72 C20 "Old Mustard"
 

My wife and daughter have started getting into horses, so they'll need a reliable truck to pull around a horse trailer with. This has been the opportunity I've been waiting for to get some work done on "Old Mustard", my 72 C20 that I've had since I was 16 in 1986. I'm stoked.:metal:


Here's Old Mustard...

Re: 72 C20 "Old Mustard"
 

Sweet! I also got my 72 c20 when I was 16. But that was this year.;) hahaha I sure know mine pulls trailers real well so far.
Posted via Mobile Device
Posted via Mobile Device
Posted via Mobile Device

Re: 72 C20 "Old Mustard"
 

The objective at this point is to replace the cab floor (pretty rotten, especially under the gas tank), replace the 3speed with a TH350 trans, and install a trailer hitch to use instead of the rusty old step bumper. I was trying to figure out how to put the floor in (in pieces) without removing the cab, but I'm now planning on just removing the cab like everybody else apparently does. I pulled the seat, gas tank, etc. out a few weeks ago. This weekend, I removed the front fenders, inner fenders, cowl, etc. in prep for cab removal. I know that a majority of vehicles that start getting torn down like this never get back together, so I've got to keep moving with this project and get it done. It helps to have a purpose (pulling a horse trailer) and to have the knowledge that a bunch of people are monitoring your progress.

Re: 72 C20 "Old Mustard"
 

I've seen your thread, Dustin. Looks like a nice truck you've got there, especially for that price. Being from down South, its in much nicer shape than mine, which has some serious rust. As soon as I get a little bit of time, I'll post more pics, and you'll be even more pleased with your blue one.

Re: 72 C20 "Old Mustard"
 

Thank you, yeah that is one of my favorite things about living out here in the super dry west, no rust. ;) Haha I do like that yellow of your truck though. Not something you see every day. Hahah
Posted via Mobile Device
Posted via Mobile Device

Re: 72 C20 "Old Mustard"
 

Yeah, I like the color, too. Eventually we'll get rid of the "ketchup" color on the bed. A girl that lived down the street from us back in the day in high school called the truck "Old Mustard" (had a yellow bed back then). My brother and I kept trying to call it tougher sounding names, but none of them stuck and "Old Mustard" did.

Below are pics of what happens when the parking spot for the truck is under a tree. We'd get leaf shreds blowing out the defrosters every once in a while.:lol:

Re: 72 C20 "Old Mustard"
 

Oops, here they are...

Re: 72 C20 "Old Mustard"
 

I haven't seen these mirrors anywhere else on this forum. I'm guessing they might be aftermarket. Anybody recognize them?

Re: 72 C20 "Old Mustard"
 

...and some more progress shots from the last few days. Ended up grinding off the heads of at least half of the inner fender to outer fender bolts, as the nuts inside the fenders started spinning. Those apparently aren't welded on, are they?

Whatever the case, I'm getting closer to being able to pull the cab. I removed the radiator and radiator support so I can replace the mounts under the support. I was only planning to do as little as possible to get the floor repaired and get her back on the road, but I can see now that there will be some cleaning and painting going on, too. Looking for some fenders/inner fenders, as well. Dang scope creap...

Re: 72 C20 "Old Mustard"
 

Haha that's about how it always works isn't it? The more you want to
Change a nickname the more it
Sticks. :lol: and man that's a whole lotta
Leafs.. Hahah
Posted via Mobile Device
Posted via Mobile Device

Re: 72 C20 "Old Mustard"
 

Wow. All I've got done on Mustard so far this week was to remove the brake master cylinder and booster. I gave our two drivers (Taurus wagon aka Mommy's Red Car and the blilver Kia Sedona aka the Man Van) a once over in the other stall of the two car garage with such pampering touches as overdue oil changes, tire rotations, etc. Unfortunately, the Man Van needs a drivers side tie rod end, which will put off progress on Mustard even more.:waah:

Although I might have a lead on some front fenders in better shape than mine, so that's a good thing:metal:

Re: 72 C20 "Old Mustard"
 

Parts store didn't have the tie rod end for the Man Van, so I ended up with some time for Mustard this afternoon. Pretty much have it ready to be braced up and picked off the frame at this point. Pulled the steering column, speedo cable, tach wiring and tach, floor shifter handle, clutch linkage (not going back in), water temp thermocouple wire/gauge, crappy, brittle plastic tubing for oil pressure gauge (probably only had a few miles left on it the way it desintegrated when I touched it). Now I gotta come up with a spreader for the cherry picker, brace the door openings and brace across the cab, and disconnect what's left of the mounts (might be blue wrench time).

