Need to replace Cab Mount Supports...help

[airbrushguy]

Beginning winter project...
Went under 1971 C10 LWB Stepside, all four cab supports are rusted out. Bought new ones and would like to replace with cab still on frame.
Where and how should I lift cab to give me room to replace/weld supports in?
Rockers are going to be replaced and a small section of floor at edge of rocker area.
Was hoping I could fix floor and make it solid before I decided whether I wanted to take a foot out of frame to shorten LWB.
Am I attempting something someone has done before or should I rethink plan?
I do/did not want this to become another project that grows larger at each part. The truck is going to get a V8 in place of 6 and the body/paint will remain as is with a little nod to aging it to become a tribute to my dad's service station with aged lettering etc.
Please only respond with helpful advice, I really don't want to sink a ton of $$$ into this as I have with all my other vehicles...help me avoid that. I am quite qualified as a welder, mechanic and very determined.
Thanks in advance

[Molberg]

They sell slip on replacement cab supports to "cover" rusted ones... but I dont recommend it. Just rot through again shortly. Cab support replacement is usually a job that stretches into repair of floors and inner rockers as well. Can be tricky enough with cab removed on a dolly. Remove mounting bolts from one side of cab and lift with a large block (to distribute weight) and a floor jack. Done it before.. easier on a dolly though

[checkmate211e]

Or build a cab hanger. I replaced the complete floor with my hanger.

[Sammy]

Depending on the amount of rust really if it can be done by lifting and doing one side at a time. If you tear into it deeply and find it more severe than originally thought you will wish you had just bought the entire floor pan in one piece with everything new. But they run about 450 dead presidents and likely impossible to do without cab removal. I have a friend who had his cab chemically submerged/ treated. Then started a similar process of mounts and inner/ outer rockers and discovered how weak the entire floor was after buying and starting the task.

[airbrushguy]

Actually, after removing rugs etc., the floors are even better than thought.
Don't need the extensions I bought, floor is solid right u to edge of rockers.
Will I be able to jack it up with the floor jack, one side at a time, without unhooking the steering column?

[Sammy]

If you are careful after you let the column drop from the dash mount and disconnect the plate from the firewall inside and engine compartment I can't see why not. Leave the rest of it connected. May need a 6X6 block on the floor jack n jack stands to be safe of course.

[airbrushguy]

Any word from someone who has done it this way successfully?
Thanks

[Carl Spangler]

Originally Posted by airbrushguy

Beginning winter project...
Went under 1971 C10 LWB Stepside, all four cab supports are rusted out. Bought new ones and would like to replace with cab still on frame.
Where and how should I lift cab to give me room to replace/weld supports in?
Rockers are going to be replaced and a small section of floor at edge of rocker area.
Was hoping I could fix floor and make it solid before I decided whether I wanted to take a foot out of frame to shorten LWB.
Am I attempting something someone has done before or should I rethink plan?
I do/did not want this to become another project that grows larger at each part. The truck is going to get a V8 in place of 6 and the body/paint will remain as is with a little nod to aging it to become a tribute to my dad's service station with aged lettering etc.
Please only respond with helpful advice, I really don't want to sink a ton of $$$ into this as I have with all my other vehicles...help me avoid that. I am quite qualified as a welder, mechanic and very determined.
Thanks in advance

Can you please post a pic of the rusty supports and inner rocker covers?

thanks
JohnG

[Molberg]

Use a grinder with a wire wheel to locate all spot welds. A step drill and air chisel are your tools goin from there. Drill holes in similiar locations, grind off paint and spot weld in place. These were done with cab on frame... lifted with a block. A small metal brake is a usefull asset.

[Molberg]

Airbrushguy... be sure to keep everythin square by tacking in cross braces before you cut out rockers. Rod or angle iron half way up both pillars angled down to floor and inwards. Slip fit panels. Trimming will be required. Remove paint.. fit panel, trace with paint marker. Remove rusted/damaged area with zipcut. Refit panel and attatch with metal screws. (Drill holes for screws in area where spotwelds will go) reinstall doors and check fit/gaps before welding. I start with the inner/outer rockers and supports. once they're welded in I moved on to cab corners. Seam sealer used on all seams. Paint or weld through primer on all exposed metal

[Molberg]

Rocker done... moving on to cab corners. Only remove as high as necessary! Previous owner had new cab corners "brazed" in. Yes... brazed. Warping was so bad, had to replace up into featured area. Not fun to do bodywork in this area. Attack rear support when cab corner is out.

[Molberg]

Youll likely have your doors on and off a few times... necessary evil.

[Molberg]

Good luck..(cab removed for paint and bodywork...easier on my old knees)

[airbrushguy]

Originally Posted by Molberg

Rocker done... moving on to cab corners. Only remove as high as necessary! Previous owner had new cab corners "brazed" in. Yes... brazed. Warping was so bad, had to replace up into featured area. Not fun to do bodywork in this area. Attack rear support when cab corner is out.

I was not going to replace entire rear support, just weld on 10-12" end pieces. Do that after I replace cab corners?
These suggestions are very helpful, thanks so much everyone.

[Molberg]

Originally Posted by airbrushguy

I was not going to replace entire rear support, just weld on 10-12" end pieces. Do that after I replace cab corners?
These suggestions are very helpful, thanks so much everyone.

Do it during... more room to work.Tight in there as it is. Likely have to repair a small patch in floor area above support..common area to rot.

[airbrushguy]

When I take off doors, should i brace opening with square tubing?
Is taking off doors necessary?
Thanks

[airbrushguy]

When I take off doors, should i brace opening with square tubing?
Is taking off doors necessary?
Thanks

[Molberg]

Removing doors takes weight off forward pillar. Reduces chance of movement. It'll give you more room to work. Trace hinges with marker to reinstall. Good time for new pins and bushings. Replace first if worn out. Hard to align gaps nicely with worn pins and bushings

[Molberg]

Originally Posted by Molberg

Airbrushguy... be sure to keep everythin square by tacking in cross braces before you cut out rockers. Rod or angle iron half way up both pillars angled down to floor and inwards. Slip fit panels. Trimming will be required. Remove paint.. fit panel, trace with paint marker. Remove rusted/damaged area with zipcut. Refit panel and attatch with metal screws. (Drill holes for screws in area where spotwelds will go) reinstall doors and check fit/gaps before welding. I start with the inner/outer rockers and supports. once they're welded in I moved on to cab corners. Seam sealer used on all seams. Paint or weld through primer on all exposed metal

You can see the 1/2" rod I tacked in

[Molberg]

You'll have to remove front fender to drill forward spot welds.(outer rocker) Makes door removal easy.

[airbrushguy]

Will post some pics as soon as I figure how to do it.
Thanks

[airbrushguy]

Originally Posted by Molberg

You can see the 1/2" rod I tacked in

Ah, now I see them, I thought I would just weld across opening and then a piece across the truck connecting them. Did that for old coupes we built. Maybe your way is just as good and less tubing, thanks.

[Molberg]

If u leave the cab corners in place while you work on the rockers/front supports... It gives you something to line up to. (Bottom of rocker level and flush with old cab corner) use a paint marker and draw lots of reference lines and record measurements. You can see some on cab corner pic. Few I've seen just weld in. Require some curling and trimming.

[airbrushguy]

I see you disconnected doors from hinge, wouldn't it be easier to disconnect hinge from post with door attached to hinge??

[Molberg]

Yes. I think I put hinges there loose after new pins and bushings