Adapting Front Sway Bar to the Rear

[Ted DuPuis]

One of the things I've never liked about my Freightliner XC chassis (2000 HR Endeavor) is the lack of a rear sway bar. I suppose that some RVs did have them stock, but mine didn't. These things will never handle well, but I have found the propensity for body roll to be annoying and it's also annoying for my family in the back.

One of the first things I did last year when I bought the RV was upgrade the front sway bar with the Roadmaster kit that brings it from 1.5" to 1.75". That did make a difference, but it was also obvious the rear needed something. While Roadmaster makes a kit, they also want over $800 for it, and I didn't want to spend that kind of money. So I kept the front bar and figured I'd look at some point to see if it was feasible to use it for a project.

In looking at the suspension on the bus, the horizontal spring mount support looked like it would be a good place to weld supports for a sway bar. So, I took some scrap metal and start that:



Basically, I'm going to bolt what was the stock front bar (1.5", same as what Roadmaster does for their aftermarket rear bar) to those brackets. The end links on the front bar bolted to the frame, which is the same width the whole way back. So I'll need to drill some holes for those. One issue with the mounting location I've done is that the rear suspension pivots at the front, so where I am mounting the bar will have the maximum vertical movement and I'll need to look at mounting and end link length (possibly needing to make end links with heim joints rather than just the stock poly bushings on rod type end links).

One potential interference issue is the hydraulic jacks:



Where the stock bar ends come, they get close to the bottoms of the jacks. I need to look at how the suspension movement goes, but I may have to move the jacks back. If so, it looks like that won't be a big deal - the hoses seem to be long enough and I could just move the front support holes to where the rear support holes are, and then drill 3 new holes on each side.

We'll see how this comes together.

[George Schweikle]

This appears to be toward the upper end of owner DIY. Looking forward to your results .

[Ted DuPuis]

Originally Posted by George Schweikle

This appears to be toward the upper end of owner DIY. Looking forward to your results .

Calling this "DIY" might be a little off. That said, I am doing this with just a standard welder, hand drill, and angle grinder. Anyone who knows how to weld could do this and the measurements aren't complicated to do, nor do you need to be precise down to the millimeter (although obviously the more precision you can get the better).

I want a drill press and band saw/chop saw for my shop, but haven't bought them yet. Those would undoubtedly have made fabrication of my brackets a bit cleaner, but it's not like the underside of the rear suspension is a clearly visible area that impacts overall appearance.

I think the big question I have at this point is the end links.

[Hittntheroad]

This sway bar was added by the PO of my Precept 31 UL by Tampa Springs. It has virtually no sway. Sway causes steering corrections. It drives perfect even without a steering stabilizer.

[Ted DuPuis]

I got the welding finished up, painted the brackets, bolted up the sway bar, and started checking out the end links. I had a feeling that the stock end links wouldn't work with the leveling jacks fully jacked up, as that gets the angle really steep. But I figured worst case was it would break the end links, and not hurt anything else. Sure enough, it worked fine with the air dump (lowest possible height), fine at normal height, but when I jacked the bus up all the way with the leveling jacks, it was too far and bent the ends. So I need to get some different ends with ball joints/heim joint rod ends, and then put it together and try again. At this point I'm pretty confident that everything does and will work. The sway bar is basically level at normal ride height, which is what you want, and it doesn't hit the jacks so I won't have to worry about moving those. I do want a setup that's as close to the total length of the stock rod ends as possible, so I have to see what I can find. I think the ideal would be some sort of adjustable heim joint. Probably some searching for the right items and see what's either available locally or order in. My preference is something that I can just find locally, ideally cross-referenced with a factory vehicle of some sort. But I have a feeling this will probably need to be custom put together.

[Ted DuPuis]

After figuring the stock tie rods wouldn’t work, I bought these adjustable top links at Tractor Supply. Overkill and will work just fine. Made up some L-brackets and will weld in some gussets then put it all together before my trip at the end of this week.

[Ted DuPuis]

I got the bus back together and did the initial test drive today. I'm happy to report that the sway bar definitely works as intended. After the next trip I'll type up a more comprehensive report, but this definitely seems to be working as intended.

[Ted DuPuis]

We just got back from a 1600 mile trip. All I can say is that this is a night and day difference in all respects. The bus doesn't sway nearly as much now and is much, much more stable both going down the road and around corners. I no longer need to go 5-10 MPH under the yellow signs around corners, and my wife pointed out that also the dishes don't seem to be clanking around nearly as much going down the road.

Even at the $800 price for the Roadmaster kit, I think it would be a worthwhile improvement. But the fact that I was able to do this for about $75 worth of parts and scrap metal, all the better.