When I started this project I noticed that the replacement cab still had the dashboard assembly, wiring, and hvac installed. Some rodents had built a nest under the dash, making all parts questionable for use. I chose to remove it all and reuse everything from the original cab.
The truck has a manuel transmission, the replacement cab had been pulled from a truck with an automatic transmission. The clutch pedal had to be transfered also, and a hole had to be cut in the floor of the replacement cab to allow fitment of the transmission shifter.
Once everything was stripped from the interior of both cabs, the hood and fenders were removed. The parking brake, hydraulic brakes, electrical, heater hoses, a/c lines, shifter linkages, and steering were disconnected from the cab. The cab bolts were removed and the cab was raised up off the chassi, followed shortly by lowering the replacement cab onto the chassi and bolting it down. Everything was hooked back up, the hood and fenders reinstalled, the interior components installed, fluids filled, and linkages adjusted.
After going back over everything to be sure nothing had been forgotten, the truck was started and a function test was done to assure everything was working properly before test driving the truck.
Step 1: The Replacement Cab
I have seen truck cabs pulled of with a chain hoist and an A frame or sturdy tree branch, but a good vehicle hoist will save time and effort. If you have access to one, use it.
All of the A/C, brake, and electrical parts still attached to the firewall of the replacement cab had been exposed to the elements for an undetermined amount of time, so they all came off and went into the scrap pile. The dashboard assembly had a rat nest in it, so all the interior was stripped off and put in the scrap pile.
Step 2: The Scrap Pile
Step 3: Stripping the Damaged Cab
The front fenders and hood were removed from the vehicle and set to the side, we did not get replacement fenders with the replacement cab. The freon was recovered from the A/C system and the lines were disconnected from the firewall, The coolant was drained and the heater hoses were removed from the firewall. After the A/C and heater hoses were disconnected the hvac assembly was removed from the interior of the cab.
The brake booster was unbolted from the cab and layed over, the hydraulic lines do not need to be removed or loosened, this will prevent the need to bleed the brakes later.
The chassi and engine electrical harnesses need to be disconnected from the cab and positioned out of the way.
If you want to teach someone about trucks this is a project that will show them more than any singular project.
Step 4: Swap the Cabs
If you are using a single hoist lower the damaged cab onto a pallet or flatbed trailer and get it out of the way so the replacement can can be put on the hoist.
Roll the chassi into position under the replacement can and lower it down slowly making sure that nothing is pinched or damaged by the cab. Adjust the cab position and bolt it down. Hook up and reassemble the truck in the reverse order of disassembly.
Fill the fluids, charge the A/C, and double or triple check everything before starting the truck. Function check everything, this project requires messing with everything so every button, switch, and feature has to be checked from the head to toe.
Step 5: Test Drive and Give the Truck Back
This was a two day job, with the help of an assistant. I have done this type of cab swap several times and this instructable is intented as more of an advisory than a highly detailed step by step.