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Veteran
Location: Kingsley Michigan | Please find Barney's write up below
FMC (Wildabeast) Steering and thoughts;
It has been many a year that I and many others have looked at and pondered the famous wandering Wilda beast steering of the FMC.
Let me advise you that I am in no way an expert on automotive designs or repairs but hold an excellent background in machining and power transmission (gears, sprockets, pulleys, etc.) as that is what I manufactured for 30 years for my own company and many others along the way in many a different fields of endeavor. That being divulged, I will appeal to your common sense (in which makes me wonder why we even own these---) and intelligence to keep you out of trouble along this self engineered path of correction to rid ourselves once and forever of the unpredictable an often uncontrollable nature of the FMC steering and overall ride.
At this time, I would like to credit the rest of the group who have spent countless hours discussing and working on the problem with undying intent. The last submission to this all was found in Missouri from the excellent Mega Rally (hosted by the all too exceptional host Jim Woestman), from Harry Day. He expounding on the improper heat treating that he was made aware of as to the front leaf spring---which led me to a journey of “I have had it with all the nonsense of this confounded beast ---there has to be a answer and solution to it all!!!!” This insanity lasted me for the last 3 months which has resulted in the revelations I will now delve into. The (hopefully) holy grail of the problem for us all.
Many years ago, when just getting started on 801, I listened intently to Les Hoagland as he ranted about the “14 points” of steering and suspension corrections that needed to be made to the FMC to handle like a sports car. My---that was 12 years ago and as I never got the full list from him, I have one of my own now that has brought me to the point were by I can steer with my knee like I do sometimes in my car when the need arises. This is something I was convinced that would never be possible!! Les had all sorts of remedies like the sway bars and the top of the line Michelin's and very expensive Koni shocks and on and on the money and list went. Sometimes he was even right, but let's face it, any improvement to your car or beast is better than hanging your head in bewilderment. Bottom line here---it's just a matter of getting it right.
What I found to hold water and truth to the overall improvement was a little here and more there---with which I will spell out in a list of what gives you the most bang for the buck and your time. Before I do, I have to tell you of the last great find and greatest and cheapest correction in the weakest link in my beast that gives me the ability to take my hands off the wheel---and not go out of control.
With the beast sitting in the barn with the motor off and turning the steering wheel back and forth with my knee against the tire, I found there was a lot of steering happening and not much intent of the tire to obey. Yes, I had done the Les Hoagland bell and idler crank improvements and replaced any and all ball joints, tie rod ends alignments and shocks front and rear, and while all of these were worthy improvements, the beast wandered, just not as badly as before. Anyway, I picked up the fiberglass shroud that covers the top of the steering box (bottom of your steering column) and proceeded to eliminate one after another of the problems that made the tires and steering wheel to be in a sponge mode.
The first and probably the most accentuated weakness came with the “Rag” coupling with my beast. What was happening was the steering shaft was moving but the gear box side of the coupling was not!!! The reason for this was two fold. One was the bolts had become loose (worn) in the holes of the rubber -canvas rag coupling. More importantly was the misalignment of the two metal plates that were connected by this coupling. You see---when you take a flat disc (where the rag coupling has all of it's strength and change it's shape to be a very badly warped and pulled apart deformed piece, it losses all of it's ability to transfer the motion from the upper connection to the lower one. Don't believe me---pick up your fiberglass shroud and do the same test and watch the steering wheel move and the way the rag coupling torques up before starting to move the gear box coupling. It is amazing to see how far it goes. Now when the motor is running, the power steering is there to do most of the heavy lifting but I will tell you this was a major find and easy fix if your rag coupling is not flat. I have seen some that merely needed the bolts tightened.
The answer to aligning my particular beast's couplings was to take the tilt support frame off of the dash and dismantle it to the point where I could cut that sleeve off that the adjusting lever goes through (which is what basically holds your steering shaft and column up or down from the rag coupling) and moving mine down 15/16” towards the floor and re weld it.
Now since you have the steering column out--(unplug the electric and unbolt the rag coupling) this is an excellent opportunity to adjust the steering box worm shaft bearing end play. Just below where the rag coupling attaches, there is a big (but thin) jam nut that holds the end cap which is how your end play is adjusted. I used a dial indicator on the end of the shaft, broke the jam nut loose and tightened the threaded adjuster end cap until I had ½ a thousandth (.0005”) end play. This would be a typical and acceptable number for most worm box input shafts that were not high speed. Anywhere between .0005” and .001” would be acceptable. Mine was .008” to start which just exacerbates the slop. (Side note here---Slop in a highly sophisticated terminology for Loosy-goosy).
