into is cast iron or cast steel. Tightening a grade 8 bolt enough to stretch it properly would maybe strip out the housing.

I agree with not using a lock washer. But I would use loctite on those capscrews rather than trying to torque to a grade 8 spec. Go to about 200 lb-ft for a 3/4” screw with loctite.

Posted By: Alvin M
Date Posted: 20 Jun 2022 at 2:26pm

After s # 24001 they used studs lock tight them in much better the bolts

Posted By: plummerscarin
Date Posted: 20 Jun 2022 at 3:25pm

TramwayGuy wrote:

“….3/4" NC diameter by 2 1/2" long- grade 8 quality and use a hard flatwasher, not a lock washer. ”

Grade 8 is probably overkill, as the material you are screwing it into is cast iron or cast steel. Tightening a grade 8 bolt enough to stretch it properly would maybe strip out the housing.

I agree with not using a lock washer. But I would use loctite on those capscrews rather than trying to torque to a grade 8 spec. Go to about 200 lb-ft for a 3/4” screw with loctite.

Curious here. Are you saying that the bolt must be under tension to achieve its full strength?

Posted By: MACK
Date Posted: 20 Jun 2022 at 9:05pm

The way it is made, I would say you need to retorque the bolts every time you use it. MACK

Posted By: TramwayGuy
Date Posted: 20 Jun 2022 at 9:47pm

“Curious here. Are you saying that the bolt must be under tension to achieve its full strength?”

No, strength is not improved by stretching, but helps keep it from loosening.

Posted By: TramwayGuy
Date Posted: 20 Jun 2022 at 9:49pm

“After s # 24001 they used studs lock tight them in much better than bolts..”

Agreed. Much less likely to strip the threads in the casting also.