2013 HR Ambassador - Wandering and Vibration Issues

[ehoger]

Our 2013 diesel pusher HR Ambassador (38 foot) with Roadmaster chassis wanders and constantly needs steering wheel correction. Also the mirrors vibrate and the shades along side of the driver really vibrate when driving. When stopped and you turn the steering wheel back and forth you can feel and hear a slight clunking noise. We previously owned a Simba Safari Motorhome and had none of these problems. This has occurred since it was purchased brand new. It now has about 17,000 miles on it. We have replaced the mirrors 3 times, 2 alignments, ride height adjustment, tire pressure adjusted, sway bars installed, new shocks, 2 new front tires. We have tire monitors so tire pressure is always correct. Does anyone have any other suggestions. Your help would be greatly appreciated. This is the first time I have ever posted so hopefully have given all the info.

[wolfe10]

ehoger,

Welcome to the FMCA Forum.

Sounds like you may have a combination of issues:

Any HD suspension shop should be able to identify the source of the "clunking".

Two alignment issues address wander: Caster and Toe-in. Please post the caster and toe readings from your last alignment.

Vibration is most likely a tire issue. Start by having RUN-OUT checked. You can balance an "egg-shaped" tire until the cows come home, but it WILL vibrate. If run-out is over about .035", find an old fashion truck tire store to fix it-- rotate tire on wheel, true tire, etc.

THEN, spin balance the front tires ON THE COACH. That way all rotating masses are in balance, not just tire and wheel. Remember, that brake drum and hub weigh over 100 pounds. Being out a couple of ounces is not uncommon.

[ehoger]

Thanks for your fast response.

We have been using a well known truck shop that has an excellent reputation. I called and asked about the spin balance on the coach. They said they do not balance on the coach as the equipment to do this is not as good as it use to be so they do not use this method on a coach our size. This shop did not balance the new tires that were put on the coach. They had balanced the old tires and we continued to have the problem. The alignment they gave me says "Before" on the top of the paper so I am not sure what the caster and toe-in are at this point. The paper states caster for the driver side is 6 40 with a toe-in of 2.6 and the caster for the passenger side is 7 30 with a toe-in of 2.6.

It is currently at the place we purchased it to try to resolve these issues. After your note I called and asked them to advise me how they balanced the new tires. The problem is we have had this vibration before and after the new tires were put on.

[wolfe10]

Again, first step with the vibration is to check tire run-out. Egg-shaped tires WILL give vibrations. There are places that can balance the front tires on the coach. Since this is an "art"-- one that Bubba can not learn in 10 minutes, it is getting more rare to find a place to do it. But, they do exist.

Favorite tire story. I checked run-out on tires on our coach because of a vibration-- guess it was 5 or 6 years ago. No sophisticated run-out gauge, just jacked it up and used a 4X4" and feeler gauges. Run-out was over .050" on one front tire and .060" on the other one. Yup, eggs. Rotating the tires on the rim did not solve it. So, I started calling around to tire stores. None would true the tires and few would balance them on the coach. Finally, a dealer recommended a trucking company shop-- they maintain a fleet of tanker trucks. He worked me in during a slack time. Started by truing the tire, then stops what he is doing and goes and gets a glass of water. Sets it on the front bumper (Our old Foretravel had a SS front bumper). He said hold the glass "until it quits jumping around". Sure enough, with a big smile on his face, he said after spin balancing it twice-- Let Go. Not a ripple in the glass of water. Smooooth drive from then on.

That shop trues and spin balances on the rig 100% of the front tires on their fleet of trucks. Say they get a lot more miles from those truly round tires that are in balance AND the drivers really appreciate it.

[Lenp]

On my last truck (2003 International 4400) the front end shake and shimmy was terrible. Ended up at a tire shop in San Antonio that did spin balance on the truck. They found both front tires WAY out of round. The actually shaved them into a nearly round condition then followed up with a balance. The difference was incredible!

Another alternative might be to try Centramatic wheel balancers. These are disks (that mount behind the rim) with a tube around the outer edge containing loose material (weighted beads?) that provides a dynamic self balancing of the tire/rim/drum/hub package. Even if you pick up a rock or some mud on the tire, they will keep the tire in balance. In essence, you don't even need to have the tires balanced if you use Centramatics. I installed Centramatics when I replaced the tires the next time and really liked them and never had a shake or shimmy problem again.

There are other (perhaps less expensive) alternatives such as beads inside the tire that do the same thing (which might be a good and economical experiment).

