Shock mount failure

[david brady]

I guess as long as the gussets are 120 deg apart they will

always sum to an equivalent of one in tension and an

equivalent of one in compression regardless of the

direction of the incident force (assuming it's perpendicular

to the stud). Are they 120 deg apart on the WB?



David

'02 LXi, NC



david brady wrote:

Hi Greg,



Three gussets, 120 deg apart. On at the top inline with the

shock in tension, two at the bottom are in compression with

each contributing 50% when projected along the axis of

the shock.



David

'02 LXi, NC



timvasqz wrote:

if there are four gussets and two are inline with the shock the
side

two do nothing. In that case the top gusset that sees compression

transfer more force on the bottom gussett that feels tension.



if they place two gussets one each on 22 degrees of the center line

from the shock across the bottom and two at 22degrees off center line

at the top, the force of the shock(action) will be shared equally by

each gusset reducing the stress at the end of either weld.



I have loader arm gussets that have a crease in them that allow the

gussett to flex some. that takes advantage of metals ability to

absord some and not crack.

the mods that have been done strengthen the post which isnt failing.

the plate fails. the point where plate first fails is the part that

allows the metal to peelup. welding the plate to the frame at the top

has no advantage either.

Greg ofTim&Greg

94ptca



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

wrote:

>

> One thing to keep in mind is that these shocks don't

> act vertically. My shocks are canted over to almost

> 45 degrees, give or take (probably take a bit, I haven't

> measured the angle). That's part of the problem. The

> mount has an almost 2:1 mechanical lever disadvantage.

>

> On the LXi, along the axis of the shock, which is how the

> forces are acting, there's a gusset in line with the shock.

> call it 10:00, then there's the 2:00 and 6:00 gussets with

> the bottom of the shock pointing at 4:00. I'll see if I can

> dig out a pic.

>

> If you look at the WB version, you'll see that there

> isn't a gusset in line with the shock opposing the rebound

> forces. The WB gussets are at 12:00, 4:00 and 8:00.

> With the shock acting on 10:00. Pete's pic in particular

> shows how that weld bead flowing between the 12 and

> 8:00 gusset broke, right where the forces are the strongest.

> I believe it broke first at this weld bead and then ripped

> the rest of the metal off to the direction of the brake line.

>

> Check for cracks at that weld bead. Wire brush the paint

> off, then repaint.

>

> Now that it's 12:00 I think I'll go to bed...

>

> David

> '02 LXi, NC

>

>

> timvasqz wrote:

> >

> > when I weld in a triangle gussett, I first cut out the right

angle or

> > just dont weld to the point. On the redesign David has I
would

think

> > the gussets are not top and bottom in line with the shock????

> > Gussetts off to the side of the line of the force would allow
for

> > some distortion in place of total metal failure.

> >

> > When you beef one thing up the next weak link becomes
evident.

first

> > thing I do when I crack an arm on a bobcat is realize the
proven

> > limit then weld it back to spec. I just think the problem is
not

in

> > the ride dynamic.

> >

> > "You can jack a bus up.... by jacking a bus up"

> > Greg of Tim&Greg

> > 94ptca

> >

> >

>

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[Don Bradner]

I can't find a photo that shows the angle definitively, but I believe they are
120. None exactly along the axis of the shock.

On 2/20/2009 at 12:00 PM david brady wrote:

>I guess as long as the gussets are 120 deg apart they will
>always sum to an equivalent of one in tension and an
>equivalent of one in compression regardless of the
>direction of the incident force (assuming it's perpendicular
>to the stud). Are they 120 deg apart on the WB?
>
>David
>'02 LXi, NC

Don Bradner
90 PT40 "Blue Thunder"
My location: http://www.bbirdmaps.com/user2.cfm?user=1

[Jon]

