John Deere Mower Repair = Fastener Hell

[BrandoJames]

My old John Deere riding mower (2007 LA130 48” cut / B&S 22 HP) quit yesterday near the end of mowing my two acres. I leave the mower in the back yard and take a look this morning. The positive battery cable is broken off at the terminal. It’s an old battery, so I decide to replace cable + battery. The battery has a 2016 sticker on it, and I’ve bought a lot of tools since then, should be a piece of cake.

I go to remove the nuts on the terminal bolts and have trouble finding the size. I start with 12mm, too small! Move up to 13mm, too big! Thinking I must be in SAE land, I break out my old man’s Craftsman USA SAE sockets. I go with 7/16”, too small! Then I try 1/2”, too big! Ah gosh, I think it must be a 15/32" which I definitely don’t have. The 12mm seemed to be the closest fit, so I try banging on the 12mm socket with a hammer (like Eric O in South Main Auto). Not a good idea for DIYers like me. Defeated, I pull out some vise grips and pliers, and finally get the nuts off.

I replace the battery and positive cable, get the lawnmower running again and park her in the garage. After all that banging & cursing, I check my John Deere tech manual for fastener specs—don’t find anything for the terminal nuts. I’m really curious about those nuts—it could be that corrosion over time has deformed them so they’re not a standard size anymore.

 

[TuxThePenguin]

SAE nut size for a 5/16" stud was* 15/32"

Battery terminals often still use standard even if most bolts on a machine are metric.

I don't own any Deere products, but it makes sense to me.

I think most fasteners on your machine should be metric, but I'm not that confident in that since I've never owned anything from that brand. Yes, I Googled it haha.

 

[seber]

SAE nut size for a 5/16" stud is 15/32"

Battery terminals often still use standard even if most bolts on a machine are metric.

I don't own any Deere products, but it makes sense to me.

I think most fasteners on your machine should be metric, but I'm not that confident in that since I've never owned anything from that brand. Yes, I Googled it haha.

SAE for 5/16 is 1/2" It hasn't been 15/32 since dinosaurs roamed. My John Deere 345 is a mix of metric and SAE. You never know which until you try to put a wrench on it. Battery bolts are often non standard. Just replace the nut with a regular size.

 

[SeisMec]

Seber is correct. SAE 5/16 nut is a 1/2" hex. Terminal nuts on lead acid batteries quickly corrode away and become a non-standard size hex. If you use shouldered hex battery terminal nuts (shoulder towards terminal), the hex seems to last a smidgin longer.

 

[Shed of tools]

It just a standard 1/2 on those mowers anything else you can blame corrosion for.

 

[Captain_Slow]

Try the 300/400 series garden tractors with Yanmar engines. Fun and occasionally odd mix of SAE and metric fasteners

 

[joe_padavano]

It just a standard 1/2 on those mowers anything else you can blame corrosion for.

^^^THIS. I've frequently had battery terminal fasteners that had corroded to an odd size. A cutoff tool usually solves the problem.

 

[wtn1271]

Battery pliers can be helpful too.

 

[RTM]

I was wondering when pliers were going to show up. If the 3rd wrench does not fit, pliers.

 

[redmondjp]

Here's a pro tip for you so this doesn't happen again. Most lawn and garden batteries (and some car batteries as well) are manufactured with a bad seal between the battery case and the terminals, which allows acid to seep up through the top of the battery and corrode the terminal.

To prevent this (either with a new or old battery), rinse off the top of the battery with water, baking soda and soap/degreaser as required. Dry with compressed air. Now apply a sealant around the base of both lead terminals where they protrude through the top of the battery. I typically use RTV or Permatex (#1, #2, or gasket sealer) - whatever I have on hand. Let dry/harden and then reinstall the battery - make sure to get clean shiny metal on both sides of the connections before reinstalling the hardware - I also add flat and lockwashers to the terminals to get more contact pressure for lower resistance.

This little trick will keep your terminals clean and corrosion-free for the life of the battery.

 

[BrandoJames]

I was wondering when pliers were going to show up. If the 3rd wrench does not fit, pliers.

I'm always worried about stripping a fastener, so going vise-grips/pliers is my last resort. What makes things worse is I'm not the most patient person in the world. Another thing: when I reach for vise-grips & pliers, those are in the budget section of my box--Duralast vise-grips and HF Doyle pliers (DON'T JUDGE, lol).

I must say, those budget tools got the job done.

 

[matt_i]

I have experienced that same issue where no tools fit.

If accessible I go for a file and start reducing the flats until a wrench will fit.

Then determine actual fastener size and replace with what its supposed to be.

I had one on a ground terminal on my 1953 Farmall Super A tractor that defied all tools until it got the above treatment. Now its just peachy and a bit smaller

 

[Mr_B]

doyle pliers ain't bad and can be even better if QC them yourself from bunch on the display hanger
Bremen visegrips also better than what you pay with little effort with coupon and QC'ing for extra nice pair .
Grips and quality cresent wench handy on battery terminals at times .

 

[jonshonda]

Fastener hell= one bolt? You come up to Wisconsin and roll under a well seasoned daily driver vehicle, and I'll show you fastener hell.

 

[MikeF2316]

My jaw would drop if a seemingly intact fastener was too small for 13 mm, too large for 12 mm and not just right for 1/2". That's when I'd break out the 6 oint stuff!

 

[Robinson1]

I thought an adjustable wrench and/or channel locks was standard equipment for changing batteries!

 

[finn]

Fastener hell= one bolt? You come up to Wisconsin and roll under a well seasoned daily driver vehicle, and I'll show you fastener hell.

Here “we’ll seasoned” equates to two model years old.

The newer style battery cables (lead free cable ends) that use the tiny 8mm or so fastener seem to last far longer than the 1/2” hex nuts the old style lead cable ends did. Those old nuts morphed to some unknown size due to corrosion pretty quickly.

 

[ttpete]

The fix is simple. Just replace the old battery with an AGM battery. No vents, no corrosion.

 

[BrandoJames]

The fix is simple. Just replace the old battery with an AGM battery. No vents, no corrosion.

I ended up buying a John Deere battery & cable at my local JD supplier. I spent $80 on parts (battery = $60, cable = $20). I’m sure I could’ve saved money by buying the battery at Walmart, but want to support my local John Deere supplier during the pandemic.