• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

8 3/4 tapered axle center section question.

Wtrfwl havoc

Well-Known Member
Local time
9:35 PM
Joined
Aug 5, 2019
Messages
69
Reaction score
36
Location
Kansas
I have kinda searched around and not got my question answered. So thought I would ask here. I have a 8 3/4 tapered axled. I came across a good deal on a set up 489 case with sure track. I am going to be rebuilding the whole axle. My plan is to use the green bearing axle kit from Dr diff. All the stuff I read says a newer center section won't fit in 64 or earlier tapered axled different thrust blocks. If I go to the green bearing axles I would be able to use a newer center section correct? Haven't messed with 8 3/4 a lot so kinda green on them. Thanks
 
if you're using the green bearings , just use regular axles of the right length and brake drums to match.
 
It's a easy swap to the newer flanged axels. Dr Diff has what you need except for the newer backing plates and drums. Who knows, he might even have a source for them. If you're sticking with a 10"x 2.5" drum you need the newer backing plate (1965 and newer) for the 10"x 2.5". The shoes and drums can be bought from NAPA or such parts houses.

20170726_184521-jpg-jpg.jpg

20170809_195959-jpg-jpg.jpg


Here's how it's done...
https://www.forbbodiesonly.com/mopa...p-new-residence.114133/page-11#post-910731376
 
The axle housings are different!!!

Do they now sell green bearings to fit a tapered axle?

The axle shafts are different lengths by 1/8” each side from and open to a sure grip In a 1964 and older tapered axle. That is because the thrust block is a different width for an open (1 1/4” wide) than a sure grip (1 1/2” wide).

Green bearings will not change this fact or remedy the problem. You cannot use axles from a non tapered axle in a housing from a tapered axle. Every part is different on the Tapered axle, axle shafts, brake backing plates, housing ends, and bearing adjustment.

The thrust block is insid the differential. The axle shafts butt up against it. Changing axles and type of bearing will not save you.
 
Last edited:
Axle length is only different ‘63 and before with non-sure grip. Sure grip and everything ‘64 and later can use the old axles.
 
Do they now sell green bearings to fit a tapered axle?

The axle shafts are different lengths by 1/8” each side from and open to a sure grip In a 1964 and older tapered axle. That is because the thrust block is a different width for an open (1 1/4” wide) than a sure grip (1 1/2” wide).

Green bearings will not change this fact or remedy the problem.you cannot use axles from a non tapered axle in a tapered axle. Every part is different on the Tapered axle, axle shafts, brake backing plates, housing ends, and bearing adjustment.

The thrust block is insid the differential. The axle shafts butt up against it. Changing axles and type of bearing will not save you.

I am not just talking about doing just axles and bearings. I am swapping the center section to a newer 489 section. I am assuming I can order the axles and green bearings accordingly?
 
The axle housings are different!!!

Do they now sell green bearings to fit a tapered axle?

The axle shafts are different lengths by 1/8” each side from and open to a sure grip In a 1964 and older tapered axle. That is because the thrust block is a different width for an open (1 1/4” wide) than a sure grip (1 1/2” wide).

Green bearings will not change this fact or remedy the problem. You cannot use axles from a non tapered axle in a housing from a tapered axle. Every part is different on the Tapered axle, axle shafts, brake backing plates, housing ends, and bearing adjustment.

The thrust block is insid the differential. The axle shafts butt up against it. Changing axles and type of bearing will not save you.

Dr.Diff aka Cass has flanged axels to replace the taypered axels. They have Green bearings on them so end play adjustments are not necessary. He suggest removing the thrust buttons if your suregrip still has them. The thrust block stays. Newer backing plates are needed along with matching pull off drums. (Read my post)

20170729_102915.jpg
 
One of the first changes I made when getting my '63 Fury was to swap out the entire rear end with a '65 Coronet rear and '64 Plymouth sure grip 3:23 to drop the tapered axles. When I changed the gearing to 3:55, a knowledgeable car buddy suggested going to green bearings and did this; but wasn't on my radar to do. I'm on my 2nd set of green's now after barely a 1000 miles on the 1st set. If they go to chit again I'll be posting a WTB for an adjuster plate and go back to the OEM bearings.
 
It's a easy swap to the newer flanged axels. Dr Diff has what you need except for the newer backing plates and drums. Who knows, he might even have a source for them. If you're sticking with a 10"x 2.5" drum you need the newer backing plate (1965 and newer) for the 10"x 2.5". The shoes and drums can be bought from NAPA or such parts houses.

View attachment 985723
View attachment 985724

Here's how it's done...
https://www.forbbodiesonly.com/mopa...p-new-residence.114133/page-11#post-910731376
Impressed with the adjuster linkage ya have. Just this week I installed new adjuster kits as the adjusters fit like crap over the star wheel...and see this is a beeitch again doing some futzing to set the plate solid against the star. Can I ask where you obtained them or is it part of the assembly you have?
 
Don’t do green bearings unless you have a particular reason to do so. The life expectancy is about 1/100 of the originals.
 
Impressed with the adjuster linkage ya have. Just this week I installed new adjuster kits as the adjusters fit like crap over the star wheel...and see this is a beeitch again doing some futzing to set the plate solid against the star. Can I ask where you obtained them or is it part of the assembly you have?

Mopar had at least three different types. Manual, Backup and hit the brakes (and for a lack of a better description) a Constant adjuster. They changed throughout the years so the newer the model you order parts for you'll get that year self adjuster. What years these changes were made I'm not exactly sure. I'm thinking the adjusters on mine were 1978 van. 10 x 2 1/2 drums
 
Here comes the Negative Nancys on the Green Bearings :eek:

They had a bad batch years ago. They are fine now.
 
