Was being a GMC an option???

[Keith Seymore]

Thanks guys -

K

[Keith Seymore]

Uh oh – now you’ve done it!! If you encourage me I’ll keep going!

So – it occurs to me that I have never, ever seen published anywhere (on the internet, or in print) WHY we have RPO codes.

I mean, you all know that we have codes to describe the options, but how does that work to control the part numbers, and which parts go on a specific vehicle?

Here’s how:

The VDS (aka “Vehicle Description Summary”) is what defines which RPOs are allowed to combine to create a vehicle. This is what says you can get a C10703 (1/2 ton shortbox pickup) but shows a 20703 (a ¾ ton shortbox) is not available, for example. This is the document that defines which engines go in which chassis, and all of the electrical options, and all the interior trim levels, etc. Every conceivable potential combination has to be captured in the VDS and either explicitly allowed or not allowed.

Remember when I said I spent my first summer at GM (back in 1979) working in the Inspection office figuring out how I would order my 1980 pickup? That’s what I was doing – poring over a hardcopy of the VDS and manually figuring out which options I could get, or not get.

The EPL (aka “Engineering Part List”) is the straight up numerical part list of every part number available for the program. Each part number has a “usage string” associated with it, telling how the part is used in great specificity. All of these codes (option codes, model codes, the VDS) allow a new specifications language to be created, a sort of detailed engineering shorthand, to create “sentences” to describe the part.

A part that is more general, say used on every vehicle (like a blank SPID label, or blank VIN tag) could be:

15516776 Label, SPID: CK000 00 QTY 1

Where the zeros are placeholders, indicating it is intended to be used on each of those permutations. 2wd vs 4wd, ½ ¾ or one ton, any wheelbase, pickup, Blazer, Suburban, Chassis Cab – it goes on all of them.

A more specific part might be:

152223545 Harness – Radio (Cassette Tape and BOSE): C100200 030616 & UM6/UM3 & UMB – WK0

Where this particular part is required on a ½ or ¾ ton 2wd vehicle, pickup, Suburban or Blazer, with a couple different radio receivers and no windshield antenna (I made all that up for this example).

Similarly, maybe there is a complementary harness that is used on the 4wd versions because it’s got more content in the harness for the transfer case and for lights in the instrument cluster:

152223456 Harness - Radio (Cassette Tape and BOSE): K100200 030616 &UM6/UM3 & UMB – WK0

So that covers the BOSE options, maybe. Now you have to do the same thing for the non BOSE:

15222347 Harness – Radio (Cassette Tape without BOSE): C100200 030616 & UM6/UM3 & WKO – UMB
15222348 Harness – Radio (Cassette Tape without BOSE): K100200 030616 & UM6/UM3 & WKO – UMB



How about a real life example? I’m looking at this brake chart for 1985. The string for front brake caliper 18008115 might look like this:

18008115 Caliper Asm FRT LH: K209 0306 & JB7/JD7 & C6P.

So ¾ ton pickup or Suburban, with either vacuum or hydroboost brakes, and 8600 lb GVW.

You have to do this for every wire harness to cover every conceivable combination. Or a brake pipe to cover every model, wheel base and brake system. A driveshaft to cover every series, 2wd and 4wd, engine, trans, wheelbase and rear axle combination.

The cross balance report I mentioned is one of the ways of verifying that ever combination is covered and that a part number exists. Each of the part numbers then has to be designed, sourced, manufactured, validated and readied to be placed lineside. That’s why it takes about 4 years of lead time to prep for a model change.

The database then runs all these combinations and spits out the information on the build sheet/build manifest. The build sheet has the boxes with the appropriate part number (or corresponding broadcast code) so that the assembly line operator knows which part to grab and install from the library of parts presented before him. All of this information resides on a “dumb” mainframe, somewhere, probably in Plano Texas. It’s been in use since the mid 1960s and is sadly out of date, but nobody wants to touch it and upgrade to more modern integrated system because it is so involved and for fear of screwing it up.



All of the above commentary is relative to production parts. I should pause for a second and talk about service:
SPID label – you all are familiar with the Service Part Identification Label. This is not used to facilitate the build, like the build sheet/build manifest, but is intended to document how the vehicle was built to enable procuring the correct service parts in the field for maintenance and repair.

Also – I think you can start to see the level of proliferation required to cover all these combinations. I want to point out that the level of proliferation for service parts might be different than those for production. For production – you want to streamline the part as much as possible. You would not give away a connector, or extra wires, where they are not going to be used because that adds vehicle mass and added pennies in piece cost per vehicle. For a million vehicles a year it starts to add up.

