Summer Project #7: PosiTraction, Completed!

Summer Project #7: PosiTraction, Completed!

Joined: January 1st, 1970, 12:00 am

June 2nd, 2018, 7:27 am #1

Yep, another log onto the fire that is what's left of my free time this summer!

However, this one too had been planned for a while, and pretty much HAS to be done outside and while it's dry, so my window is pretty short. Back in February, I posted that I'd completed the new rear axle that I plan to swap into my Cutlass, and hoped that come summertime I could get it done.

Well, it's summertime, and regardless of my workload, our summers are way too damn short, and this one so far as proven to be cold and rainy. So I need to strike while the iron is hot.

Besides, the axle has been occupying my welding table all bloody winter, and it's been pissing me off. I have a welding table for a reason! 😁 Worse, I have some client work coming in for which I really need a clear and open weld-and-fab surface, so it's time to get the damn thing done.

Thankfully, this should be quick. Barring the inevitable rusty bolt- hey, it's Alaska!- and having to run new brake lines, virtually all of this is a bolt-on. Unbolt old rear, bolt new one in. The only fab I have to do is I still need to "box" the rear control arms, and modify them slightly to allow the rear swaybar to bolt on. Easy-peasy.

But it'd be a lot damn easier if I had a clear welding and fab table! Y'see how this all ties together? πŸ˜†

Anyway, all I've done to start so far is just clear off and sweep the concrete in front of the shop, and... well, parked the car on it. 😁



Hey, I was lucky to get that far, considering the day I'd had.

Anyway, the two reasons for this areΒ  to replace the old worn-out 40-year old drums, to exchange the wimp 10-bolt for a beefier 12-bolt, add a PosiTraction... three reasons, the three reasons to do this is to swap the brakes, upgrade to a stronger 12-bolt, add a PosiTraction, and install a rear-FOUR! The four reasons I'm doing this are to refresh the brakes, upgrade to the stronger 12-bolt axle, add a PosiTraction, and install a comfy chair rear sway bar!

Here's what we're starting with:



A 1972 "Corporate" 8.5" GM 10-bolt, with an "open" differential. Nothing to write home about, apart from the fact that, being in an Oldsmobile, it very likely has the 'bolt on' axles, and as such still apparently has some value to the occasional hotrodder.

Typical 10 and 12-bolts from this era of GM production use "C" clips to retain the axle at the center differential- if the axle breaks, the entire wheel and drum can leave the car. The "bolt on" axles retain the shaft at the brake end, so if the axle snaps, the wheel is still retained to the car. Mostly irrelevant to me, as I have no plans to race this thing, and even if I were to some day swap in a big-block (as opposed to this 130,000-mile-old smog-era small block that might have made 120 HP when it was new) it'd still be a mild big block and unlikely to snap an axle- especially with street tires.

Do I "need" it? No, not really. I could have saved a pile of money by just rebuilding the brakes on the existing axle and calling it good. 😁  But barring some unforeseen future turn of events, I plan to keep this car for a good long while, and improve it steadily as I have time and funds. Rather than racing, I want to simply try to improve its handling- to make it feel less like a worn-out forty-year-old musclecar and more like a modern car- or at least as close as a worn-out forty-year old musclecar can get. πŸ˜†

Doc.
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Joined: September 29th, 2016, 1:55 am

June 2nd, 2018, 5:54 pm #2

Cheech and Chong discussing one of your neighbors:

Cm: Oh, yeah, they were really nice people man. And so much class, man...
They had so much class, y'know. Like, give or take da way they used ta
Deliver da toys, y'know. It's, like, Santa Claus used ta have this
Really charp chort, man, y'know? It was lower to da ground, had twice-
Pipes, candy-apple red and button top. Oooo, clean!

Tc: Hey, that sounds like a hip snowmobile, man.

Cm: No, no, it wasn't a snowmobile; it was a sled, y'know. One of those big
Sleds, y'know? And he used ta have it pulled by some reindeers, y'know,
Like, reindeers?

Tc: Some what, man?

Cm: Some reindeers, y'know. He used ta hook them onto da sled, and then he
Used ta stand up inside da sled and hold on to da reins, and then call
Out their names, like, "On, Donner! On, Blitzen! On, Chewy! On, Tavo!
C'mon, Becto! " And then, the reindeers used ta take off into da sky and
Fly across da sky, man!
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Joined: January 1st, 1970, 12:00 am

June 3rd, 2018, 2:03 am #3

Yyyyeeeahhhh... let's try and keep it a bit more on-topic next time, shall we? πŸ˜‹

Anyway, here's the aforementioned welding table:



The axle has been resting there since last... September or so, as I recall, as I did the last few bits and bobs to it, which I finished up in February.

But, between basically not being able to use the table thanks to the bloody great bit of iron in the middle, and having to move... well, pretty much everything in the shop thanks to the machine dismantling-for-rebuilds, it basically got piled high with junk.

Summer, however, is here, and I have work flying at me from all corners of the globe, and more on the horizon. I have some welding-and-fabrication work coming up, both for clients and myself, and I need this table.

An hour later...



And no, I didn't just sweep it all off the table and onto the floor. 😁 Almost all of it got properly put away, and that which wasn't, is set aside as it'll be needed soon anyway.

A stout buddy helped me carry the axle over and park it behind the other project car (not mine, but which will get its own write-ups before too long) where it can be easily rolled forward and under the Cutlass when the time comes.



on excavating the table, I also found this little bracket, which I'd saved from the original setup on the 12-bolt, and then forgotten about.



That bracket goes right here, to hold the flexible line from the body.



