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Front end set up and air bags: Coach #809
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BigRabbitMan
Posted 2018-01-15 8:53 PM (#5239)
Subject: Front end set up and air bags: Coach #809



Elite Veteran

50010010010010025
Location: Cottage Grove, OR
The following is a post that Steve Centracchio, owner of coach #809, made on the Yahoo group. I felt that it would be good if a wider audience had the opportunity to read what Steve says. With his permission, I am reposting his comments below.

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" Sorry for taking so long on this, I believe somebody already listed the early and later coach numbers on the front suspension, I'm sure everybody know where the differences are. As far as the setup on mine and later coaches, I did mine in my garage with simple tools, level, string, tape measure and angle finder, although I have 25+, years in the auto collision, frame business its not brain surgery. First thing first, the lower A arm has to be parallel with the ground. If the coach sits too high in the front the tie rod will be at a angle down to the spindle, because the design wasn't the best, you will get bump steer. The early coaches have this problem no matter where the suspension sits. This is a must to solve the wandering problem on a fmc I believe. Like I said there is a youtube video I will try to find that shows it......

Basically you want to get as much caster as possible in either right or left wheel, move the upper rear A arm adjuster all the way in, which will move the top of the wheel back, with a level against the side of the tire vertical, move the front upper adjuster out until the level shows plumb, do the same on the other side, after both sides are done set the toe at 1/16". Now I may get an argument on this but I've found 1/16" to be the best as far as controlling wandering, my opinion is every coach will be different.

Test drive and if it pulls to one side or the other you will have to take some of the caster out of that side by moving the rear upper adjuster out and readjusting the front adjuster for the camber. Reset the toe, now it may take some time but the caster will make a difference. The idea is to get as much caster into the front wheels but equal on both sides.... any front end shop can do this.

Also, another major difference in 809 is it has an airbag rear suspension, which I engineered. I have my rear torsion bar adjusters backed out all the way, no timbrens, just a 1 1/2" suspension bumper which the suspension arm sets right down on when there is no air in the suspension. My air bags are mounted 12" behind the wheel centerline. I run 40 lbs of air in the bags and the coach sits at the recommended height in the manual. The rear rides on air bags and not torsion bars...so the coach chassis is being held up behind the rear wheel centerline. My rear shocks are mounted just in front of the bags still behind the axle, which gives them more travel than the stock location, which was a bad design in my opinion.

I Looked in my manual at the early front suspension mainly to see the caster adjustment. I don't think you can get allot of caster adjustment without modification. I think if I was going to make changes I would try to move the lower arm with the strut rod forward, but I believe you would get allot of binding on the inner arm bushing where it attaches to the frame. you would have to modify that end with a swivel bushing or something like a uniball. If you could make that swivel you could move the arm forward which would increase caster. Again you have to solve the bump steer first which is what I would do then tackle the caster.

I have a 1960 flxible bus with torsilastic suspension. The bus has very low miles and I have replaced nothing in the suspension, other than maintenance to bearings etc, and I will tell you I have never driven anything that goes straighter in my life. It is unbelievable, my goal was to make the fmc do the same, its good but not as good as the flx... yet....

stevec
#809

Note: Steve is not active on this site so any responses need to done on the Yahoo site.
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