Slow and steady: '91 F-250 diesel build


I've gotten a lot of inspiration from other folks on this and other boards posting their builds so I figure I'll start one myself.

This will be the home of all the repairs and upgrades to my 1991 F250 ext. cab 4x4 diesel. 7.3L IDI motor -- normally aspirated (which I plan to change). Here is a pic. as she stands as of now:


I live in a pretty urban environment and don't use my truck on a daily basis. We have a "family" vehicle that is more modern and comfortable for when we're all together. I have a selection of motorcycles and bicycles that handle most of the commuting and errands. The truck gets pulled out on rainy days, lazy days and the mercifully un-common "moving stuff" days.


New member
Nice looking truck. That motor is a good one to have. I have two buddies with em and ATS turbos that do awesome. :smiley_drive:


I've only learned the joys of working on one's vehicle in the past 4 years since I've started riding and maintaining the ever-growing fleet of motorcycles. I never used to like putting my cars in the hands of some random shop -- but back then I didn't have much of a choice. Now the choice is: use some under-paid, over-worked dude who couldn't give a rat's *** about my vehicle, OR... save a bunch of money, learn something new and have the satisfaction of a job well done? Not a hard choice. The saved money can't really be considered as an advantage though as that tends to fund my "tool habit."

That reminds me of a time I was working on this truck that *wasn't* fun. As my friend Peter once put it succinctly, "The enjoyment of working on a car is inversely proportional to how much it *needs* to be worked on."

At first I was just going through my new-to-me truck and doing regular maintenance stuff that I didn't think it had had done yet. Although I'd never done it, draining and refilling the rear diff seemed simple enough so that was one of the first ones I tackled. It was going great until I got it RTVd and all buttoned back up. The fill bolt wouldn't come loose. Whoops. It dawned on me pretty quickly I probably should have checked that before draining the damn thing. Lesson learned. Ok...

First up, I go through what I've learned from working on bikes: thread penetrant, heating with a torch and smacking it with a hammer. Nothing! I put a cheater on the chinese crap 3/8 socket wrench I'm using and started kicking the snot out of it. Destroyed that socket wrench... Next I got out a big 1/2" breaker bar I had recently gotten for something else and put 1/2" to 3/8" adapter on it from the same chinese Kragen set. Snapped the adapter apart, too. By this point the square hole was now a circular hole. Grrr. More hammering, more torch, more thread penetrant. Nothing is working. After about 2 hours of what amounted to banging my head against the wall I found another method I could try from reading on Weld a 3/8" socket extension into the plug.

It took awhile to get set up since the TIG machine was one of those recent "tool habit" purchases and everything was still setup statically in the garage. Once I got it all going it ended up working like a charm. Awesome! Even though I was really frustrated for most of that project I did learn a few new lessons on wrenching and the got great feeling of solving a tough problem.

# broken 1/2" -> 3/8" adapter

# I'm lucky my fiancé got me some intro welding classes for my bday last year -- wouldn't have the limited skills or equipment to have done this otherwise

# extension welded to plug; I've assumed that is red lock-tite there in the threads and that the heat from welding did all the work


Expedition Leader
There you go! Now you can see what a few hard lessons does for your experience in repairing vehicles!:victory:


using a 1/2 impact works really well too, with a non chinese 1/2 inch to 3/8 impact grade adapter. i like the truck by the way! there are some good idi builds on here.


The Brown Beast's predecessor

The "blue truck." Another 8th gen. F-250, however she was a 4x2 standard cab with the 5.8L gasser. She had a nice Browning topper w/ interior carpet and a locking gun cabinet.


That camper shell was great. It came off of a 9th gen. Ford so it wasn't an exact match, but most of the time you couldn't even really tell. We camped out of there a few times. Here's a pic. outside of Death Valley. We were trying to get down there after leaving at about 7pm from the bay area (CA). By about 1:30am we were both beat and pulled over off of 395 and hit the sack! This is the next morning:


I liked the blue truck. The 5.8L had enough of power for anything I needed and compared to my current ride, could turn much sharper and the front end didn't rattle your spine over every single bump.

