i have done lots of mechanical work and a little body work in the past 6 years. this weekend i noticed that the core support had finally started to sag on my 70 f-100. the core support is not hard to change but it also needs cab mounts floor pans and cab supports. what is the easiest way to change the floor pans and cab mounts? with the cab removed from the frame? or is it about as easy to do it still sitting on the frame? a little imput from experience would be nice. thanks

 

Taking cab off and setting on the back wall would be the easiest way to work on it. I replaced mounts this way. I made a jig up so the holes for the mounts would be in the right place when I was done(height and position). My floors were great so I cut down the replacement mounts so they only fit where the original ones came off. Then normal mounts come with an extra foot or so of metal to cover up any other rust behind the mount(toward rear of truck).

I have slipped the replacement type mount under a cab once. It was not too easy, but it did work. I just used screws/pop rivets to hold in place. It worked.

It does take at least two+ people to remove these cabs. I used four and it still was quite heavy.

Good Luck
Larry

 

I am right in the middle of the same project as we speak. I left the cab on the truck, here's how I did it. I took the hood off and then pulled the lower rear bolts on the front fenders and then the bolts inside the door hinge access, then the two holding the radiator support on, and lastly the six that hold the inner fenders on. Now you also have to disconnect your wiring and radiator hoses battery, etc. But this is all pretty easy, then I got a buddy to help and pulled the entire front clip off all in one piece. Without the hood it's not that heavy. That made it easy to get to my front cab bolts(your going to have to pull the inside gas tank to take the rear ones off) I then took the steering loose and the brake lines and tranny linkage and jacked up the front of the cab and put 4" blocks under it about 2/3rds of the way towards the front. This gave me the clearance to get to the cab mounts. I did have to pull the right side exhaust pipe to get to a couple of the spot welds(depends on which engine you have.
I then drilled out all of the spot welds, you can get to some from inside the cab also, then use the holes that are left in the cab to weld the new cab mount back in place(it doesn't need holes).
I have to replace a small section of the cab floor on the drivers side, once I get that made I will be ready to start welding it all back in place(hopefully by this weekend.

A word of advice don't pound on the old mount to get it off or you will distort the metal around it, make sure the spot welds are dilled entirely out and the mount should almost fall off with very little effort. They do make special drill bits for drilling out spot welds, make sure you center punch them in the right spot before drilling. You will also be better off to get a 90 degree drill for the really hard to reach ones over the frame.
I'll let you know how the reassembly goes.

Ralph

 

Got the new cab mounts in this weekend, went pretty easy except the patch I made for the floor was a little off so it took some work to get it right. If I had it to do again I would have bought a patch piece rather than made one(it was only about 7" x 18"). It was right where the cab mount attaches on the drivers side. The cab mounts went in good, look like factory, I had to shape them a little, but for the most part they fit ok. I still have to align the cab on the frame before I punch holes for the front mounting bolts.
Now the only cancer left on my cab is the right rear corner of the cab. I've seen the outside section for sale, but I have not found the inner section. Does anyone sell this or the entire corner as a whole(inner and outer panels pre welded together)?
Another question, should I put two extra holes in the mount for water drain as in the originals, I don't want to let any more dirt in than is necessary?

Ralph

 

My thinking is the more drain holes, the better. There is probably some trick way of letting water out and keeping dust out also.

Does your truck show any signs of rust at the rain gutters. Also where the metal kick panels come down to the floor (in front of the door openings).

 

I might put some holes and then put a rubber plug in them so I can pull them out and clean it ocaisionally. No other rust on the cab except the right rear corner, I plan to tackle that next. I did have a 69 once that was rusted bad on the kick panels. I replaced the entire floor section and rocker/kick panel. Too much work though, If I had it to do again I probably would just replace the cab with a rust free one.

 

I have a 76 supercab. My left front cab mount is shot. I bought a new one from MotorHaven but i have not started the project. I use the truck everyday and need to make the repair in a timely manner. Do I have to remove the front clip and all cab mount bolts, or can i just remove and jack up the drivers front corner of cab? How long will this process take. How do I make sure I get it all aligned correctly. Thanks

 

You might not heve to take the front clip off, but you will probably have to take all your mounting bolts out(or really loose to get the cab to raise high enough to get the mount in and out. I would say also that your steering and brake lines might not have enough play in them to avoid being disconnected also. I am sure it is possible to do this without all the trouble I went through, but I am also cleaning and rustproofing the underside while I have it all apart.