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Since day one (April’25) I was unable to sufficiently tighten the negative battery terminal. GM in all their brilliance came up with a true Rube Goldberg contraption in the design of their battery terminal clamp. Even super human wrenching on the 10mm nut yields only sloppy tightness, a C5’s undoing in the offing. Thanks to our Moderator and Tech Contributor C5 Diag, who broke out the heavy guns ( an hydraulic crimp tool) and a bunch of experience, new traditional battery terminals were installed. No longer will I have to cross my fingers going over bumps. A shout out and many thanks to C5 Diag for his time and valuable experience.
What great timing. I put a new battery in my '04 C5 today and I'm struggling to get the negative terminal tight. I guess the answer is to put new terminals on the cables. Thank you for your post!
What great timing. I put a new battery in my '04 C5 today and I'm struggling to get the negative terminal tight. I guess the answer is to put new terminals on the cables. Thank you for your post!
Just get yourself some bare copper or tinned copper lugs and a good hydraulic crimper…a good TEMco crimper that I use is a little over $200.00 but is the best on the market…some of the dies that come with these cheap Chinese crimpers are not sized correctly.
Since day one (April’25) I was unable to sufficiently tighten the negative battery terminal. GM in all their brilliance came up with a true Rube Goldberg contraption in the design of their battery terminal clamp. Even super human wrenching on the 10mm nut yields only sloppy tightness, a C5’s undoing in the offing. Thanks to our Moderator and Tech Contributor C5 Diag, who broke out the heavy guns ( an hydraulic crimp tool) and a bunch of experience, new traditional battery terminals were installed. No longer will I have to cross my fingers going over bumps. A shout out and many thanks to C5 Diag for his time and valuable experience.
Rob is a great guy. It's interesting seeing your OEM "clamps." My 2000 was, and is still, a side post. Don't remember when they went back to top post. But yeah, those would look pretty chintzy on a $15,000 car, much less a $50,000 C5. This may be partly driven by the attempt to eliminate, or reduce, the lead content in everything. But you'd think GM could do a bit better than whatever you want to call those things. They probably come with nice, sharp edges in places, too. Shame on GM
Last edited by grinder11; Aug 21, 2025 at 07:45 AM.
Rob is a great guy. It's interesting seeing your OEM "clamps." My 2000 was, and is still, a side post. Don't remember when they went back to top post. But yeah, those would look pretty chintzy on a $15,000 car, much less a $50,000 C5. Shame on GM....
Mike, they went to top post in 2004…also replaced the terminals on my 2008…the GM engineer who designed those should be tarred and feathered !!
Keep in mind that the diameter of the positive and negative top posts are NOT the same, hence the different noted items. Also an adapter fitting with lugs on the cable ends as shown above can be handy when adding extra cables for what ever reason.
Keep in mind that the diameter of the positive and negative top posts are NOT the same, hence the different noted items. Also an adapter fitting with lugs on the cable ends as shown above can be handy when adding extra cables for what ever reason.
Great solution for a temp repair or any battery that is static.
Great solution for a temp repair or any battery that is static.
I have used these compression type fittings for +50 years on any number of both off- and on-road vehicles and never had any long term issues with them. Just make sure to use dual wall heat shirk tubing to seal things up. Yes, I also have a larger HD hand crimper tool with numerous jaw set for any number of battery cable gauge sizes, similar to this tool;
I have used these compression type fittings for +50 years on any number of both off- and on-road vehicles and never had any long term issues with them. Just make sure to use dual wall heat shirk tubing to seal things up. Yes, I also have a larger HD hand crimper tool with numerous jaw set for any number of battery cable gauge sizes, similar to this tool;
Terminal illness
