66 Differential Diagnostic Help Wanted
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Re: 66 Differential Diagnostic Help Wanted
Gary and Michael,
Thanks for the input. While I won't drive the car back and forth to work I feel that a few hundred miles of weekend driving, based on what I've learned in this thread, should be fine. I will keep a close eye on the diff to be sure there is no damage done to the case. Pulling the rear apart in January or February is what I'm shooting for since those are good months to lay up the car. I will definitely continue this thread when that happens as I value the expertise I find here.
I am also curious if the noises I was hearing were due to the differential oil needing to be changes. I will report back after more miles.
Thanks all, now I can enjoy a bit more of this weather without too much worry. My Vette turned 50 this year and I'm planning on taking it up to Mystic Connecticut to the address of the dealership where it was delivered. A beautiful area on the water, now condo or something, but it will be fun to say "net displacement = 0" for that instance. It's and easy ride from Long Island especially since most of it is on a ferry.- Top
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Re: 66 Differential Diagnostic Help Wanted
John
There is a nice vette show in Mystic on Oct 2 this year. If the weather is good I plan on being there with my 72. Nice time and area.
- Top
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Re: 66 Differential Diagnostic Help Wanted
Gary and Michael,
Thanks for the input. While I won't drive the car back and forth to work I feel that a few hundred miles of weekend driving, based on what I've learned in this thread, should be fine. I will keep a close eye on the diff to be sure there is no damage done to the case. Pulling the rear apart in January or February is what I'm shooting for since those are good months to lay up the car. I will definitely continue this thread when that happens as I value the expertise I find here.
I am also curious if the noises I was hearing were due to the differential oil needing to be changes. I will report back after more miles.
Thanks all, now I can enjoy a bit more of this weather without too much worry. My Vette turned 50 this year and I'm planning on taking it up to Mystic Connecticut to the address of the dealership where it was delivered. A beautiful area on the water, now condo or something, but it will be fun to say "net displacement = 0" for that instance. It's and easy ride from Long Island especially since most of it is on a ferry.
John------
I highly doubt that the noises you heard had anything, at all, to do with the differential lubricant needing to be changed. Just guessing but I'd say the most likely source of the noise is the u-joints. Unless these things are horribly bad, you can't assess their condition while installed on the car. Check to see if these u-joints have grease fittings. If they do not, they're most likely original to the car (since, when folks replace u-joints they usually do so with the greaseable type although I do not recommend that). 50 year old u-joints are not apt to be in pristine condition.
You can tell if you have bad bearings in the rear spindle by jacking up the car and "rocking" the wheel at the 9'o'clock and 3 o'clock positions. If you have more than the slightest amount of "wiggle" you likely have bad bearings.
Can you drive the car a modest number of miles before servicing even if you have all of the problems suggested by myself and others? Probably. However and while I'm not trying to scare you, if a u-joint or rear wheel bearing fails catastrophically, it can take fiberglass with it or, worse, you could lose control of the car.In Appreciation of John Hinckley- Top
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Re: 66 Differential Diagnostic Help Wanted
I've watched the video dozens of times and can't see what you're referring to. Even if such movement was there, it has nothing to do with the yoke pulling out of the diff housing.- Top
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Re: 66 Differential Diagnostic Help Wanted
Joe,
The wheels feel solid when grabbed at 9 and 3. While at Carlisle I spoke to the men at Van Steel and they told me to check the 9 and 3 for bearings and 12 and 6 for axle wear in the diff.
Regarding the u-joints I believe they may be original, or replaced by the previous owner with service replacements, though I can't say for sure. What I do remember is watching my father remove all of the what I call "cups", cleaning them and all the needle bearings (if that's what they are called) packing them with grease and reinstalling them. Memory is a funny thing... I now just recalled that when he got the car it would squeak horribly and I think he may have replaced the u-joints and then some years later we serviced them. Either way they will be looked at as per your suggestion. If I do need to replace them I plan on using as close to original as possible, without grease fittings.
Since the wheels are solid when moved from 9 and 3 I feel confident that the bearings are okay. I admit however that I've not done enough with u-joints to be able to tell their condition while they are on the car. I am driving easy and local and if I hear that sound again, the car will go in the garage and stay there until I take the rear suspension out along with the drive shaft and all the u-joints. The last thing I want to do is lose control of the car. By this time next year I will have gone through all the areas suggested in this thread. Thank you Joe, I appreciate your help.- Top
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Re: 66 Differential Diagnostic Help Wanted
John
In addition to what Joe said, if you replace the joints you want to bolt the flange to a plate or another flange to keep it from bending under load. Even with that I burn them out with an oxy-ace torch. This really works the best if you have that option. I also have a thread on DC on joint replacement if you want it. I use only spicer solid joints, they are larger then original but will fit with minor mods.
