I just bought a 78 Bronco and after talking to everyone in here I'm certain that I have a 460. I pulling the motor to rebuild it and had planned on a few mods while I had it out. Today was the first time I really crawled under the truck and the frame and body have a little more rust than I thought. My question is how strong of a frame is under this truck. Should I try reinforcing it and dump my money into that or is the truck sturdy enough for a buillt 460. The truck will mostly be driven off road and boggin so function is more important than looks. I can post some pics if some can tell me how.

 

What kind of rust action is going on under it like big chunks? If you are planning on beefin' the 460 up some more I would suggest clean any rust up, big & small areas so you are seeing what is going on under that. Then if you feel the frame needs reinforcement do it and coat it with something after you are done welding.

 

well after doing some picking and pulling it looks like the frame is pretty solid its the bottom of the body that is so bad. Its wierd that the body is in such good condition and the under side of the floor boards is so bad. Is this common on this truck? anyways after discussing it with a few friends and after a few drinks I think I have decided that she will hold up to the slight mods to the 460. I'll keep everyone informed of my progress

 

My knowledge of this truck is very minimal only because I havent had one yet, but I had a 1976 F150 4x4 that had rotted floor pans so maybe its just the sheet metal they used.

 

sb, very common for the floor board to rust away before the rest. my entire floor has been replaced in mine. my truck is nothing but rust but still going very strong.

 

To me - any rust is too much rust. I will not purchase a vehicle with rust and have not for at least a decade. I prefer my vehicles factory unmolested for one thing, and I hate to do bodywork for another. But I don't mean to discourage you, because if you are proficient at body work then it's the opposite - you can repair anything that is rusted out. Even the frame - but that is where a lot of people draw the line and, depending on how severe it is, is the real answer to your question. Another area that are bad for rust repair is around the windshield and pillars. I won't touch those with a fifty foot pole!

 

These trucks are bad about rusting the floors, because they get moisture trapped in the floor insulation from having the tops off or tracking it in with wet feet. Most common is under the drivers feet where a hole gets worn in the floor mat which allows moisture under it. If you have carpet, which mine did, then it gets wet and never seems to dry. The top had been off mine and the carpet had held the moisture till it rusted through. Other common spots are above the rear wheel wells where mud and salt get trapped. To solve this, one needs to stick a garden hose above it and let it run for a bit to flush it out. The tailgate is a bad spot as well, this is because the drain holes get plugged very easily from debris like leaves that get around the ends of the window seals. Periodic cleaning and flushing of the tailgate and door drain holes helps to alleviate this.
As to the frame strengthening. The bronco has a very rigid body, so a flexy suspension is needed as well as making sure that the frame is solid. Otherwise the body will fatigue and begin to crack.
If you remove the body and weld all the cross-members to the frame rails (they are riveted from the factory), it will dramatically stiffen the frame.

 

welding the crossmembers to the frame isnt a good idea.. rigid frames get stress cracks.. and these old ford frames are designed to twist a little.. if you weld all the crossmembers in a fixed position it WILL transfer that stress somewhere.. and more then likely crack your frame.


Ray