Replacing the differential pinion oil seal

I am preparing to replace the pinion bearing oil seal at the differential on my 1953 Pontiac. Two questions come to mind:

1. To remove the outer flange to pinion nut- is this a right or left hand thread?

2. When putting the pinion nut back on- what torque value is given to this nut?

Thanks in advance for any help.

Dave

hi dave, i'm not home where my Pontiac library is, but the only lefthand threads that i'm aware of is the left side wheel lug bolts & nuts. use a torque wrench to remove the nut, that will tell you how much torque to put the nut back on with. Charles coker, 1953 Pontiac tech advisor.

Charles,

Thanks for getting back to me with that info- you are such a fine asset to the flathead community!

Dave

Hi Dave

I have just replaced the pinion oil seal in my Dads 53 chieftain in Aust, its a relatively simple operation to do so.

Its a RH threaded nut by the way. The shop manual I have does not list a torque value for the nut when replacing the seal either. It list bearing preload figures only when the diff center is removed from the diff housing .....10-12 pound / inches is the figure nominated on used bearings according to the shop manual.

The most important thing in my experience is to not change the pre-load on the pinion bearings by increasing the nut torque on re-instatement. This can have disasterous effects if you over tighten the nut from original setting and change the bearing pre-load as a result.

I have changed many pinion oil seals as an auto mechanic, the best way to do it is to mark the nut, the pinion yoke and the pinion shaft with a witness mark or centre punch all in the same line ....

Remove the nut and yoke, change the seal out, using oil on the seal lips before re-instatement.

Then when you have changed the seal out, ensure all components are re-instated in exactly the same orientation with the witness marks lining up. That way the torque will be the same as will be the pinion bearing pre-load. Its never failed me yet.

Rgds

Rgds,

Thanks for the procedural input. That's what I did based on other comments in the Tech. section of the forum. I did have a good result.

Dave