1955 Frame Question

[Bubba L]

We have begun the renovation of a 1955 Flying Cloud. I have the shell off and currently working on the frame. The main frame members are 2" x 4" 14ga tubing. It's in overall good shape with some loose topical rust, which I'll wire brush off before I POR 15 the frame. The main frame has about 1/8" deflection downward in the rear.

At this stage I have three options considering the frame rigidity. I can: 1) slide a 1 1/2" x 3" x 1/4" channel 12 feet into the frame, drill 1/2" holes 18" O.C. and puddle weld the channel (see photos), 2) install a 1 1/2" x 1/4" tube 12 feet long to the outside of the main frame (see photos), 3) or, do nothing and let the shell assembly keep the rear rigid. As stated, the frame is in pretty good shape, just wanted to get some opinions whether the added rigidity is even needed.

Would appreciate any and all opinions.

[markdoane]

If you add any metal I beef up the area around the axle.

There should be a stiffening plate that extends fore and aft of the spring mounts, that's the most critical area for reinforcement if there is any rust or decay. If it looks good there, I would not worry about 1/8" frame deflection. The shell will hold it up just fine.

Also, if there is not a rear hold down plate to secure the joint between the frame and the body I would add one. I use 2" aluminum angle bolted to the rear frame crossmember and riveted to the shell.

[Bubba L]

Markdoane, thanks. What gauge angle did you use for the hold down plates? At this point I could weld 1/8" plate as hold downs if necessary. All will get POR 15 anyway. Also, I will replace the leaf spring axle with a Dexter torsion I'm getting next week. If it helps, I can still weld a couple of 4 foot tubes alongside the main frame members to reinforce the span around the axle mounts. I'd rather overkill than under achieve if you think it is necessary. Thanks

[markdoane]

For hold down plates I think 1/8" is great. I used 12 gauge which would also be OK.

If you are switching to a torsion axle I think there are mounting plates available. I didn't do a leaf spring to torsion axle conversion.

I'd put out a question to torsion axle owners for advice on mounting plates.

[HiHoAgRV]

I just finished a '55 rebuild including the conversion to rubber axles. I was pleased with the overall frame, it didn't flop as much as the C channel version on my '63. I fabricated the torsion plates from .190 steel, plenty stout, and welded straight to the sides of the frame.

[Bubba L]

Thanks HiHoAgRV. I plan on welding the mounting plates I fabricated from Colin's drawing. I think markdoane had a good idea with additional support along the main frames at the axle location. I have some 3/16" x 4" flat stock I plan on welding along the inside of the 2"x 4" main frame members about four feet long. This should add some rigidity to the most stressed area of the frame.
Thanks

[raphspeaks]

Hey Bubba, quick question - from that 2nd picture are you planning on using channel or c-channel?

I literally just finished my frame last night. I replaced the rear 8 foot of my 1975 31ft excella. I went from the 5x2 flimsy channel to to 5x2 tube. I cut about 15 inches of the top and bottom of the 2in. Short side to act as plates. That allowed me to transition the channel to the tube acting as a reinforcement plate on the inner and outer side of the channel, essentially forming a tube. I made holes on the outer side of the tube so that i could spot weld just to reinforce the abutment to the old main frame rail. I cut all new out riggers with the 5×2 tube as well. Plasma cutter came in handy (lotos ltp5000d $500 - highly impressed) I etched the new steel and painted on por-15. Everything turned out great no more rear sag or separation. I used teks screws for securing the floor to the tube and 7/16 bolts to secure the floor to the shell and through the outriggers. I couldn't be more happy with how it turned out.

I'll upload pictures of the new floor shortly.

[Bubba L]

Thanks raphspeaks. The second picture just shows a couple of options I considered in reinforcing the main frames aft of the axle. One option was to slide the 1/4" x 3" channel into the 14ga tube, drill holes and spot weld as you did. Since my 2"x4"x14ga tube is in really good shape for 61 years old and only had 1/8" sag, I decided to abandon any slide in channel and instead weld a couple 4' pieces of 3/16"x4" flat stock to the tubing around the axle. The channel would have added nearly 80 lbs to the frame. Your idea of splicing I plan on using to extend the bumper out to accommodate a bumper trunk. Thanks for the help.

[HiHoAgRV]

A couple of photos

[Bubba L]

Thanks HiHoAgRV. I copied you on the bumper. Got it all fitted and tacked today for the 7" bumper trunk. I plan on terminating the gray water clean out valve there. I'm just a little concerned about the 3" pvc flow line. I don't want to get below the belly pan. 4" tank in a 4" frame with a 3" drain pipe doesn't give much slope. Thanks

[HiHoAgRV]

Kinda tough to get any drop and still keep the valves inside the belly pan, huh?
I have been placing the black valve flat under the tank with a straight shot out the bottom. It dumps FAST. The gray, not so simple. It's gonna drain slow even if you jack up the nose. I've place the pull handles in the bumper trunk and also out the side. The trunk protects them but out the side is easier to pull.

[Bubba L]

Thanks. Looking for options. Given the lack of slope, has anybody ever used pumps or air pressure to empty the tank quicker. We will only have a grey tank in the belly pan.

[millertimeUS]

Given the tanks are vented there would be no way to build pressure right?

[HiHoAgRV]

I guess I should quantify 'slow' in my experience. The black tank, :15 second dump. Gray, 4x as long or a full whole minute.

Yup, I'm the guy standing in front of the microwave hollering HURRY UP!

[65CV]

Using 2 VTS 15 gallon grey tanks, I'd love to dump in 1 minute! Try several.

Vernon, how did I miss your '55 thread?

John