1980 F350 4X4 C6 Project

[Atlas75]

I should have mentioned that the first photo was a “cold” engine.  That said, the ambient temp this morning when I took the pictures was 75 degrees.

[Atlas75]

I’ll see if I can get a few more pics tomorrow morning.  It will be cooler also.

[Atlas75]

What is an RPO bumper?

[Gary Lewis]

Probably Regular Purchase Order, which I think would mean if the truck came from the factory with a bumper.

So, what publication do you have?  It shows the ground w/o the bumper to go to G1004 and with the bumper to G1001, which is exactly backwards from what the 1981 EVTM shows, below.

[Atlas75]

I have the 1980 EVTM.  The photo I took is from the page on rear turn signals/running lights.

[Gary Lewis]

Interesting!  So the documentation changed from '80 to '81.

Below is what the '81 EVTM says for the placement of G1001 and G1004, and both say "On frame forward of LH rear light assembly".  In other words, the same position, and that doesn't make sense so I'm betting one of those is wrong.

But the 1980 EVTM says G1001 is "On "D" pillar reinforcement, forward of L.H. rear lamps", and G1004 is "Attached lower L.H. side panel".  At least they are different from each other, which makes sense and I'd bet it is correct.

[Gary Lewis]

But, I'm pretty sure we know that RPO must mean a regular production option bumper, 'cause in '81 it just says "with bumper" and "without bumper", and the documentation is for how it left the factory.

[Atlas75]

I’m guessing mine must have come with a bumper from the factory as I have two pair of wires hanging down behind my current bumper (which is not factory).

Passenger side wires.  One hot, one ground.


Drivers side wires.  One hot, one ground.  The wire sticking out of the steel leads to the current license plate light.  I’m guessing the empty butt connector was hooked to it at one time.

I think I also discovered the cause of my electrical issue where both turn signals will blink when the lever in the cab is in either position.  Something is not right with this.  Maybe it is just dirt and crud and/or bad ground but as I was messing with it, I was able to get each side to blink individually.




I scraped a bunch of crud out of this connector.  Is there anything I can spray into the connector to flush it that won’t hurt the wires or the plastic?


That single connector is the ground and it goes up to the rear cross member and anchors there. It looks crusty at the cross member but my test light did ground on it.

Anything else I should try other than a good cleaning?

[ArdWrknTrk]

CRC QD electronic cleaner is intended for corrosion and gunk in plastic connectors.

https://www.crcindustries.com/products/qd-174-electronic-cleaner-11-wt-oz-05103.html

"PRODUCT No. 05103
QD® ELECTRONIC CLEANER, 11 WT OZ
DESCRIPTION
Cleaning delicate equipment is a critical job to perform on many electronics. Due to the delicate nature of electronic components, not all cleaners are suitable. CRC QD® Electronic Cleaner is designed for precision cleaning on electronic equipment. It is plastic safe and formulated for use on sensitive electronic parts, including electronic circuits, lighting, plugs, computer components, switches, contacts, and even electronic parts in automotive applications.

APPLICATIONS
Circuit breakers, circuits, coin mechanisms, computer components, contacts, electronics, fiberglass, flux removal, sockets, lighting, plastics, nylon, plugs, relay switches, PVC, PTFE, tape heads, terminals."

[Gary Lewis]

Yep, I like that CRC cleaner.  Use that and clean the ground and you might have them working.

[Atlas75]

Definitely a ground issue.  When I grounded out the drivers side license plate wire everything worked as it should have.  Next step will be to repair the main ground.  I love repairs that take very little money!

[Gary Lewis]

[Atlas75]

Well my 41 year old truck greeted me with some good news and some bad news today.  First the good news.  After redoing numerous connections, putting a new bolt through the frame, and bolting the grounds to it, all the rear lights started working as they should!  Left and right turn signals…one at a time, stop, and tail lights. It was great!

Now for the bad news.  As I was laying under the truck I happened to glance toward the drive side rear wheel and noticed the bottom of the backing plate and the drum where wet.  I hoped it was just water from the rain we had but no dice…it was brake fluid.  The reservoir in the master cylinder was nearly empty.  So now I have to take that side apart again and most likely replace the wheel cylinder.  Ugg…not so great!

[Gary Lewis]

Glad you got the lights working.  But on the brakes, I wouldn't do it one piece at a time.  If you have to replace one wheel cylinder I'd replace both.  Then you only have to bleed the system once.

[Atlas75]

Yea, I’m learning that the hard way.  I replaced the one on the passenger side and didn’t do the drivers side because it seemed fine and was not leaking.  I must have tweaked it while I was in there cause it’s leaking now!  You know what they say…hind sight is 20/20.

[Atlas75]

I decided to put some fresh gas in the truck today so I grabbed a can and went to the station and filled it up with 5 gallons of ethanol free premium.  When I got home I poured it into the tank and started the truck.  That is when I noticed my gas gage stopped working!

I am not sure what the cause is at this point but I know the wiring was hacked into when the aftermarket dual tank system was added and then hacked again when it was removed.  I think I’ll start there and see what I can find in the way of loose connections.

The ground for the system says G701 according to the 1980 EVTM and is located “in harness, attached to ‘Y’ brace”.  Based on other parts of the circuit, I think it is somewhere under the dash, but I am not sure.  Anyone know what/where the “Y” brace is?

Would adding the gas cause any issues?  Maybe the sending unit has a bad spot where it doesn’t register?

What else should I check?

[Gary Lewis]

I don't know about the Y brace, but G701 is said in the later EVTM's to be "Behind I/P (instrument panel) near right hand side of radio."  In other words, it is screwed into the firewall in the cab ahead of the radio.

As for the sending unit, if you are lucky the ground will fix it.  If not, maybe there is a "hole" in the potentiometer and it reads right above and below that point.

To check, I'd pull the wire off the sending unit and ground it.  The gauge should go to Full and then some.  (Don't leave the ground on too long.)  That will prove the wiring, ICVR, and gauge are good.

[Atlas75]

As luck would have it, I gave a few of those cheap splice connectors a squeeze today and the gas gauge came back to life!  I’ll rework those connections at a later date seeing as the gauge is now working.  I have a few other items on the list to tackle first.

[Atlas75]

Over the last two weekends I was able to get the leaky wheel cylinder replaced, bleed the brakes…again, and reinstall the axel.  No leaks and the pedal feels pretty good.

I took both my daughters for a ride and we had a blast.  I did notice something though.  When I applied the brake it pulled pretty hard to the left.  IIRC, that is an indication that the brakes on the front left are grabbing harder than the brakes on the front right, correct?  I’m guessing there is a caliper issue on the front right.  With the little bit of daylight I had left, I removed the front right wheel and took a few photos.  I noticed the rotor has a spot that looks unworn and I also noticed the brake pads were not roughly equal thickness.  Anything else look suspicious?

[Atlas75]

And just for fun, I took a few general photos today as well.  I realized I had only shared the one photo from the day I brought it home so here are a few more angles.