Trailing Arm Service (aka: Torque Tubes)

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Trailing Arm Service (aka: Torque Tubes)

November 14, 2015, 09:00:59 pm

Quote from: kenhat – November 14, 2015, 01:13:31 am

....A couple of years ago they replaced all bushings in my torque tubes, custom built adjustable torque tubes for drivers side rear, and did a 4 (6 really) wheel alignment....
ken

So I PMed Ken to ask what "torque tubes" are and he told them they are the trailing arms (which seems to be the more common term). He said Torque Tube was the term Kaiser Brake and Alignment used that did the work for him. I realized this is one of the few technical subjects that hasn't had much coverage and I want to hear what others have had done on their coach in this regard. I have always assumed the bushings were good for the life of the coach, but maybe not?

So whatever you want to call them, how many have had to replace the bushings?
What were the symptoms?
Ken, can you tell us why they replaced the arms and also why did they make them adjustable?

Thanks, John

P.S. The trailing arms in question apply to Unihome and Unicoach coaches, not Oshkosh/Torsilastic chassis coaches

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #1 – November 14, 2015, 10:24:20 pm

The "Torque Tubes" serve to allow the axles to move up and down without moving side to side. The upper and lower tubes form a parallelogram with one side attached to a frame member and the other to the axle which moves up and down as you encounter bumps going down the road. There is also a tube that is mounted at a right angle to the assembly that restricts the movement of the axle either left or right. Crawling under the front of the coach looking for the square tubes (at least all the ones I've seen have been square tubing) with bushings on both ends. Once you see it it's pretty easy to understand how it works.

I discovered my bushing were bad when I took my coach to Kaiser Brake & Alignment in Eugene, OR for an alignment due to a lot of wander in the front end. After they had Big Agnes on the rack for a while one of the techs pulled me under the coach then reached up and grabbed one of the tubes and twisted. He could twist 10º to 15º by hand. He used a large pipe wrench on the tubes for additional leverage to show me how all of bushings had some movement in them. I agreed we needed to replace the bushings. They don't do much work on Foretravels mostly Country Coach & Monaco country in Eugene but they have very similar design. They couldn't figure out what bushing Foretravel used and wanted to build new tubes with high end Monaco bushings to the tune of about 5 coach bucks! I had them call Foretravel to find out what bushing they used. Foretravel said they were Hutch (sp?) bushings. Kaiser was not impressed. Said they had only seen the Hutch bushing used in trailers. Well the Monaco bushings were like $89 a piece and I needed 20 of em' and they would have to custom build 10 new arms. The Hutch bushings were around $15 a piece and I could use my OEM arms. Guess which one I picked! I figured the ones that were in place had been there for twenty years. That was good enough for me. It came out to a little more then 2 coach bucks using the Hutch bushings.

As to your question about the adjustable rear arms I had installed. One of the tech suggested that we replace 2 of the rear arms with custom adjustable arms since there is no adjustment for alignment on the rear axle. It sounded like a good idea to me. Don't remember the price. I don't think it was to bad. After they finished the alignment I got a spec sheet on it. Turns out they had to adjust the rear axle 1/32" to bring it into alignment. Looks like Foretravel did a pretty good job with the original placement of the axle.

All of the work did help with wander. On a test drive on a flat road I could take my hands off the wheel 1/4 mile or so without having to correct but I still had slop in the steering. They put it back on the rack checked the steering box. Yep had 1/4" to 3/8" slop. Since the m100 is not adjustable they wanted to trade it out with a Monaco box that was adjustable. I didn't even want to know the cost of that and had heard Brett talk about Redhead Steering blueprinting the m100 and though I'd try that instead.

Jump forward 2 years and I'm back up in the PNW. Redhead Steering is in Auburn, WA just 12 miles away. So I pull my steering gear and take it to Redhead. 2 days later and $500 lighter I have a rebuilt steering gear. The steering gear feels fantastic but I still have some play in the wheel and I'm constantly saw back and forth on the steering wheel. Arggg! I then start reading cashflashbobs hunt to fix his steering play. He mentions preloading the wheel bearing. OK I've done ever thing else why not give it a try. I'm heading south through Eugene might as well have Kaiser take a look. When we get there I go for a test drive with the tech and I tell him the whole history and why I want to check the preload. He is really impressed at how well the coach drives and he test drives a lot of coaches. Compares it to the Signature Monacos and even to the Marathon coachs. I happen to notice a brand new Marathon in front of the shop when I came in. I tell him maybe I'm expecting to much out of the coach but I do think something isn't right. We get back to the shop put Big Agnes on the rack and 2 techs start going at it. They start bad mouthing the Hutch bushings (in a good heart jesting manor) and then they check the wheel bearings. Bingo drivers side has about 1/8" play in it and the seal is leaking. So they replace the seal and do a preload on the bearing. I drove 250 miles today all I5 Eugene to Weed, CA. My original plan was to write this up and for the subject use "kenhat get's a brand new coach!" because that's what it feels like. Finally, finally Big Agnes drives like a Foretravel is supposed to!

