Unexpected repairs are sometimes an unfortunate part of driving older cars. Last week, in the process of replacing a halogen low beam I accidentally busted a ground stud on my 2004 Jaguar XJ8. The combination of age, sub-freezing temperatures, and possibly a little too much of a rush on my part sheared the aluminum stud right off. DOH!
I don’t have an aluminum spool gun setup for my welder, so I ordered an aluminum bolt, nuts, and washers, and went about making a new ground post. Here’s a simple solution if you need to fix a broken ground stud on your old ride.
How To Fix A Broken Ground Stud
- 1 Bolt
- 3 or 4 Flat washers
- 1 Lock washer
- 1 Nut
- Sandpaper – coarse or medium grit
- Electric drill
- Drill bit
- Round file (optional)
- Disconnect the battery.
- Determine what size and material bolt you’ll need. The bolt should be as close as possible to the length of the broken stud. Be sure to factor in the thickness of the section of metal the bolt will be passing through. It’s also important that the bolt be made of the same type of metal as the structure it will be attached to, or the ground will eventually fail due to galvanic corrosion. Our 2004 Jaguar XJ8 required a 1.25″ long 5/16-18 bolt made of aluminum. The accompanying nuts and washers should always be of the same material.
- Identify the spot on the car where you want to install the ground stud. Be sure your wires can reach the stud in its new position and that there is enough space to pass the bolt through and slide a washer over it without interference. Once you’re satisfied with placement, pound a dimple into the spot with a hammer and punch.
- Carefully drill a hole for the bolt to pass through. The dimple you made in the last step will prevent your drill bit from walking. Check first to see what’s on the other side of the panel you’re drilling to ensure you don’t accidentally damage something behind it. Be sure to use a drill bit that is appropriately sized for the bolt you’ll be using for your stud.
- Sand the area surrounding the bolt down to the paint. Ideally you want your washers to be in complete contact with bare metal, but you don’t want to remove a larger area of paint than necessary. We also knocked all of the burrs out of the edges of the hole with a round file.
- Slide a flat washer over the bolt and pass the bolt through the hole from the back. Slide another flat washer over the bolt, then the ground wires followed by another flat washer, a lock washer, and a nut. Tighten the nut until it’s snug, but do not overtighten.
- Check connections and reconnect the battery.