Well, I was rolling the rear over on top of the jackstands to clean the other side, and I snapped off the vent cap flush with the axle tube. If I run without a vent cap will it cause any type of damage?

 

The vent prevents water and dirt from getting in, so while you can run without it, over time there may be a build up of moisture/dirt in your diff oil. If you really don't want to replace it, I would put a dab of sealer over the hole to prevent anything from getting in.

Wow, I just looked and saw some Olds resto houses want $13 or so for one, whereas this place has one for ~$4:

http://www.cascade4wd.com/store/inde...oduct_id=30516

 

The only reason im hesitant to replace it is because the bottom of it is still inside the axle housing. If I try to get it out, im afraid of any plastic pieces/shards falling down into the housing. I might try to find the smaller breather, and press it into the leftovers of the old one...

 

I just ordered (2) of those vents from Motorcity Supercars/Inline Tube for $6.50 ea. Its real easy to pop them off. I use a cutting pliers and get a firm grip around the vent and pry it off. Oh yea, they make (2) different sizes so make sure you get the right one. I do believe its 3/8 and 7/16.

 

I would replace it prior to reinstalling the housing back in the car. It should be very easy to remove the broken piece.

 

Just a thought but you may try a
bolt extractor. If you can get a few turns
on it, before it starts to spin the broken piece,
you may be able to pop it out.

 

It also acts exactly as it's name implies to limit internal pressure as the differential heats up. I would remove the broken piece aNd replace it. The OEM vent on my car was easy to pop out. I noticed it has a green cap compared to the repro ones.

 

If you seal this vent, won't it blow lube out the seals when the rear heats up?

 

I don't think I even have one of these breathers. Is this where you fill the diff up from? I've got one of those plugs in there that you put like a 3/8 extension to remove it.

Where does this breather go?

 

Any fluid under conditions of pressure and temperature will find the weakest place in the axle assembly and likely do that. A replacement vent cap is the best way to go IMO. Try tru-blu's suggestion to extract it. This piece is a type of nylon plastic.

 

The 3/8 plug is a fill/check.
The breather plug is on top, pass.side.

 

That is the bung you use to fill the differential with gear oil. Yes it's a 3/8" socket extension.

Here's a picture of the OEM one on my 72. File pics from when I rebuilt it.

 

That rear is a thing of beauty Allan.

 

Thanks for the explanation.


Thanks for the picture Alan. Next time I'm under the car, I'll look, just to see. Sorry for the thread hi-jack.