Interchangeable parts?

This is relevant to the modern interchangeable parts and output impedance discussions.
The other day my truck had a no-start problem that turned out to be a
poor cable connection at the battery clamp that I'd missed during an otherwise thorough spring electrical cleanup. I found it -after- I had removed, disassembled and thoroughly checked the starter.
The corrosion hidden inside the cable clamp still allowed about 30 - 40 Amps, not enough to spin the starter motor with the Bendix engaged but the voltages were correct everywhere that was easily accessible, the solenoid clicked and the battery dropped to 11.5V.
I bought Autozone's solid brass battery terminal to replace the previous replacement and just found that it's too large for the negative post and too small for the positive. It would have been a problem for someone without my collection of blacksmith tools to swage open the tapered hole and a milling machine to recut the square bolt head seat at the new angle.
Autozone had a set of combo wrenches for not much more than HF's price which is a better match to the odd sizes Ford used, like 18mm. This time the socket set wouldn't get everything. I work on vehicles with the tool kit kept in them and add to it whatever I had to borrow from the garage set. Since I've taken almost everything apart already cheap wrenches are good enough to undo bolts that have been lubed with LPS-3 or Never-Seez. (r) -jsw
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On 8/2/2014 7:58 AM, Jim Wilkins wrote:

Our old Mercedes Benz 300SD, 1983 model, had brass battery connectors on the cables. They were good when we bought it in 1993 and still good as new when we traded it last year. I had to replace the battery twice in 20 years. The battery that was in it when we bought it lasted almost 7 years.
Paul
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On Sat, 02 Aug 2014 10:58:32 -0400, Jim Wilkins wrote:

I'm not sure what your actual question is, but if I were in your shoes I would certainly be pondering the wisdom of buying parts from the World's Cheapest Source to equip a vehicle upon which I depend. Either the Autozone parts are just crap, or someone didn't match up the battery part # to the clamp part # correctly.
The cables in my '69 truck were bought as assemblies from (I think) NAPA when we rebuilt it 22 years ago. They work great and are showing little signs of wear other than the ugly white slime that batteries get.
--
Tim Wescott
Control system and signal processing consulting
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On 08/03/2014 10:28 AM, Tim Wescott wrote:

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I don't know the specific part, but if it doesn't fit a standard automotive battery terminal post, it probably wasn't intended to but is for another application.
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The label reads "For post terminal batteries", without specifying positive or negative.
Do you know of another similar application? Marine battery terninals fit both automotive and deep-cycle batteries.
I think they made it halfway between the positive and negative post sizes so one part can be tweaked to fit either, but the brass doesn't bend as easily with hand tools as a lead alloy terminal. I pounded a tapered mandrel into it to keep the hole round.
Autozone carries two or three quality/price/warranty levels, whatever that means when everything comes from China. I don't touch the patch-it-to-sell-it level.
-jsw
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On 08/03/2014 11:56 AM, Jim Wilkins wrote:
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Specific application, no, but doesn't seem to make any sense if it's too large for the smaller standard post it doesn't work for either...
There is an A-Z franchise here, but I never go in for anything but on occasion they have had some of the accessories like the plastic xmas-tree pushie-panel mount thingies that NAPA has been out of stock on (the local NAPA has been sold and the new owners are terrible about restocking which is a real pita as it's the only place in town on the side closest to us).
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wrote in message

Since I needed to expand it for the positive post I didn't first try compressing it to see if it would grab the negative post before the ends closed together. Probably it would, there wasn't much play.
Anyway, it's a contemporary example of a consumer replacement part that requires hand fitting. -jsw
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On 08/03/2014 2:50 PM, Jim Wilkins wrote: ...

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I suppose, but still surprises me -- I'd think if it were that difficult to adapt they'd get 99.997% returned by the consumer and quit carrying them...
--


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Suggest next time feel the cables and connectors first, when this happens usually something gets hot.
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When something electrical malfunctions my experience-conditioned reflex is to mentally photograph the symptoms and then quickly shut off before something gets hot enough that the expensive magic smoke billows out. I use the IR thermometer or as a last resort my hand to chase less dire emergencies.
I did jump the relay with a screwdriver and heard the starter click but not chatter, the usual indication of insufficient current from the (12 year old) battery. Mostly I checked meters set up on the cowl to show voltages and current while I turned the key. Seeing up to 40A in the cable to the starter and still 11.5V at the clamps mislead me. In the spring I had thoroughly cleaned, labelled and Ox-Garded all engine compartment electrical connections (except this one).
I'd already rebuilt the starter once with new brushes and kinda suspected the solenoid contacts, which had eroded away on my Accord and been built up several times with brazing rod . The factory manual gives 75A for the no-load starter current but doesn't break out how much of that the solenoid coil draws. -jsw
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Mostly just giving you a reminder but yeah, it's easier said than done, especially if you don't have a helper.

480 watts give or take, were it your lucky day, you'd have heard something sizzling.

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message wrote in message ...

Another experience-conditioned reflex is not touching bare electrical connections without stopping to think. Other than home stuff the last live vehicle battery I worked on was for a 300V electric car. -jsw
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wrote in message

That's what the helper is for....
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wrote in message

That's what the helper is for....
===============================My potential helper came over looking for some replacement stainless nuts while I had the terminals off the battery, leaned on the fender and nearly shorted the exposed posts with the Vise-Grips he was holding to tighten the nuts. I often have to start small engines for him. He definitely has his skills but they don't include machinery, electricity or plumbing.
He volunteered to help reshingle my roof and taught me how to handle the Bituthene and keep the rows straight and the spacing even.
Especially with electricity the less I have to explain the more I get done. -jsw
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    Without the high current, get a voltmeter and stab one probe into the battery terminal and the other into the terminal clamp. If you get *any* deflection of the needle (or reading on the LCD display) that means a poor connection through the terminal/clamp interface.
    I've been known to get people home by putting a large wood screw between the terminal and the clamp at the split. That bites well enough to get them home (or to a place which will clean/fix it) without needing to call a tow truck.

    :-)
    Enjoy,         DoN.
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The stainless steel pocket knife I carry isn't harmed by scraping the terminals clean or prying open the vent caps. It doesn't hold much of an edge, but the triangular needle file in the tool kit will temporarily let it saw through thick nylon rope.

11.5V from the (+) terminal clamp to a ground screw on the inner fender was misleading. It showed the battery was capable of supplying current and the (rebuilt by me) starter was drawing some but not enough. The dash lights dimmed only a little. The first thing I did was recharge the battery. The automatic charger shut off within a few minutes, ruling out an alternator (also rebuilt) problem.
I've described only the symptoms visible from the engine compartment and cab, mostly as voltage, to add to the list of things to check beside the road. I don't expect most people to have a DC clamp-on ammeter probe for their DVMs.
The problem was obvious when I crawled underneath and clipped a longer meter lead to the starter solenoid terminal. The voltage on the heavy cable from the battery dropped from 12.5V to 0.2V when I turned the key. Hmmm!
-jsw
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