Hi Bill, I=E2=80=99m not Ken but can offer a couple of observations ba=
sed on designing an alignment kit for our GMCs (which I no longer produce).=
The first step in any alignment is to set ride height. As others have sai=
d, you have to set the rear ride height first (by altering the amount of ai=
r pressure in each rear air bag) and block the rear of the coach at proper =
ride height. Now measure the front ride height. Unless something is reall=
y amiss, both front adjusters should be set at about the same place. =
Jack up and safely block the front while you use a professional torsion =
bar unloading tool to take the pressure off the adjusters. The thing on th=
e end of the torsion bar is referred to as a =E2=80=9Cpork chop=E2=80=9D be=
cause of its shape. The hex end goes over the end of the torsion bar and t=
he part of the pork chop facing the center of the coach has a small platfor=
m onto which the adjuster bolt rests. The centerline of the torsion bar to=
the center line of that platform is only around 3=E2=80=9D so trying to li=
ft the weight of the front of the coach by just cranking on the adjuster bo=
lt will not work. There is just too much weight load over that short lever=
distance and you will strip out that adjuster bolt and nut. That is why y=
ou must use a professional torsion bar unloading tool first, to take the we=
ight load off. Once the weight is off the adjuster remove the bolt and the=
rectangular nut, clean the threads and lubricate them with anti-seize comp=
ound. Place them back in position. If you have access to a set of scales=
, use them under both front wheels. If not, then assuming the coach was ri=
de height low in front (most all of them are), then turn the adjuster with =
the most bolt threads showing upward with the load off six to eight turns. =
Release the torsion bar unloader slowly to confirm the adjuster bolt sits =
properly on the platform on the pork chop. Go to the other side and do the=
same thing until the amount of thread showing is about the same as the fir=
st side. Now slowly and carefully lower the coach, remove the rear blocks =
and drive two to five miles to allow the suspension to settle into where it=
will be when driving down the road. Leave the rear alone and recheck =
front ride height. Readjust if necessary. There is enough hysteresis in t=
he suspension (stickiness or unwillingness for the suspension to move easil=
y) that the only way it will settle to where it will be is by driving those=
two to five miles. No amount of yanking on or jumping on the bumper will =
do it and is just a wast of time. Most people fid it takes two to three it=
erations of measure, adjust, drive and remeasure to get it right. If you t=
orsion bars are weak from age then you might run out of adjustment room on =
the adjustment bolt and a replacement, longer, bolt will be needed. The GM=
C vendors have them. Just because you have the ride height right using=
this method does not guarantee that you are properly weight balanced left =
to right. For that you need scales and the weights at all four corners. =
There is lots of controversy about whether to use the stock =E2=80=9Caut=
omatic=E2=80=9D rear ride height adjustment or to use the wireless system w=
hich sets air pressure in each bag independently in order to achieve proper=
ride height. If the stock system is working perfectly, with no air leaks =
or other maladies, then it is just fine. After 40 plus years, most are not=
not working properly. And, to add insult to injury, check the factory spe=
cs. The devices that measure ride height with the factory system is either=
a lever moving a mechanical linkage or an optical shutter and it has a wor=
king range of +- 3/8=E2=80=9D. The factory spec for ride height is +- 1/4=
=E2=80=9D. Hmmmm. In all the coaches I checked or measured during the tim=
e I was doing the alignment jigs, I found that hysteresis was way more than=
+- 3/8=E2=80=9D so I found the wireless air a simpler, more reliable way t=
o control ride height. To each his own. You need to make that call for yo=
urself as there is no right or wrong answer here from my POV. But, you do =
want to wind up with nearly equal weight side to side in the rear and the f=
ront while ride height is at the factory setting front and rear. Doing tha=
t, and centering your steering box will likely make your coach into a one h=
and on the steering wheel relaxing ride. Final observation. Ignore th=
e factory alignment specs as they were established for bias ply tires and n=
ever changed after a quick adjustment of cutting back on static caster betw=
een 73 and 74 even though GM offered both bias ply and radial ply tires at =
different times during the production run. Bias ply and radial ply tires b=
ehave differently at speed. So, with radial ply tires you need all the sta=
tic caster you can get so long as both sides are equal. Most coaches run b=
est with camber and toe set to zero on the front wheels, and about one degr=
ee of tire in at the top camber and toe zero for all four rear wheels. =
Jerry Jerry Work The Dovetail Joint Fine furniture designed and ha=
nd crafted in the 1907 former Masonic Temple building in historic Kerby, OR=
glwork
http://jerrywork.com =
Message: 3 Date: Wed, 19 Sep 2018 09:54:11 -0600 From: Bill=
Van Vlack To: gmclist Subje=
ct: Re: [GMCnet] Torsion bar porkchop Message-ID: Content-Type: text/plain; charset "utf-8" Thanks, =
Ken. Couple questions.... Is there a way to set height without we=
ighing between each adjustment for those of us who don't have scales? =
If the rear weights are not equal when the coach is lowered, won't the h=
eavier side (more pressure in the bag on that side once the rear bags make =
the rear level) change the ride height on the opposite front wheel? =
What is the expected deadband for the levelers, and will approaching automa=
tic leveling from different directions affect the rear height? -- =
Bill Van Vlack '76 Royale; Guemes Island, Washington; Twin bed, full (=
DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator=
; new owner a/o mid November 2015. =
