63-82 Jack & Wrench Retaining SPRINGS (plural)

[Geoff C.]

[Joe L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

AIM info:
GM part # 3785772 listed in 1963 thru 1968 manuals.
GM part # 3963108 listed in 1969 thru 1982 manuals
(Note the 1963 AIM illustrations show 1 hooks to pull on the spring. My 1964 AIM is missing that page & the 1965-1982 AIM’s all illustrate two hooks to pull on the spring.

Parts & Accessories manual info:
1938-1963 P&A as well as the 1938-1967 P&A manual agree with above AIM – use 3785772.

The 1972 P&A reprints through the last printed edition in 1982 shows the same applications:
63-68 use 3785772.
69-82 use 3963108.

OK if one hook is 3785772 & 2 hooks is 3963108 – how come the accepted consensus of 1 hook to 2 hooks is “around” 1964 but the AIM as well as part manuals are showing 1969?

Are the books: AIM & P&A 5 years behind the times of the change – but the illustrators go it right?

Or are the 1 hook & 2 hook the same part number – 3785772 with a minor difference. Please don’t insist it be a different part number – because of different hooks - because that is NOT a 100% true fact.

Blueprints may tell the tale. I don’t have these numbers.

Geoff------


I can tell you, for certain, that my 1969 was originally supplied with the "2 hook" spring. However, my 1969 was a very late build and would almost certainly be equipped with the GM #3963108. I also have an NOS 3963108 and it appears identical.

I don't have any information on the GM #3785772. By the part number, I'd say this was a part released sometime during the 1961-62 period. It's very possible that it was revised at some point without a change in part number and morphed from a "1 hook" spring to a "2 hook". If so, there may have been some other difference between the 3785722 and 3963108. It's curious that the change took place sometime early in the 1969 model year. It's also curious that the part number appears to be one that would have been issued very late in the 1969 model year. That implies that it might have been "rushed", likely to deal with some issue that arose. It's further curious that the width of the jack changed from the 1968 to 1969 model years. So, maybe the wider jack necessitated a longer spring. Perhaps that's the difference between the two part numbers.

In any event, it will be interesting to hear from some 1964-69 owners as to the configuration of their springs. This would not be an often-replaced part.

[David L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

Enclosed is one of my old photos of jack springs.

Dave

[Joe L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

Dave-----


Great. Looks like my guess that the difference between the later 3785772 and 3963108 was a longer spring length turns out to be correct.

I'll bet any use of the late 3785772 on early 1969's turned out to be problematic because of the wider jack.

[Jim S.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

The 6th Edition of the 65 Judging Guide states that '65 used single hooks until "late production" cars. (Pg.43)

[David L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

Dave-----


Great. Looks like my guess that the difference between the later 3785772 and 3963108 was a longer spring length turns out to be correct.

I'll bet any use of the late 3785772 on early 1969's turned out to be problematic because of the wider jack.

Joe,

Not only is the spring length longer on the 3963108 but the "double hook" is also a distinctly different shape.

Dave

[Loren L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

'65 #23561 has the double hook with the shorter spring as illustrated by David L.

[Jim D.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

'65 #23561 has the double hook with the shorter spring as illustrated by David L.

65's #14790 & #16786 have the single hook.

[Geoff C.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

Gentlemen,
Thank you very much. Perhaps the change from 1 to 2 hooks did not change the part number – as most would assume. That’s a fairly different change in design – perhaps it only appears as a note at the bottom on a blueprint – as an revision..
Or there is another part number not yet identified …
Thank you very much

[Gary B.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

The original jack spring on my July 20 build date '66 has the single hook.

Gary

[Joe L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

Joe,

Not only is the spring length longer on the 3963108 but the "double hook" is also a distinctly different shape.

Dave

Dave------


Below are photos of the spring from my original owner 1969. You will note that it has the "two hook" style as used on later versions of the 3785722 but the longer spring as you show in your NOS 3963108. I strongly suspect that the style hook seen on your NOS 3963108 is something that occurred to the 3963108 sometime after 1969, perhaps even after its use in PRODUCTION ended.

It will be interesting to see observations of original springs from 1970-82 if folks will take the time to check their cars.

[David L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

Joe,

I bought my NOS 3963108 in the early or mid 1980's. I guess the part number did not change because the change was insignificant.

Dave

[Joe L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

Joe,

I bought my NOS 3963108 in the early or mid 1980's. I guess the part number did not change because the change was insignificant.

Dave

Dave------

There was an even greater difference between the "one hook" used on the early 3785722 and the " two hook" used on the later 3785722 and that, apparently, did not result in a part number change.

GM has some protocol regarding when a part can be revised without a part number change. As I vaguely recall, it has something to do with functionality.

By the way, revising a part without a part number change got GM in big trouble fairly recently. This has to do with the ignition switch recall affecting a large number of GM cars from the mid 2000's. As I recall, when GM revised the switch to eliminate the problem, someone made the decision not to change the part number. That caused a huge mess.

[Patrick H.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

Dave------


Below are photos of the spring from my original owner 1969.

If that is your original spring, and not one of your NOS ones, it is in incredible condition for a part actually installed on the line, whether you ever used the jack or not.

[Joe L.]

Re: 63-82 Jack & Wrench Retaining SPRINGS (plural)

If that is your original spring, and not one of your NOS ones, it is in incredible condition for a part actually installed on the line, whether you ever used the jack or not.

Patrick------


The spring pictured is, without a doubt, the original spring and hook that was with the car the day I took delivery. I've had no reason to change it. My NOS springs are residing in the collection.

And, actually, I've had the jack out of the car many times. In fact, in the "old days" I didn't have an hydraulic jack and I used the car's jack whenever I needed to raise the car at a wheel. It got used quite a lot. Of course, I always put in back in its storage compartment when I was through with it.