May 24, 2015
247
136
VetteCoins
959
Car
1978 Corvette
Last summer my mom's bf took my car to his mechanic and he put it on his hoist and he told him that I need to have my rear differential yoke replaced. He told my mom's bf that my rear wheels were loose. So I put my car on jacks this weekend and I tried to see if I could move my rear wheels like the mechanic said and it wouldn't budge.

So I am wondering if he was giving me a bad diagnostic or he is has no clue how are Corvette works.

What are the symptoms to look for when the rear side yokes needs to be replaced?
 
Hi SM....
I'm not a mechanic and never played one on TV but here's a cursory test to try at home..
Jack rear wheel off the ground..
Grab tire at 12 & 6 o'clock and move tire....
Then try this at 3 & 9....
Back to 12 & 6.... While moving the tire look at the half-shafts and ascertain if the movement is in the trailing arm bearing or side yoke play in the diff. Too much in either is not good.
Of course taking it to a trained professional is recommended.
But the above procedure will give you an opportunity to keep a check on it for yourself.
Too much play in the side-axles is usually a result of end wear, within the diff.

Safety first while the car is on the jack...
Maybe have someone else move the tire while you look at the diff.
Good luck.
Graham
 
G09344477.png


Maybe he was talking about the yoke at the differential itself. I suggest you check if there is some play at the diff. where the half shaft is bolted to the diff not necessarily at the wheels. Here is the exploded view, you can clearly see the side gear yoke.
 
what usually wears is the groove that the "C" clip sits in on the half shaft yokes . if the play is under 050", don't worry about it. with out the wheels and half shafts removed it can be difficult to check the freeplay on the yokes.
 
what usually wears is the groove that the "C" clip sits in on the half shaft yokes . if the play is under 050", don't worry about it. with out the wheels and half shafts removed it can be difficult to check the freeplay on the yokes.


Is the ''C'' clip at the wheel or at the differential? Any shims can be use to fix it or do you have to replace the yoke?
 
So today I check the side yokes on while the rear wheels on and they seem to be ok. So I am not sure why the mechanic said that they needed to be replaced.. Anyway I will still remove the differential and inspect the gears and get it rebuild. I also want to clean and paint the differential to factory paint to make it look nice.
 
...I wouldn't panic yet. Your first post stated the wheels are lose. When I bought my 82 I grabbed the rear wheels up on the hoist and they were wobbling like I thought holy crap I'm glad I made it home from edmonton with it. I bought new bearings and the setup tool and set it to spec. All back together on the car and the wheels are still lose. They are not like the front wheels, the rear is made to run this way. So I did all that work for basically for a learning experience. The diff side yokes move slightly, no leaks so that part I pegged as good. I replaced all the u-joints since it was apart. Should last my lifetime I think. So if your rear wheels are tight and yoke move slightly I think I would just keep driving.
 
When my mom's boyfriend took my car for a test drive he then took the car to his mechanic friend and he told him that rear tires where loose stating it can be move from side to side..
So when I checked the car last weekend the rear tires weren't loose at all..
 
So last weekend I remove the bushings on both sides of the bottom part of the rear leaf springs. I had to cut the bolt using a electric saw since the bottom bolts was seized. Then I removed the 4 bolt with the plate that is holding the rear leaf spring and the dam thing doesn't want to come off.. I even removed the bolt at the bottom of the leaf spring and holy s**t the whole spring leaf fell to the ground. It scared the crap out of me.. Right now I cannot removed the remaining of the leaf spring off the car.. man this is hard and I will post some pictures later on today to show you where I am at,..
 
Last edited:
Here is some pictures like I mentioned. The bolt that is going thru the rear spring does it mean that it's screwed in the differential too?
 

Attachments

  • 100_2117.JPG
    100_2117.JPG
    307.5 KB · Views: 122
Sly..
There is much discussion on many forums about this issue.
Here is what may be some decent advice on the limits of play.

End play:
Less than .025 No problem
.025 - .050 Starting to wear, consider inspection
.050 - .100 Beyond normal cluth wear, possible clutch damage
and/or heavy stub axle wear. Needs attention
.100-.150 Excessive wear and/or damage. Needs immediate attention.
.150 -.200 Severe wear and case damage

Now measuring this may be a challenge...!

Graham
 
Well I am in the process of removing my differential and I noticed that my both m rear trailing arms bushings are shot so that explains why my rear yokes were loose. I just ordered a new set of rear trailing arms and I was wondering what type of bushing would be recommended to be long lasting? regular bushing or poly type?
 
I called my friend at a parts depot and told me that stock bushing will be fine. I really really started to hate this car. Every time that I think that the car only needs a few things it seems to be more and more..

So far I got a new factory leaf spring, pair of new rear leaf bushings.. new adjustable strut rods.. My differential is going to be rebuilt and I will keep the 3.70 gear ration and also going to be power coated.. The half shafts, crossmember and strut road will be powercoated.. I just spend $2000.00 alone of parts at Corvette Central..

Basically the rear end will be new..
 
Hey SLY..
I like your approach... Doing it right.
Did you get new trailing arms c/w bearing assemblies and everything?
They can be pricey but it is the proper way to go to avoid having to go back in there later.

3:70 gears are pretty stout for a four speed... Even my 3:55s rev more than most people like.
I love it myself but I'm not like most people.! (so they say!).

keep us posted.

graham
 
Thanks Graham for the message.

I have the 3 speed auto (TH350) not the four speed. The previous owner upgraded the rear end to a 3.70 but I will find out soon what is the actual gear in that rear end.

I will get a price for switch back to 3.55 but I will see what the price difference is..

Before I put everything back I will do exactly as the owner did with her car..

Juliet's 1970 Corvette Rear Suspension & Frame Restoration

While everything is out why not right?
 
Old Thread: Hello . There have been no replies in this thread for 100 days.
Content in this thread may no longer be relevant.
Perhaps it would be better to start a new thread instead.

Similar threads

Users who are viewing this thread