Removing bolt for ground/negative wire on transmission case?

[zuzu_]

One of the two grounding wires from the negative battery terminal goes to a bolt on the transmission case, and I nearly stripped the head trying to turn it to remove it. Any advice on getting it off? It's kind of a cramped space under the air filter / engine intake (which I'd prefer not to have to remove).

The head of the bolt is 12mm in size.

I'm thinking of trying penetrating oil over night, and then using a wrench that grabs all six sides of the hex head of the bolt.


p.s. I'm doing this in the pursuit of the "Big 3" upgrade. It seems like this, maybe 8 AWG wire, constitutes both the "battery negative to chassis" and "chassis to engine block". Though there's also a smaller, perhaps 12 gauge, grounding wire that goes from the engine block right next to the alternator case to the chassis, on the passenger's side under the hood.

[fishexpo101]

Yup, put on some good penetrating lube (PB Blaster, Kroil, etc.) and using a 6-point socket instead of a 12-point socket will help minimize the risk of rounding off the bolt head.

If you can get a wrench on it, you could give it a few taps with a hammer (on the wrench, not the transaxle case) - might break it free. Don't go wild on the transaxle case - as I've seen people crack the aluminum case.

[CJCride]

And get the air filter box removed [not major stuff], then you will have more room.

[zuzu_]

Originally Posted by CJCride

And get the air filter box removed [not major stuff], then you will have more room.

You're right, the air filter box can be removed by itself without removing the other tubing. The top half with all the wires/sensors plugged into it can just be removed via the same unclipping used to open it to change the air filter. The bottom can be removed by unscrewing the clamp that attaches it to the big ribbed hose that connects to the engine and unscrewing the three bolts underneath the air filter. There's also two wire harnesses that affix to the bottom of the air filter box with pressure clips that can be unclipped.

With the top half of the air filter box pushed to the side (towards the firewall of the engine) and with the bottom half removed, I had clear access to the bolt. The PB blaster that I'd been dousing the bolt with made it unscrew like butter after I finally got it to initially "crack" / "break the seal"... but in order to get that initial break, I had to resort to using an 8 amp power drill (Milwaukee 0302-20 Magnum) set to reverse with a socket adapter and a 12mm six-sided socket. My old 3.5 amp Craftsman drill couldn't even crank it.


As for further details on my big-3 upgrade. I'm using Radnor 1/0 AWG welding cable (high strand 100% oxygen free copper), that is sold by the nearby Airgas store for $60 for 25ft. I'm using a large gauge wire cutter (also available at Lowes), and 0 gauge ring terminals (5/8 holes) for the ends (allen screw kind, rather than crimp and solder), with 1" heatshrink wrap covering them and onto the cable.

I'm using new battery terminals each with allen screws for one 0 AWG, one 4 AWG, and two 8 AWG wires. So far I've (almost) completed the negative wiring. I've run the 0 AWG wire from the new negative battery terminal to the ring terminal bolted to the transmission case, which also bolts from there to the chassis. I will also run 4 AWG wire from the negative battery terminal to the chassis. This is replicating the layout of the factory negative / ground wiring, but with higher capacity (i.e. thicker) power cable. I also used 0 AWG wire to replace the alternator case / engine to chassis grounding on the passenger's side.

Then, once I've received my 160 amp high output alternator, I can run 0 AWG wire from the alternator to the battery positive, with a Bussman 150 amp circuit breaker (part # 181150F, automatic reset) in between (just as soon as I figure out where to mount that). Factory wiring drawing on the positive feed can plug into the 8 AWG hole in the positive terminal.