Help a Novice Out
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=113463
Printed Date: 15 Sep 2025 at 2:34am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Help a Novice Out
Posted By: meteorbrews
Subject: Help a Novice Out
Date Posted: 18 Oct 2015 at 11:23am
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Hey All, Could someone help a novice out and clear something up for me? Lately, I have been taking off and putting on the battery cables for my B in the wrong order, not the wrong way, just the wrong order, taking the ground off second and putting the ground back on first. Now, I haven't done any damage to myself, thankfully, but would I do any damage to the electricals in doing such a thing? Thanks, Brad. ------------- 39/43' Franken B Amature Homebrewer and Allis Chalmers Novice |
Replies:
Posted By: Dan73
Date Posted: 18 Oct 2015 at 11:31am
| Nope it is just safer to unhook the ground terminal on a battery first incase you hit the frame when you unhook the non ground terminal. In fact with cars with computers I think they recommend that you unhook the hot side first so that you don't have non grounded electronics. |
Posted By: DougS
Date Posted: 18 Oct 2015 at 11:49am
I have never, ever seen where anyone recommends that you unhook the hot side of a battery first for any motor vehicle. Safety trumps all other considerations. Your wrench can slip from the ground terminal and hit a metal part of your vehicle and it does no damage. Let that wrench slip and hit the frame while unhooking the hot terminal first and you'll be holding a handful of fireworks. |
Dan73 wrote:Posted By: Dan73
Date Posted: 18 Oct 2015 at 11:53am
| Well my brother was a GM mechanic in the 80s when the first electronics went into them and he gave me heck for unhook in the ground first said I would blow the computer he had the service notice from GM about it. I told him I didn't care for the same reason you mentioned it is safer for me to unhook the ground first. |
Posted By: WF owner
Date Posted: 18 Oct 2015 at 12:33pm
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No matter how you unhook the battery on a B, I'm pretty sure you won't hurt any computer. One of the big reasons to unhook the ground first, is to avoid sparks. A battery gives off (potentially) explosive gases. A spark can lead to a nasty battery explosion that sprays acid everywhere. |
Posted By: DougS
Date Posted: 18 Oct 2015 at 12:52pm
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IMO unhooking the hot terminal first and causing sparks is more likely to blow a computer than merely unhooking the ground terminal first. |
Posted By: DaveKamp
Date Posted: 19 Oct 2015 at 6:11pm
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It doesn't matter to any computer or electronics WHICH side you unhook first... the circuit is just a loop, so lifting one side is no different from the other. The difference, is that when you have a negative ground still connected, and you loosen the nut on the positive post, and land the wrench against chassis or fender, you have a dead short across the battery, which causes substantial outgassing of hydrogen, and a really, really, really hot contact point where that current is flowing. This is the perfect recipie for a bomb, and you're still holding the wrench. Always disconnect the grounded side first. ------------- Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest. |
Posted By: Stan R
Date Posted: 19 Oct 2015 at 6:32pm
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I know firsthand about a battery bomb. It was winter time, D15 needed to be jumped to so I could spread some manure. Hooked up my Fathers '71 (??) Ford Bronco. Didn't know much about positive ground on the tractor. Battery blew up when I made the final connection to the Bronco--> thought I lost my thumb from the explosion. Never again..... I think the biggest battery pieces (plastic) were maybe 3 or so inches. Be safe |