8.75, 741 pinion seal replacement.

[rp23g7]

So Its time to replace my seal, its been leaking a few drips each day on the garage floor.  Just gotta find a really big socket now. 
   
I checked the fluid, its still fine, but its got some pressure in there.  Wondering if the vent is plugged.  How do you clean it?  Does that little cap pop off? 

Going to do the axle seals too, as one is leaking a bit.  While I have the axle out I may as well adjust the back lash.
How do you do this?  I googled it, but all I get is the same axle info, on all the sites, but none really explain how to set the back lash.

Sigh, seems like I have taken my wheels off and on 100 times in a week dealing with that stuck wheel cylinder too.

[John_Kunkel]

I would remove the breather by unthreading it from th brake splitter fitting and see if you can blow air through it. If it's clogged, a good soaking in solvent followed by compressed air should clean it out.

Backlash is the play between the ring and pinion gear in the differential, it doesn't need periodic adjustment. I suspect you mean the axle end play, if it was properly adjusted the last time components were changed shouldn't require readjustment. End play is set by a threaded adjuster in the passenger side axle bearing retainer, thread it in or out to achieve and end play of about .008". 

[rp23g7]

I would remove the breather by unthreading it from th brake splitter fitting and see if you can blow air through it. If it's clogged, a good soaking in solvent followed by compressed air should clean it out.

Backlash is the play between the ring and pinion gear in the differential, it doesn't need periodic adjustment. I suspect you mean the axle end play, if it was properly adjusted the last time components were changed shouldn't require readjustment. End play is set by a threaded adjuster in the passenger side axle bearing retainer, thread it in or out to achieve and end play of about .008". 

thanks John