OK sorry got off thread but once I started I couldn't stop! I won't go into all the brake work I ended up doing after just asking for a chassis lube and check the brakes for the correct lube!

So now back on topic. To check your torque tube bushings take a big pipe wrench (you can do this by hand to find the big offenders) under the coach and twist the tube if it moves relative to the bushings they are worn. Should be very little movement when twisting.

see ya
ken

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #2 – November 14, 2015, 10:39:17 pm

Ken, how many miles when your bushings needed replacing? My '91 has approx 135,000 and drives straight and tight. I think I will try the twist test tomorrow.

Also, you mentioned brake work. Was the shop up to speed on Meritor brakes, proper grease etc? Was this the shop that did your chassis work?

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #3 – November 14, 2015, 10:42:29 pm

Here are pics of my adjustable torque arms on the rear axle.

see ya
ken

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #4 – November 14, 2015, 11:15:17 pm

Ken,

Wow, 1/8" play= .125" play. Spec is .001-.005".

That should have made a significant difference in tracking!

Good catch!

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #5 – November 14, 2015, 11:33:20 pm

Dumb question Ken... The torque tubes you are referencing (the ones that would take 20 bushings to replace them all)... are in the front, correct?
Don

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #6 – November 14, 2015, 11:44:34 pm

Peter,

My milage was around 185,000. As long as you drive true and straight you are probably ok. Never hurts to check though.

Kaiser was amazingly competent with Meritor brakes and yes they were the ones who did all the chassis work on the torque tubes.

Brett,

The 1/8" wasn't at the wheel bearing with a dial indicator. With the wheel in the air the tech put a large bar through one of the holes in the Alcoa wheel and lifted. I'm not sure how accurate the 1/8" is but I could visibly see the wheel move as he put pressure on it. Don't think it was a lucky catch. It was the result of trying all options and advice from all the experts and wanna be experts on this site! (I put myself in the wanna be category)

see ya
ken

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #7 – November 14, 2015, 11:49:07 pm

@Don Front and rear. 5 front & 5 rear. The adjustable torque tubes I had installed and posted pictures above are on the rear axle.

see ya
ken

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #8 – November 15, 2015, 12:06:53 am

Quote from: kenhat – November 14, 2015, 10:24:20 pm

As to your question about the adjustable rear arms I had installed. One of the tech suggested that we replace 2 of the rear arms with custom adjustable arms since there is no adjustment for alignment on the rear axle.

Ken,
First off, thanks for the detailed write up. I'll have to check my bushings.
Second, the alignment for the rear axle is adjustable. There are 4 large clamping bolts on each side of the axle holding the suspension to the axle. Nominally there should be 3/16" to a 1/4" of fore/aft play if the bolts are loosened. I only know this is because recently, a (non-computer using) buddy with a'95 U320 had a strange tire wear problem on the front axle and it turns out the thrust angle on the rear axle was off. The techs loosened the bolts and shifted one side forward a little. He said it drives great and thinks it's been this way since he first bought it 14 years ago.

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #9 – November 15, 2015, 04:29:53 am

What exactly is a preload on the bearing?Is it something we can do ourselves?What would the specs be?

Sounds like it would be a lot of muscle work but you could do the bushings yourself.

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #10 – November 15, 2015, 06:22:57 am

John, doing a search on preload should provide lots of info. If not, consider asking the question with a new topic to avoid getting off topic here,

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #11 – November 15, 2015, 12:04:32 pm

John44,

Here is a thread where preload is discussed. There is a video posted there that is particularly good.

front wheel bearing preload?

see ya
ken

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #12 – November 15, 2015, 12:27:16 pm

Quote from: JohnFitz – November 15, 2015, 12:06:53 am

Second, the alignment for the rear axle is adjustable. There are 4 large clamping bolts on each side of the axle holding the suspension to the axle. Nominally there should be 3/16" to a 1/4" of fore/aft play if the bolts are loosened.

Yep that would work. They could drill em' larger or oval em' out if they needed more adjustment. I do wonder if there would be enough holding power to keep the adjustment from moving around. There is a lot of torque on the torque tubes! Especially on the drive axle. Plus the adjustment would be a little crude I think.

