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Topic: Steering Wheel Adjustment (Read 703 times) previous topic - next topic

Steering Wheel Adjustment

Quote from: Chuck Pearson –
Not saying you're wrong to do so, but the steering wheel is normally centered by adjustment of steering components.  This happens to be a classical mechanic's quiz thing..."what do you do if the steering wheel is off center?"  Repositon steering wheel=wrong.    Might want to check and see if your cut angle is equal in both directions.  Just sayin.
Chuck, that's an interesting response. I'll explain why I took the action I did. Here is some history.

2010: Wayne at FOT aligned the steering. It was a great improvement. Coach had wanted to go to the right side ditch since we bought it. Steering was much better after the alignment, but I thought the steering wandered more than it should.

December 2011: Wayne at FOT replaced steering gear because of a leak in the seal on the Pitman arm side. After the replacement steering gear was installed, the steering wheel was not centered for the direction of travel. Handling was OK, but not as good as I thought it could be.

January 2013 (+- ?): Along with a lot of other work, we had Wayne align the front end and center the steering wheel. We also rotated three tires to deal with a possible "bouncy" steer tire, balanced tires, and added Centramatics. Coach handled very well. I was satisfied that it was as good as it would ever be for a 30K# "box on wheels." It appeared from tool marks on the drag link that Wayne had centered the steering wheel by adjusting the drag link.

October 2013: Steering gear blew the top seal near Billings, MT. This was not a leak. It was a blowout. We dumped 3 1/2 gallons of hydraulic fluid in less than 50 miles. We made it to our campground with minor engine heating and the power steering mostly worked. We were three blocks from Hanser's Towing, RV, Automobile, Truck repair facility. We took the coach there. I called FOT to see if we had any warranty coverage - no. Triana recommended I call Sheppard, the manufacturer of the rebuilt steering gear. The Field Service rep at Sheppard said the only reason the top seal blows is if there is excessive pressure in the wrong place. It is almost always caused by the "pressure relief plungers" not being properly set to unload the steering gear before the steering components hit the axle stops. Hanser's put in a new top seal. The steering wheel was centered when they started. It was not centered after they put it back together. The only pieces they disconnected/reconnected were the steering wheel shaft and the top seal of the steering gear.

After we returned home, Marilyn and I adjusted the "pressure relief plungers" to provide 1/8"-1/4" clearance at the axle stops.

My conclusions, maybe correct or maybe not, are as follows:

Wayne probably adjusted the steering wheel centering with the drag link. That changes the relationship of the piston in the steering gear with respect to the axle stops. I am guessing that he did not adjust the "pressure relief plunger" for sufficient clearance after adjusting the drag link. "Guessing" is a key word with respect to my conclusion. At some point, or perhaps more than once, we made a hard turn that put pressure on the top seal. It failed as we arrived in Billings. I can't provide a specific precipitating event.

The steering wheel was straight when we arrived at Hanser's. It was put back on with a slightly different alignment on the splines than when we went in. I changed the alignment on the splines. It is cocked off to the left now instead of the right. I plan to put it back in the position it was in after Wayne last straightened the steering wheel, i.e., dead center on a smooth straight road.

I am satisfied with the setting of the "pressure relief plungers" after Marilyn and I adjusted them. She turned the steering wheel hard right and left after the adjustment. With about 1/8" to 1/4" clearance from the axle stops, we could hear the steering gear "unload" and she couldn't turn the wheel any more.

I am satisfied with the tracking and handling.

I was satisfied with the position of the steering wheel before Hanser's worked on it. I think I can put it back like it was by "undoing" the change in alignment of the splines between the steering shaft and the input shaft of the steering gear.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Steering Wheel Adjustment

Reply #1 –
J.R., in my (non-expert alignment mechanic) opinion you are right on track.  You've corrected a lot of wrongs, primarily the pressure relief valves which most likely caused the blown seal.  Your steering wheel misalignment is almost certainly due to slightly improper reinstallation of steering/input shaft by mechanic.  I do not know if adjusting the pressure relief valves could cause any recentering of the mechanism but think it's unlikely.  So, you're left with the job of correcting it which you have done by recentering the steering wheel.  This would normally be done by adjusting the drag link like Dave M says but in this case it's a pretty sure bet that the problem is spline misalignment at steering sector.  So, your plan to reset this seems proper.  One thing I would, for sure check to make sure it's within spec is that the adjuster for pitman link has not been grossly misadjusted by the fellow who worked on steering box.  Normally there are a couple small holes in these things, kind of look like a place for tie wire.  You should probe those to ascertain that the male threaded components are engaged up to this point. 