--- In WanderlodgeForum@yahoogroups.com, "Don Bradner"
wrote:
>
> I can't find a photo that shows the angle definitively, but I
believe they are 120. None exactly along the axis of the shock.
>
> On 2/20/2009 at 12:00 PM david brady wrote:
>
> >I guess as long as the gussets are 120 deg apart they will
> >always sum to an equivalent of one in tension and an
> >equivalent of one in compression regardless of the
> >direction of the incident force (assuming it's perpendicular
> >to the stud). Are they 120 deg apart on the WB?
> >
> >David
> >'02 LXi, NC
>
> Don Bradner
> 90 PT40 "Blue Thunder"
> My location: http://www.bbirdmaps.com/user2.cfm?user=1





I have been following this post and I know most people wouldn't know
a gusset from a pineapple and this kind of scares me. When folks pay
out a hundred thousand dollars for a Wanderlodge they must expect
that there buying a machine that will go for hundreds of thousand of
miles without a major problems.

Kind of makes our older Wanderlodges look a little bit better as I
have never heard of this type of problem with them.

Oh well I just hope if I ever get enough cash to buy up to a newer
model that this gusset problem won't happen to me but what a pain in
the butt to keep on thinking about while going down the road. Jon
>

[timvasqz]

Jon, it is not a big problem. It is more of a forseen issue now that
the members have recorded reoccurance. most of what is posted is theory
followed by an explanation to support a theory in the hopes that we
find truth. I looked at my 94ptwb today and there are no cracks in the
welds. I believe when it cracks then tears it takes time as evident by
Dons photo showing old rust at the crack then fresh cut at the tear.
Had the shock installer been alerted to the problem area, I believe
Don could have gouged out the crack and run a bead weld in the crevice
($100). The service here is a reminder to check the failure prone area.

My dump truck is checked several times a year by DOT inspectors so I
look over the underside real good to keep from being redtaged
roadside. . Never has a year gone by that a suspension component was
not replaces due to wear or failure.

the million mile engine wives-tale fails to credit the quarter million
dollars of maintenance/repair during those miles. we here seek to
reduce that 250K.
Greg ofTim&Greg
94ptca



>
> I have been following this post and I know most people wouldn't know
> a gusset from a pineapple and this kind of scares me. When folks pay
> out a hundred thousand dollars for a Wanderlodge they must expect
> that there buying a machine that will go for hundreds of thousand of
> miles without a major problems.
>
> Kind of makes our older Wanderlodges look a little bit better as I
> have never heard of this type of problem with them.
>
> Oh well I just hope if I ever get enough cash to buy up to a newer
> model that this gusset problem won't happen to me but what a pain in
> the butt to keep on thinking about while going down the road. Jon
> >
>

[Don Bradner]

I got the bus back today with the shock mount repaired - also had a leaking
drive axle seal replaced, generator serviced, etc.

Original damage: http://www.arcatapet.net/image/shockmount.jpg
Repaired: http://www.arcatapet.net/image/shockrepair.jpg

As you can see, they took a substantially different repair route than was used
on Pete's.


Don Bradner
90 PT40 "Blue Thunder"
My location: http://www.bbirdmaps.com/user2.cfm?user=1

[Pete Masterson]

That's a very nice, clean-looking repair. I suspect that the bent, torn piecefrom the base platemight have pushed them in that direction. CCW had a press that they used to flatten it in about 10 seconds -- but it's not the kind of tool I'd expect to see in most shops.

It's impressive how much alike the before image was to mine...

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 4:10 PM, Don Bradner wrote:

I got the bus back today with the shock mount repaired - also had a leaking drive axle seal replaced, generator serviced, etc.

Original damage: http://www.arcatapet.net/image/shockmount.jpg
Repaired: http://www.arcatapet.net/image/shockrepair.jpg

As you can see, they took a substantially different repair route than was used on Pete's.


Don Bradner
90 PT40 "Blue Thunder"
My location: www.bbirdmaps.com/user2.cfm?user=1



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[Eric Perplies]

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?

[Don Bradner]

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?

[Pete Masterson]

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?

[Dan Williams]

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?