Ground strap locations

[FirstOwner69]

Originally Posted by BrianG

Were all of the boxes mounted on rubber washes? Can this be confirmed by anyone? I've seen the pads in maybe one online source. I didn't put them under my bed, maybe I should have.

My wood bed 69 fleetside never had rubber pads. I can't vouch for steel beds, but I don't think any came new with pads. I've seen this discussed on here before with that conclusion. Maybe someone can confirm. Also my box was not grounded from the factory. In fact, when I had taillight problems in the 70s, the Chevy dealer suggested I ground the bed.

[chrismoore701]

The first thing I did on my taillight issue was use alligator clips to ground lights to the bumper and bam. Ground problem. Wire installed between the two. Problem resolved

[gobigorgohome]

just added some grounds staps to my 67 gmc now led tail lights are working propley
thanks for the help

[71CHEVYSHORTBED402]

Originally Posted by gobigorgohome

just added some grounds staps to my 67 gmc now led tail lights are working propley
thanks for the help

Very cool, simple fix.

Can I ask, if you have a steel bed, you happen to know where the strap is supposed to fasten? My replacement bed didn't have one. Go figure I had tail. Didn't have reverse though, but I suspect that was the power side.

I think the strap runs from the wall of the frame to the bottom of the second from rear bed cross rail, on the RH side of the truck. Might matter my truck is SWB.

[gobigorgohome]

i have a wood bed. i did one from frame to fender well
cab to frame
frame to bed
battery to block
block to frame

[hotwls13]

Originally Posted by LockDoc

-
I am going to bump this back to the top and add a picture of the instrument cluster ground clip location.

LockDoc

Thanks for that pic LockDoc. I am almost to the electrical troubleshooting part of getting my truck driveable. I KNOW that metal clip is dangling below the dash. Maybe why my headlights don't work.

[LockDoc]

Originally Posted by hotwls13

Thanks for that pic LockDoc. I am almost to the electrical troubleshooting part of getting my truck driveable. I KNOW that metal clip is dangling below the dash. Maybe why my headlights don't work.

No problem. It is easy to miss it.

Thanks,
LockDoc

[Stocker]

My truck is working fine now, no electrical (alternator) issues, thanks to input from great board members. I'm looking into grounds now, and my FSM isn't much help. The only chassis grounds I have found on my truck (1972 K20) are one from each valve cover to the firewall and one from the pass. side front cab mount to the frame, like this:


Are there supposed to be any others that I have not yet seen? One post I read stated the bed was not grounded because it's bolted metal-to-metal. I thought there should be a cab-to-frame ground but have not found one yet. All grounds on my my truck are factory original. I can add some but I'd like to know if there are more factory grounds that I've missed. Thanks, guys.

[Roady’s truck]

Radiator to frame x1 for electrolysis
Motor to frame x2
Motor to cab x2
This is how I remember it. Not saying I’m right. Not saying there were or were not any others ground straps.

Bed is bolted to frame. Factory new no ground strap was need.

How ever , you can not ever have to much ground.

[Metaldoc]

I used some old tread mill track , cut up into 2" squares with a hole in the center for anti-rattle between the bed rails and frame. I had to add more grounds for my tail lights to work all the time.

[franken]

My 72 4x4 has the remnants of frame to cab straps under the floor maybe like pst 58...

[mattfranklin]

I know this is an old thread that has been revived at least once before. Here is my two cents. I had a '54 Jeep and we changed out the engine. I ignored those funny looking braided things when I put it back together, thinking that the factory engineers were always adding worthless clutter. I was wrong. I could not figure out why the vehicle would start just fine and run strong and then after a few minutes always die. Sent it to my ace mechanic former Amoco station owner who knew a lot. He said the gas line got really hot and boiled the gas in the line. The gas line got hot because it was acting as the ground wire because my ground straps were missing. Once the straps were reinstalled the engine quit dying.

[Mike_The_Grad]

Damn MattFranklin, talk about scary. Glad you got it fixed before something bad happened.

[MySons68C20]

ttt....pertinent info which is timeless

[Metaldoc]

Static electricity discharge straps so the wheel bearings don't get arcs on them. Braided straps.

[zicc1835]

subbed

[brown7373]

I found very few straps when I pulled my 350 engine. There are no holes on the unrestored firewall for any straps from the valve covers. ??

