The Truck of Doom: An Occasional Build Thread

[Dorsai]

Please go see what you think on the Ignition Switch tab at Documentation/Electrical/Ignition.

Your update looks great...although I think you meant C305A instead of C305?

But the more I look at the drawings Jeff shared, the more I question things. From the positioning of C305A in that drawing, I don't see how it could connect to the bracket. I'm going back under the dash today after work, so I will try to figure things out then. I'll let you know what I find.

[Gary Lewis]

Your update looks great...although I think you meant C305A instead of C305?

But the more I look at the drawings Jeff shared, the more I question things. From the positioning of C305A in that drawing, I don't see how it could connect to the bracket. I'm going back under the dash today after work, so I will try to figure things out then. I'll let you know what I find.

Thanks. I’ll update it once you report.

By the way, I’ve never seen one of those and have taken lots of these trucks apart. I’m thinking that they were discontinued early on.

[Gary Lewis]

Thanks. I’ll update it once you report.

By the way, I’ve never seen one of those and have taken lots of these trucks apart. I’m thinking that they were discontinued early on.

I found it in the Illustration section of the MPC, as shown below.

The only problem is that when I looked 14A163 up in the Text section of the MPC to get a part number I realized that generic part number is a RETAINER (WIRE HARNESS), and there are dozens of wire harness retainers all over these trucks. And here's the only one that appears to be the right one. Note that the same part is used in two other applications on our trucks - as indicated by the "1" in the right column, which is titled "QTY" and shows how many are needed for each usage.

And again, I've never seen one of those despite having worked on many of these trucks. So while the MPC says they where used from 1980 through the end of the catalog in '89, I doubt that or surely I'd have seen one, somewhere. I can see that mechanics may well have left them off when replacing an ignition switch, but I doubt all the trucks I've worked on had all their ignition switches replaced.

[BigBrother-84]

Please go see what you think on the Ignition Switch tab at Documentation/Electrical/Ignition.

[Dorsai]

I found it in the Illustration section of the MPC, as shown below.

The only problem is that when I looked 14A163 up in the Text section of the MPC to get a part number I realized that generic part number is a RETAINER (WIRE HARNESS), and there are dozens of wire harness retainers all over these trucks. And here's the only one that appears to be the right one. Note that the same part is used in two other applications on our trucks - as indicated by the "1" in the right column, which is titled "QTY" and shows how many are needed for each usage.

And again, I've never seen one of those despite having worked on many of these trucks. So while the MPC says they where used from 1980 through the end of the catalog in '89, I doubt that or surely I'd have seen one, somewhere. I can see that mechanics may well have left them off when replacing an ignition switch, but I doubt all the trucks I've worked on had all their ignition switches replaced.

Ah, excellent sleuthing!

Is there maybe a clue in the second column of the table? What do (81,85) in the first row and (80,86) in the third row indicate?

[Gary Lewis]

Ah, excellent sleuthing!

Is there maybe a clue in the second column of the table? What do (81,85) in the first row and (80,86) in the third row indicate?

That's an excellent question. I can't figure it out, but my first thought was that those numbers meant something like Chassis & Cab, but that didn't work.

 

[kramttocs]

Your update looks great...although I think you meant C305A instead of C305?

But the more I look at the drawings Jeff shared, the more I question things. From the positioning of C305A in that drawing, I don't see how it could connect to the bracket. I'm going back under the dash today after work, so I will try to figure things out then. I'll let you know what I find.

The diagram isn't great for sure. In the connector there is a slot and it slides over the narrow end of this bracket. Due to the way everything is being forced/twisted, I've seen a number of the connectors where one lip of the slot has been snapped off (plastic losing to metal).

[Dorsai]

The diagram isn't great for sure. In the connector there is a slot and it slides over the narrow end of this bracket. Due to the way everything is being forced/twisted, I've seen a number of the connectors where one lip of the slot has been snapped off (plastic losing to metal).

Winner, winner, chicken dinner! Behold my C305A:

That bit of broken plastic is exactly where it would have clipped on to the mystery bracket. I'm sure it's been broken for years and the truck runs fine, so I left the bracket off and finished bolting down the ignition switch. Testing showed that the windshield wipers, washer, fuel gauge and temperature gauge are all back to normal, so this one is mission accomplished. As an added bonus, the spring pressure returning the key to 'run' from 'start' is much better - previously it felt very weak, and in cold weather wouldn't always return the key to position without a little assistance. It's much more authoritative now.

 

Took care of some other things today as well...one thing I noticed while working on the ignition switch was this:

 

That's the roll pin holding the gear selector to the column, and apparently it's been backing out. This happened once before about 10 years ago, and I didn't notice until the selector fell into the floor while I was driving. I'll need to keep an eye on this.