I just pulled my old receipt and it shows the arms were only $125 for the pair. There was also R & R of the tubes and of the bearing and the bearing itself covered in the labor of the 20 bushings. On mine I don't even think it was necessary. 1/32" adjustment is basically nothing and don't think it really helped that much in my tracking but I do have one less thing to angst about before I go to sleep at night.

Also noticed on the Hutch bearings were $13.95 not $15.95.

see ya
ken

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #13 – November 15, 2015, 01:13:03 pm

Quote from: kenhat – November 14, 2015, 11:44:34 pm

It was the result of trying all options and advice from all the experts and wanna be experts on this site! (I put myself in the wanna be category)

Is that something I should be concerned with? Bess tracks well on the crappy roads down here.

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #14 – November 15, 2015, 01:38:20 pm

Quote from: mike leary – November 15, 2015, 01:13:03 pm

Is that something I should be concerned with? Bess tracks well on the crappy roads down here.

No, the U225, U240 and ORED's have a completely different suspension.

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #15 – November 15, 2015, 02:20:08 pm

Mike of Pamela & Mike PM'd me to get part number for the Hutch bushings. (RBT201 if anyone else is interested) While looking at the receipt again I noticed that they call the torque tubes torque rods. That is probably the more correct term for the "tubes". Also noticed in the parts section there is a $400 charge for 2 torque rods plus $58 for steel for torque rod. So I think $458 is the price of the 2 adjustable torque rods and the $125 I saw is for the alignment of the rear axle. And another correction the Hutch bushings were $13.02 a piece.

Not sure how long FOT used the Hutch bushings. Does anyone know? I think the suspension was essentially the same up through the 2000s?? (with the few IFS being the exceptions) As the coaches got heavier they may have had to upgraded/upsize the bushings.

Can you tell I'm setting out a snow storm in a campground with good wifi? Haven't posted much of anything for 6 or 8 weeks and now I can't shut up!

see ya
ken

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #16 – November 15, 2015, 02:37:24 pm

Here is the info I have.

This is from a 97 u270

Looks like the factory changed the bushing setup but used the same locating arms

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #17 – November 15, 2015, 06:26:58 pm

Quote from: JohnFitz – November 15, 2015, 12:06:53 am

Second, the alignment for the rear axle is adjustable. There are 4 large clamping bolts on each side of the axle holding the suspension to the axle. Nominally there should be 3/16" to a 1/4" of fore/aft play if the bolts are loosened. I only know this is because recently, a (non-computer using) buddy with a'95 U320 had a strange tire wear problem on the front axle and it turns out the thrust angle on the rear axle was off. The techs loosened the bolts and shifted one side forward a little. He said it drives great and thinks it's been this way since he first bought it 14 years ago.

Hmm. Our coach had a strong tendency to veer to the right when we bought it. At our first alignment at FOT, I asked Wayne about alignment of the rear axle. I could see that some of the bolt holes for securing the drive axle were elongated. I assumed that would allow adjustment. Wayne told me the drive axle was pinned and was not adjustable.

These two stories seem to be in conflict. I wonder which is more correct.

Fortunately, after the most recent alignment and truing of steer tires, our coach steers well. It still reacts to wind, crown, surface changes, etc. On a straight flat road with no cross winds it will track straight for 1/4 to 1/2 mile with hands off the wheel.

Ken's experience suggests several issues to check if you have a coach that is prone to wander on its own.

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Trailing Arm Service (aka: Torque Tubes)

November 14, 2015, 09:00:59 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #1 – November 14, 2015, 10:24:20 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #2 – November 14, 2015, 10:39:17 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #3 – November 14, 2015, 10:42:29 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #4 – November 14, 2015, 11:15:17 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #5 – November 14, 2015, 11:33:20 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #6 – November 14, 2015, 11:44:34 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #7 – November 14, 2015, 11:49:07 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #8 – November 15, 2015, 12:06:53 am

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #9 – November 15, 2015, 04:29:53 am

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #10 – November 15, 2015, 06:22:57 am

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Reply #11 – November 15, 2015, 12:04:32 pm

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Reply #12 – November 15, 2015, 12:27:16 pm

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Reply #13 – November 15, 2015, 01:13:03 pm

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Reply #14 – November 15, 2015, 01:38:20 pm

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Reply #15 – November 15, 2015, 02:20:08 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #16 – November 15, 2015, 02:37:24 pm

Re: Trailing Arm Service (aka: Torque Tubes)

Reply #17 – November 15, 2015, 06:26:58 pm

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