[Scarebird]

Both sides of my 8.5" out of a 71 Cutlass have around 60 thou movement in/out - I am thinking this is not normal. Should be the same as the 8.2".

I am wondering if the seal is crushing here and why?

[JLMounce]

It's not entirely apples to apples, but my Moser 12 bolt with bolt in axles have virtually zero endplay.

[Scarebird]

That is my thought too - this is the RH axle stack

['ol Pinion head]

The pic you have from SuperCars Unlimited shows an original tapered axle bearing which was originally used on late '69 Firebird & '70 Pontiac 8.2 axles, had as well as numerous '70 Olds type "0" axles. There also was a '70 type "O" Olds A-body housing that used the larger diam (A10) sized tapered axle bearing.

On original '71-72 8.5 A-body axles, most used the same exact style tapered axle bearing as in the first two pics. Note the parallel black lines. This style was mfg by GM's Hyatt bearing division. Having bought thousands of $ of A9 & A10 axle bearings since the early 90's, I've never ran across any like the first style from BCA-Bower (now National), Timken, F#G, etc.

The last pic shows a typical A9 style tapered axle bearing with the cone that can "pop off" if one is not careful in handling. The tapered bearing not being intact with the integral race is where you are getting the .060 slop. Over the years, have dealt with a few cone popping off, this was after banging a few loose axles around. Another issue, in a hurry, when pressing on a new A9 or A10 axle bearing, one should carefully creep up on the bearing to seat when pressing the bearing on. Then, press the machined steel lock collar on separately. Getting carried away with several strokes to manyon the press will also pop the cone style race off. That race is supposed to be an integral part of the bearing, not a separate cone. When I've had the rare instance of a cone popping off of a A9 axle bearing, I've just ate the cost of a new axle bearing & carefully installed another new A9 axle bearing. In the early years, I used to occasionally sell axles or set up a '73-77 A-body rear up for the factory stock circle trackers, & they seemed have a high incidence of banging their rear tire/wheels to other race cars, & have a higher amount of A9 bearings that the race had popped off.

One thing you will find out is unlike their predecessors the junk RW507C sealed axle bearings, very very seldom does a tapered axle bearing wear out. I've run across a bunch of original A9 axle rears that had just occasional 80/90 gear oil changes, had over 300k miles on them, & wlth no wear to the original A9 axle bearings. Have also reused quite a few smooth spinning A9 axle bearings.

[Scarebird]

Looking at this it is a piss poor design. Taper roller bearings do not do well when that loose. I will measure the slop on either side and make some shims for a temporary fix.

A long tern fix would be this:




The seal would be mover to the outside of the retainer plate, held in by a carrier/spacer that is clamped into position by a thicker retainer plate and sealed by an O-ring. This way the bearing will be loaded correctly regardless if the bearing case comes apart.

[gtobob67]

I bet you have the wrong seal on there. The 71426 original Timken seal measured .490. Most all seals now including the 71426 number measure way less. Why, who knows. It's discussed quite a bit on the Buick Forums. I have the 8.5 out of a 72 skylark in my 67 GTO and ran into this exact problem. Found original style roller bearings, not the tapered A9, and original seals. My axle play went to 0 on the driver side and .020 on passenger side. Here are 2 examples of the correct parts. Seals have several correct GM part numbers as do the bearings. You can cross reference the part numbers on the internet and find the others. If you try this, wait to install the locking ring on the axle until after you check end play.


https://www.ebay.com/itm/124012429389
https://www.ebay.com/itm/195421463795

[gtobob67]

Just checked my notes and my axle endplay is .010 not .020. The factory spec for endplay is .018

[Scarebird]

That makes sense; I was mulling this last night and that possibility came up.

I will measure the seal depth when I get tot the shop and see. The crappy thing is I will need to wreck the bearings to change the seal.

[Singleton]

Put a .060" shim behind the bearing race in the axle tube?

[gtobob67]

Here's a picture of an original bearing instruction sheet I have showing the correct bearing is a cylindrical roller and not a tapered roller bearing. Tapered rollers do not like endplay whereas cylindrical bearings can live with a bit.

[Scarebird]

Originally Posted by gtobob67

Here's a picture of an original bearing instruction sheet I have showing the correct bearing is a cylindrical roller and not a tapered roller bearing. Tapered rollers do not like endplay whereas cylindrical bearings can live with a bit.

No, they don't at all. That is C-clip axle ground.

Originally Posted by Singleton

Put a .060" shim behind the bearing race in the axle tube?

That may be the interim solution, especially if the end play is the same and both seals are undersized.

Originally Posted by gtobob67

I bet you have the wrong seal on there. The 71426 original Timken seal measured .490.

My seal measures 0.375"

[Scarebird]

Dial indicator shows 0.106" runout, confirming gtobob's thesis.

Making brake stuff, my shop has all sorts of non-standard items laying about. One of them are A5 bearing shims, which are the correct outer diameter and thickness I need to shim out the race per Singleton.

Now I need to see if I can pluck out the races without leaving a trail of blood, guts and feathers...

[Scarebird]

Conclusion:

The bearing races would require welding a bead on to the race itself to remove like I had to do last time - there is almost nothing to grab on the inside to pull them out. I thought then of grinding a pair of removal grooves in the housing like some hubs have, but since the chunk was in this was a no-go.



What I did was take the shims I had, opened up the inner diameter 0.040" in a lathe to fit the ledge of the seal, then cut them in half and "glued" them to the seal and carefully tightened down the retainer. 0.002" play max now.



Thanks to all that helped! I still have a few of the spacers left if somebody else has this issue.

[Richie Hoffman]

There are 2 different thickness seals

[Scarebird]

This is what I found:

SKF 16404, NAPA NOS 16404 M and P axles (?)

Width (IN) 0.5
Shaft (IN) 1.618
Outer Diameter (IN) 2.579




BCA NS2146

Housing Bore (IN) 2.560
Shaft (IN) 1.687
Width (IN) 0.375



SKF 16735, NAPA NOS16735 B and O axles

Outer Diameter (IN) 2.556
Width (IN) 0.47
Shaft (IN) 1.688



TIMKEN 712146 8.5" ring gear

Outer Dia (IN) 2.562
Seal Width (IN) 0.470
Shaft Size (IN) 1.688



NATIONAL 2146

Housing Bore (Inch) 2.560
Inside Diameter 1.687 in.
Width (IN) 0.375




As you see there is one outlier (M or P axle = 12 bolt?). Other than that there are 2 heights, 0.375" and 0.470".

Earlier 8.2" BOP axles are smaller, so it is not that - nor is it later C-clip axles...