47-55.1 Cab Question

[Dachshund]

I have the cab off of my 47(2) 3600...What I need to know is - how much space between the cab floor and the frame is there? I want to put a stiffener sideways (wall to wall), under the floor.

[b-mac]

Holy crap. Trenton, Mo. I'm from Gallatin! (Originally)

Without an exact measurement, the back of the cab, where it is notched up, is basically where the frame rails pass. So if you keep your brace north of the back middle part of the cab, you should be good.

[dsraven]

check the style of cab mounts you have as well. some are like leaf spring shackles and may need some wiggle room. you could always update that style if not going with a stock build though. maybe something like the energy suspension urethane donuts would work.

[dsraven]

also check the park brake linkages for interference, if you plan to use them.

[mr48chev]

It is in the assembly manual. The measurements are in the first and third images in this album. http://s173.photobucket.com/user/mr4...?sort=4&page=1

If you click on the two images you can read the measurements. i finally found the assembly manual but still haven't found those pages.

I took those with my camera long before I have the scanner I have now so if I can find the manual i'll scan it in a bit.

[Dachshund]

Thanks guys! Mine has the "shackle" type cab mounts. I am PLANNING on using the park brake, but that may change as I move along.

[mr48chev]

Where most of us run into problems with the park brake rod hanging up is because we decided to cut the center crossmember out under the bellhousing to run a different engine and trans combo and the weight of the cab pushes down on the body mounting bracket and twists the frame rails until the cab has sagged down to where the floor supports are laying on the frame rail and pinching the brake rod where it goes over the frame.

That happened on my truck and you can see it on a lot of older builds with V8 automatic swaps that have been driven a lot when you look at them from the side and they look slightly bent at the cowl and the hood won't line up.

I thought I had an example photo but can't find it but if you stop this video 24 seconds into it where it gives a straight on side shot from the passenger side you can see that the hood doesn't flow just right and the gaps are wrong. No doubt it wasn't built that way but over time the cab has sagged because the body mounts on the frame have twisted the frame and sagged from the weight.

https://www.youtube.com/watch?v=LbC921wvUyo

[Dachshund]

Yeah, I can see that has sagged! I'm still using the stock motor/trans, so HOPEFULLY that won't be a problem! Thanks for the info!

[dsraven]

if running drum brakes out back then you NEED to run a park brake for proper service brake operation. it is likely a law anyway.

[dsraven]

the same saggy effect can happen on the 55-59 trucks too when the original trans cross member is removed. it can be supported better with a well built "new" trans cross member that connects the upper and lower frame rails. the spreading effect of the frame rails "twisting" can affect the cab mounts and the cab because it effectively makes the mounts further apart. this can warp things and make it hard to line up door and fender gaps besides the affect it has on the floor etc.

[nvrdone]

dachshund: just checked mine and its 1 7/8" at the front mount and 2 1/8" at the rear. the front mount is a rubber "donut" bushing and the rear are shackles. hope this helps.