filling front diff through breather? update

Post by **wimwolf** » 20 Sep 2010, 11:45

Is it possible to fill the front diff (GL4 oil) through the hole for the air breather?
The filling nut is completely worn out and I would like to know of it is ok to fill it this way?

On a section I can see the oil will arrive in the house where the VC is, but there seems to be a connection pipe? Or am I wrong?

HELP.

Post by **Aidan** » 20 Sep 2010, 16:43

you can do it that way but it will take a long time, ideally you'd want to make up an adapter for the 500ml fluid syringe with a M10fine coupling on the end to fit the breather hole as behind the hole is a restricted passage and the opposite face of the next part of the case so it is only a few mm aperture inside, it's only meant to allow for the expansion and contraction of the air inside the box - the oil will be distributed throughout by the balance pipe in the bottom.

it could be quicker to take the diff out and take the cover plate off refill and reseal and reinstall

Post by **syncropaddy** » 20 Sep 2010, 17:30

Aidan wrote: it could be quicker to take the diff out and take the cover plate off refill and reseal and reinstall

Yes it would and while you have it out you could send it up to Warrington and have it refurbed. Then you could fill it up as you'd have a new bung in your diff (!)

Why are you wanting to do this job anyway?

Post by **wimwolf** » 20 Sep 2010, 18:45

well,
I recently changed the front CV boots (inner and outer), the plan was to take the diff out but I kept it in place and could finish the job with the front diff loose but still hanging underneath the van. I thought I was going to take it out so already removed the oil to lose some weight, (only 1.5kg I know...) after 25 years it was time to change the oil.

So now I have a front diff in position with no oil at all. and a worn filler plug. In the meanwhile I already welded a bolt on the plug, which has broken also. hurray!

I found a syringe (100ml) onto which I could attach a small pipe and already started to fill it via the breather hole, when I suddenly was in doubt if the oil would arrive in the right place...But it seems i made the right choice?

Should take me an hour... taking front diff out takes much more time (for me at least)

So the balance pipe will divide it over the 2 houses?

Thanks!

Post by **Aidan** » 20 Sep 2010, 21:22

if doing both shafts then taking the diff out is quickest as per bentley

Post by **wimwolf** » 22 Sep 2010, 07:33

I understand it will be the easiest way to remove the old plug when the diff is out but I'd like to wait to take it out again.

Main question is: Can I damage any parts by filling it via the breather hole?
(speedometer, bearings,..?)

(Why is the breather hole in the VC house and not in the front part?)

Post by **wimwolf** » 27 Sep 2010, 12:59

I think it is not possible:

If you pour oil through the filler plug (situated in the front house), the air in the “VC house” (=rear compartiment) will escape through the breather hole.
But if you fill it through the breather hole, the air in the front house will be stuck and has no way out. So there will be more oil in the VC house than normal.
(too much in the VC house and too little in the front (diff) house)

Thank you Gay-Lussac p.V=n.R.T

So, I have to get it out again, damn.

Post by **Aidan** » 27 Sep 2010, 15:11

the whole thing breathes across the pinion bearing it's not air tight

Post by **wimwolf** » 27 Sep 2010, 18:39

THAT would be great! I managed to fill it this way.

thank you for the help in this rather weird topic

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filling front diff through breather? update

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