For service – you might not want to create, stock, package, and maintain inventory on all those part numbers. So for service you might choose to open up the release a bit and give away some content in order to cover more vehicles. These cost tradeoffs would be analyzed and direction determined by the Program Team, a cross functional team with all the disciplines represented (Program Management, Engineering, Marketing, Service, Containerization, Logistics).

So – how does all this get managed?

The official document is called an ECA (“Engineering Change Authorization”) or, in later years, and EWO (“Engineering Work Order”). This is the document that gets written, passed to all the various interested parties, releases and controls the parts, and drives the work.

Each engineer would have a "cheat sheet" of their part numbers and applications. When I had the air induction system I had about a dozen part numbers (air cleaners for 7 engines, and the associated duct work) so I just about had them memorized. If you were the brake guy, or the radiator guy, or the propshaft guy, you might have a more formal matrix like the brake chart shown above that you would reference as you wrote your initial release work order.

Here is a copy of the ECA that canceled the GTO option at the end of the 1974 model year, just to give you some flavor:



These were hardcopy paper forms, typed on a type writer in my day, and inter-office mailed (or physically hand carried, in order to expedite) to each signer on the distribution list. I remember one time I was driving through Pontiac and saw my Chief Engineer having a cigarette in the McDonalds parking lot at Woodward and South Boulevard. I stopped and had him sign a work order while he was (somewhat) available. He was a good guy. (I’ve got a couple stories about him, too).

K

[sloGMC]

Thanks for all of that Keith.
I have spent some time trying to decode build sheets, particularly my own '71. Some of it is fairly straight forward (the engine code on a build sheet is actually stamped on the engine), other boxes are a bit more cryptic. You used the term "brake pipe", and that's one that I'm not familiar with but does show up on the build sheet. What exactly does that phrase refer to?

[Steeveedee]

Originally Posted by Keith Seymore

So you could have it painted in a color not normally available. If you owned your own company and wanted to paint it Petty blue, or whatever.

Back in the day - the mass production body work on a Corvette was so bad that you could not order a black car from the factory.

You could, then, get a primered car and have the prep work done and painted black after the fact.

K

Yeah, that makes sense. Still, the steel cars are going to have to get blown pretty far apart to get a decent paint job. They didn't a nice galv dip in those days, did they?

[Keith Seymore]

Originally Posted by Steeveedee

Yeah, that makes sense. Still, the steel cars are going to have to get blown pretty far apart to get a decent paint job. They didn't a nice galv dip in those days, did they?

They did, starting in the late 70's.

It was called ELPO and was electrically applied. The current passed through the carrier and into the body sheetmetal, opening the "pores" of the metal. After the body was submerged in the tank the current was cut off, thereby closing the pores and trapping the paint.

You could rinse the body off with water to clear the excess as soon as it came out of the dip tank.

K

[Keith Seymore]

Originally Posted by sloGMC

Thanks for all of that Keith.
I have spent some time trying to decode build sheets, particularly my own '71. Some of it is fairly straight forward (the engine code on a build sheet is actually stamped on the engine), other boxes are a bit more cryptic. You used the term "brake pipe", and that's one that I'm not familiar with but does show up on the build sheet. What exactly does that phrase refer to?

That's the hard, pre-bent metal brake line (as opposed to the flexible rubber hose).

You'd need one to cover each combination, so it would have an assigned part number and/corresponding broadcast code. In other words, pipe number 12345678 might be called out by the last digits of the part number ("678", or "78") in the Brake Pipe box of the build sheet, or the broadcast code ("BP" or whatever). There would be a small paper tag on the brake pipe that would have this same information. Some original vehicles, or highly restored vehicles, still have these tags hanging off springs, shocks, brake lines, and such.

The operator would pick the appropriate brake pipe off the rack and often would create a "bundle" consisting of other lines (fuel line, return line, vent line) by installing them all in the clips and feeding them down the frame rail all at once, usually while the frame was still upside down on the chassis line.

K

[Keith Seymore]

See the Radiator callout on my build sheet (second row from the bottom, RH side) = "TT"?

Here's what it looks like in the car.

The actual up assembly full part number (3003154) for '65 Tripower and/or HD cooling (both manual and auto trans).

"154TT" is stenciled on the tank.

[Keith Seymore]

My car was built in Pontiac Michigan.

Here's how they did it in Kansas City:

[sloGMC]

Originally Posted by Keith Seymore

That's the hard, pre-bent metal brake line (as opposed to the flexible rubber hose)

Aha! Pipe = tube, that makes sense. So there's probably a different code for longbed, shortbed, C10 or 20/30, leaf or spring, H052 or Dana, and maybe even power brakes or not..? Or maybe it's just the brake line running down the frame rail, and the rear-ends were already plumbed.

