Shocks, stabilizers, sway bars and 'road wander'

[JohnH59]

We have a 40ft '97 American Dream DP with Cummins C8.3 and Allison MD3060 that likes to 'wander' quite a bit. We have a Howard's Power Steering System installed and I can feel it's tighter with it on at about 140#'s and I can 'trim' it to help hold against high crosswinds. But, on many roads there's still a lot of 'wander'. I was wanting opinions on how much new shocks might help. I'm not sure when these shocks were last replaced. The coach has 46,000 miles on it. On new, smooth highways, it drives like a dream. Even some crosswinds don't seem to bother a great deal. But, get on the older highways where you can see the grooves or they are trash (like coming home through Oklahoma today) and it's just not fun. It's not unbearable, but very monotonous having to constantly correct the steering.

So. could new shocks make a lot of difference? Should I look at replacing the Howard's with the newer steering stabilizers. Or perhaps, would adding a rear sway bar make a huge difference.

Thanks for all input.

[Mike Canter]

John, take a close look at your shocks and see what color they are top and bottom. If the have yellow main cylinders and yellow metal dust covers on the top half then they are most likely Monroe shocks. If they have a yellow lower cylinder and a blue rubber (soft, not metal) top dust cover then they are Bilsteins shocks. If they are all red or all gold they may be Koni shocks. If they are the yellow metal top and yellow bottoms of a Monroe then they need to be replaced for sure. If they are Bilsteins or Koni shocks then they are most likely still good and your money can be spent on other components. If they are any other color then they are some other brand and most likely should be replaced with a Bilstein or Koni FSD. The other thing worth checking is if they are Bilstein or Koni shocks then check the lower cylinders to make sure they are not covered in oil indicating a bad shock. If so then you can replace just the bad one(s) in pairs in the same position on either side.

The other thing to check is the front end alignment. If the toe is out of specifications or you have too much negative caster then the motorhome will wander. Have the front axle adjusted to more positive caster does wonders for wander. If you get the front end aligned then be sure to tell the tech that it wanders.

[JohnH59]

Thanks, how much do you think the addition of sway bars in front and/or rear would help?

[JBDISCOVERY]

One more thing to check is the lash in the steering gear. If the lash is too loose, then the driver will have to continually turn the steering wheel to correct the heading of the coach. To tighten the lash is a simple adjustment. On a Freightliner chassis there is an access hole on the inside of the frame rail where the steering grear is mounted. A 3/4 or 19 MM socket will release the lock nut for adjustment and then the use of a straight blade screwdriver to tighten up the lash. Did it, and it works. Good luck, hope this helps.
JB

[Pusherman]

Shocks generally do not contribute to road wander. Here's what I would suggest:

1) weigh the coach and set tire pressures according to the tire manufacturer's recommendations. Over inflated tires contribute to coach wander. Under inflated tires can cause blow-outs.

2) Check your alignment.

3) Check your steering gear. If you have a FL chassis and the steering gear is tight, I would suggest a Super Steer bell crank.

4) If your coach is air-bag equpped, install motion control units in the air lines just in front of the air bags. Improves side-to-side sway on air bag equipped coaches.

5) Install Koni FSD shocks. Will improve the ride more so from a ride quality, not so much from wander.

6) Install a steering stabilizer. Will help 'rutting' and if you have a tire blowout, keeping the coach tracking where it should.

Only install the after market items after you have checked the coach's basics and underpinnings. Once you know the tire pressure is correct, alignment is correct, suspension does not have any problems, then go with the aftermarket products. They do help significantly.

[Billieg]

Originally Posted by Pusherman

Shocks generally do not contribute to road wander. Here's what I would suggest:

1) weigh the coach and set tire pressures according to the tire manufacturer's recommendations. Over inflated tires contribute to coach wander. Under inflated tires can cause blow-outs.

2) Check your alignment.

3) Check your steering gear. If you have a FL chassis and the steering gear is tight, I would suggest a Super Steer bell crank.

4) If your coach is air-bag equpped, install motion control units in the air lines just in front of the air bags. Improves side-to-side sway on air bag equipped coaches.

5) Install Koni FSD shocks. Will improve the ride more so from a ride quality, not so much from wander.

6) Install a steering stabilizer. Will help 'rutting' and if you have a tire blowout, keeping the coach tracking where it should.

Only install the after market items after you have checked the coach's basics and underpinnings. Once you know the tire pressure is correct, alignment is correct, suspension does not have any problems, then go with the aftermarket products. They do help significantly.