 

I also cleaned up my Duraspark modules - at one point I had three in there, although recently it's been down to two. But now it's just one shiny new Motorcraft replacement, and I added a few washers under it to hopefully provide a little better airflow underneath. Driving all day to Skiatook in the summer heat is what killed my original module, hopefully this one will fare better.

 

And while I was working on that I discovered this:

 

Those of you with good memories will recall this is the manifold bolt that was loose that caused the weird rattling noise from my A/C compressor to propagate through the exhaust system. I tightened it back down this evening, although now that I think about it that thick washer is probably the problem - the added thickness of the compressor bracket is probably reducing my thread engagement. I'll remove it if I get around to it, otherwise I'll just do a better job of keeping it tightened down.

 

Finally, new windshield wiper blades went on. And with that, the to-do list looks like this:

• Air and fuel filter replacement
• Oil change
• Windshield wiper replacement
• Brake fluid check/possible replacement
• Engine coolant replacement
• Hood realignment
• Radio antenna repair
• Ignition switch replacement
• Duraspark module cleanup
• Fix loose manifold bolt
• Fix gear selector roll pin
• Carb adjustment/tuneup
• Tire check & rotation
• PCV valve/vacuum leak

That last item is new - stay tuned for the next post for details.

[Gary Lewis]

The diagram isn't great for sure. In the connector there is a slot and it slides over the narrow end of this bracket. Due to the way everything is being forced/twisted, I've seen a number of the connectors where one lip of the slot has been snapped off (plastic losing to metal).

Winner, winner, chicken dinner! Behold my C305A:

That bit of broken plastic is exactly where it would have clipped on to the mystery bracket. I'm sure it's been broken for years and the truck runs fine, so I left the bracket off and finished bolting down the ignition switch. Testing showed that the windshield wipers, washer, fuel gauge and temperature gauge are all back to normal, so this one is mission accomplished. As an added bonus, the spring pressure returning the key to 'run' from 'start' is much better - previously it felt very weak, and in cold weather wouldn't always return the key to position without a little assistance. It's much more authoritative now.

 

Took care of some other things today as well...one thing I noticed while working on the ignition switch was this:

 

That's the roll pin holding the gear selector to the column, and apparently it's been backing out. This happened once before about 10 years ago, and I didn't notice until the selector fell into the floor while I was driving. I'll need to keep an eye on this.

 

I also cleaned up my Duraspark modules - at one point I had three in there, although recently it's been down to two. But now it's just one shiny new Motorcraft replacement, and I added a few washers under it to hopefully provide a little better airflow underneath. Driving all day to Skiatook in the summer heat is what killed my original module, hopefully this one will fare better.

 

And while I was working on that I discovered this:

 

Those of you with good memories will recall this is the manifold bolt that was loose that caused the weird rattling noise from my A/C compressor to propagate through the exhaust system. I tightened it back down this evening, although now that I think about it that thick washer is probably the problem - the added thickness of the compressor bracket is probably reducing my thread engagement. I'll remove it if I get around to it, otherwise I'll just do a better job of keeping it tightened down.

 

Finally, new windshield wiper blades went on. And with that, the to-do list looks like this:

• Air and fuel filter replacement
• Oil change
• Windshield wiper replacement
• Brake fluid check/possible replacement
• Engine coolant replacement
• Hood realignment
• Radio antenna repair
• Ignition switch replacement
• Duraspark module cleanup
• Fix loose manifold bolt
• Fix gear selector roll pin
• Carb adjustment/tuneup
• Tire check & rotation
• PCV valve/vacuum leak

That last item is new - stay tuned for the next post for details.

Well, you win the chicken dinner and I updated the webpage to say C305A. Obviously the bracket isn't required, but it is good to know where it goes.As for the roll pin, I think I'd put it back with a drop of Loctite blue on one end. Ditto the bolt. That should keep them in place.On the ignition module, it wouldn't hurt to have one of those spares under the seat.Anyway, you are making good progress and the truck should be in fine fettle for the trip.

[Dorsai]

Thanks. I’ll update it once you report. By the way, I’ve never seen one of those and have taken lots of these trucks apart. I’m thinking that they were discontinued early on.

So what's up with that vacuum leak bit? I'm glad you asked.One of the items on my to-do list is carburetor adjustment...I put this in there because my truck has been idling rough lately, and it's been a while since I've tuned the carb. It made sense at the time, but today I noticed this:

 

 

That's my PCV valve, obviously, and there's supposed to be something on that upper port. I know this because I have a photo from three years ago:

 

 

But...what connects there? I know, I know...you're thinking "Duh, just look for a disconnected vacuum line!" Except...I did, and I can't find anything. Maybe something fell down underneath where I can't see it, but a more-than-cursory search turned up nothing. I checked the vacuum routing diagram on the radiator support, and that shows only one line going to my PCV valve to begin with.And to top it all off, I can hear a hissing when the engine is running that I am pretty sure wasn't there before. What am I missing?