72 C20 "Old Mustard"

[sduckworth13]

Mustard72, nice work on the cab corners

[Mustard72]

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.

[Mustard72]

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.

[Mustard72]

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.

[87Jimmy4JP]

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!)

[gdavis]

Originally Posted by Mustard72

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.

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.

[Mustard72]

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.

[Mustard72]

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.

[mjensen]

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

[Mustard72]

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. 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'.

[87Jimmy4JP]

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

JP

[Mustard72]

Thanks, JP

[Mustard72]

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.

[Mustard72]

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.

[Mustard72]

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.

[Mustard72]

Started working on getting the engine cleaned up, too, but didn't get too far yet. Gonna replace the valve cover, oil pan, and exhaust gaskets and go through the ignition system with plugs, wires, cap, rotor, and maybe get rid of the points. I've also got a different Quadrajet with the kickdown linkage ball on the throttle link that I might use. It's from a late 70s Vette, so the choke is different, it's got an idle stop solenoid, and looks to be different in a few other ways, as well, so I'll have to give this a little more thought. The alternator still works, but the bearings sound like crap, so I'll probably end up replacing that, as well.

[sduckworth13]

Nice job Nick, its looking good.

[Mustard72]

Thanks, Scott.

Haven't had much time to get more done for the past week and a half or so. I am still in the process of cleaning up the engine. My Dad came over the other day and helped out with this a bit, too. I wish we would have had something more glamerous to do while he was here, but it was fun working with him nonetheless. Got the timing cover off and it looks like the timing chain really needs to be replaced, so I'll have to get that on order. Probably get that from the local parts store along with a new alternator, steering box, and rubber brake hoses....and more brake cleaner.

Placed an order several days ago for a Class III hitch, Mallory points eliminator conversion kit, MIP floor mat, kick panels, undercoating, and a new set of keyed locks, ignition switch, and glove box lock. The ignition switch was replaced years ago after blowing apart a couple mufflers from cutting out and refiring, and the door lock keys were lost shortly thereafter. Ordering parts is too fun.

Are two cans of aerosol rubberized undercoating from LMC enough to do the bottom of the cab?

[sduckworth13]

I'm not sure if two cans of undercoating will cover it, seems a little light. I bet it nice having that new floor in there. No more surprises of rust anytime soon.
Posted via Mobile Device

[87Jimmy4JP]

Originally Posted by sduckworth13

I'm not sure if two cans of undercoating will cover it, seems a little light. I bet it nice having that new floor in there. No more surprises of rust anytime soon.
Posted via Mobile Device

Get 3 or 4...youll always use the stuff elsewhere....I would say you will go through at least 3...

lookin good!

JP

[Mustard72]

Yep, should've got at least 3 or 4 cans. 1 can ALMOST covered one coat in the center of the cab between the support rails, and I'll use another can for a second coat in there. The garage is only heated when I'm in there working, so this stuff takes a long time to dry/cure.

Well, after what seemed like years of scrubbing on the engine, I finally got the thing MOSTLY cleaned up. Looks like I'll be replacing the timing chain, though.

[gdavis]

Originally Posted by Mustard72

Yep, should've got at least 3 or 4 cans. 1 can ALMOST covered one coat in the center of the cab between the support rails, and I'll use another can for a second coat in there. The garage is only heated when I'm in there working, so this stuff takes a long time to dry/cure.

Well, after what seemed like years of scrubbing on the engine, I finally got the thing MOSTLY cleaned up. Looks like I'll be replacing the timing chain, though.

Yea, i would say that yu need a new toming chain and both gears. How iss yor liftres are they also worn.

[Mustard72]

I haven't checked the lifters. I wasn't planning on pulling the intake manifold, actually. The engine's got about 50,000 on a rebuild that took place in the early 80s before we got the truck. I would assume the lifters would have been changed at that point, but then again I would have assumed the timing chain would have, too, and that didn't look like a 50,000 mile timing chain. Not that I'm an expert on timing chain wear, but still. I've got a pic of wear on the timing cover from the chain rubbing it, actually. Now that I think about it, I wonder if that wasn't the noise I was starting to hear when the revs got up to the 4000 or so range. I was thinking alternator bearings, but only guessing at that.

So, now I've got to decide whether or not to pull the intake manifold and check out things under there. Hmmm. Decisions, decisions, decisions.

[sduckworth13]

Might as well just pull the heads off and put new gaskets on it since its going to be down awhile. Have everything checked out, you'll be glad you did. We can help you come up with ways to spend more cash lol

[Mustard72]

Yeah, but neither cash nor time are on my side. Still, all this stuff will be much easier when it's on the engine stand, and I don't need any problems when my wife and daughter are pulling a horse trailer with Mustard all over NW Wisconsin next summer.