Re: [Amc-list] F('ing)ailing parts 2

[Tom Jennings <tomj@xxxxxxx>]

On Tue, 6 Mar 2007, JOE FULTON wrote:

> I really think you should lodge a complaint with NAPA
> over those crappy Echelin parts.  Someone has to be
> listening.

Yeah, you're right -- I'm just getting a bit numb from
complaining and increasingly sound like a crank when I demand
that something I bought actually perform half of what's claimed!

I wonder at the NAPA replacement ball joint I installed, since it
didn't even have a gasket between halfs, and the grease squirt
out the side, which means it didn't reach the bottom ha;lf of
the ball.

I realize the bottom half of the ball bears no load normally;
but grease reaching there means it reached everything else DOWN
TO there. That's what matters.

I should have insisted on a Moog part, but I'm not convinced
it matters even any more. Call me crazy, but I disassemble,
examine, and determine WHY parts fail on pretty much everything
I work on, cars or otherwise. I photo them and make drawings.

It used to be that bad-by-design or bad-by-manufacture was
rare. Now it's common. Parts look the same, but use cheaper
materials and cheaper assembly processes (eg. ball joint lube
system). Corporate growth needs are killing us, penny by penny.

>> The Ron Francis Wiring switch really is superior.
>>
>> Echlin specs the SAME PART!! for oil pressure
>> sensors. Guess

Here's my 2002 note on the Echlin switch (email to my friend
David who was having similar problems in a 50's chevy). It
seems to me now that this is an engine-oil sensor, that some
bean-counter smart-ass "cross checked" in a catalog, noted
matching mechanical/electrical specs and OK'd the substitution
and subsequent inventory shrinkage. And overlooked that brakes
generate 1000PSI where an engine can't generate 100PSI.


Tom Jennings
2002-09-20

So I took apart that failed brakelight switch. It was pretty
interesting (in a small way).

The immediate failure was a pitted contact -- there's a phenolic
block with two brass contacts poking through, radially opposite. In
the center is a small spring, that pushes a brass disk away
from the contacts. A rubber disk lies on top of the brask disk.
This is set into a steel housing w/pipe thread and crimped.

Hydraulic pressure pushes against the rubber & brass disks,
shorting the contacts together.

             ##     ##
          ___##_____##___
         /   ##     ##   \
         |   ##  Z  ##   |
         |___##__Z__##___|	# brass contacts
        S|   ##  Z  ##   |S	S steel housing
        S ==============  S	= brass disk
        S rrrrrrrrrrrrrrr S	r rubber disk
        S                 S	Z spring
        SSSSSSSS  SSSSSSSSS
              SS  SS
              SS  SS
              SS  SS


* One of the contacts and matching spot on the brass disk were
deeply pitted.  Probably barely adequate for the old 1157's,
definitely too wimpy for the 2057 bulbs.

* There was brake fluid (DOT5 silicone) inside. The rubber/crimp
seal is poor by design. There was ooky black on the electrical
parts; maybe the rubber isn't silicome compatible? Seems unlikely,
rubber otherwise OK. Might have simply been carbon from arcing,
in solution.

* Design-wise, it always sucked; the brake lights don't come on until
a lot of force is applied (not soon enough). And I've got disk
brakes (retrofit) so the initial pressures are higher before the
brakes start working.

_______________________________________________
Amc-list mailing list
Amc-list@xxxxxxxxxxxx
http://www.amc-list.com/mailman/listinfo/amc-list