What is the reason for the left front shock mount failures on 90's buses?

[david brady]

And BB knew all along.



The shock could "just fit" with the air dumped. But when

owners drop their birds off the jacks, the front goes

crashing down, the bump stops compress, and the shock

mounts take a huge impulse. It's a good theory.



The rough road scenario doesn't fit for me. You'll never

find a road rough enough that will cause the air springs

to bottom on their rubber bump stops. The air springs

are enormously progressive. At full compression

they can support something like 4G's. That's equivalent

to dropping the bus in free fall from 15 feet (give or take).



David

'02 LXi, NC



timvasqz wrote:

Dave this kinda supports your "shock stroke too long theory" if BB
moved the mount farther away from the other mount.

pot holes are violent at 70 mph. if you ever see a slomotion of a PU
truck hitting them the entire truck frame twists. In the bus there is
no twist so the only place the equall reaction force is felt is in the
suspension (and tile grout)

Greg of Tim&Greg

--- In "WanderlodgeForum%40yahoogroups.com",
david brady "dmb993@..." wrote:

>

> Eric,

>

> There's been a whole lot of discussion on this Forum

> relative to the shock mount failure. You may want to

> search the archives for "shock mount".

>

> David Brady

> '02 LXi, NC

>

> Eric Perplies wrote:

> >

> > When I discovered my front left shock absorber mount had
failed just

> > before the Q rally in 08' I thought my experience was unique.


> > Evidently it was not. There seems to have been several
similar

> > failures on 90's vintage buses. All of them appear to have
occurred on

> > the left front shock mount. It might be both interesting as
well as

> > useful for all of us that have experienced the failure as
well as

> > other interested parties to discuss what had caused the
failures. If

> > there is a design flaw we know we are on our own, of course.
Right now

> > it continues not to be clear to me what caused the problem.

> >

> > I realize that some of you have already discussed your
failure. I do

> > hope you can participate in what may be on line
troubleshooting. Let

> > me start out by discussing my failure.

> >

> > Just before the Q rally in 08' the left front shock absorber
mount on

> > my coach failed. The whole piece of metal on the frame of my
bus was

> > pulled away from the frame, leaving the shock mount still
connected to

> > the chunk of metal that was pulled away from the frame. CCW
in

> > Riverside repaired the problem. They had extensive
discussions with

> > the engineers at Ft. Valley. I will tell you that CCW was
less that

> > fully communicative with me about what they discussed in
their

> > multiple phone calls to Ft. Valley. Always say they
"discussed the

> > problem and solution."

> >

> > The fix was to weld a 1/2" plate to the area ripped out of my
frame

> > and re-weld the still good shock mount back in position.
(Caution:

> > what I am about to say is unreliable It looked to me as
though the

> > repair shock mount was re-welded back in position just
slightly lower

> > than it may have originally been located. When I asked CCW
about the

> > location of the mount they said something like: "We put it
back in

> > where it should have been." Never saying that they relocated
it.

> >

> > When I strongly suspect that the failure occurred on my bus
is when I

> > traveled a poorly maintained road (US 30) between Chicago and
Ft.

> > Wayne, IN. While along that roadway my bus developed a
"squeak" coming

> > from what I thought was the right front of my bus. I could
not see

> > anything wrong with the underside of the coach. I did not
look at the

> > left upper shock mount. I was looking for at problem on the
right side

> > of my coach. I took my coach to a big rig shop in Ft Wayne
that did

> > among other things, front end work. They said everything
looked fine.

> > On my trip from Ft. Wayne to Las Vegas I did a lot of
inspections,

> > greasing and spraying of lubricate on the front right of the
coach. I

> > even removed the Steer Safe. By the time I got to Sante Fe
the noise

> > had stopped. When I went to put my Steer Safe back on in Las
Vegas,

> > just before the 08 Q rally, I discovered the failed shock
mount on the

> > left side of the coach.

> >

> > (By the way, sorry for the long post.) The question still
remains in

> > my mind: What caused the failure. I have been on many bad
road in my

> > life with this coach. The road I was on when the "squeak"
started was

> > bad but not ridiculously bad. I would hate to think that
every time I

> > might ride a bad road that I may be replacing a shock mount.

> >

> > Eric Perplies

> > 96' 42' WBWL

> >

> >

> > ----------------------------------------------------------

> >

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