Drilling holes underneath the front seats

Draco · **Posted:** Thu Feb 17, 2011 1:26 am

I need to mount a radio underneath one of the front seats in the next week or two. More than likely it will be the passenger side.

The default plan is to use four self-tapping sheet metal screws that came with the mount. Those are also going to ground the radio to the frame, by the way.

Other than generally being careful, are there any things in particular to watch out for when drilling under either of the two front seats? Like maybe a wiring harness?

I've read a few cautionary tales by people who drilled into things they ortn't have.

???

JL Rockies · **Posted:** Thu Feb 17, 2011 1:37 am

Look before you drill... that's all. As for shooting screws though carpet into metal, that does not a good ground make.... unless you have conductive carpeting.

devlish · **Joined:** Thu Sep 30, 2010 10:50 am **Posts:** 163

remove seat, lift carpet, put small square of 1/2" wood (same size as radio) under carpet where radio is going. replace carpet, screw radio into piece of wood using screws short enough to NOT go through to the metal, replace seat.

Draco · **Posted:** Fri Feb 18, 2011 11:43 pm

Thank you JL Rockies and devlish for the replies!

That's a good point about grounding. I may not get the perfect ground right away, but one way or another I'll make sure there's a good connection to the frame.

Putting the matched piece of wood under the carpet is an interesting alternative. You'd definitely need a special ground wire for that method.

I'll at least get started on the installation this weekend and post some pix when it's done.

Draco · **Posted:** Sun Feb 20, 2011 7:56 pm

Plan A was to install directly to the floor. In fact, I drilled the holes and attempted to install the screws. But that thick pad beneath the carpet was a pain. First of all it made it hard to locate the holes in the metal. But more significantly it's so compliant I didn't think the radio mounting bracket was going to be very well located.

So I followed devlish's advice and mounted to a scrap piece of plywood I had lying around. It was only a 1/4" thick piece. Top grade stuff, but starting to check from lying around without ever having been sealed. I used the four screws that came with the radio. They're for sheet metal but looked fine for wood. If that had been plan A I would have gotten six or eight wood screws, as the the bracket had plenty of holes.

Here is the result:

I ran a ground wire from the mounting bracket to the front left seat mounting bolt. I scuffed the paint on the bracket with steel wool. The wire at the seat mounting bolt is bare and tinned. You can't tell from the photo, but I routed the wire up through the hole in the seat frame, so that it's pinched between the seat frame and the lower facet of the mounting bolt.

In retrospect the rear, right seat mounting stud might have been a better location. My Lido LM-300 faceplate mount still hasn't arrived. It attaches to the front left seat mounting bolt. I'll probably have to redo the ground when the mount arrives.

Drilling holes underneath the front seats

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