Your wife will love the Mystic show- it is in between an outdoor shopping plaza and Mystic Aquarium right off rt 95. On a nice day there are 150-200 cars there.- Top
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Re: 66 Differential Diagnostic Help Wanted
Gary,
I have an oxy-acetelene torch, but what I don't have is a decent press. I've been wanting one for a while and this may be the job that gets that tool into my garage. In fact I've been wondering what a minimum set of tools for differential and wheel bearing work looks like. I have a metal lathe but I'm just getting started with that and won't put any expensive parts on it. I'd love to get a Bridgeport machine but that's not going to happen for a while and is just a dream at this point. But I imagine a few brass drifts and decent quality pullers are in order. I've tested out the inexpensive dial indicators form Harbor freight and while they aren't built like a Starrett, they seem very accurate.
I showed my wife where the show will be... she's looking forward to it.- Top
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Re: 66 Differential Diagnostic Help Wanted
Mike------
I think what Russ is saying is that if the half shaft is attached at both ends, for the inner end to move laterally with the yoke axle, then the outer end must be moving that much, too. If attached, the only way the outer end could move laterally would be if the outer bearings had excessive clearance. That's true. Usually, to detect stub axle end play either the outer u-joint flange has to be disconnected or the half shaft has to be removed entirely. I assumed that the outer half shaft flange was disconnected before the video was taken.In Appreciation of John Hinckley- Top
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Re: 66 Differential Diagnostic Help Wanted
John
I show a lot of the tools I use in the threads on DC covering diff and TA rebuilding. A 20 ton harbor freight press is all you need. Some pipe or fence post to make tools out of. A CDI or Snap- ON 0-30 in/lb dial Torque wrench, micrometer, caliper, indicator. The cheap indicators are ok but start to stick after awhile or the springs break. I had some large Starrett indicators on my table last week for sale. Let me know if you need one.
If we meet at the Mystic show I can go over rebuilding arms and diff's for you.- Top
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Re: 66 Differential Diagnostic Help Wanted
Michael, My bad mistake. So bad I hate to admit it. I didn't pay enough attention as I was concentrating on the yoke only and thinking the video was of the opposite end of the half shaft. Sorry.- Top
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Re: 66 Differential Diagnostic Help Wanted
I can't agree Joe. What's seen in the video is the entire rear wheel assembly (including tire,wheel, spindle, bearings, spindle housing, rotor, caliper and trailing arm) rotating as an assembly into a severe positive camber position. The pivot point for this rotation is the junction between the outer end of the lower strut rod and the lower arm of the spindle housing as well as the trailing arm bushing.
On C2/C3 Corvettes, the half shaft forms the upper link of the rear suspension and is almost always under compression thereby limiting and controlling camber. The lower strut is normally under tension with the inner pivot being adjustable to set camber. If the side load on the tire is sufficient to put the half shaft into tension and the yoke is not restrained by the snap ring, then the wheel assembly is free to rotate into the severe camber position seen. This will happen irrespective of bearing condition or clearance.
If the outer half shaft flange had been disconnected, the car wouldn't have moved an inch as the half shaft transmits torque to the wheel assembly to push the car forward. Had the driver attempted such a thing, most likely the halfshaft and flange would have deflected radially allowing the rear wheel assembly to collapse inwards bringing a whole new definition to negative camber.- Top
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Re: 66 Differential Diagnostic Help Wanted
I can't agree Joe. What's seen in the video is the entire rear wheel assembly (including tire,wheel, spindle, bearings, spindle housing, rotor, caliper and trailing arm) rotating as an assembly into a severe positive camber position. The pivot point for this rotation is the junction between the outer end of the lower strut rod and the lower arm of the spindle housing as well as the trailing arm bushing.
On C2/C3 Corvettes, the half shaft forms the upper link of the rear suspension and is almost always under compression thereby limiting and controlling camber. The lower strut is normally under tension with the inner pivot being adjustable to set camber. If the side load on the tire is sufficient to put the half shaft into tension and the yoke is not restrained by the snap ring, then the wheel assembly is free to rotate into the severe camber position seen. This will happen irrespective of bearing condition or clearance.
If the outer half shaft flange had been disconnected, the car wouldn't have moved an inch as the half shaft transmits torque to the wheel assembly to push the car forward. Had the driver attempted such a thing, most likely the halfshaft and flange would have deflected radially allowing the rear wheel assembly to collapse inwards bringing a whole new definition to negative camber.
Mike-------
You must be watching a different video than the one I am seeing. In the one I see, all I can see is the inner end of the half shaft, the stub axle, a small part of the differential carrier case, and the very top of the spring.In Appreciation of John Hinckley- Top
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Re: 66 Differential Diagnostic Help Wanted
I'm referring to this one
watch carefully at 1:24 and again at 1:45 approx. You'll see the left wheel ass'y go positive camber as the yoke is pulled out of the diff. housing. Gary made an excellent observation of the tire coming close to snagging the spring bolt.- Top
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