1971 halfshaft markings

[Jeremy D.]

1971 LT-1 2-7-08 001.jpg

1971 LT-1 2-7-08 027.jpg


Can anybody tell me, if these pictures actually become VISUAL, what these markings on my '71 halfshafts are? They're green stripes in paint, not grease pencil......

[Chuck S.]

Re: 1971 halfshaft markings

...Can anybody tell me, if these pictures actually become VISUAL, what these markings on my '71 halfshafts are? They're green stripes in paint, not grease pencil......

Good grief!...It's hard to believe that those paint(?) marks survived all the environmental abuse those half shafts have suffered. Jeremy, if you're SURE it's paint, then its a "paint PEN" mark; it's too narrow and sharply defined to be applied with any kind of brush applicator, which was typical.

I hope someone here knows a specific answer to your question, but it probably meant that AN inspector checked the half shaft fasteners for proper torque, halfshafts for expected turning torque, endplay, etc. That one mark could indicate that a number of items were inspected and found satisfactory.

[Michael G.]

Re: 1971 halfshaft markings

Jeremy,
That really is amazing that those markings survived. My 71 shafts are in slightly better condition than yours but show no indication of those markings. Is that an early or late 71?
Mike

[Jeremy D.]

Re: 1971 halfshaft markings

You're right, they weren't applied with a brush...but my guess is that you're probably right. But they're actually better than the pics show....I'd just never seen them on ANY C2/3 I've been under...Early VIN, #2485.

[Chuck S.]

Re: 1971 halfshaft markings

Similar observations on my halfshafts; there was absolute no pitting. I bead blasted them, burnished them, and the surface finish was close to the day it was made...I never saw any paint or crayon marks. Based on Jeremy's photos, I would say mine never had any marks.

Once you hang around long looking for chassis marks, you will realize that types of inspection marks vary all over the map for every car. In my opinon, the only people that understood the full meaning of the marks were the people who made them; they were responsible for ensuring that a safe and reliable car left the plant...it was their way of keeping track of what they had inspected and what was not inspected. JMHO.

[Jeremy D.]

Re: 1971 halfshaft markings

Now, on the same note, my driveshaft has yellow rings, similar in thickness to my halfshafts, painted (penned) the whole diameter of the shaft; I tried getting a picture but I shot it at high res & it's too big to download. Did they somehow use those to balance the shaft at the factory?

[Tom L.]

Re: 1971 halfshaft markings

This mark was on the back of my 1970 drive shaft. There was nothing on the half shafts.

[Chuck S.]

Re: 1971 halfshaft markings

Tom, that's the alignment stripe on the differential end, correct? That one is definitely painted; it appears to have been green originally.

Jeremy, I am unclear on the purpose of the circumferential stripe pair on driveshafts. I believe they've been observed since the C2s and were applied by the driveshaft supplier. As I recall, they are not paint penned or crayoned, but are painted wider, and are more uniform that a chassis mark. There was no visible evidence of any such stripes ever existed on my 70's driveshaft...that doesn't mean they weren't there at one time.

While researching my books to see where I had seen the stripes on the driveshaft I ran across a photo in Dobbins' Fact Book of the 1968-1972 Stringray, fourth edition, page 252 that makes sense for the first time in the context of your photos showing halfshafts marked with Xs.

In that photo, Dobbins shows a "HD suspension" chassis marked with an X on the differential mounting crossmember...that X is marked above and directly adjacent to the differential universal joint. I believe an inspector checked the universal joint and made that mark, just as your half shafts are marked. I doubt the mark has anything to do with the chassis being an "HD suspension" chassis.

[Jeremy D.]

Re: 1971 halfshaft markings

I saw the Dobbins' picture as well, and I saw the similarity, but since it's a '69 and a small block (no end caps on the yokes...or had they gone to putting caps on the BB cars yet in '69?) I dismissed the mark as having a different purpose being on the frame and not on a rotating piece...but as I had more coffee and after reading your post, I think you're right. But it FLIPS MY LID that those marks are still on the halfshafts, which were at one time moving at ridiculous RPM'S!!

[Chuck S.]

Re: 1971 halfshaft markings

I saw the Dobbins' picture as well, and I saw the similarity, but since it's a '69 and a small block (no end caps on the yokes...or had they gone to putting caps on the BB cars yet in '69?) I dismissed the mark as having a different purpose being on the frame and not on a rotating piece...but as I had more coffee and after reading your post, I think you're right. But it FLIPS MY LID that those marks are still on the halfshafts, which were at one time moving at ridiculous RPM'S!!

I suppose the mark could have been for the soundness of the bolted crossmember, but the impact of a loose fastener there would not be nearly as serious as a loose u-joint.

The rotational speed of the shafts would have been nothing under more ideal conditions...the fact that the marks have resisted penetration by moisture in order to persist for nearly forty years under conditions causing all that rust and pitting is truly astounding. Thanks for showing us the pictures.

[Jeremy D.]

Re: 1971 DRIVEshaft markings...just wait..

'till you see the markings on my driveshaft look like. I'll try to get some pics up today if I can get to it.



Ok, I got to it....1971 LT-1 2-8-08-Driveshaft shots 004.jpg1971 LT-1 2-8-08-Driveshaft shots 008.jpg

Can anybody tell me if that front U-joint is the real deal? It's a Spicer, it has a number on it which I couldn't photograph, and it has "Spicer" on all the caps, including the one with the daub of paint on it.

[Michael W.]

Re: 1971 halfshaft markings

But it FLIPS MY LID that those marks are still on the halfshafts, which were at one time moving at ridiculous RPM'S!!

Keep in mind that the half shafts turn at the same speed as the wheels, which at typical highway speeds is well under 1,000 RPM. The main drive shaft turns at a much higher speed, three to four times as fast depending of differential ratio.

There was no need to balance the half shafts, only the main drive shaft as a result.

[Jeremy D.]

Re: 1971 DRIVEshaft markings

So is that what the yellow(at least I think they WERE at one time) patterns are on my driveshaft were for?

[Michael W.]

Re: 1971 halfshaft markings

The yellow or green marks are called alignment marks. I believe the driveshaft was balanced on it's own and not as part of a matched set with the yokes or universals. If so, I'm not quite sure what it's supposed to align with and why. Possibly others will have an explanation.

You should find at at least one balance weight on a driveshaft, a square or rectangular piece of stamped metal that's been spot welded within a few inches of the driveshaft end.

[John H.]

Re: 1971 halfshaft markings

The paint mark on the aft driveshaft yoke was to be aligned with a corresponding paint mark (usually blue) on the pinion yoke (as noted in the assembly manual); even the pinion yoke was individually balanced - balance weights are frequently noted there, welded to the O.D. flange on the deflector. Photo below shows a pinion yoke that still has some of the original blue alignment mark on it.