Shock mount failure

[David Brady]

Dan,

Additional stress is only created if you lift a tire off the ground via
the jacks and the suspension is still aired up. Of course, under
most circumstances, the height control valve should dump air,
but this takes time and in the meantime the air spring is fighting
against the shock and shock mount.

David Brady
'02 LXi, NC

-----Original Message-----

From: Dan Williams

Sent: Mar 10, 2009 3:30 PM

To: WanderlodgeForum@yahoogroups.com

Subject: RE: [WanderlodgeForum] Re: Shock mount failure

Pete, I may be getting in on this
late, but how does lowering the leveling jacks with the
suspension still aired up put stress on the front shocks and mounts?

Dan Williams, 88WB38, Jackson, MS

---

From: WanderlodgeForum@yahoogroups.com
[mailto:WanderlodgeForum@yahoogroups.com] On
Behalf Of Pete Masterson

Sent: Tuesday, March 10, 2009
12:20 PM

To:
WanderlodgeForum@yahoogroups.com

Subject: Re: [WanderlodgeForum]
Re: Shock mount failure

There is
a sub-frame that holds the shock mount, air bag, and other parts of the front
end. It's a piece that's about 24 to 30 inches long. That piece comes from
Ridewell. (Although Ridewell might claim that Blue Bird provided the
specification.)The speculation is that the Ridewell piece is not
thick enough (or otherwise not sufficiently strong) to take the constant
hammering.

Awhile back on one or the other WL lists, someone reported that
lowering the leveling jacks with the suspension still aired up puts an
unusually large stress on the front shocks and mounts. That may start the
weakening process. However, I know that it was rare for me to forget to dump
the suspension before I leveled the coach.

Before the complete failure of my shock mount, I'd noticed a 'popping'
noise in the front end when encountering theporpoisingmovement that
occurs after passing over one of the multitude of ground subsidence undulations
that are frequently found on the freeways, especially in the SF Bay Area where
the highways are frequently built on fill (near the bay) or unstable clay soils
(nearly everywhere else in the area). Later I realized that the noise was cause
by the flexing of the split (and eventually broken) piece of the Ridewell
sub-assembly. (The acoustics caused it to sound like it came from the opposite
side.)

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42 (For Sale)

<http://www.aeonix.biz/BBforsale.html>

El Sobrante CA

"aeonix1@mac.com"

On Mar 9, 2009, at 7:40 PM, Don Bradner wrote:

Did your tear look at all like mine (mine looks almost exactly like
Pete's)? Presumption is that the slamming downward when the wheel bottoms into
a pothole or similar is the issue. Countless slams, and the metal gives way.
Note that it is not the frame, but rather the steel mounted to the frame - that
steel is a part of the axle assembly and was presumably not welded by BB.



The repair done on mine comes close to matching the original assembly, making
it possible/likely that sometime in the next 20 years it will fail again. I'm
going to try to remember to stick a camera in there for photos every few months
(more often to begin with!) that it is driven.



On 3/10/2009 at 2:22 AM Eric Perplies wrote:

My front left shock mount broke just before the Q rally in 08.
CCW in

Riverside
fixed mine shortly after the Q rally. On my coach the shock

mount ripped out a chunk of metal on the frame. A piece of steel
about

1/2" x 8" x 6" was welded onto my frame. A hole
was drilled in it to

accommodate the brake air line. The original shock mount with it's
three

gussets were removed from the broken out piece. That original
shock mount

was then welded back onto the 1/2" plate mentioned above.

The welds made during the repair were VERY thorough. There was an

indication that the original BB welds may not have been as through as
they

could have been. (One side of one of the gussets had not been
welded onto

the frame.) That having been said this could not be the reason
for the

failure. After all the frame on my coach had a section ripped out
of it.

The shock mount itself did not fail.

A far more interesting question is: What causes the failures on
the shock

mounts?