2X. Have the complete front end checked out FIRST. Then after repairs if it still wanders add a rear stabilizer bar and then a Steer Safe on the front end. For a better ride add Koni FSD's. Don't waste $$ on after market stuff if your front end is worn. Been there done that...

[Mike Canter]

I think we are all in agreement that the first step should be a front end alignment with lots of positive caster. Worn shocks such as Monroes have a lot more effect on stability more than does a stabilzer/sway bar. Stabilizer/sway bars are exactly what the name implies. The bars put an equal and opposite motion and pressure on the opposite side of the vehicle when the vehicle is in a turn or quick lane change and controls body roll. It will do absolutely nothing when driving in a straight line. The stabilizer bars do help in a high crosswind by applying and equal and opposite force because to stabilizer bars the crosswind feels like the MH is in a turn and so it will control body roll. As far as shocks all test reports show that you will not tell the difference between a Koni or a Bilstein. They both premium shocks and both will give you an excellent ride and both will last you a 100+K miles. If you find that you have the Monroe shocks as I originally described them then replace them regardless. If they have over 15K-20K miles on them then they shot and dangerous.

[JohnH59]

Thanks to everyone.

I have had the steering gearbox checked and it showed to be fine, according to the shop I took it to. The chassis is a Spartan chassis, not sure about the adjustment mentioned for a Freightliner by jbdiscovery. Does Spartan chassis have this same steering adjustment? The shop I took it to may or may not know about this adjustment. They mainly work on cars and pickups and I see a few MH's around there. They replaced the output shaft seal on my trannie, and fixed a hydraulic line hose, for me when they looked at the steering. They told me the gearbox was good and that I needed to put 120lbs in the tires. From what I can read, that's too much.

I'm running Goodyear G395 LHS 295/75R 22.5 tires. For the weight of my coach, I believe it's calling for around 90-95lbs. I do have them at 95lbs right now. The wander is about the same as when they were at 90lbs.

I'll look into finding a shop that does alignments around here on MH's. We don't seem to be fluent with service centers for MH's here in Amarillo, TX.

The coach is air-bag equipped. I had not heard of the motion control units for sway. (good information)

I do have a Howard's Power Center installed and have been running it at around 140lbs.

I'll crawl under and take a look at the shocks. According to the original brochure, it shows to have come with Bilstein shocks. I'm not sure if they have been replaced or not. I got the coach from my father-in-law when bought a newer Beaver Solitaire (he bought the American Dream new in '97) and he's out of touch right now (out of country) to ask.

This is the second year owning the coach. Last year I just figured it would take me some time getting used to driving this size rig. Now, after reading comments from folks on these forums, I'm convinced there's something I can do to make it MUCH better.

Thanks again,

[GlenB]

I recently decided to deal with my RV and its driving in the wind. I replaced my shocks with Koni shocks. I put a track bar on the front and back. These changes have made a great deal of difference. I have a pretty good over hang on the back end of my RV so I will always have some movement but it is much better. I would say try all of the above or start with the shocks....GlenB

[micd]

I don't know what type of airbag system you have. I bought an excellent driving coach and after an alignment got back one that wandered all over the place. After much checking, realignment etc. what we found is that the alignment shop had lowered the pressure in my front airbags to 50 lbs. I need between 65 to 70 lbs for it to feel good on the road. Otherwise it tends to feel mushy and wander all over. After the airbags were aired back up it drove great again. They hold air great all summer but in the winter they tend to loose some so I have to reair them back up in the spring.

I agree that if your shocks are old, new ones are in order. I had what was probably the original Monroes on the back and Bilsteins on the front. Since I got all the service records from the guy I bought it from and he had it for 6 years I knew they hadn't been replaced in 6 years so went ahead and replaced them all so as to have them all performing at the same level.

I also replace my Bilstein steering stabilizer with a new one as it was leaking.

How old are your tires? Lots of people report a better ride after old tires are replaced.

Good luck finding your problem.

Michelle

[JohnH59]

I had the alignment checked and according to the shop that did it all was good. The suspension/steering parts were all in good shape. They made some minor adjustments to the camber and toe. They said they couldn't adjust the caster on IFS and air ride.

They didn't do anything to the air bags. They said they aren't set up for air bag adjustment. They did say the ride height appear to be fine.

I'm not convinced they truly knew about the Spartan chassis with IFS.

Based on the weight and my tires (new in 2008 and around 8,000 miles on them, always stored inside) decided the air pressures should be at 115lbs all the way around. I've been running about 95lbs in the front and 95lbs in the rear.