I'd mounted the new braided-stainless line vertically, as shown, but even at the time I wasn't sure if that was correct. Turns out, of course, it wasn't. I'll need to clean up and paint the bracket and mount the end of the braided line properly- hopefully I have enough stretch in the brake lines to fit it.

Doc.
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Joined: January 1st, 1970, 12:00 am

July 2nd, 2018, 5:05 am #4

It's weird that this was one of the top projects on my list of stuff to get done this summer, and one of the only ones that has to be done outside- meaning I need to do it while the weather is clear, warm and dry.

And I still haven't touched it in a month. 😁

But hey, it's back up to the top of the list! Today, I hung the rear swaybar outside and gave it a good coat of self-etching primer, then two good coats of glossy black.



Then I dusted off my spare set of rear control arms, and set about finally "boxing" them. The factory control arm is an open U-shaped stamping, sufficient for a daily driver, but a little flexible- it twists easily- for either high horsepower or hard cornering applications.

The trick mod, then, is something the factory did for the 442s and other special models- they welded a plate across the bottom, making a full square box that is considerably more resistant to twisting.

The other mod was, in order to mount a rear sway bar to these things, they need internal supports so that tightening the bolts doesn't simply crush the stamping. There are inserts available, that duplicate the factory inset piece, and I have a set, but I wanted the arm to be a little bit better boxed than that.

So first, after consulting the internet to find out where the sway bar mounting holes were supposed to go, I located and drilled both of them. (Both arms, that is, not just both holes. Wiseass. 😁 )



Then I found a likely chunk of heavy-wall tubing in my stash-o-magic, and bandsawed off four likely looking chunks and hardly any fingers.



I then faced each one, and turned them to precisely fit into the arm...



That is, if by "precisely fit" we mean "tapped into place with a small hammer." 😁

Those collars got located more or less centered over each mounting hole, and welded into place.



I found a likely looking strip of 10-ga by 2" sheared strip, that by a pleasant little stroke of luck, was precisely the right length to cut exactly in half and have a perfect piece to cover both arms. And, of course, not being satisfied with the mundane, I got out the belt grinder- I really am just looking for excuses to use this thing, some times πŸ˜‹ -Β  and ground each end slightly concave, purely for looks. (On a piece that no one will ever see unless I wind up upside down in a ditch, in which case I doubt anyone's going to care whether or not my rear lower control arms have a pleasing little swoop to the ends. But I digress.)



And those, of course, got welded into place. Tacked first with the MIG (the old red MIG not the "new" blue MIG) and then TIGged. Why the TIG? Cleaner weld, less mess. I welded them in sections, letting it cool down between strings, as the arms had newish poly bushings already installed, and I didn't want to melt anything.



Ground sorta smoothish...



And given the standard coat of self-etch and two coats of glossy black.



Later this week, time and weather permitting, I'll back the Cutlass in and start swappin!

Doc.
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Joined: September 16th, 2014, 7:01 am

July 2nd, 2018, 8:56 am #5

"... the other Project Car (not mine)..."Β  An Avanti? The taillights just whispered "Studbuster... "
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Joined: January 1st, 1970, 12:00 am

July 3rd, 2018, 1:47 am #6

Now to spiff up the axle itself. Here she is, dusty and dirty from the winter spent covered in crap in the shop:



Scrubbed, degreased, Purple Powered and pressure washed:



A quick coat of self-etching primer...



The tubes and backing plates sprayed with two coats of gloss black...



And, of course, since a real W-27 axle has an aluminum center section, the pumpkin gets somewhat indifferently masked and given two coats of "Hammered" silver.



And done!



Keeping in mind that this is Alaska, and this is ostensibly a daily-driver. The paint is more to simply protect the axle from rust and gunk, not really to produce a "show quality" assembly. Alaska, is, point in fact, one of the worst places for a "show car"- if you only drive it on the dry, sunny, warm days, you pretty much get about six days total of drive time, scattered around a three week period between the end of June and the middle of July. 😁

And that sad part is, that's not even a joke. 😫

Anyway, I'll let that sit overnight to allow the paint to cure well, and since i'm caught up on customer work again, unless somebody shows up in the morning with another frikkin' broken hydraulic pump or something again, I'll start swappin' 'er in tomorrow!

Doc.
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Joined: April 15th, 2003, 12:28 pm

July 3rd, 2018, 2:20 pm #7

Is that top bolt a banjo for a breather tube? If so, thats pretty clever.Β 
__
Designer / maker of Jeep gauges and assorted automotive bits and baubles.
TeamADW.com
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Joined: September 12th, 2014, 3:32 am

July 3rd, 2018, 3:23 pm #8

another frikkin' broken hydraulic pump or something
... I'm pretty sure there's a story there.Β πŸ˜€

But then, that kind of mundane stuff fascinates me. most of the broken stuff I work on is either ones n zeros not doing what they are supposed to, or electronicals that won't accept magic pixie dust anymore (or have let the magic smoke out...)
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Joined: January 1st, 1970, 12:00 am

July 3rd, 2018, 7:30 pm #9

Renegade_Azzy wrote:Is that top bolt a banjo for a breather tube? If so, thats pretty clever.
-Breather? No, that's the brake line. Braided stainless flex line from the body to the center pumpkin, then split left and right to the wheel cylinders with cupro-nickel hardline and stainless steel nuts.

The actual pumpkin breather is a typical old-GM plastic vent on the passenger side of the center casting.

Doc.
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Joined: April 15th, 2003, 12:28 pm

July 3rd, 2018, 9:31 pm #10

Ah, Im more familiar with the Chrysler version, that has the brake and breather in one.Β 
__
Designer / maker of Jeep gauges and assorted automotive bits and baubles.
TeamADW.com
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