What the wild card for me is, though, is whether or not there is a "high point" in the power steering gear as referred to by Dave M.  I have not been able to find any info on this for Shepard boxes, but plenty for older mechanical steering sectors. If there is one, you dang sure want it to be at the straight ahead null point.  To me it just seems to work like a pressure balanced servo.

I'm editing some prior content here. 

One of these days I'd like to get together and swap coaches for driving impressions.  Might be instructive. 



"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Steering Wheel Adjustment

Reply #2 –
Chuck, thanks for the thoughtful response to my long story. I am interested in fixing stuff that's wrong and learning the proper way to do things.

Sheppard has manuals and videos on their web site. I've studied them carefully over the last couple of years.

According to the Sheppard manual (http://www.rhsheppard.com/mseries_complete2.pdf), the steering gear "does not require center point adjustment." The diagrams and explanations indicate that in the "neutral or non-steering position," the piston in the gear is centered. It indeed appears to be a "pressure balanced servo." On our coach, with zero pressure input to the steering wheel, the coach goes straight down the road in the absence of wind, crown, or other perturbance. This indicates to me that the relationship between the steering gear and the wheels is correct, i.e., the pitman arm and drag link are adjusted appropriately.

The problem is that the steering wheel center position does not correspond with the "neutral or non-steering position" of the steering gear and wheels. That is the issue I am addressing by tweaking the connection between the bottom of the lower universal joint on the steering wheel shaft and the input shaft to the steering gear. It was correct before being pulled apart and put back together. I am trying to regain those nice balanced steering wheel spokes.

Indeed we should get together to share stories and coaches.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Steering Wheel Adjustment

Reply #3 –
JD, thanks for the info on the Sheppard gear, sounds like you've made quite a study of it and a great explanation.  After thinking on it a bit I agree you're doing the right thing in realigning joint and input shaft as opposed to recentering the steering wheel by adjusting drag link.  Reason for this is adjusting the drag link will do it also, but it seems to me that it will also "bias" the centering of the steering to either right or left.  Not that it would tend to steer or pull in that direction, just that you would have more potential turning one way or the other.  Might make a difference, might not.  Very well may require readjusting the stop valves. 

So, as it reads from the shade of this tree, you're doing the right thing in defying conventional wisdom that steering wheels are never to be recentered on the shaft.  I'm with ya on the necessity of the wheel being straight, with balanced spokes.  Sounds like you had it right before and this oughta get you back to that spot.  Thanks for the info on the Sheppard and rundown on sequence of your quest for handling nirvana. 
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Steering Wheel Adjustment

Reply #4 –
Chuck,

If the steering wheel is off center less than a full tooth/spline, there is nothing wrong with using the drag link to adjust.

But, it does require that you re-set the pressure relief plungers (not difficult) and recheck axle stop clearances.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Steering Wheel Adjustment

Reply #5 –
Success! My bride of 46 years, life partner, and driving partner helped me get the steering wheel back to the position it was in before a mechanic in Billings, MT, reinstalled it a couple of "spline dits" off to the right.

I just went for a test drive on a smooth straight divided highway. Wind was calm and there was little traffic. "Two finger" steering was easy. All steering corrections were minor and were either side of dead straight on the steering wheel. "Hands off" steering would hold steady for around a 1/4 mile.

We are back to settings that were in effect before we blew a top seal in the steering gear, except we are using more conservative settings for the "pressure relief plungers" to avoid a repeat of the failure of the top seal.

Thanks to those who provided information, suggestions, and the benefit of experience during my current repair adventure.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Steering Wheel Adjustment

Reply #6 –
JD,
Very good info.  I am surprised there is no master spline.  I could really see issues arising if the shaft had been improperly installed and left for a new owner not aware of the change and a shop setting the steering from the drag link.
Definitely would mess with the turning radius rt. VS Lft.  Again I would have expected a master spline
Jerry & Nanci
1999 U270 34'WTFI
2011 Malibu
A smart man knows what to say, a wise man knows when to say it.