Pinion Bearing

[Stumper]

Would you replace this? Pitting is only on that one roller, the rest seem fine.

Difference between a new Dr. Diff 742 seal and an old original

 

[RemCharger]

Yes, yes you would. Along with the race, if doing properly.

 

[Potts]

Yes.
That 1 pitted roller won't spin around as freely and will progressively deteriorate.
As fast as that driveshaft rotates, it wouldn't take long until the metal pieces will wreak havoc on the entire bearing.

 

[Stumper]

Anyone have a recommendation on a bearing and race - it’s a 742 rear end?

 

[Potts]

There should be numbers on the inner race of that bearing pictured.

 

[Potts]

NAPA (or any decent auto parts supplier) should either carry it, or be able to cross reference it to their number.

 

[R413]

Shirley, you must be joking?

that will ruin everything else.

there are numbers on the bearing and race.

 

[Fran Blacker]

Saw a NOS bearing $60 and the cup $40 on ebay.
The seal https://www.amazon.com/National-Seal-7216-Differential-Pinion/dp/B000C5H330
None mine.

 

[R413]

I bought a nation 7216 from rock auto, it looks like the new cheapo seal. And it leaks! I’m not happy. The house and everything was very nice.

The photo on rock auto looks like the original seal, and then they have this cross section drawing which is the new cheap seal.

 

[RJRENTON]

Yes, yes you would. Along with the race, if doing properly.

ABSOLUTELY CHANGE THE BEARING (cone) and the race (cup) and the seal. IMO....use TIMKEN components (first choice) followed by SKF, Bower-BCA now Toyo, possibly RBC (Roller Bearing Corp.) but not NDH Hyatt (Delco New Departure Hyatt) was a GM subsidiary. Inspect the other bearings and races on the same pinion and possibly the carrier bearings as well, for FOD or Foreign Object Damage. Just my opinion of course.
BOB RENTON

 

[Fran Blacker]

On my 742 I had a C/R7216 (Chicago/Rawhide was able to find one think ebay.

 

[ruffcut]

If you have it apart, why not replace all bearings? Yes, more money, but peace of mind and you won't be tearing it apart again if done properly the first time. JMO ruffcut

 

[Stumper]

I pretty much figured it needed replacing. Especially since it was already out. I was just going to replace the seal and decided to pull the bearing out. Glad I did now. I’m showing a Timkin M803149/M803110 combo for this, does that sound right?

 

[4mulas]

Yes, look closely, the other rollers look like crap too

 

[Stumper]

Got a set of timken bearing and race on order. Already have the seal. This bearing looks to be packed with grease. Wonder if that somehow would hurt it in this type of application?

 

[Stumper]

Ok, so what’s the secret for pulling the bearing cup/race out if you don’t have the “special tool”?

 

[RJRENTON]

Ok, so what’s the secret for pulling the bearing cup/race out if you don’t have the “special tool”?

My experience is the cup is a "light" press fit in its housing. If posdible, from the back side, and the use if a brass or steel drift pin, gently tapping, from side to side, at the exposed cup's flange will USUALLY free the cup. Sometimes, an inside puller (with a screw or slide hammer) can remove the cup. Thoroughly clean the bore of all old grease and crud b4 installing the new cup. Using the same brass drift pin or using an appropriately sized arbor, it can be pressed in up to the retaining shoulder in the housing.....OR....try freezing the cup for ~ 1 hour, it will shrink, generally enough, to drop in the housing up to the shoulder. I'm sure others will will have their own methodology and experiences.
BOB RENTON

 

[Stumper]

Unfortunately this is the outer bearing on an installed rear end so tapping it out won’t work. Nether of my pullers will work to grab the inside lip. Might need a trip to Napa in the morning to see if they have a puller that will work… or just leave the race in there..

 

[khryslerkid]

Difference between a new Dr. Diff 742 seal and an old original

Dr Diff has the proper seal. Like the one you have from him, it does look different by not having the outside flange like the original. The thing is you'll have a hard time finding one with a double lip. The ones that the parts houses carry will be mostly a single lip or a leather one. Both don't last long at all. The new one you got from Cass is a double lip.

Do they both measure the same? The old one looks larger in the pics.

 

[khryslerkid]

Unfortunately this is the outer bearing on an installed rear end so tapping it out won’t work. Nether of my pullers will work to grab the inside lip. Might need a trip to Napa in the morning to see if they have a puller that will work… or just leave the race in there..

I never heard of anyone removing the race without removing the center section and driving it out from the inside. They don't come out that easily.

It's quite involved setting up the pinion preload. The proper preload on pinion bearings are measured in resistance using a inch pound torque wrench with the center section/carrier removed. The use of shims sets the preload. Removing the yolk to replace the seal and reinstalling it is mostly guess work for the proper preload. Marking the nut before removing it might get you in the ball park when re-installing it but it's just a guess. Also if your rear used a crush sleeve you should replace it with a new one to do it right. Again this should be preformed with the center section removed.

Can you get by with what you're doing? Many have but it's not totally advised. If you plan on leaving that race/cup in there, inspect it for a pit that matches the one on the bearing. More than likely that rear sat for some time and moisture in the top half cause the rust. The teeth on the ring gear that wasn't submerged in lube probably has rust pitting also. If the cup is pitted a new bearing may not last that long either.

Just throwing some thoughts out there.