CRG Discussion Forum
Camaro Research Group Discussion => Originality => Topic started by: My68SS on July 13, 2011, 12:53:46 PM
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I thought this topic worthy of it's own research thread as there seems to be very little info on plastic pin injection and the 1st gen Camaro.
At first I wasn't sure about my drive shaft, but after 'Big Iron' Bob mentioned that he has a known original 68 BB/TH400 shaft [he bought the car new] with the same plastic injection, I suddenly have lots of questions surrounding the topic.
All the pics that others have contributed so far in the driveshaft thread http://www.camaros.org/forum/index.php?topic=7861.0 (http://www.camaros.org/forum/index.php?topic=7861.0) are all sb shafts with outboard snap rings.
So, when did GM use plastic injection and was there some design criteria that required it, or was it purely economics?
If economics, why [seemingly] only BB's?
And then:
Was it only BB/TH400 cars?
Was it all 1st gen BB's
Research I've done so far suggests that ony GM did this and it's not just a 'pin' of plastic, but that there is a groove in the trunnion caps and matching grooves in the yokes. Plastic is then injected through the holes to fill the grooves.
It seems they are quite tough to get apart. The common removal method I've seen so far is to heat the yoke with a propane torch to melt the plastic as per this youtube video http://www.youtube.com/watch?v=YZZUjzNCPF0 (http://www.youtube.com/watch?v=YZZUjzNCPF0) which seems a bit harsh!
This site http://arrc.epnet.com/autoapp/8844/8844R07_U_JOINT_REPLACEMEN1.htm (http://arrc.epnet.com/autoapp/8844/8844R07_U_JOINT_REPLACEMEN1.htm) shows using a cross press arm pressing onto the spider [fig 4.] to sheer out one side at a time.
This not only avoids heating anything, but would maintain an aspect of originality as the 'pins' are left intact :)
All input warmly appreciated :)
A couple of pics of what mine looks like
(http://members.iinet.net.au/~dream/images/crg/injected%20pin%201s.jpg)
(http://members.iinet.net.au/~dream/images/crg/injected%20pin%202s.jpg)
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Research I've done so far suggests that ony GM did this and it's not just a 'pin' of plastic, but that there is a groove in the trunnion caps and matching grooves in the yokes. Plastic is then injected through the holes to fill the grooves.
It seems they are quite tough to get apart. The common removal method I've seen so far is to heat the yoke with a propane torch to melt the plastic as per this youtube video http://www.youtube.com/watch?v=YZZUjzNCPF0 (http://www.youtube.com/watch?v=YZZUjzNCPF0) which seems a bit harsh!
This site http://arrc.epnet.com/autoapp/8844/8844R07_U_JOINT_REPLACEMEN1.htm (http://arrc.epnet.com/autoapp/8844/8844R07_U_JOINT_REPLACEMEN1.htm) shows using a cross press arm pressing onto the spider [fig 4.] to sheer out one side at a time.
This not only avoids heating anything, but would maintain an aspect of originality as the 'pins' are left intact
Removal and replacement of the plastic-injected U-joints is covered in great detail with photos in the 1967 Chassis Service Manual on pages 4-40 and 4-41.
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Yes, there were two types of drive shafts used in 1968 for Turbo 400 cars. The first design used the Saginaw drive shaft as shown in your pictures. The second design used the Dana drive shaft which utilized the clips (and shown in the driveshaft thread you referenced above).
Ed
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Cheers John, that's one book I don't have as yet. Does it describe a method of pressing the old joint apart?
Ed, I take it from what you say that sometime during the production of the 68 model, there was a switch from injected saginaws to clipped dana's?
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Ed, I take it from what you say that sometime during the production of the 68 model, there was a switch from injected saginaws to clipped dana's?
I'm not sure if it was a "new" design or just two different suppliers. The P&A just says "1st design" and "2nd design". What's the date of your car? We may have to do more research on this.
Ed
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My build is 12C.
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Do you happen to know what 'Big Iron' Bob's build date is?
Ed
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Do you happen to know what 'Big Iron' Bob's build date is?
Ed
Funny you should mention that, I just pm'ed him to drop by with that info :)
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My 05C 69 BB/auto had clips in the universal.
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Cheers John, that's one book I don't have as yet. Does it describe a method of pressing the old joint apart?
Yup - essentially, just press all four until the injected nylon shears, and throw the caps away; the Service kit includes new caps and steel snap rings that go in grooves on the inboard end of the replacement caps.
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The 1969 396/TH400 driveshaft I mentioned in that thread had the clips.
I have a 1968 TH400 driveshaft in the garage from a Firebird, and it has clips.
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Going by the P&A, all 67 Turbo 400's came with the Saginaw drive shaft (nylon injection), and all 69 Turbo 400's came with the Dana drive shaft (clips). Only the 68 Turbo 400 had two versions. Go figure!
Ed
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Going by the P&A, all 67 Turbo 400's came with the Saginaw drive shaft (nylon injection), and all 69 Turbo 400's came with the Dana drive shaft (clips). Only the 68 Turbo 400 had two versions. Go figure!
Ed
Ok, so this suggests a change in design/supplier during the 68 model rather than two different suppliers.
I take it that all non-T400 67 - 69 shafts were dana's?
If that's the case, then it would also suggest that inititally, only saginaw were tooled up to make the longer yokes for the T400 and sometime during the 68 model, dana tooled up to make the yokes as well?
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I was just steam cleaning under a 68 SS 396 I have. T400 car, Still has the injected ujoints...02E car
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Thanks Charley for another data point and the great pics of the color bands!! :)
I also note the green on the trans yoke of which there is a hint of that on mine too.
So far we have:
68 models
12C - pins
02E - pins
69 models
05C - clips
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Funny that my car still has it's ujoints since it has a 427 and traction bars..
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Yeah they're a pretty tuff shaft! I've asked my motor to exercise some authority at times 8)
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Charley, if you have not done it already could you please check the length of your driveshaft from center of one u joint to the center of the other and post it here? http://www.camaros.org/forum/index.php?topic=7861.0
Is the rear axle original and it looks like it uses bolts and straps, correct? I was thinking that was 69 only but I could be wrong.
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Ron.
My 69 P@A shows that the plastic injected 1330 series u-joint was only used in 67-68 w/T 400 and the driveshaft pinion flange used straps.
The 69 used 1300 series u-joints with straps. The 67-68 used 1300 series but used u-bolts.
I have no idea why GM used the heavier 1330 series u-joints in the 67-68 TH 400 and not in the 4spd.
The 69 P@A also shows that sometime in 68 there was a second TH 400 designed driveshaft with lock rings. I may dispute this as I ordered my 68 in late July and received it in Aug.
I am trying to get the build date of my 68 but that is another very sad story.
If anyone has different or additional info. on this subject , chime in.
Bob
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Do you happen to know what 'Big Iron' Bob's build date is?
Ed
Ed,
Update. I found this old thread and believe I can give closure to it.
I ordered my 68 RS/SS 396 in middle to late June 1968, took delivery in the middle of July. I do not have the build date ( that is another sad story ) but should be around end of June or early July. When I ordered it I was told that I just made the closing date for factory orders.
I believe all 1968 Camaro T400 drive shafts where built with plastic injected ujoints.
Bob