Next, it is time to mess with the lash adjustment. This is a set screw that is in line with the pitman arm but on the opposite side of the gearbox. This can typically be adjusted from below from where the front bumper attaches to the frame but you will need to remove the floor plate for the next part so with the removal of a dozen screws or so around the floor plate that covers the whole area just in front of the battery box under the drivers feet and up on the wall under the left head light box. Taking this out will make life a lot easier as you will need to “feel” the adjustment happening and using another person at the wheel while you are below is just not going to give you that!
Ok, so you put an 3/16” allen wrench in the set screw that protrudes from the gearbox and has a 5/8” lock nut holding it in place. Hold the set screw in one place and break the lock nut loose and continue to back the nut off a good 2 full turns to make sure this does not interfere with your setting the lash. Take the wrench off of the nut and tighten the set screw while wiggling the steering wheel back and forth. You should feel the slop in the wheel disappear. Be careful as there is a point that you will bottom out the gears a it would become almost impossible to turn the gearbox as well as it will cause permanent damage if left that way!!! Once the set screw bottoms the gears out---( make sure it is not bottoming on the lock nut---) you will need to back the set screw off 90 to 100 degrees and hold it there while tightening the lock nut. If the feel is all to tight when you start the motor---you have over done this adjustment and/or the end play of the steering backlash adjustment but otherwise, you will really start to feel the steering respond when you move the wheel—and stay there until you move it at all---
What a concept!!!!
Now the last part of this all---( and this probably should be before the is the pitman arm adjustment but I was on a one way mission so this is where my little pea brain cataloged it). For some reason---even though I have #801, I have the steering box that is shown in the manual for the 0 to 645 coaches that employs the splined pitman arm. Now you have to understand that this is not the pinch bolt style of the 646 and up coaches but either way---you should take a real hard look into this as if it happened to me---and the FMC beast after 40 years—that it probably is happening to you!
This is where having that sheet metal floor plate below the fiberglass collar out is critical. Once again. Motor off and beast on the ground. (Also check the gearbox mounting bolts at this time as I found I had a loose one). What I found was that the steel pitman arm and it's tapered spline were not holding the same axis as the gearbox. Huh? What you might see while wiggling the wheel back and forth is that the arm with start to cock left to right when viewed from as I did, from the top and looking from the drivers door side. It seams the pressure of the offset tierod end has been working on the spline and to wallow out giving you that extra bunch of give and slop that helps wing this coach all over the road. If you carefully watch the face of the pitman arm---or clamp (vise grip) a straight edge on the face of it to accentuate the movement it is easier to see. If you have this give in the pinch bolt style---I would take it off and have it honed as it might be hour glass shape in the bore and no matter how much you tighten it---that will never change. As for the tapered spline style that I have, the answer was easier---and that was to tighten the nut on the end of the arm---which did me absolutely nothing!!! I couldn't get the nut to go more!!! I took the nut and lockwasher off to see why and low and behold---it was bottoming out on the top of the spline and not able to move the pitman further up the taper..
The answer, I welded a pair of washers together that had a 7/8” and 1 1/4” inside diameter so that they would stay centered on the shaft and installed them under the pitman lock washer and nut. Would you believe that I got that pitman to move up the tapered spline a good 1/8” !! The slop was gone!!
Wow---another fatal FMC design error that reared it's ugly head more and more as the machine aged---and without the poor owner being any the wiser and their mechanics being totally unsuspecting as the nut was tight and the problem invisible to them----Go figure!!!!
I hope this doesn't come too late in the season for you to start tearing your coach apart again but I am sure the day or two that you spend here will add years to your enjoyment of being able to go camping without mass hysteria of chasing the wheel in order to get there--;-)
If you have any questions of problems along the way---Call Bill Sit-- No—don't do that---I will take full responsibility for this article and be glad to help if I can.
Barn
barney4u@usa.com
231-590-0210 | |
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Expert
Location: Cottage Grove, OR | Barney, excellent write up! I had to do most of that to my coach including adding the washer. | |
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Elite Veteran
 
Location: Victoria, BC. Canada | Freakin' awesome write-up Barn!
Going into my special folder for sure.
Read every word but surely will have to read it again for it to sink in to my thick skull.
Front end work on #846 is a ways down the road yet but when it does happen I'll reference this treatise on the steering gear with great attention and appreciation.
Thanks!
Terry
#846 | |
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Contributor
Location: Bluevale, Ontario | Great article Barney. "ALL" of the details have to be correct to make the coach handle properly. Frank#645 | |
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Extreme Veteran
Location: Ignacio Colorado | Hauling 4 unmachined brake drums up front in the hallway produced the best steering I’ve had on #902. Still a bit of wheel play but no wander or wrangling the beast. Get as much weight as you can on the front side of the rear wheels.
Bill | |
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Taming the wildabeast steering