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#846 - Cummins Swap
Author: andy1canada (Show all albums)

Howdy Folks!

Going to give this another try as my first attempt didn't go so well on the 'Diner-conversion' thread (Will update/edit that soon).

Started my Cummins swap by pulling off the bumper; only took better part of an hour. That sucker is HEAVY! Better part of a 100 lbs I bet. Will be looking to knock substantial weight off that baby while still retaining a 5000 lb towing standard.

This will take a while as it will unfold as time and resources permit, so please be patient.

More pics and hopefully some videos (FMC-TV) to follow.

Show Newest Photos First | Show Oldest Photos First210 Photos - Page : [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18]

Again, good access for another weld along the entire bottom edge.

Some simple brake-line re-routing will be in order here to keep stuff away from chaffing the bag.

Good 4" or so clearance from bag to tire.

Now... to make it all out of steel!

Included this pic to illustrate the close proximity of the bottom shock-mount to the edge of the air-spring mount beam. Got to thinking it might be a good idea to fab a simple bracket to provide an additional support-connection between the trailing arm and the air-bag arm while still providing the shock mount in the same position. Plan to look closer at this.

Air spring trailing arm mounts completed. As I cobbled these together from some gifted steel, they're rather patchworked together. They're about 36" long and the 6" round lower disc is tilted about 10 degrees upwards off the plane of the beam. If they prove not able to do the job, I'll simply make new ones out of heavier box channel steel.

Disclaimer: This is a sketch of the general idea of the direction I've gone with on this air-spring mod on my coach. Any sketches and all related pictures I'm sharing here on this subject are simply to provide my fellow coach owners with another perspective on an air-spring install on an FMC motorcoach. I am not in any way endorsing/suggesting/advising that this method will work, or, is safe to copy or use on other coaches. Anyone who does so, does so at their own risk.

As Frank and Lenny and no doubt others have, I decided to mount the air-spring support on the trailing arm somehow. The road I took relies entirely on this 5/16" pc of angle iron being securely welded to the upper end of the trailing arm and to the outer torsion bar tube. This needed to be done right, so I hired a professional welder to do this particular job. All other parts I welded myself and as I am a woodworker by trade, I make no apologies for how sloppy many of the welds are.

Prep work on the trailing arm/torsion bar tube mount bracket footprint.

Added two 5/16" small gussets to the angle bracket to beef it up some. Drilled 3 x 11/16" holes for the 3 x 5/8" (gr.#8)bolts that will secure the air-spring mount arm to the mount. Note: I made the bolt holes 1/16" larger for two reasons (1)I'm not a machinist and only have a simple drill press to drill these holes in correct alignment and knew I'd be off a bit so this would provide some wiggle room. (2)slightly larger holes would also provide useful horizontal adjustment to help correctly align the lower spring mount with the upper one on the chassis. The following pics show the mount in place and the welding tracks where it's attached to the trailing arm.

Ignore the extra hole in this view; it was already in the beam material I used.

Here you can see the weld on the radius of the outer torsion bar tube. Had to grind off a bunch of what appeared to be asphalt black undercoating to expose clean steel.
Show Newest Photos First | Show Oldest Photos First210 Photos - Page : [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18]

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