[TR] When to change rubber bushings

[Jerry Van Vlack]

Tony and others,

I was in Senior Management and came up via the Sales and Marketing
organizations. I am by no means a rubber compounder (usually chemists) or an
engineer. My knowledge is limited to identifying the need for development and
having the right folks in my organization assigned to the task and making
certain that we met the various technical requirements identified by our
customer.

As it relates to rubber parts I could be helpful if the original drawings were
available and the material specifications were detailed on the drawings.
Rubber material specifications can be detailed in many ways. The best is what
we referred to as a Line Call Out which was a method of detailing the various
performance characteristics required of the compound and the parameters that
the compound must meet. In the absence of a Line Call Out those same
parameters can show up as a table on a drawing or in the various drawing
notes. Unfortunately many times material is spec'ed out as it must meet
specification xxxx dated xx-xx-xx which is located in some manual or book of
specifications. Worse yet would be that the drawing says the material is to be
Company x's compound # xxxx. I suspect that if the original drawings are still
available the material specifications are not. That being the case the
material is then left to the overseas supplier to decide and we have our
problems that are the topic of this discussion.

As it relates to the steering rack boots my guess is that the suppliers are
not using a compound with sufficient plastisizers in the compound and as a
result the elongation is less than needed to expand the boot during
installation. They will fail every time.

I suppose that my help would be better than none at all but my guess is that
there are better qualified folks in this group than me when it comes to rubber
components.

JVV
  ----- Original Message -----
  From: Anthony Rhodes
  To: Triumphs List ; jerryvv at adelphia.net
  Sent: Sunday, July 22, 2007 8:41 AM
  Subject: Re: [TR] When to change rubber bushings


  Jerry,

  I wonder if you, or anyone else on this list, have the expertise, interest,
and time to offer some help to our suppliers when they arrange to have
"rubber" parts made.  Maybe it is only important when we see certain parts
failing prematurely (like steering rack boots).

  I have heard (Nth hand) that the VTR is considering how to have a
centralized (I.E. VTR based) reproduction parts advisor.  This would be
similar to what some of the Clubs in the UK do.  I would assume that the VTR
committee would be working hand-in-hand with the UK-based committees to have a
world-wide unified source of design info for use by manufacturers and
suppliers.

  -Tony


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