subford
Ok metal to metal contact not a good source.
Hmmmm I'll have to think about that one. I'd comment more on that fact but well I'll leave it with that statement.
I intentionally left out your trust towards the factory strap. Either way I have no concerns over using the frame or body to plant a ground wire for anything.
As long as my ohm meter reads a good ground I am happy. If I even get it out. Though a clean spot of metal is needed. Funny thing is every piece of the frame and cab has done just that for me on my vehicles.
Maybe I am just lucky to own a few that are odd. Either way the point this was originally making is to make sure to check the ground wires. He probably meant to state it as checking them before condemming a part. Either way If there is a electical problem it is the best place to start.

Read my signature. I'm outta here.

 

I am not posting a reply to this because of a "your wrong I'm right" thing. I just want to get good info out there that people can use.

pacer88220, you are correct, most of the time you can bolt to the body or the frame, and get a good ground, especially on a un-disturbed factory built truck. A lot of these guys get way beyond factory though, swapping cabs, frames, engines, etc. This is were the ground straps get left off, causing problems. I truely do not know how the frame get's a reliable ground, but I can confirm there are special straps from the engine block to the body to ground the body.

I would like to disagree with some of your comments in your post.


Everyone seemed to leave out the fact the trans is hooked to the motor, ( it is not made of rubber or plastic give a hint shiny stuff), then it off to the drive shaft (made of more shiny stuff but rusts)where it attaches the rear end and springs ( really heavy rusty shiny stuff) all of which is in way or another connected to the frame, then yes there is a ground to the frame.

I would like to disagree with the above comment. You are correct that there would be a good ground from the engine, to the tranny, and probably a decent ground from the tranny to the driveshaft to the rearend, and then to the springs, but if I were a engineer, I would not rely on a ground that runs through anything in motion like a bearing or bushing in the tranny or a u-joint. But you do probably get a ground. But you do not get a ground from the springs to the frame. The springs are mounted in rubber. The rubber is molded to an inner and outer sleeve. The bolt pinches the shackles to the inner metal sleeve of the bushing, but there is NO contact between the inner metal sleeve and the outer metal sleeve of the bushing. If there was, there would be a grease fitting there like there is on the old 50's Ford pickups which do have metal bushings and do have grease fittings on the shackles.

Let alone the fact that the steering column which attaches to the metal under the dash ( of a already grounded cab) and runs to the steering gear box and attaches on the frame by bolts.

The upper steering column shaft bearing is mounted in rubber, so there is no electrical contact between the shaft and the column. The lower bearing is also usually plastic, and lets the steering shaft collapse in case of an accident. Most all vehicles of the mid 60's up have a rag joint that connects between the steering box and the steering shaft. There is no elec contact between the steering shaft and the steering box because of the rag joint, but if you look close on some models, the factory actually puts a metal strap across some of the bolts so the shaft will be grounded. This is usually so the horn will work, but it would not ground the cab.

That and yes there are rubber mounts for the body but the hole the bolt goes thru and tightens down to are yep you guessed it metal there is only rubber in between the threads not at the head of nut end of the cab mounts or the frame. Unless they are using plastic/ rubber/wood/ you get the idea non- conductive bolts so yes there is a ground.

When you mount the body, if you have metal to metal contact between the body, the bolt, and the frame, then the mount is not assembled correctly. One of the rubber mounts usually has a lip to keep it centered, because the hole in the body is twice as big as the bolt is. This is so the bolt will not touch the body, thus preventing noise as the body moves around going down the road over bumps. They usually also have a metal sleeve in the middle, that does not touch the body, but tightens down on the bushing and gives the bolt something to tighten against. There are several pieces to a body mount, so it's rather hard to explain, but there is no metal to metal contact between the bolt, the frame and the body. There are possibly some mounts that have a small metal strap that electrically ties the body to the frame like they do around the steering joint, but I am not sure about this.

If someone knows how Ford made allowances for the frame to be properly grounded, I would curious to know how they did it. There must be a strap somewhere.

 

As I said above on my 95 F150 Ford did run one ground strap from the body to the frame at the bottom of the radiator on the passenger side. This is a strap with push on clips on both ends and I think it was put there for static ground but I would not trust it for grounding something. Ford must not trust it either as they ran ground wires to each license plate light.

In pacer88220 post I did not find any place where there was metal to metal contact.

I think Franklin2 post above stated this all very well.

 

Franklin
Firts none of my trucks are near factory specs either. The 85 3/4 ton 460 is my plow vehicle. The 97 is a street toy (till a buyer comes along). The 88 is a mud dog.
Anyways My 88, 85 and 97 columns dont have a rag joint, they are metal on the column passing thru to the steering gear box. It does have a rubber boot in the cab, but still keeping a full metal contact in between. The boot is there to keep out drafts it does not isolate the connections. I know this all to well due to, 2 of them being theft recovery purchases (the 85 believe it or not and the 97). The 88 being bought with a bad column. Which I am in the middle of replacing. For grins I ran I ran voltage test and guess what The bottom of the column where it contacts the mount is 11 volts. Not bad seeing the battery reads the same.
I am almost postive Ford did not design only my trucks this way.
Anyways I just added new lift bushing's on my 88 and well the bolts appear the same as all the other trucks Ranger included. The bolt has a washer at the top (head of the bolt), a rubber washer, then the sleeve you mentioned. Then onto the bottom of the frame where it has a washer in between the nut. Even though the rubber is in between my washer still contacts the floor on all the trucks. No the 97 cab wasn't removed in the repair process, and No the rubber washer isn't bad and neither is the cab mounts (as they are new).
As for the springs on there is contact. Look at the pinch bolt it contacts the spring. Yes there are bushings in between the mount but the 'eye' ends do contact metal to metal.
I remember all to well when I ran new wiring for the fuel pump on the 85 the bolt for the spring being the easiest to use for the gound on my test light.
Either way magically the frames are grounded.
As for allowances for properly grounding it doesn't take much when you are dealing with 12 volts and metal.
Either way I am done with this got ***** to do and this post is getting real old at this point.
Believe what you want.

 

On the 67 to 72 (pre-plastic) trucks there are two emergency brake cable housings mounted on the rear backing plates and the frame up forward.
Tight fit contact areas under the worse conditions with dirt and rust, a poor ground vs a bolted bonding jumper. I did see a truck that was jump started with one cable hooked on the hood hinge, it blew the rag joint jumper like a under sized fuse.

 

While working on trailer plug problems with a test light I have found it very hard to find a ground in the area. I have had to run a ground wire to the battery to get a ground.
By the way those push on static grounds from the body to frame I mentioned above Ford only puts them on factory radio equipped trucks.