Radio Receptable and Harness Assembly.

[horse]

Hi, just bought the above from Mid West and have been fitting the assembly today.

All has gone well fitting the live through the Dash and up to the battery post.
The ground runs down through tool box and then along under the Jeep to the Body Hold Down Bracket.

My question. On the picture Figure 196 Radio receptacle and ground cable page 89 of M38 Reference Guide, how is the ground terminated?

The wire has a finished loop end. Do I simply drill into the Hold down bracket and bolt it to that?

My Jeep still has the two fixings for the Clips under the Tool box but no sign of a second hole in the Body Bracket.

Any help appreciated.

Thanks.

Horse.

[wesk]

Larger file size photo: http://willysmjeeps.com/v2/modules/gall ... an0003.jpg
This is about all the data that can be found in the manuals.

Yes the bolt is a 1/4" diameter that fastens the finished end of the cable to the tub mount bracket and yes you will usually need to drill a hole for the new bolt.

[horse]

Thanks Wes.
Just in time for drilling this morning.
Horse

[TomM]

The ground lead attaches to the frame. There is a pre-drilled hole about 1.5” to the rear of the bottom rivet of the body-mount bracket.

[wesk]

"A" hole looks a bit large for the 1/4" ground strap terminal bolt?

"B" might be a hole. I can't tell from this photo.

[horse]

I have not drilled the hole yet as I did spot A and thought that could be used..
Good information.
Thanks.
Horse

[wesk]

If you go to the larger file version of the photo I posted above: http://willysmjeeps.com/v2/modules/gall ... an0003.jpg



You will see that the bolt PN 120854 shown attaching the ground cable to frame is installed on top of the tub mount support and very close to the right frame rail.

[horse]

Thanks for the information.
Yes when you blow up the picture it is clear.
I will have another look at the Tub Mount Support in the position shown and see if a hole did exist.
Horse.

[horse]

I have had another look and there is not an extra hole in the Tub Mount Support.
The pre drilled hole in the frame will take the 7/16 headed bolt which came with the assembly from Mid West.
I would like to keep things original but the Frame hole is in reach and no extra drilling required.
I wonder why the Army did not use the frame hole as Tom suggests?

Horse.

[wesk]

No telling today. Could have been the hole had a certain purpose back then and they didn't want to tie it up with a simple ground connection which only needed a 1/4" hole. Of course you are aware that letting the 1/4 screw wallow around in that big hole will not insure you maintain a quality ground for any long length of time.

[horse]

Good point.
Out with the drill.
Horse.

[TomM]

Use of hole B referenced above may be a challenge due to the available cable length and lack of access and space for a nut between the body mount and hat channel.
If you would like a photo of my install to hole A let me know.
I wanted the least resistance between the battery ground and cable connection and frame to frame connection has worked well for the GRC-9 and GRC-19 radios. Both have/had dynomotor power supplies and their inherent high starting current requirement. The body bracket connection will depend upon the riveted connection which is likely fine. But 70 years of weathering could electrically deteriorate those mechanical connections.

[horse]

Length of cable is good for both locations, but as you said access is tight.
Yes always willing to learn so a photo would be good.
Thanks.
Horse

[wesk]

I did not say it would not ground. I said using a hole twice the diameter of your grounding bolt is not wise. This is quite simple for Horse to simply drill a 1/4" hole in the frame rail, shove the bolt thru and install and tighten a nut rather than try to us a 3/8" hole for the 1/4" bolt and try to jury rig a retention method that may or may not last 5 years.

[TomM]

I just dismantled my cable connection to see what I had installed. The frame hole A on my frame will accommodate a 1/4” bolt - no larger. I do not have hole “b” in the body mount bracket.

I did Jury-rig this setup as the cable end crimp connection can accommodate a larger bolt.