Re: 72 C20 "Old Mustard"
 

Here's what the floor under the gas tank looked like when I removed the tank. I'd like to blame the PO for this work, but I can't. We did this repair back in HS to keep her on the road. Not good work, but remember, Mustard was just another old truck back then, only 15 years old or so. Sort of like working on a rusted out late 90s pickup now.

Re: 72 C20 "Old Mustard"
 

Yep, that was an expert application of bondo, roofing tar, and window screen covering up the new "structure" we had to hold the cab together and bolt seatbelts too (safety first, after all). I was dreading tearing it all out, but the tar was pretty dried up and it all came out rather easily. Good golly, there really isn't much holding the cab on, is there?

Re: 72 C20 "Old Mustard"
 

OK. Got the cab popped off the other day. Here are some shots of the process. Made a spreader out of two old 2x4s with some plywood screwed to the tops at each end to hold them together and act as stops should the cab want to slide one way or the other. Removed the chain from the cherry picker and attached the spreader to the lifting arm with an old tire iron (didn't have the right size bolt...). Worked pretty dang good, I guess.

Re: 72 C20 "Old Mustard"
 

You can see in the shot above of the rear of the cab that I might be in trouble when it comes time to weld the new floor in, as the bottom of the back panel of the cab is in pretty rough shape. Nothing a little extra sheet metal welded in won't fix, I imagine. We'll see how things go.

Here's a shot of the shop helpers for the day. :chevy:

Re: 72 C20 "Old Mustard"
 

...And, since I had it this far apart, I veered off track and yanked the greasy blob of an engine, with the plan to get it cleaned up, change some gaskets, shoot a coat of paint on it, clean up the frame and maybe get a coat of paint on it, too. It's a lot of work so my wife and daughter can pull horse trailers around, but they're worth it, and I'm having a blast with this. :metal:

Just hope I can get it all back together...

Re: 72 C20 "Old Mustard"
 

Once I had the cab on it's back, I ground off the welds connecting the "floor" to the back of the cab, then proceeded to find all of the spot welds in the floor/firewall joint. I think there's just shy of a bazillion of the dang things. I'm also thinking that the spot weld guy back in '72 didn't have any sort of jig to use to place the things, as they were sort of all over the place on the flange. Many of them were right close to the bottom (or top, depending on which way the cab is sitting, I guess) of the flange. I ended up being too cheap to spend the $5 for a spot weld cutter from Harbor Freight (would have cost more to ship it here than the cost of the cutter itself), so I just drilled out the spot welds using two smaller diameter bits and then the 3/8 bit. With some of the spot welds that were close to the cab floor, I ended up removing some floor material, too, but it seemed to be almost unavoidable, and not that big of a concern at this point anyway. I didn't get the floor all the way out, however, before I ran out of time for the day, so that'll have to wait. Even with the spot welds theoretically drilled out, there is still some areas welded together which will obviously take some more work. I used a cutoff wheel and made a cut a few inches down (or back if it were sitting normally) from the flange all the way across, but I haven't gone through the two major front to back ribs (can't remember exactly what they're called), and I didn't get all the way through one of the sheets scabbed in under the drivers side footwell. That, too, will wait for another day.

Re: 72 C20 "Old Mustard"
 

I'm not sure if you have or not.. But I would brace the hell out of that cab before you consider pulling that floor out.

Re: 72 C20 "Old Mustard"
 

It's braced, but not as heavily as most of the others I've seen on here. I tried to keep the bracing towards the bottoms of the door openings and then put a brace across between the two door braces. The floor is out now (need to update the pictures here), so it's all the bracing, now, and it seems to be holding well, actually.

Re: 72 C20 "Old Mustard"
 

Dang Mr. Mustard, that was one rusty cab! You made the right choice on the full floor replacement. Kinda wish I did myself but mine was nowhere near that bad. Great job on the truck!
It has been a long time but actually half of me is from Wisconsin, Menomonie to be exact. You have a great start on this project and I can't wait to see the finished cab repairs. Keep up the great work man! I'll be watching you. ;)

Re: 72 C20 "Old Mustard"
 

Thanks, Dan. Yah, it's pretty rusty. But I know of guys that rebuilt obscure pre-war trucks that had trees growing up through them, so I use that type of thing for inspiration when working on this "relatively new" truck that has all of this aftermarket support available for it. Still spend quite a bit of time just standing there staring at it figuring out what to do next, though:lol:

Hoping to get some more time out in the garage this afternoon. I'll try to get the pics updated some time this weekend.

Re: 72 C20 "Old Mustard"
 

Time for catching up on posting progress info. I managed to get the floor out a few weeks ago. I did as I've seen elsewhere on this site and cut the floor apart a few inches behind the firewall/floor seem, then chiseled the seam apart, which still needed to be done even though the spot welds were drilled out.