Good luck,

Lenp

[dkreuzen]

The 8 bag Roadmaster chassis has wandering issues. Read the two threads in iRV2 forum below. They are very long but do address the issues and the corrections. I have done both on my 2012 Monaco Knight and the steering box change made all the difference.

http://www.irv2.com/forums/f115/wandering-sway-bars-alignment-ride-height-oh-my-124491.html

http://www.irv2.com/forums/f115/steering-box-play-sheppard-m100-shim-or-swap-for-a-trw-210152.html

As for the vibration I can only suggest that you find out which end is causing it. If I had that issue I would spin the front tires while off the ground up to speed to see if that's where it is and if not, do the same with the rear. Once found then check the balance and runout and go from there.

As for balancing I recommend you never use the beads.

[hermanmullins]

When you have vibrations when driving you can determine front or rear this way: if the vibration is in the steering wheel then it is the front wheels. If the vibration in felt in the seat then it is coming from the rear wheels.

Herman

[ehoger]

Thank you for all the great suggestions and information. You have all opened alot of new avenues for us to explore. Hopefully it will help to resolve our problems. I will keep you posted.

[hermanmullins]

ehoger,

As Brett said you have several questionable areas.

Wandering, can be caused mostly by Toe-in. Too much of either, In or Out, will cause the unit to continue to try and correct itself, aka Wandering.

Vibration and clunking noise, can be caused by bad Tie Rods or a bad Idler Arm. Either can cause the clunking and vibration. Both should be looked at ASAP by a Heavy Truck Garage with alignment capabilities.

Herman

[huffypuff]

dkreuzen

I don't agree that the 8 bag Roadmaster has issues with wandering. What those two threads you posted was worn steering gear boxes. They had a choice to either rebuild the non external adjustable Sheppard gear box or change it to a external adjustable TRW gear box. The Sheppard box is shimmed internally to take out play and must be done correctly by the rebuilder or it can wander.

Another problem area is keeping clean fluid up to the proper level and changing the hydraulic filter. I've seen just low fluid shake the steering wheel violently because of sucking air. It's a good idea to flush the fluid as needed to prevent the above worn gear box.

My coach 8 bag Roadmaster chassis has the Sheppard gear box and do not wander as the gear box is not worn out. There is no ride enhancing kits installed and the coach steers like a dream.

[dkreuzen]

dkreuzen

I don't agree that the 8 bag Roadmaster has issues with wandering. What those two threads you posted was worn steering gear boxes. They had a choice to either rebuild the non external adjustable Sheppard gear box or change it to a external adjustable TRW gear box. The Sheppard box is shimmed internally to take out play and must be done correctly by the rebuilder or it can wander.

Another problem area is keeping clean fluid up to the proper level and changing the hydraulic filter. I've seen just low fluid shake the steering wheel violently because of sucking air. It's a good idea to flush the fluid as needed to prevent the above worn gear box.

My coach 8 bag Roadmaster chassis has the Sheppard gear box and do not wander as the gear box is not worn out. There is no ride enhancing kits installed and the coach steers like a dream.

Normally I would agree with your worn steering box comment except that I had the problem and the Sheppard steering box was new. I did the swap to the TRW box and my wandering issues went away just like many others who have done the swap. I have also done the read cross brace which has also helped. If your Sheppard equipped 8 bag chassis doesn't have the wandering problem you are one of the few and you should feel lucky.

[huffypuff]

dkreuzen,

I believe more recent gearboxes have quality control problem as new wasn't shimmed properly from the factory new. It can be mass production to meet demand and same shim was thrown into all gear boxes. You know how that would work and the result would not be equal over the entire line. That would send a few out well over spec and those few will complain.

You said that cross brace helped you kind of prove that your problem wasn't the gearbox alone. The only problem I had with steering on my coach is the Goodyear 670RV tires. I replaced them with Michelin and with about 8,000 miles on them still drive like a dream.

[jimkate]

It is a confirmed fact that some of the coaches built on the 8 air bag Roadmaster chassis have serious wandering problems. It has been proven to be caused by an inadequate design of the trailing arms and panhard rods that maintain the position of the H frames within the chassis frame. In addition, many of these chassis were fitted with inferior suspension bushings at the factory. New design aftermarket bushings have recently been produced to address this issue. As per the threads in irv2, trailing arm cross braces have been designed by Van Williams and have been installed in many coaches with resounding success. Van Williams has since designed an additional improvement in the form of a Watts link to further stabilize the positioning control of the H frames.

It is also a confirmed fact that the Sheppard steering boxes have produced a wandering problem in that most of those steering boxes have too much steering wheel free play, and the boxes are not adjustable. Some owners of Roadmaster chassis coaches have found that switching over to the TRW steering boxes solves this problem.

My coach was a road wild, uncontrollable wandering all over the road white knuckle beast. None of the standard approaches such as alignment, ride height, etc. had any influence whatsoever on solving the nightmare. The new design suspension bushings and Van Williams rear trailing arm braces changed our coach into what I believe is now one of the finest handling and riding coaches on the road today.

