[alfa] Hot wheels and a scorching rear end

[alfacybersite <acs@xxxxxxxxxxxxxxxxx>]

Andy Menapace wrote:

>For some time now I have noticed that after a drive the rear wheels on
>the ol' Spider were warm; I'd say around 140F on hot summer days, less
>in cooler ambient air.  Obviously, something is amiss.  I rebuilt the
>brakes, I changed the rear rubber brake line, I checked the parking
>brake, I checked the rear brake compensator valve.  Hmmm, still getting
>hot.
>
>I had focused all my effort on the brakes, but am now convinced it's not
>the brakes.  Sometimes, you just have to stop and think. I drove it
>yesterday for 15 minutes or so, and then got under the car and felt the
>entire rear suspension looking for heat.  I found it.  The differential
>was unbearably hot to the touch.  I keep it full of gear oil.  Bearings?
>Would bad bearings heat the aluminum diff housing more than the steel
>axle?
>
>Any ideas?
>
>Andy Menapace
>Brandon, MS
>79 Spider
>*************
>
Andy, I can't help you with your questions but once again I'm going to
bring up my new toy - the ES 585 multimeter. A few days ago I checked
out the temperature function (measures from -4 to 1400 degrees F) on it,
just for fun. As soon as I plugged it in it indicated close to the
ambient temperature. Though it simply could have been the temperature of
the wire and tiny probe. Let me say here, the wire appears to be about a
1/10th version of the wire which once went from my '75 Alfetta GT's
catalytic convertor to the "thing" under the dash - meaning, it should
be treated delicately. I placed it on various parts of the fairly hot
engine (same car) and it took a while to get there but temp started to
soar from about 75 to about 155 or so.

The point being, it won't solve your problems, but a "unit" such as this
will help pinpoint pretty exactly where (and how much) the "hotspots"
are - not that you can' t feel them with your hand.

I will take a stab at your rear brake problem and suggest the emergency
brake cable might be too tight even though you say you've checked it
(did you reach around and put your hand on the emergency brake drums?),
or even though rebuilt, the pistons in the calipers might still be
semi-frozen - in that they move, but very reluctantly. Again, sounding
like a snake oil salesman who also sells multimeters, you could use the
meter to check the temp of the calipers from front to back - though
again will admit a quick touch will pretty much answer your question.

The aluminum center diff is going to get much hotter than the steel
housings, but doesn't mean you might not have a bearing problem.

Biba
Irwindale, CA USA
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