# Why is the battery terminal bolt different for positive & negative

**URL:** <https://community.cartalk.com/t/why-is-the-battery-terminal-bolt-different-for-positive-negative/149594>\
**Category:** Maintenance/Repairs\
**Created:** [September 27, 2019, 3:27am UTC](https://community.cartalk.com/t/why-is-the-battery-terminal-bolt-different-for-positive-negative/149594 "2019-09-27T03:27:08Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\
**Post date:** [September 27, 2019, 3:27am UTC](https://community.cartalk.com/t/why-is-the-battery-terminal-bolt-different-for-positive-negative/149594/1 "2019-09-27T03:27:08Z")

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The bolt that clamps down the contact for the negative terminal is 10mm; the bolt on the positive is 11mm. Why? '87 Toyota pickup Xtracab Delux long-bed, carbureted, 5-speed manual, red with white camper shell, green power crystals, platformate,and gl-7 (gets my teeth whiter.)

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**Author:** ![Scrapyard-John](https://avatars.discourse-cdn.com/v4/letter/s/f6c823/32.png) [@Scrapyard-John](https://community.cartalk.com/u/Scrapyard-John)\
**Post date:** [September 27, 2019, 3:37am UTC](https://community.cartalk.com/t/why-is-the-battery-terminal-bolt-different-for-positive-negative/149594/2 "2019-09-27T03:37:17Z")

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Are you positive both bolts are the factory original bolts? Maybe the threads on one of the terminal clamps got a little boogered and someone stuck an oversized bolt in there to take up the slack.

Or maybe a 10 mm bolt will not withstand the juice put out by those green power crystals… Red power crystals, 10 mm might work. Green needs 11 mm.

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**Author:** ![Whitey](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/whitey/32/24680_2.png) [@Whitey](https://community.cartalk.com/u/Whitey)\
**Post date:** [September 27, 2019, 3:42am UTC](https://community.cartalk.com/t/why-is-the-battery-terminal-bolt-different-for-positive-negative/149594/3 "2019-09-27T03:42:39Z")

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If they’re top-mounted terminals, I’m betting the previous owner replaced one of the battery cables.

If they’re side-mounted terminals, maybe it’s to make sure you don’t hook up the terminals backwards.

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**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\
**Post date:** [September 27, 2019, 4:17am UTC](https://community.cartalk.com/t/why-is-the-battery-terminal-bolt-different-for-positive-negative/149594/4 "2019-09-27T04:17:08Z")

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Someone may have replaced the metric bolt with a 1/4" bolt, that would have a 7/16" head which is close to 11 mm.

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**Author:** ![PvtPublic](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/pvtpublic/32/13089_2.png) [@PvtPublic](https://community.cartalk.com/u/PvtPublic)\
**Post date:** [September 27, 2019, 11:36am UTC](https://community.cartalk.com/t/why-is-the-battery-terminal-bolt-different-for-positive-negative/149594/5 "2019-09-27T11:36:32Z")

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That would be my guess. Just as an aide the bolts are 6mm the nuts should take a 10mm wrench on most Toyota’s.