Jim Sanderson

1995 Monaco Dynasty 36'

Canada, eh?

[huffypuff]

Jim

Two things and they both go to the same problem, worn parts.

First the Sheppard gearbox is adjustable. It just has to be taken apart and shimmed by the rebuilders. That is less expensive than a new gearbox.

Second worn bushings on a 10 year old coach will give you problems. There is always somebody claiming to make better and I know those supposedly beefier bushing will wear out as well. I can't begin to tell how many bushings on trucks and trailers I replaced when I worked fleet. That included greased bushings that supposedly not supposed not to wear out.

Jim at Source Engineering didn't think of something new, just made replacement ones a little beefier.

I was almost fooled by his replacement fan blade but that is another subject.

[jimkate]

To Ehoger,

If you want to find out why your 2013 Roadmaster 8 air bag chassis motor coach is wandering,

I am confident you will find a solution if you join the conversation here:

http://www.irv2.com/...-my-124491.html

Jim Sanderson

[huffypuff]

ehoger, I don't know where you are located but if you can take it in for factory service in either Decatur, Indiana or Coburg, Oregon it maybe covered by warranty. 800-509-3417 is contact for both location. Please be aware that if you had vibration since new, it could wear out suspension and steering parts. Three set of mirrors is just the start of problems if allow to continue.

[ehoger]

We have had our coach at Decatur and Wakarusa (before it closed). They told us to go and get an alignment at a Truck shop and replaced the mirrors. Both did not fix the issues. We just had automatic wheel balancers put on the front tires and the shades no longer vibrate. The mirrors are better but still vibrate more than they should. You can not feel the vibration in the steering wheel or the seats but through your feet. The wandering is still a major issue. The parts are not worn as it had a new steering box installed recently. Trying to find out what steering box is in on our coach but haven't received an answer to that question yet. Looking forward to reading Jim's link he provided. Been away from internet access for a while. Thank you all for your responses.

[ehoger]

I have been reading the links given by dkreuzen and Jim Sanderson. Excellent information. Thank you.

[Walt2137]

Emoter, I am betting you have a Shepard 100 gear box, you should be able to see the info on the gear box. The info Jim furnished is good info there are two long threads to read and both has extent info on the Roadmaster Chassis and it's short comings.

[ehoger]

We do have a shepard steering box.

After reading the threads on the iRV2 forum we have decided to have our steering box changed to the TRW Steering Box and have the Van Williams cross brace and Watts Link installed. We feel confident after reading these threads that these changes will solve our wandering issues.

We are also looking for a shop to spin balance our tires on the coach to resolve the vibration issue. If this does not fix the problem does anyone have any other sugguestions as to what is causing the vibration?

Will keep you posted.

[wolfe10]

Another good option with the Sheppard steering box is to have it blueprinted by: http://www.redheadsteeringgears.com/

Several of the well known RV suspensions shops recommend and stock them.

[dkreuzen]

I recently came across a vibration issue for the out-of-round condition that had been mentioned already. I installed two new front tires (got rid of the rivering Goodyears) and all of a sudden I had a 60mph vibration. The new tires had the balancing beads which I didn't like anyway so I went and had the tires removed, the beads vacuumed out and the tires spun balanced. Slightly better but not smooth like it should be. I checked the tires for out of round and found one at the limit of .045 and the other way too much at .125. Next stop I took them to a tire shop that could warranty the tires as I figured at least one was bad. The tire shop checked the tires using the spin balancer and found that the tires were not centered on the wheels (and that is after they have been mounted twice). They removed the tires from the wheels, cleaned everything, carefully remounted and spun balanced and found the tires running true. The vibration is now gone.

You could have the same problem...

[huffypuff]

dkreuzen, I remember the truck tire place that replaced the tires on my coach really scrub the rim and used a good amount of tire lube. That must make a difference as it is very smooth and not much weights on them.

Brett, that shop you mention is in the same city I brought my coach a few years ago. Interesting

[jleamont]

Wheel to hub runout could need to be corrected. When the front wheels were installed on a hub piloted design the wheel will never be at a true center, over time the tire will wear with a high and low spot on the tread causing a vibration in the steering.

To correct you will need to lift the tire from the ground, locate the hub flange tabs and place a feeler gauge between the flange tabs and the wheel (.060 is where I check them), on one of the tabs the gauge will slide in the easiest, mark the tire directly above this tab, spin the wheel 180 degrees and loosen the lugs, this will allow the wheel to reposition itself on the flange in the opposite position it was in, retorque the wheel. I would try this first since it will be the most cost effective with little to no out of pocket expense, especially if you can do this yourself.

[ehoger]

Thank you again for all of the good info. Everyone is so helpful. Don't know what I would have done without your good advice. Looking for a good tire shop. Will keep you posted.