> Larry,
>
> Thinking that there would be a good drawing to satisfy John L's
> suggestion to familiarize yourself with GM front suspensions, I check
> the web. NOPE! I found not one drawing worth referencing. So, my best
> suggestion is to jack up the front end and safely block it, then crawl
> under there on your back.
>
> Once under the front of the coach, the arrangement and purpose of most of
> the suspension will become quite clear -- and even the common names
> assigned to most things may become obvious (here, I'll use what I know as
> the common names for components; the manuals don't always use the same
> terms): The wheels are mounted on bearings which run in "knuckles".
> Those knuckles are attached to "Upper" and "Lower A-arms" through
> "ball joints" which allow the knuckles to move vertically and to rotate
> about their near-vertical axes. The A-arms are mounted at their wide ends
> through "bushings" to the frame, restricting their movement to rotation
> about their horizontal axes. As those A-arms pivot about their bushings,
> they keep the knuckles attached to their outer ends approximately
> vertical.
>
> Since the knuckles can rotate about their vertical axes, rotating the
> wheels with them, that rotation must be controlled. That control is
> supplied by "tie rods", which are attached to arms on the rear side of each
> knuckle via more ball joints, called "tie rod ends". Those tie rods, and
> the knuckle arms to which they attach, are positioned about 1/2 way of the
> vertical height of the knuckles (and, therefore, the distance between the
> upper and lower A-arms). The lengths of those tie rods is approximately
> the same as that of the A-arms (or the length one would require if it were
> at that 1/2 height). This arrangement of A-arms and tie rods minimizes the
> steering geometry variation as the suspension move up and down.
>
> Almost coincidental to this discussion are the torsion bars which provide
> the "springs" for the front suspension: They are hefty round spring steel
> shafts which are hex-keyed into the lower A-arms at their forward ends.
> Their aft ends are hex-keyed into adjustable "pork chops" mounted inside a
> frame crossmember. Those "pork chops" have adjustment screws which enable
> one to set the ride height -- but NOT by merely turning the screws --
> they'll probably strip their threads if special torsion bar adjusting tools
> are not used to relieve the weight from them.
>
> Now, to the latest of your understanding problems: The left and right tie
> rods must be connected together so that they synchronize the rotation of
> the front wheels. So, the inner end of each of the tie rods is attached,
> via tie rod ends, to the "Center Tie Rod" which runs horizontally behind
> the "front" (main, under-engine) crossmember. That large, non-adjustable,
> member is kept in its appointed location from all movement except
> length-wise because it is suspended via rotation-only bushings from two
> "arms" -- the "Relay Arm" and the "Idler Arm". The Relay Arm, at the top
> left of the mail crossmember "relays" steering signals from the power
> steering box's "Pitman Arm" to the tie rod. In addition to its pivot
> point, it has two attachment arms, one for the Center Tie Rod and one for
> the "Drag Link", which connects to the Pitman Arm. The Idler Arm is
> symmetrically located on the top right of the main crossmember merely to
> maintain the Tie Rod's proper position. It rotates about its pivot and its
> single arm attaches to the Center Tie Rod. The Center Tie Rod arms on the
> Relay Arm and the Idler Arm should be parallel to the side frame members
> when the steering is set dead ahead.
>
> There are a number of adjustable components: The Ride Height adjustment by
> the torsion bars has been mentioned. The wheels' Caster and Camber are
> adjusted by eccentric mounts at the inner pivots of the upper A-arms. The
> toe-in/toe-out of the wheels is set by the adjustable-length Left and Right
> Tie Rods. Those adjustments also affect the centering of the steering if
> they are not equally adjusted. The final adjustment is not present on all
> coaches: Early (and modified) coaches have a Drag Link between the
> steering box's Pitman Arm and the Relay Arm which is adjustable in length
> to allow minor adjustment of the steering center; later coaches came with
> an non-adjustable Drag Link.
>
> There are a LOT of minor details not mentioned here, but hopefully this
> will help you understand suspension discussions better.
>
> Ken H.
>
>
>
> >> Open the engine cover and look down at the position of the relay arm and
> > idler arm. They should be pointing straight back, parallel with the main
> >> ladder frame. If not, then the link between the tie-rods out to wheels
> > is off of its center point of movement. Use the tie-rod adjustment sleeves
> >> to get the relay arm and idler arm in the center of their swing
> > (straight back, parallel with the chassis frame). Turn the sleeves a little
> > bit on
> >> each side, alternating side to side and in the opposite direction so you
> > do not move the front wheel position. You only want to shift the connecting
> >> rod to the center of its movement by setting the relay arm and idler arm
> > point straight
back.the center of its movement swing.
> >
> > Bruce - what are the relay arm and idler arms? Any chance of a diagram or
> > photo of these things? I need to get them "straight back and parallel with
> > the main ladder frame(?)" Main ladder frame? What's that? The coach frame?
> >
> > Like I said, my steering vocabulary is that of a 3 year old ..HELP!!
> >
> > Larry
> > --
> > Larry - Victoria BC -
> >
> > 1977 Palm Beach VIN TZE167V101295 - 39,000 miles, PO said everything
> > working but forgot the word NOT. New wiper blades, New SS exhaust system ..
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Well thanks for that comprehensive description, Ken - I was under there today and I now see what the idler and relay arms position is - it isn't the
"front" that has be parallel to the frame, but the rear section. And it is, so all good there!
Found a bit (understatement) of an issue when we jacked her up and gave the wheels a shake ...the passenger side upper A control arm was moving about
quite a bit. At first I thought I'd be looking for bushings, but no, on further examination it was the bolt that was loose allowing the wiggle. It had
been stripped at some point and couldn't hold the bushing and adjustment cams in place.
The auto parts places, NAPA, Bumper to Bumper and LORDCO told me there were none available in Canada anywhere and it would be 6-8 weeks special order
to bring a kit in from the manufacturer, prepay and no returns. Real friendly like.
I did order a set that are theoretically in stock from
TheWrenchMonkey.ca but I may find there's no stock available to them either and it will also go
to backorder. I think they're like RockAuto, just drop shippers - I don't think they have any warehouses themselves..
Anyway at one point I thought about buying a #8 bolt and taking it to a machine shop to have it milled but then I remembered a guy who was a Toronado
nut who lived a few miles away. Gave him a call and yes he had two spares and I'm on my way out of the door right now to pick them up. Very lucky
day.
The cams are marked from the last alignment so I'm going to start by putting them back on their marks and see what happens. After I get that buttoned
up tomorrow, we'll have another go at the steering box!
Thanks for all the assistance everyone, I sure appreciate having you guys there to save me from myself!
Larry
--
Larry - Victoria BC -
1977 Palm Beach VIN TZE167V101295 - 39,000 miles, PO said everything working but forgot the word NOT. New wiper blades, New SS exhaust system ..
