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Group 31 Batteries

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=209483
Printed Date: 22 Mar 2026 at 6:49am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com


Topic: Group 31 Batteries
Posted By: Tbone95
Subject: Group 31 Batteries
Date Posted: 25 Dec 2025 at 1:51pm
K, dumb question I guess. If a stud (post) can wiggle, albeit slightly, is that a problem?



Replies:
Posted By: Les Kerf
Date Posted: 25 Dec 2025 at 1:57pm
It sure can be a problem, but it also might work fine for a long time. It is certainly not desirable, and I wouldn't want it on any machine/vehicle that I considered to be critical.


Posted By: Tbone95
Date Posted: 25 Dec 2025 at 2:23pm
That’s kinda what I was thinking. It sure didn’t come new that way. I think I’ll take it back where I bought it and see what they say. Friggin’ paid enough for it that’s for sure.


Posted By: SteveM C/IL
Date Posted: 25 Dec 2025 at 8:30pm
Sounds faulty from the get go. They don't come loose with normal use and should take some abuse as well before that happens. Worst case is poor connection internally and hydrogen BOOM!


Posted By: 1963D17
Date Posted: 30 Dec 2025 at 4:00pm
That post attaches to the grid plates. Quality group 31's use a 1/2" rod to the grid. Cheaper one's a 3/8". When they wiggle the rod is usually corroded and getting thin allowing the stud to move. This is made worse by the farmers best friend. Using his pliers to wiggle off the cable instead of prying it straight up.


Posted By: SteveM C/IL
Date Posted: 30 Dec 2025 at 9:11pm
Originally posted by 1963D17 1963D17 wrote:

That post attaches to the grid plates. Quality group 31's use a 1/2" rod to the grid. Cheaper one's a 3/8". When they wiggle the rod is usually corroded and getting thin allowing the stud to move. This is made worse by the farmers best friend. Using his pliers to wiggle off the cable instead of prying it straight up.
A stud post should not require any prying. Remove nut and lift coble off.


Posted By: 1963D17
Date Posted: 30 Dec 2025 at 11:22pm
Missed the stud type. Both my 7120 Magnum and 1660 combine have that style.


Posted By: Tbone95
Date Posted: 31 Dec 2025 at 6:35am
Well I'll be taking it to the store Friday, we'll see what they say.  Battery is only 7 months old.  


Posted By: Steve in NJ
Date Posted: 31 Dec 2025 at 7:58pm
Ditto to what Les said. Loose posts can cause a lot of electrical gremblins.
Steve@B&B


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39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife


Posted By: AllisFreak MN
Date Posted: 02 Jan 2026 at 6:31pm
Originally posted by Tbone95 Tbone95 wrote:

Well I'll be taking it to the store Friday, we'll see what they say.  Battery is only 7 months old.  

Well?


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'49 A-C WD, '51 A-C WD, '63 A-C D17 Series III, 1968 A-C One-Seventy, '82 A-C 6060, '75 A-C 7040, A-C #3 sickle mower, 2 A-C 701 wagons, '78 Gleaner M2


Posted By: Tbone95
Date Posted: 02 Jan 2026 at 8:20pm
Originally posted by AllisFreak MN AllisFreak MN wrote:

Originally posted by Tbone95 Tbone95 wrote:

Well I'll be taking it to the store Friday, we'll see what they say.  Battery is only 7 months old.  


Well?
lol! Yeah, crazy last couple of days, let’s make it Monday!


Posted By: Ed (Ont)
Date Posted: 03 Jan 2026 at 4:46pm
Stud post batteries are great! The entire trucking industry runs on them. But you can also damage them if you use too long of 9/16 wrench on them. And never use a gun on them! Lol.  I use short wrench or ratchet and snug carefully. Not sure what the torque would be   Maybe 15-18 ft lbs at most. I have never torqued those. Just be careful.  😀😀


Posted By: Tbone95
Date Posted: 06 Jan 2026 at 7:50am
Well, guy at the parts store said yeah that’s not good, I’ll grab you another one! I noticed the other stud on that battery was slightly loose also.

As far as what Ed just said, I don’t think I over tighten them. One can just sort of sense that’s not the strongest thing to reef on.


Posted By: PaulB
Date Posted: 06 Jan 2026 at 10:38am
Originally posted by Ed (Ont) Ed (Ont) wrote:

Stud post batteries are great! The entire trucking industry runs on them. But you can also damage them if you use too long of 9/16 wrench on them. And never use a gun on them! Lol.  I use short wrench or ratchet and snug carefully. Not sure what the torque would be   Maybe 15-18 ft lbs at most. I have never torqued those. Just be careful.  😀😀
 Yes the trucking industry has almost gone to exclusively Group 31 stud post batteries. They are supposed to use LEAD nuts that will NOT over torque the stud but have the nut strip out. Then some Yahoo just goes to the hardware bin and grabs a 3/8" coarse thread nut, then the problems begin.
  Locally I can buy a quality 7 year Group 31 stud post battery for under $100. Whereas a small 5 year car battery is close to $130. I use Group 31 stud post batteries in everything that they will fit in. That way when the big truck gets a new set I can use the good singles until they give up.  


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If it was fun to pull in LOW gear, I could have a John Deere.
Real pullers don't have speed limits.
If you can't make it GO... make it SHINY


Posted By: Tbone95
Date Posted: 06 Jan 2026 at 11:00am
Originally posted by PaulB PaulB wrote:

Originally posted by Ed (Ont) Ed (Ont) wrote:

Stud post batteries are great! The entire trucking industry runs on them. But you can also damage them if you use too long of 9/16 wrench on them. And never use a gun on them! Lol.  I use short wrench or ratchet and snug carefully. Not sure what the torque would be   Maybe 15-18 ft lbs at most. I have never torqued those. Just be careful.  😀😀

 Yes the
trucking industry has almost gone to exclusively Group 31 stud post batteries. They are supposed to use LEAD nuts that will NOT over torque the stud but have the nut strip out. Then some Yahoo just goes to the hardware bin and grabs a 3/8" coarse thread nut, then the problems begin.
  Locally I can buy a quality 7 year Group 31 stud post battery for under $100. Whereas a small 5 year car battery is close to $130. I use Group 31 stud post batteries in everything that they will fit in. That way when the big truck gets a new set I can use the good singles until they give up.  


Be nice if they’d supply the dang nuts!


Posted By: SteveM C/IL
Date Posted: 06 Jan 2026 at 1:36pm
All 10 of my stud post 31's have stainless nuts. That's what they sell at the truck dealership. Neve seen a lead nut. No issues for 42 yrs.


Posted By: Les Kerf
Date Posted: 06 Jan 2026 at 4:44pm
This is the first I ever heard of lead nuts on battery posts Tongue


Posted By: PaulB
Date Posted: 06 Jan 2026 at 8:02pm
Originally posted by Les Kerf Les Kerf wrote:

This is the first I ever heard of lead nuts on battery posts Tongue
 The new Freightliner I brought in 1986 had them and the local HD truck parts place and local battery store have a bin for them. I've never seen anything but soft battery nuts for OEM parts.  I have however seen many standard hardware nuts on things I've worked on over the years. Very much like the special battery bolts for side post batteries. They are made of a softer material and have a 5/16" or 3/8" hex so the wrench ape can't over torque them.


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If it was fun to pull in LOW gear, I could have a John Deere.
Real pullers don't have speed limits.
If you can't make it GO... make it SHINY



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