Mopar had at least three different types. Manual, Backup and hit the brakes (and for a lack of a better description) a Constant adjuster. They changed throughout the years so the newer the model you order parts for you'll get that year self adjuster. What years these changes were made I'm not exactly sure. I'm thinking the adjusters on mine were 1978 van. 10 x 2 1/2 drums
Good to know, thanks - had I known this about 4 days ago this is what I'd have ordered; but the kits didn't cost much so may order what you mentioned.
 
Here comes the Negative Nancys on the Green Bearings :eek:

They had a bad batch years ago. They are fine now.
Negative Nancy's lol. I had chatted with Dr. Diff on this after my 1st set went sour and he mentioned this so hope my 2nd set will last...hell it takes me 5 years to drive my old ride 5,000 miles and at my age could be about enough.
 
If your 489 housing has a factory sure grip with the thrust spacer, then you can use your original axles and bearings. If your car came with a sure grip then the axles will bolt in like stock. If your car came with an open diff, then the axles will have to be shortened by 1/8" each and then installed like stock. I would mock it up to check that 1/8" dimension, or measure the thrust blocks in the original,and the new center section. If the original is shorter, then shorten each axle half of the difference.
 
Here is what happened to my green bearings after just 200 miles. The grease all leaked out from the seals. I junked them and went back to original tapered bearings. Its not that difficult to get the endplay adjustment done with tapered bearings, actually its rather simple.
20160920_165755.jpg
 
Negative Nancy’s in this case include a large population of people who have had them fail and mechanical engineers who design stuff with bearings and know the B10 life of this ball bearing in the application is Probably an order of magnitude shorter than the factory roller.

If you’re making rolling element bearings post 1935 and you have a “bad batch” you don’t care or don’t know what you’re doing. Most likely these failures drop right into the normal distribution. It’s also possible that these bearings do or have at a time come from China and no, they don’t know what they are doing.

If someone can give me the part number of the green bearings (real one, etched on the bearing itself) I’d love to do the calculation. The rollers are a Timken M201047. Maybe I’m wrong. It would be interesting to do the actual calcs for expected life.
 
Last edited:
Negative Nancy’s in this case include a large population of people who have had them fail and mechanical engineers who design stuff with bearings and know the B10 life of this ball bearing in the application is Probably an order of magnitude shorter than the factory roller.

If you’re making rolling element bearings post 1935 and you have a “bad batch” you don’t care or don’t know what you’re doing. Most likely these failures drop right into the normal distribution. It’s also possible that these bearings do or have at a time come from China and no, they don’t know what they are doing.

If someone can give me the part number of the green bearings (real one, etched on the bearing itself) I’d love to do the calculation. The rollers are a Timken M201047. Maybe I’m wrong. It would be interesting to do the actual calcs for expected life.
I'M WITH YOU....
In all the discussions about Timken Tapered axle bearings vs single row radial ball bearings, aka " Green" bearings, the Green bearing proponents have not supplied the actual bearing's part number to allow for actual design load comparisons to be shown. The physical dimensions of the bearing package not withstanding are not the only consideration.
Some of the other factors involved, specifically, RPM of the bearing's rolling element, radial load, axial load (combined) at maximumload points, temperature, and lubrication.
If all previous detrimental comments about failures are related to earlier installations, WHY are there continual instances of Green bearing failures reported, like in the previous posting (#16 above), where the bearing's lubricant is being extruded? USUALLY, internal seal failure and subsequent lubricant displacement is due to the bearings AXIAL load rating is being exceeded on a continual basis as well as temperature for the lubricant, due to internal heat generated because of loads imposed.
Perhaps, another underlying question needs to be asked: WHY was the Green bearing suggested as a substitute for the Timken Tapered bearing? COST? LONGEVITY? Because my "buddy" used them?
Am I a "negative Nancy".....YES....without actual calculations presented, one type of hearing vs another, to demonstrate the capabilities of each including the B10 and L10 factors, everything is just an opinion....."my way is better than your way" comments not withstanding.
BOB RENTON
 
No one is saying that the sealed ball bearing is better than the taypered roller bearing, although the sealed ball bearing has found it's place in the hobby mainly for ease of installation and in some cases it's the only way to upgrade to newer components like changing to a flanged axel from the taypered axels on 1964 and earlier housing.

If someone can give me the part number of the green bearings (real one, etched on the bearing itself) I’d love to do the calculation. The rollers are a Timken M201047. Maybe I’m wrong. It would be interesting to do the actual calcs for expected life

Here's an explanation from Cass (Dr. Diff) on what has taken place with the bearings in question.

Unfortunately, the original Mopar Green wheel bearing design has 2 problems.

First generation (RP-400) Green bearings, still sold by Mopar Performance and others, are problematic because the crimped-on flange will not allow the bearing to wiggle around inside a housing that is not perfectly straight (none are).

In addition, the design causes the axle to be inserted DEEPER into the housing than necessary. This results in pre-loading against the differential thrust block and early bearing failure.

Second generation (MO-400) snap-ring style Green bearings are forgiving because they can move around inside the housing and they do not preload the differential thrust block in a stock application.

Most guys who have problems with Green bearings are running the RP-400 first generation version or incorrectly made aftermarket axles or housings or poorly designed rear disc brake kits, all of which cause pre-loading and premature bearing failure.


http://www.doctordiff.com/blog/tech-info/why-green-bearings/
 
Perhaps, another underlying question needs to be asked: WHY was the Green bearing suggested as a substitute for the Timken Tapered bearing? COST? LONGEVITY? Because my "buddy" used them?

Hey Bob, just answered your question in my last post. As always thanks for your input. It's how we get a better understanding on such matters. Dr. Diffs explanation has merit. He's made a lifetime career at knowing what's what in order to create a great business. Checkout his link.
 
Auto Transport Service
Back
Top