Big Bertha build thread

[buggy5872]

I have had many request to do a build thread on Big Bertha so here goes.... It all started one rainy day in June 2011. We were camping in our 1967 Serro Scotty 13' camper. The wife, 2 kids, 1 dog and myself were jambed in there due to a down pour. After about an hour the rain stopped. We got out and were walking around looking at all the people camping in big 5th wheel campers and enjoying the rain more than we did. The wife said that it was time to get one of those big campers. I told here we could get one if I could build a truck to pull it. I had been thinking and planning Big Bertha on paper for years but never had a reason to have something so big. She agreed and the hunt was on for the perfect truck. I found several out west but it would cost a small fortune to get them to PA. I ended up finding her on the "HAMB" web site. 1957 Chevy 5700 Low Cab Forward truck. She was only 4 hours away. I hooked up the trailer and my dad and I headed out too get her. Here is what she looked like when I got her home.

[buggy5872]

The next step was to figure out how to fit all of us in the cab. I had planned on making it a crew cab so I needed to start digging through my stash of parts, or as my wife calls it "that junk you really do not need to keep", and start figuring it out. I stripped the cab off the chassis so i could get it in the garage.


This is when I thought it would be a two year project. This was just after Labor Day weekend. The wife asked me if I could be done by spring so we could get a new camper then. I said "what?"...."then sure but I don't want to hear it about spending some money". What was I thinking??????? We did not have a trailer yet so I figured I would shoot for spring and see what happens.

[Dunenutt]

This is going to be awesome! I like big trucks!

[buggy5872]

I started researching axles, chassis, and engine options. I settled on the GMC W4500/Isuzu NPR for several reasons. The frame width was the same as the original, front axle is only 1" wider than the original, wheel bolt pattern is the same as the original 57 (its 6 on 222.25 mm but works out the same as the 6 on 8.75) and they are every where. I looked at all the medium duty chassis but the axles were too wide. I found a 2003 GMC W4500 HD with 73,000 miles on it. It had a 350 vortech with a 4L80E tranny. So I bought it.

[buggy5872]

I then built a rack the same width as the frame and bolted the original front frame mounts to it. Set the cab and calmped the rear mounts. Out came the sawsall. No turning back now. I had a 56 GMC cab that was in pretty good shape so it became the donor for the back half. After a couple hours here is what I had.

I moved the original rear mounts to back of the gmc cab and used them to slide the cabs together and apart about 50 times as I cut and figured how it was all going to work. I did all the planning I could up front but until I got into it I did not know exactly what I was doing. I even thought that this was going easy and I would be done in no time.....boy was I wrong.

[69CST-V]

I'm in. Looks like quite the project.

[buggy5872]

Next came the rear doors. I had thought about them but really had no good plan for them yet. I was looking at how the original doors were hinged and decide to go ahead and try to use them. I first thought about mounting them with no B pillar but quickly decide to give that up due to the door swinging forward and the front doors not being able to open. The other issue was the cabs become more narrow at the windows as you go toward the front windshield. I sliced and diced a few doors be fore I had something I thought would work. I decided to make them suicide doors for easy of hinge mounting and they are just cool.


I had seen some other crew conversions on TF trucks that had used full doors on the rear and did not look factory so I wanted to make sure it looked good enought to maybe be factory.

[Kim57]

This is a great build.
Kim

[buggy5872]

After I had one door sort of figured out, I quickly leared I need to start figuring out the roof. I cut, bent, mangled, and threw away a bunch of pieces of metal before I came to the rationalization that I was in trouble. I could not figure out the roof at all. I spent about a week tring to figure it out. I fianally realized that I need a panel truck or burb to cut the roof off. A new search began for a suitable donor that I would not feel bad about cutting up. I found one about three hours away. hooked up the trailer and away I went. The thing was rusted up about 18" high the whole way around. The perfect donor. I stopped on the way back at a place I get parts from to see if I could get the title notorized, its always good to have extras of those, and they asked what I was doing with the panel. I told them my plans and they wanted to buy the chassis after I stripped the body off. I sold it to them for 50 bucks more than I paid for the thing! The roof went pretty quickly from there.




The pics show that I had her cut pretty far apart but the key is to weld in bracing to keep everything square. Measure 3 times before welding anything.
My lunch time is over so I have to get back to work....more to come later

[_Ogre]

dang. nice progress so far
the lines look good too.
takes a brave man to cut up a new truck.

it'd be nice if you could get it low enough to drive in a 7 ft door.

[seanery]

way cool project!

[richard2717]

Cool Idea....looks like a nice start.

Richard

[Denee007]

OMG! that's incredible!

[xpickup]

buggy5872, great job. Looks like the factory should have done it like that. Keep up the great work.

Shannon

[buggy5872]

I have a couple minutes before I have to duck into a meeting here at work.... At this point it is mid October 2011 and the wife got the itch to look at 5th wheel trailers. We ended up getting a screaming deal on a 2012 Coachman and they took it to my storage place for me since I had no truck to pull it. This made my time line a bit shorter to get Bertha on the road.

[buggy5872]

Over the next month or so I finished welding the roof, doors, floor, and bracing. Finally shot some primer on the roof and one B pillar so I would feel like I made some progress. I also was lucky enough to find some rust free doors for the front

[JRANGER]

o this looks cool

[Maximus]

Originally Posted by buggy5872

There has been so many pictures and questions it gets old sometimes. Best was a girl haning off the back of a harley taking pictures

lol - well its a seriously cool truck, fantastic craftsmanship. I hope when i am able to put a shop up and line up the tools, that i can put together half of the fab skills you have.

if i didnt know anything about these trucks i woulda thought it was factory.

CLEAN

[shadow1967]

Thats cool!

[Rods57]

Really cool so far, cant wait for the rest...

[buggy5872]

I was to the point where I really needed to tare the other truck apart and see what I needed to do to fit her to its new chassis. It only took a few hours and some creative lifting to get the cab off.


Mounted the 22.5 wheels and started looking at what I had to work with.

[buggy5872]

I set the front clip on so I could start to take some measurements and figure out how I was going to make it a one piece tilt front end. I re used the tilt mechanism from the GMC. notice the top of the hood is only about a foot from hitting the garage door.


Its so tall I had to push it out side to tilt it forward.

I soon realized the steering was pointing straight up at the fender. I had to re-index the steering box back about 40 degrees to make it work. I marked all the relationships to the front suspension and draglink so I did not create any bump steer.

[buggy5872]

Now that I had measurements, I could cut out the firewall and front floor section and make it all work. I wanted to use all the wiring, heat/ac and dash from the GMC. I wanted to use everything in case we have problems out on the road, I can give the vin for the GMC and they could order the correct parts to fix it.


I made the center section of the floor the same width as the engine so it could be removed to work on the engine. The engine ended up completely under the floor

At this point I hoped it would all fit because I had no way of sitting the cab on the chassis to test fit. the first time it was set on the chassis was after it was painted.

[buggy5872]

I needed to change the dash to the 56 GMC dash in order to use the gauge cluster from the newer truck. Changing the dash is no small task in these trucks. drilling out a ton on spot welds was in order. here is what it looked like with no dash.

I cut and fit everything in the GMC dash before I welded it into the truck. I even had to french in one AC vent beside the glove box door because I ran out of room.

[buggy5872]

Now that most of the fab work was done on the cab I focused on getting the rear doors finished. I used power window units from Balls power windows. They have some nice units that work well for flat glass. Then it was on to the body work.


and it seemed like it would never end.