We are having some pretty good winds (again) here in Amarillo and the drive home, about 20 miles, did seem a little better. I'm not sure if the 115lbs tire pressure made the difference or it was just extreme wishful thinking.

They did tell me they looked at the shocks and they are Bilsteins. They are original, but the coach only has 46,000 miles.

micd,

How do you check/adjust air bag pressure? That's also new to me.

Next options, look into front/rear trac bars????

Thanks for everyone's help. I still think I can get it much better to drive.

[micd]

Originally Posted by JohnH59

micd,

How do you check/adjust air bag pressure? That's also new to me.

Unfortunately I have no knowledge of your actual coach so may be way off base with this suggestion but I thought I would throw it out there just in case.

Ours has air bags in the front springs. They had attachments to them to air them up. However, there was no way to access them to check or adjust them when we got the coach without crawling underneath. I had an extension kit put on that brought them out to the front bumper. Similar to:
Air Lift Co - Front Extension Hose Kit - Air Springs & Accessories - Camping World

I had seen this on a number of coaches I looked at so knew there was a better way than crawling under the coach. When I had them extended to the bumper I had them drill holes in the bumper and put the air valves there. They look and are the mechanical equivalent of tire air valves. Our air bags are just like the picture above, in the front springs.

Now we have the tire pressure monitor system sensors on them so I can check them before driving. My TPMS allows me to turn on and off some sensors so I turn them off for driving after checking to make sure the pressure is OK. Otherwise while driving they set off the alarm as they change quite a bit when going around corners.

The mechanic's shop I was working with were at their wits end as to why after they checked everything and had realigned it twice it still wandered. Once I found out that they changed the air bag air pressure and put it back my wander problem was solved.

Your tires sound good and likely you did see better handling with the correct air pressure.

However, you may want to do some research on the life of shocks. Some folks say 50K miles for cars but really it depends on if they are worn out. A motorhome could have been overloaded and driven on rough roads, with the shocks then wearing out. How does it handle over bumps? Does it return to an even ride pretty quickly after a bump or does it continue to oscillate? If oscillating or if a mechanic indicates they are leaking then it is time for them to go.

When ours were replaced they seemed to me to be Ok but when they were inspected one was leaking. I decided to replace all 4 just because I wanted the best ride possible. When they went to take them out they found that one of the bolts on a rear one had sheared off so they had to do some welding to have something to attach the new ones to. We did seem to have a bit of a thunk over bumps but I just figured it was something in the coach or in the storage bays. I was very glad I had them replaced.

Michelle

[Billieg]

One suggestion, When I got my coach it wandered all over the road. I took it to 2 garages and had the front end checked out. Both told me it was fine. I then took it to a truck center which works on nothing but trucks with frames like mine. This is what they told me:
Bad bell crank, bad ball joints, bad upper and lower bushings, bad steering stabilizer and out of alignment.

Fixed it all, put on a steer Safe and Koni FSD's and it handles great now. I thought I'd never get done with it. You need to make sure the garage you take it to knows your unit and not just guessing.

[JohnH59]

Originally Posted by JBDISCOVERY

One more thing to check is the lash in the steering gear. If the lash is too loose, then the driver will have to continually turn the steering wheel to correct the heading of the coach. To tighten the lash is a simple adjustment. On a Freightliner chassis there is an access hole on the inside of the frame rail where the steering grear is mounted. A 3/4 or 19 MM socket will release the lock nut for adjustment and then the use of a straight blade screwdriver to tighten up the lash. Did it, and it works. Good luck, hope this helps.
JB

JBDISCOVERY,

I found a fellow on the American Coach Yahoo Group that had the same problem with his '97 American Eagle. It was the adjustment you mentioned on the gear box. He sent me the PDF on the adjustment. I also contacted Spartan and they sent me a PDF as well. They were identical except the set screw on their model used a hex screw instead of screwdriver. Mine definitely has the screwdriver set screw. But, the problem is, I can get the lock nut loose, but CAN'T get the set screw to turn. at all. I've covered it in penetrating oil a few times and will keep trying. I talked to the gentleman with the Eagle and he described exactly what I'm experiencing. He said he only turned the set screw about 3/4 of an inch, but it took out all his nearly 4" steering lash. If I had a pit to pull the coach on top of, I think I could get enough leverage with a wrench on the screwdriver. Just can't get both arms up there lying on the ground.
Maybe I'll take the PDF instructions to the shop I took it to for them to inspect the front end. They are supposed to be a Spartan Authorized Service Center.

Thanks for the idea. It got me searching and without the idea, I wouldn't have found the gentleman with the exact same symptom on the same year and chassis.

Thanks again,