Re: 72 C20 "Old Mustard"
 

I apologize for the quality of some of these pics, along with the fact that I forgot to rotate them before attaching them to the post.

I went down the path of replacing both of the cab corners and bottoms of the rear pillars before getting the floor in. This proved to be a bit of a bad idea, as getting the flooor in the right place with the new cab corner in place proved to be a bit problematic. The door just didn't fit right, etc. The cab corner (LMC) didn't really fit that well, either, without a little bit of bending into shape to better match the curve of hte back of the original cab. Nonetheless, here are pics of the wasted effort...

Re: 72 C20 "Old Mustard"
 

Looks like it will be a nice truck when your done, I notice that the cab roof looks pretty good above the visors. Thats a plus.

Re: 72 C20 "Old Mustard"
 

Mustard72, nice work on the cab corners

Re: 72 C20 "Old Mustard"
 

So, after getting the first cab corner tacked in place and then realizing th floor didn't fit right with it in, I cut it back out. Can you tell I haven't done this before? But I tend to be a stubborn cuss sometimes, so I won't let a few backwards steps keep me from proceeding on.

Now that I have this fancy new complete floor assembly, I don't need a bunchof the parts I'd been collecting before the fancy floor assemblies were available. So I used one of hte inner rockers to make a piece to replace the rotten steel on the bottom of the rear wall of the cab. I put a radius on one of the edges for strength (like I think was on the original) with my bench vise. It's certainly no sheet metal brake, but it did a surprisingly good job, especially seeing as though this will by no means be a show truck when it's done. This piece gets welded to the bottom of the rear cab wall and spans between the cab corners, which I'm now planning to replace after the floor is in.

Re: 72 C20 "Old Mustard"
 

Thanks anyway, Scott. I thought they looked pretty good, too, until trying to get the floor to fit right.

Yeah, the roof is in pretty good shape. It's pretty much stereotypical rust-belt rust, with most of the damage being done on hte lower half of the truck. Hood is pretty good, too.

Re: 72 C20 "Old Mustard"
 

So that brings me to the present. I've got the floor placed in the cab, but the front seam isn't shaped quite right. I've seen worse on this site, but it's still a bit of a problem at this point. I can get the flanges to line up rather well at either end of the seam, but the seam opens up in the middle at the hump and the transition into the hump isn't quite right, either. I'm gonna post a question in the paint/body forum to see if I can get any suggestions on how to get this seam to line up better prior to welding it in place. Any help on this thread is very welcome, too.

Re: 72 C20 "Old Mustard"
 

I would take a look and see if you can get some accurate measurements for the cab....either the floor is a little off, or the cab has settled or moved out of specs a bit.....

If you cut the floor to fit....and the cab is off...it wont do you any good later on...you could move the cab to match the floor...but that might not be right either!....I think I understand what you are going through. lots of head scratching, eh?....

accurate measurements are the only way, I think.....

JP

(theoretical post...no actual experience!)

Re: 72 C20 "Old Mustard"
 

I worked on my old cab off and on for three weeks and then made a disission to scrape it. sometimes u have to back step to made a forward move.

Re: 72 C20 "Old Mustard"
 

Well, I was able to make a step forward and get the floor mostly welded in place yesterday. The hump flange fit problem was cured by many low frequency high amplitude force applications. I other words I hit it a bunch with a hammer, using a block of hardwood to increase the accuracy of where the force was applied when necessary. After pounding down the bottom corners of the firewall hump so that its flange better (still not perfect) matched the floor flange in those corner areas, the firewall flange through the hump area needed to have the lip straightened in order to better match the floor flange. This has caused the holes (from the drilled out original spotwelds) in the firewall flange to only half overlap the floor flange. So I plug welded what I could through that area, leaving half a hole exposed to the inside of the cab (which I'll patch later). The edges of the flanges were pretty much flush with each other, so I welded the edges together, as well. Once outside of the hump area, the rest of the old original spot weld holes were able to serve as plug weld holes to connect the firewall to the new floor.

Re: 72 C20 "Old Mustard"
 

I have to say at this point that I wish I would have braced the cab more originally. I knew it was on the light side, but figured it was good enough. I've made it work so far, but it's been more work than it should have been with a better bracing job. My bracing is basically across the lower parts of each door opening with these braces extending from the kick panel in front to the back wall of the cab. A cross brace runs between these two door opening braces. The biggest problem with this setup is that it does not prevent racking in most directoins. When laying the cab on its back, the door opening without the floor in place drastically changes when pushing or pulling on the floor of the cab. I basically had to spend quite a bit of time getting the position of the cab just right just right and then blocking it up under the back of the roof so that the doors would work acceptably prior to welding the floor in. Plus, the bracing did not prevent the cab from racking side to side too much, either, meaning with the cab on its back you could push the cowl side to side quite a bit. The bracing would spring it back to close to its original position, but that's still pretty flimsy.

