Just an update on the AEC Doughnuts. They were installed last week
on my Sierra at annual. It took the shop one day for the
installation of all three sets. They found the installation
instructions extremely helpful. The discs were pre-mompressed for
about 4 days under a heat lamp which prepared them for the install.
The end result is a smoother taxi and softer landing. I can highly
recommend these.

Bob Palamara
'72 Sierra

--- In musketeermail@yahoogroups.com, "Michael Rellihan"
<rellihan@...> wrote:
> I thought I had posted an update on this, but I now can't find it.
Here is
> my understanding of current status on the AEC cushions.
> - AEC designed the cushions to the upper end of the range of the
> Durometer hardness (per their PMA), to assure long life.
> - There have been no problems with installations on the fixed gear
> nor with the Sierra nose gears. These are all the smaller diameter
> having the single centered bonded metal disk. There have been
several posts
> on the installation process, and there are some photos on BAC
(including an
> Igloo cooler "heater" and a pre-compression rig). If the
> pre-heating/pre-compression process is followed (as outlined in the
> Manual), the job goes problem-free.
> - There have been several installations on the Sierra main gear.
Two owners
> experienced problems with achieving adequate pre-compression. It is
> believed that the non-machined upper inside surface of the main
gear housing
> casting can vary in thickness as much as a quarter of an inch.
With the
> upper-end hardness of the new rubber, and the two-sided metal
bonded discs
> on the larger-diameter cushions, it is apparently possible to have a
> stack-up of circumstances that makes it impossible to get enough
> compression on the Sierra main gear.
> - AEC has addressed this by ordering more of the large cushions
having a
> Durometer reading on the lower end of the permissible range (in the
> They will resume sales of the Sierra main gear sets by configuring
> sets. These will have several of the softer cushions at the top of
> stack, and the harder ones beneath. The softer rubber will be up
inside the
> upper gear housing, where it will be more protected from the
elements (sun,
> ozone, solvents, etc.). The AEC original-design hardness cushions
will be
> placed in the lower exposed positions, and will be better able to
> the environmentals as intended. The combined cushion stack will
> proper pre-compression, even if a thicker casting is encountered.
It will
> also function as a sort of variable-rate spring, to provide a good
ride even
> while the cushions are new and stiff.
> I'll ask Kamran for an update on resumption of sales of the retract
> gear sets. Sales of the smaller-diameter fixed gear (and Sierra
nose gear)
> sets have continued, though at a very slow pace. Several of those
> stories have been posted on BAC and MML.
> Just as a reminder to those who are contemplating a cushion
change: The
> large roll pins that secure the stack tube to the compressor plate
> supposed to be checked for straightness during the cushion work (as
> described in the shop manual). Many are found deflected due to
> hard landings. The original MilSpec pins are obsolete for design
> manufacture, and are generally unobtainable. There is a
superseding MilSpec
> for a stainless-steel version of the pins (per the US Qualified
> List). These are standard hardware parts, and the superseding part
> perfectly legal to use. I actually found a company to make me some
> these, so we would have a source. Of course, I had to have a
> quantity made, and I am frankly still well in the hole on the deal
(though I
> have sold maybe a dozen sets). If you are planning a gear donut
> please consider purchasing a set of pins to have on hand. I have
> listed in the BAC Classifieds along with my other items, and they
are very
> inexpensive.
> _____
> From: musketeermail@yahoogroups.com
> On Behalf Of bpalamara1
> Sent: Tuesday, January 24, 2006 11:13 AM
> To: musketeermail@yahoogroups.com
> Subject: [musketeermail] Alternator
> Has anyone used the new AEC Doughnuts? It's about time as they
are 34
> years old.
> How long should it take a good mechanic to do a retract?
> Bob Palamara
> '72 Sierra
> MC96
> _____
> [Non-text portions of this message have been removed]

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