[Steeveedee]

That was my job on the line in '70- installing the brake lines on the diff. Remove 2 screws, put on the clips, reinstall the two screws. install left and right lines to banjo fitting and wheel cylinders. You get 60 seconds. And you better get the lines tight, because if they aren't, the next operation bleeds the brakes, and those guys get annoyed when they are sprayed with brake fluid. That machine does a hydro test to 3000 (I think) psi. That was a long time ago.

[Keith Seymore]

Originally Posted by sloGMC

Aha! Pipe = tube, that makes sense. So there's probably a different code for longbed, shortbed, C10 or 20/30, leaf or spring, H052 or Dana, and maybe even power brakes or not..? Or maybe it's just the brake line running down the frame rail,

Yep (not code, but yes - a different part number for each).

Originally Posted by sloGMC

and the rear-ends were already plumbed.

.

Not in our case. Complete rear axle assemblies (from drum to drum, with fluid in them) were received in racks and sent to the "axle bay". That was a remote area in the plant where the correct axle was chosen, per the build manifest, and hung on the line to be trimmed out. The hard brake line was added, the soft hose installed, correct shocks installed. The correct prop shaft (or shafts) were placed on the carrier as well.

All of this was conveyed to the main line in build order sequence.

K

[special-K]

This is all great "inside" info on the process from someone who was actually involved. But what my buddy down at the corner bar told me is ................

[72c20customcamper]

Corvettes we’re terrible at that time . My cousin bought a metallic red 1976 he complains so much about the paint GM paid us to repaint it . Brand new car stripped down to the glass . We fixed all the body lines too.

Not saying it was just a gm thing all the cars had crappy paint and body lines

[Keith Seymore]

Originally Posted by special-K

This is all great "inside" info on the process from someone who was actually involved. But what my buddy down at the corner bar told me is ................

I'm always surprised when people try to argue.

The guy I'm thinking of: he got suspended from both the Pontiac board and this forum.

[Keith Seymore]

Originally Posted by 72c20customcamper

Corvettes we’re terrible at that time . My cousin bought a metallic red 1976 he complains so much about the paint GM paid us to repaint it . Brand new car stripped down to the glass . We fixed all the body lines too.

Not saying it was just a gm thing all the cars had crappy paint and body lines

My GTO has the worst paint job I have ever seen to come out of Pontiac or maybe even anywhere.

That doesn't even mention hairs in the paint, carpet cut too short, seat trim sticking out from behind the chrome, headliner cut too short, or the screw shot through the main wiring harness which shorts the whole car out when you turn on the high beams.

K

[72c20customcamper]

Originally Posted by Keith Seymore

My GTO has the worst paint job I have ever seen to come out of Pontiac or maybe even anywhere.

That doesn't even mention hairs in the paint, carpet cut too short, seat trim sticking out from behind the chrome, headliner cut too short, or the screw shot through the main wiring harness which shorts the whole car out when you turn on the high beams.

K

Well they were all bad . My 64 Hawk has a run on the lower rear 1/4 panel and one on the roof sail piece . Judge at Hershey said I should talk to the guy who painted it . Said “ I highly doubt the man is alive he painted it on the Studebaker line!” Guy then looked at it real close and read the little sign I had on it . Like you my dad bought it new and as of today it has just a tad over 30k miles . It’s factory original down to the carpet

['68OrangeSunshine]

Nice Studebaker, Mark. I almost thought it was a Mercedes with that Grille and Ringsight.
Where abouts in the Catskills are you? I was born in Tarrytown.
Brian

[72c20customcamper]

Originally Posted by '68OrangeSunshine

Nice Studebaker, Mark. I almost thought it was a Mercedes with that Grille and Ringsight.
Where abouts in the Catskills are you? I was born in Tarrytown.
Brian

Just outside of ellenville last road in Ulster county near the Rondout reservoir. I grew up in Thornwood and settled in Pleasantville NY . I worked at a body shop in Tarrytown for a few years . Buddy worked at the GM plant in Tarrytown

Studebaker was the importer of Mercedes in the late 50s early 60s . My uncle that owned a Studebaker dealership refused to sell them after a year or two. Way to many warranty repairs and he said MB would try every thing they could to not pay the dealer . After Studebaker he became went AMC . He even had Honda for a very short time .

['68OrangeSunshine]

My Grandfather liked Studebakers and Packards. He worked for IH in Chicago.
I was born in Tarrytown, but we moved to the Bronx. Then we moved to Chicago when I was three. Just before turning 17, we moved to LA. And when I was 21, the parents moved to Tucson. I followed. So I don't know New York much at all.
My Dad gave me the family '61 Mercedes 190B to go to college. Loved it to death. Parts were expensive. A real Driver's Car, though. It blew up on me after a couple years of college kid abuse, and I bought a '68 C/10 Stepside.
Still have the truck, and was out in it yesterday.