Cutlass 8.5 Axles

Mike H.
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Cutlass 8.5 Axles

Postby Mike H. » Sat Jan 23, 2016 5:16 pm

Well I took my axles out of my 1972 Cutlass 8.5 posi rear end only to see one axle starting to going bad. I noticed that the axles only go into the factory posi unit about 1" with the last 1/2" about to tear out. So here are my questions:
1. Do I replace both of them?
2. Do I replace them with originals? If so, what years and models will fit?
3. Who makes a good aftermarket axel? Mostly street use with the occasional burn out.
4. Even though mine are not c-clip can I use C-clip axles? They seem an easier aftermarket find...

My current axles are non C-clip 28 spline. Any help or direction is appreciated. Thanks, Mike

IMG_0507.JPG

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monzaz
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Re: Cutlass 8.5 Axles

Postby monzaz » Sun Jan 24, 2016 11:39 am

mEASURE THE LENGTH OF THE AXLES TO THE 1/16" Just draw the tape measure from flange to spline end. See what that is first. Jim
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Re: Cutlass 8.5 Axles

Postby monzaz » Sun Jan 24, 2016 11:42 am

Mike, YOU CAN NOT use c-clip axles. No Way no how. TOTALLY different rear end housing.

What type of posi unit are you using? Need pictures.

Your going to need to open the differential cover again anyway... We need to reinstall the axles after you measure the length and see how far they go into the side gear and how close to the center cross shft the spider gears spin on.

We have axles and can have CUSTOM axles made also.
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Re: Cutlass 8.5 Axles

Postby Mike H. » Mon Jan 25, 2016 9:55 pm

Jim,
My axle length is 29-1/4" on the bearing side and 29-5/8" on the wheel side of the flange. I have included a pic of my limited slip unit as you requested. I really cannot afford custom axles so I'm hoping there is an aftermarket stock answer you can sell me. I'm wondering if the '72 Chevelle axles are the same size? I really appreciate your reponses.

Thanks again, Mike
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monzaz
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Re: Cutlass 8.5 Axles

Postby monzaz » Tue Jan 26, 2016 2:46 pm

here is what you need to do. Take a tape measure in the end of the tube and run it all the way tpo the cross shaft that runs in the center of the posi unit. Tell me the distance from that center shaft to the outside edge of the flange. Then do the other side. See how different the two measurements are. Jim

The posi you have is a factory GM Borg warmer unit. What ratio is on the posi carrier? Egde of the ring should have stamped numbers on its most outer diameter of the ring. Keep spinning till you find them.
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Re: Cutlass 8.5 Axles

Postby monzaz » Tue Jan 26, 2016 2:48 pm

29 3/4 is what we are looking for... That is stock.

I have stock axles No chevelle or any Chevy will fit the rear. You need 71 72 Cutlass or Buck skylark ONLY They were the only 2 cars in the 71 72 era that had this 10 bolt 8.5 rear with BOLT IN AXLES.
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Re: Cutlass 8.5 Axles

Postby Mike H. » Tue Jan 26, 2016 7:56 pm

Jim,
I put the round center pin back in the middle of the posi unit and measured to the flange. I came up with 27-1/4" and 27-5/16" respectively. I took the numbers off the ring gear and even counted the ring and pinion. I have a 3.08 gear set. I hope you have something to put back in this thing. Thanks for all you advice.

Mike

Measure 2.jpg
Measure 1.jpg

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Re: Cutlass 8.5 Axles

Postby monzaz » Thu Jan 28, 2016 1:20 am

ok so then the carrier seems to be centered then correct as your measurement were only 1/16" different in distance - correct?

Just can not see why the edn of the axle got mashed ... just does not make sense unless this had happened from a previous owner.

Have you looked at theses axles before?

I have used axles or NEW. Jim
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Re: Cutlass 8.5 Axles

Postby monzaz » Thu Jan 28, 2016 1:29 am

Oh an d by the way the axle engagement is totally correct. You axle shaft should stop at the end on of the spider gear and there will be a gap (NOTHING between the side gear to that center cross shaft that the little spider pinion gears rotate on. The side gear is 1/2" and the cone spline is 1/2" which is one inch.
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Re: Cutlass 8.5 Axles

Postby monzaz » Thu Jan 28, 2016 1:31 am

The only thing I can think of is the posi is going away and there is slop between the 2 pieces and it is rocking and wanting to shear the axle... You might have to tear that posi apart and see if the cones are bottomed out.

WHEN was the last time you did a burn out and laid some rubber? What were the marks looking like?
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Re: Cutlass 8.5 Axles

Postby monzaz » Thu Jan 28, 2016 1:34 am

looking at your spline on the mashed axle ...see and make sure your posi unit splines are lined up. take your good axles and slide it into the side the bad axle was in. See if it engages all the way in smoothly.
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Re: Cutlass 8.5 Axles

Postby Mike H. » Thu Jan 28, 2016 10:55 pm

Jim,
I got the posi apart. One cone surface is galled, the flat surface between the spider gear and cone looks really rough and the inside teeth of the spider gears look a bit worn. They are definitely not as sharp as the inside cone teeth.
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Re: Cutlass 8.5 Axles

Postby monzaz » Fri Jan 29, 2016 10:09 am

Well the pictures you gave are not what I need. :) Need the bottom of the cone and the spider gears ..That galling do not worry about ... That is because of dirty oil and heat and debris getting smashed in between them. More pictures...parts pictures are better when not cleaned and just as is when removed for inspection
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Re: Cutlass 8.5 Axles

Postby Mike H. » Tue Feb 02, 2016 11:36 pm

Jim,
The bottom of the cones have no wear. They look new on the ends. The spider gears are in good shape as well. My concern was the odd looking wear between the cone and side gear. There was NO washer between either set. The previous picture shows what I'm talking about. If that is not a problem I would assume the only thing that would really need replacing is both side gears. Of course, this is the first posi I've torn into so I know next to zilch. Thanks for any help you can give. Mike
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Diff 2.JPG
Diff 1.JPG
cones.jpg

Mike H.
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Re: Cutlass 8.5 Axles

Postby Mike H. » Tue Feb 02, 2016 11:37 pm

More pics....
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spider 2.JPG
spider 1.JPG
IMG_0526.jpg


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