[Metaldoc]

Originally Posted by brown7373

I found very few straps when I pulled my 350 engine. There are no holes on the unrestored firewall for any straps from the valve covers. ??

These are the factory holes with straps

[68 P.O.S.]

Originally Posted by brown7373

I found very few straps when I pulled my 350 engine. There are no holes on the unrestored firewall for any straps from the valve covers. ??

Take a look at the first post again. The very first picture shows you exactly

[brown7373]

I looked at the first pictures, but noted my truck shows no evidence of ever having straps attached from the valve covers to the firewall. The firewall has not been refinished or repainted, as it still has all the factory crayon markings...and no holes in the firewall as evidence that straps were ever installed. I am not opposed to adding them, just question if by 72 they were not installed there.

[dmw319]

Originally Posted by brown7373

I looked at the first pictures, but noted my truck shows no evidence of ever having straps attached from the valve covers to the firewall. The firewall has not been refinished or repainted, as it still has all the factory crayon markings...and no holes in the firewall as evidence that straps were ever installed. I am not opposed to adding them, just question if by 72 they were not installed there.

I also do not have any on my firewall to valve covers and don't see any obvious locations where they would have been. anyone have any more real pictures (not diagrams) of these closer up?

[71CHEVYSHORTBED402]

Originally Posted by dmw319

I also do not have any on my firewall to valve covers and don't see any obvious locations where they would have been. anyone have any more real pictures (not diagrams) of these closer up?

I don't know if there's a variance BBC Vs SBC, but on a BBC they're on the bottom front of the firewall pocket. The LH hole is next to the clutch or clutch plate. They take tap screws. If you can't locate them I can take a picture.

[brown7373]

Okay, either I am stupid or blind, but I just found 2 small holes in the firewall, right where the ground straps should be located. Very small and hard to see, but they are there.

[jcwren]

I was reading through this thread and saw the comment about wheel bearings getting destroyed by lack of grounding, and that didn't make much sense to me. I did a little reading and found this thread which explains some of it. However, I don't think it applies to the C10's. I believe there are too many other return paths, such as through the fuel line, brake lines, throttle linkage, etc. I CAN see this happening in other types of vehicles, depending on how the driveline is mounted.

https://rennlist.com/forums/924-931-...ml#post2284670

As several have mentioned, large grounding straps add no benefit. The effective gauge of the wire needs to be no larger than the wire gauge that runs from the battery to the fuse block (12 gauge, in the case of '70, not sure if later trucks went larger).

Braid is preferred over solid or stranded wire because of flexibility. The strap(s) between the engine and frame will have more vibration than any of the chassis to chassis grounds, like shown in the pictures early on in this thread. Imagine using solid core wire, and how soon it would fail. As you reduce the size of each conductor they become more flexible, and by braiding them, you don't need insulation to keep them from separating.

Bonding of body panels helps reduce AM static noise (assuming there was anything worth listening to to begin with...) by preventing static build up. What happens is if a panel isn't bonded, once the voltage reaches a certain potential, it discharges into the closest thing with a lower ground potential. This discharge is in the form of a minuscule spark, but it's enough for an AM receiver to "hear" (the very first radios were spark gap transmitters, which were subsequently outlawed because they create noise over a wide section of the radio spectrum). Bonding the panel prevents static buildup. In an ideal world, each individual body panel would be bonded to its friend. The reality is that in most cases the bolts provide adequate connectivity.

Someone mentioned skin effect in wires. This is not a thing with DC power systems. It's only present in AC power systems and when dealing with radio frequencies. At 60 Hz in copper, the skin depth is about 8.5 mm (~5/16's). It becomes a factor when dealing with larger currents, but generally isn't of any concern for people not dealing with power sub-stations and the like.

Summary: Grounding is important. Over-sized grounding doesn't hurt, but you'll just make bigger holes for bigger bolts. Bonding all the panels will reduce AM noise, but not Rush Limbaugh or Stephanie Miller noise.

[Steeveedee]

All good information, there! I would add that using a copper wire as a ground strap is going to lead to early failure as the copper work hardens when it flexes and will break sooner rather than later. That's why the ground straps are not copper. The steel is going to eventually break, too, but the large multitude of strands makes the straps quite long-lasting.