Onward and upward, though! Who wants a 4x2, gasser and std. cab when you could have a 4x4, diesel powered extended cab? Not me!


Rot Box

I love your IDI! :drool:

Awesome trucks imo. They do have some quirks (what truck doesn't?!) but overall they are very simple and very reliable. My advise: All the aftermarket and stock IDI turbo's are great and they offer a big improvement in power also if you change your glowplugs do NOT use anything but Motorcraft Beru's under any circumstance :Wow1: Looking forward to this one--can't wait to see what you do with it,



I love your IDI! :drool:

Awesome trucks imo. They do have some quirks (what truck doesn't?!) but overall they are very simple and very reliable. My advise: All the aftermarket and stock IDI turbo's are great and they offer a big improvement in power also if you change your glowplugs do NOT use anything but Motorcraft Beru's under any circumstance :Wow1: Looking forward to this one--can't wait to see what you do with it,


I've read a lot diff. threads but most recently yours is the one that pushed me to make my own thread. I love what you've done w/ your truck. I've been keeping an eye open for a FWC ever since I saw one on your rig.


one trail at a time
I had the same colour combo complete with topper 250 before only regular cab and just 235/85/16s. Was a good truck with the 6.9 IDI


I like the all-brown. I'm not one for appearances -- at least when we're talking about shiny paint and being blemish free. I prefer the dents and scratches cause I don't want to worry about messing up the appearance. However, I do prefer the two-tone look of my old truck. Blue and white looked classic. Ah well, paint and dings and whatnot are down around 60 on a long list of items to deal with.

My current stuff is minor niggllng things. I finally figured out that my front fuel tank that wouldn't accept any fuel was actually filled up into the filler hose and the gauge is just off. It registers 1/16 above 'E'.

My voltmeter hasn't worked since I got the truck. Recently the battery light has been flashing on briefly under hard acceleration. It doesn't come on over bumps so I figure it's engine RPM dependent (and consequently) output-dependent. I found the culprit. One of the signal wires (I don't know what you call them) that come off the top of the alt. is very frayed so I figure that's that. Could this be related to the voltmeter? It looks like these wires go into a regulator box and the wires that go to the voltmeter go out from there. If this was the case I'd figure the voltmeter would act up at the same time the battery light came out -- it doesn't. It never moves.

Lastly, my rear anti-lock brake light has also been on since I got the truck. I've read it's likely a corroded elec. connection. I'll look into that last since I don't really care too much about 20 y/o rear-wheel only ABS. I've done enough auto-cross to feel comfortable dealing with locked up wheels... Still, I like to know what's going on.
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Rot Box

Your best bet may be heading over to for more info than you'll know what to do with. Great crowd over there that's for sure.

With decent sending units the factory fuel gauge(s) is usually pretty accurate. That said never drop below 1/8 tank--purging air is a pain on the IDI as you probably already know.

As for the rest of the gauges they are known to give problems. The water temp gauge is basically worthless on the IDI and its a really good idea to install and aftermarket unit.

Anyway I don't think there is a question that doesn't have an answer on OB :bike_rider: Good luck.




Update since I haven't posted in a while. I got a FWC pop-up camper. It is awesome. It has it's issues. I've actually been looking forward to tearing it apart and mending and replacing here and there but I have actually already decided to sell the thing. It comes down to not having any place to store it off of the truck.

This is the ad if you're interested.

If I don't sell it within about 6 weeks though it'll be taking a nice trip to Death Valley with me. :)

I'm pretty sure I'll end up with another one of these one day but for now the camper shell will have to do. A furnace and built-in stove almost makes me feel like I'm in a hotel! I could get used to it.


She was dirty! I got around to cleaning the exterior this weekend:



Anyway, I'm still working and pondering what the next steps are for the truck. For now I've got a nasty leak coming from my fuel filter area. I replaced the filter and cleaned the water separator out since it was due but that didn't change anything. Looks like it's the return line? I think that's what that is. This might be a further development on what was previously just hard starting after being parked up hill. The idea is that air was getting into the lines and the fuel was draining back to the tank making it hard to start. I replaced all the return lines, caps and o-rings and it didn't fix the issue. Hopefully this ends up being the cause.

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