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Green bearing question

727

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I'm installing Green axle bearings on my 8 3/4" rear end. I have a plate type sure grip. Do I need to remove the thrust buttons from the sure grip when upgrading the axle bearings?

727
 
In or out, the block should make no difference as long as there is clearance between it and the axles.

I think you could verify the clearance by using a thin pipe, or broom stick, and measure into the thrust block with the axle out. You would need to use something smaller than the splines of the axles. Push in so the block moves over to the other side and mark it to the axle housing or something like that, for a reference. Then compare to the axle. You will likely find the axle with the greens on it is about 1/4" shorter than the area you have to work with.(clearance is a good thing!)

FWIW I just installed new axles with greens in a 8 3/4 with thrust block and no issues. I had the same concern prior to the job, about whether it would work. I was assured by mopar differential parts guru Doctor Diff from moparts, that it would work and it did.
 
If you leave the thrust block in, the axles will not seat where they should......take the thrust block out!!
 
If you remove the thrust pins just make shure to save them and the bearing retainers and adjuster lock.
 
I don't have disc brakes on the rear of my car but I'm somewhat curious about these things called "green" bearings. Has anyone pulled the seals off to see what the rolling members are - balls, rollers, double roller? As a millwright for 30 years, I'm suspicious of any high load bearing that only relies on internal lube. I also know that any roller type bearing is not meant for latitudinal thrust.You know that the lube in the bearing is specific to load, temperature and rolling resistance. Most bearings in new vehicles are packed with "low temp" grease because the manufacturer doesn't know if the car is headed for California or Alaska where temps get to -40 degrees. Ordinary all-purpose grease would go like wax at those temperatures. Has anyone removed the inner seal to allow the diff lube to provide cooling of the bearing as well as lubrication? Why not? The reason I ask is because these bearings have to handle both high radial and longitudinal thrust and the only design I know of capable of this is double taper roller bearings. Like the bearings in a front hub which has both inner and outer tapered roller bearing rather than being all in one housing. I'm not sure of the quality of these "green" bearings but I know you won't replace your front inner and outer Timken's for $60. I, and probably many others would like to see the inner workings of these bearings so we can judge just exactly what China's sending us.
 
I just won't use green bearings. Used them once. Never again. Setting pre-load with the correct bearing is NOT hard.
 
From the Dr Diff site
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Tech Info » Why Green Bearings?
Why Green Bearings?

Drawbacks of the OEM design

An OEM adjustable, Set 7 (A7) tapered wheel bearing is definitely strong but it is has a few drawbacks.

The bearing is flipped around backward, so the race is captive between it and the axle flange. This means the bearing must float in the housing end and requires an adjuster, thrust block or thrust pin. Of course, an adjuster, thrust block or thrust pin must pass through the center of the differential. A hole drilled in the cross shaft of a 4 pinion carrier creates a stress riser that is prone to breaking. A 2 pinion carrier allows the thrust block to pass around it unobstructed, but the 2 pinion design also limits the differential’s strength.

Axle spline engagement also suffers because the width of the thrust block (which must have room to slide side to side) protrudes into the splined area of the side gears. This limits spline engagement in differentials with a 2 piece cone or clutch-hub/side gear arrangement.

Beaded steel and foam gaskets don’t keep water from running into the housing end and into the non-sealed wheel bearing. Don’t forget to check your pickup’s A7 wheel bearings if you ever back a boat into the water.

Axle flange stand-out is not held constant unless you blueprint the axle lengths. Measure the axle flange stand-out on both sides of any stock 8 3/4″ rearend. Because of production tolerances, a single adjuster causes the axle flange to stick out farther on 1 side than the other.

The length of both axles, and the housing width is critically dependent on each other. Because everyone uses tape measurements to specify axle and housing lengths, making a set of axles with adjustable set 7 wheel bearings for a custom application is very hard. Axle flange standout varies greatly unless the axles are cut long, installed then blue printed to length.



The need for non-adjustable wheel bearings

Most of these problems can be avoided by installing non-adjustable sealed ball “Green” wheel bearings. The name comes from the Green Bearing Company which first produced them. The company has since been purchased by Bearing Technologies.

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.

I have several customers running MO-400 snap-ring Green bearings in daily drivers. The design is no different than what came stock in millions of other vehicles, including ’60s era Mopar 7.25″ and Ford 9″ rears. (For example, see here) I do not stock, nor do I recommend the first generation RP-400 Green bearing with the crimped-on 5 hole retainer. I only carry the “loose fit, snap ring style” second generation MO-400 design.



Products:

OEM-style Set 7 (A7) Tapered Axle Bearings

2nd Generation snap-ring style Green Bearings

Posted by Cass Eslick at 11:09 pm
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Good evening all,

I have a 73 Roadrunner, Changed for a 742 center section and rebuilt the clutch pack. I recently had "Green" Bearings ( snap ring type) from moser eng. put on and now i can get the passenger side half shaft in. The snap ring is about 1/32" from seating to the housing and the half shaft is bottoming out.

I tried swapping sides and the other side is worse. 1/8" or so from seating. I dont want to force the snap ring to the shoulder and i dont like bottoming out the half shaft to what ever it is hitting inside. I have read on thrust buttons. What are these and how do i get them out?

Stock half shaft but 742 out of 68 RT.

Thanks,
 
Good evening all,

I have a 73 Roadrunner, Changed for a 742 center section and rebuilt the clutch pack. I recently had "Green" Bearings ( snap ring type) from moser eng. put on and now i can get the passenger side half shaft in. The snap ring is about 1/32" from seating to the housing and the half shaft is bottoming out.

I tried swapping sides and the other side is worse. 1/8" or so from seating. I dont want to force the snap ring to the shoulder and i dont like bottoming out the half shaft to what ever it is hitting inside. I have read on thrust buttons. What are these and how do i get them out?

Stock half shaft but 742 out of 68 RT.

Thanks,
I've read where people said they were able to get the centering pin out without removing the 3rd member but I don't see how without breaking it. This is what the center thrust pin looks like http://www.ebay.com/itm/MOPAR-Clutc...EM-THRUST-PIN-Package-1958-1968-/371491189175 and the lock pin is generally nothing more than a roll pin. Remove the 3rd member and you should be able to get the thrust pin out without taking the 3rd member apart. If it were the Borg Warner unit, you would have to totally tear the SureGrip apart to get the thrust pin out. It's a totally different design and looks nothing like the one in the clutch plate unit.
 
I have been running green bearings for about 7 years when I put my Detroit Locker in and its a street car I drive alot. Ron
 
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