The flip side of this is that I don't think the cab was right to begin with. In other words, it was already tweaked from continued use in it's very deteriorated condition when I welded the bracing in. The inner rockers were non-existant and basically only the tops of the outer rockers were left. When you put your foot on the top of either rocker, you could push down and pull the rear pillar inward with very little effort. So, in a weird sort of way, maybe the less rigid bracing was a plus in this example because it allowed me (I think) to get the cab to the position it needed to be in so that everything would work out.

Re: 72 C20 "Old Mustard"
 

It's looking good! I know what you mean about sitting there staring at it wondering what to do next. I think I worked on my cab for about a year. Of course there were probably only 10 real hours of work into it :lol:

Re: 72 C20 "Old Mustard"
 

Ha ha.

Based on my experience from the past, the worst thing you can do with a car or truck project from a time perspective is put a couch in the garage to sit and think on.:lol: That one never did get finished. Apparently its better to not be too comfortable when coming up with a plan...

No couch in the garage for this one, though, and today we made a deal on a horse that needs to be pulled around, so I better get crackin'.

Re: 72 C20 "Old Mustard"
 

Way to overcome a huge obstacle.....I think you are probably right in the end...a little flexibility was a good thing.

JP

Re: 72 C20 "Old Mustard"
 

Thanks, JP

Re: 72 C20 "Old Mustard"
 

Here are some pics of the improvement of the floor/firewall seam. You can see where I had to remove the lip through the tunnel area and how the drilled out spotweld holes no longer line up as well as they should have. What isn't visible in the pictures, though, is that they overlapped probably half of the floor flange, allowing plug welding through half hole through the hump area, anyway.

I was really pleased with the plug welds when I got done with them. I then turned down the power on the welder to try and fill the remainder of hte holes without burning through the single layer of steel and proceeded to make big ugly gobs of hole-filling weld. Sort of a disappointment in the finished product, but I know the plug welds themselves were good. And no, for some reason I failed to take pictures of hte pigeon poo filling weld work.

Re: 72 C20 "Old Mustard"
 

Here are some pictures of the work done to weld the new lower section of the back wall to the cab and the back of the floor to the new lower section of back wall. With the cab still on its back at this point, I welded the floor to the inside of the wall from outside the cab. Apparently I didn't take any pictures of this, but it worked out pretty well. I wanted to get more than just one row of welds for this floor/wall connection, so I welded the top of the back of the floor to the rear wall from inside the cab, too, resulting in the weld legs shown in the picture. I'm not really thrilled with how this worked out. There was a gap between the floor and the wall in this area due to a radius in the bend of the floor there, so I couldn't really fillet weld it properly. I'll probably go back and plug weld some more holes through the back wall of the cab into the rear floor flange from outside the cab once I get it off its back. The row of welds closer to the camera in the pictures from inside the cab is from the new lower rear wall extension I had to add on to replace the rotten junk.

Re: 72 C20 "Old Mustard"
 

Shifted gears a bit to get the chassis cleaned up a bit and painted. I also removed the original manual trans crossmember, as when this whole mess goes back together it'll have the TH350 installed for ease of wife operation. I'm probably going to sell the old 3 speed stick, Hurst Indy floor shifter, and crossmember to help offset the other costs. I gave the chassis a quick cleanup using brake cleaner and some foo foo juice I brought home from work that seemed to degrease fairly well, tooo. This is definitely not a show truck, but I wanted to do something as long as I had the cab and engine out. I used a coat of Rustoleum primer and covered it with a coat of Ace Rust Stop black paint. Spray bombed the tight areas and brushed the rest. Nothing fancy whatsoever. Pictures make it look good, and it'll be nicer to work on in the future if its cleaner and painted rather than rusty and/or greasy.

I'm torn about not tearing into the front suspension at this point, but it really needs a power washing, I think, and I cant do that in my garage and don't have the means to haul the thing anywhere at this point. I'm thinking at this point I'll get the truck done and drive it over to the self serve car wash place. Jack it up, pull the front wheels, throw a bunch of quarters into the machine and go to town on it. At this point the front brakes look good (although I'm going to replace the rubber lines) and bearings are OK. I can always tear into it more at that point once it's cleaned up. It'd just be nice to do it now without the fenders and everything in the way.