pads/disks for 90

[Larry C Leung]

That doesn't make sense for drum brakes. Frome materials and
coefficient's of expansion, the larger surface (the drum) contracts
further than the smaller surface (the shoes), so as things cool, the
brakes should be further "on". (this assumes that the shoe lining is
either thin enough or has about the same coefficient of thermal
expansion). This principle is why heating stuck bolts or nuts works. If
it didn't, heating would expand the nut and bolt equally, and things
would still be stuck (hmmmm, then again, having just done front
brakes......). Anyway, perhaps that's why Saab dumped the front drum
P-brakes after one year. The disk version seemed to work just fine. And,
incidentally, with Saabs, the only way to withdraw the key was to put the
gear shift into reverse, hence the highest multiplication gear was used
to help hold the car with engine compression. Their autoboxes had to be
in Park to remove the key. As I said, those thoughtful Swedes!

LL - NY: Audifan and Owner but admire the engineering of Saabs (pre-GM,
Lancia, Fiat, etc)

On Wed, 11 Jul 2001 11:03:15 +0100 (GMT+01:00) Phil Payne
<phil at isham-research.freeserve.co.uk> writes:
>> FWIW Saab decided on it's 1971 99 series through the heavily 
>related
>> Ur900 ('89 - 90?) series that the P-brake should be on the FRONT 
>brakes
>> so that it'd be actually effective as an emergency brake (those 
>crazy
>> thoughtful Swedish aircraft engineers
>
>One of the recent French cars did the same.  They had no end of 
>problems with cars moving off on hills as the brakes cooled down and 
>contracted.
>
>
>
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