joe0508
charlotte
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Joined: 05/11/2010
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I have a 92 30ft motorhome on a chevy p30/32 motorhome chassis.I have a problem when driving it.I will be driving it and all of a sudden it will try to go one way or the other sometimes to the right and sometimes to the left.It doesnt do it very often but when it does it seems for no reason and unpredictable causing me to guide it back straight.what is causing this and how can i fix it.
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BobsYourUncle
Surrey, BC Canada
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Joined: 12/12/2003
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Look for severely worn suspension parts.
I have experienced this several times over the years. It is certainly un-nerving!
It could be a badly worn upper or lower ball joint, but I would think more likely a bad control arm bushing or the control arm itself.
It goes like this:
Lets say an upper control arm bushing is severely worn or the control arm itself is cracked. When conditions are right - IE - pressure a certain way caused by common road conditions, the control arm suddenly moves drastically on its shaft. The result is the caster and / or camber being suddenly thrown way out of alignment. It is like suddenly taking the axis of your front wheel and moving it back an inch or so.
This throws the geometry of your steering way out and can cause the effect you describe.
You need to have every single piece of your front suspension and steering very thoroughly checked out for wear and / or damage. Look for cracks in the control arms - look at everything under there.
2007 GMC 3500 dually ext. cab 4X4 LBZ
Duramax / Allison
Fire Red
95 Sportsmen 25.5' TT
81 Citation 25' "Tail dragger" "Under construction"
"Workin' man's rig"
Bob's Trucks
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farmer_boots
Weirsdale, Fl
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Joined: 11/20/2003
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Another thing to check is the front tire tow-in. If the tires are towed out they will hop causing the motor home to hunt it way down the road. You must constantly keep your eye on the road and correct with steering.
I had problems with my motorhome but being new to motorhomes was not sure if this was normal. It would constantly hunt (move left or right) without any reason. You could not take you eye off the road for a second. It would wear you out after a few hours. Finley I thought tow-in, took it to a shop and had it checked. It was out (not too much) had it realigned and now you can drive it with one finger, actually you can let go of the wheel and it goes strait down the road (if flat). Big difference.
2006 Monaco Diplomat
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Tom/Barb
Oak Harbor
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Watch the road surface, when the tire track is worn hollow (like a ditch) your coach will want to drive to the high side, as you pull it back, it will drive out the other high side. and cause you weave back and forth in your lane.
2000 Newmar mountain aire 4081 DP, ISC/350 Allison 6 speed, Wrangler JK toad.
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BobsYourUncle
Surrey, BC Canada
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I just remembered one time this happened I found that the nut holding the alignment shims in place on the upper control arm had become loose. The shims fell out and the control arm rested in a certain position until pressure from driving a certain way caused it to suddenly move all the way out, causing a rapid lane change.
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J-Rooster
Port Orchard, Wa. / Lake Havasu City, Az.
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Joe, IMHO, I would have the suspension checked out (inspected to see if everything is a OK) If it checks out OK it's probably road ruts.
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RCL
South SF bay area
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Joined: 07/29/2004
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If you trust your partner, start up the motorhome and climb underneath and look at the steering linkage. Have them wiggle the steering wheel back and forth about 4 inches at the rim and look first at the arm attached to the steering box. Continue with the linkage connected to that arm and look for where the motion seems to stop or at least is greatly reduced. That way you can pinpoint the bad joint. On my old P-30, it was the relay arm on the driver's side.
The wander was especially noticable on asphalt roads where there was a lot of 18 wheeler traffic. The road develops a couple of ruts or valleys. The track width of an 18 wheeler is greater than that of the p-30, so one front wheel or the other was always climbing out of one of these valleys.
Replacing that relay link completely fixed the problem.
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vtbigdog
VT, GA
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I would simply start with making sure you have the correct air pressure in each front tire. If the tires are overinflated you will be riding on the center of the tire as opposed to the entire width of the tire. This will make the coach dart around.
Richard
2003 Safari Trek 3011
8.1 Workhorse/Allison
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supra24valve
Jackson, Ohio
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Second thing to check......after you checked for worn parts and didnt find anything. Is to check the air bags. With a good quality air gauge. One side or corner differ can create wonders....lol. Also tire pressure. Notice if you have a sway more with things filled like onboard tanks, mainly fresh water. weight location will changed the feel dramatic. I know with my P30-32 I much rather have the toad behind me as this keeps my tail straight. Could just be the way life is on this chassis. After a good safety check. Just learn to drive it. A P30 will drive like a over loaded dump truck. As you have a 30', my guess is you have the shorter wheelbase version like me. Say a 12' rear overhang? that will keep things moving. If only we had a tag on our shortys...
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