Oily brake and butchered axle level plug

RogersJimmy wrote:
Looking forward to response or my other quandaries.

The breather is a one way valve, The Plan is to prevent the increased pressure in the axle when hot blowing oil out of the oilseals.

Landrovers and Jeeps have a ballbearing under that cap that blows off its seat and stays on it to seal the axle if it goes under water.

The cover is held on by a light crimp I think, the rubber washer goes against the breather spout, and the light spring presses it down from the top of the cover. Make sure the spout is clear into the axle.

If you take the cover , spring and washer away, you can attach a tube, that goes upwards to above any possible water level, usually this means exiting on the firewall under the bonnet.. The top of the tube is bent down, like an umbrella handle, to stop dirt getting into the tube, and hopefully if you do dunk it, water wont get in.

I don't bother, as if you go through water deeper than the tyres it gets in the swivel hubs and wrecks the bearings and the CV joints. Better to spend 20 minutes driving round a flood than 4 hours and a wad of cash fixing flood damage.

Thanks for the information on the diff breather. I have removed the cap, cleaned everything up and coated the inside with WD40 to retard future corrosion. The rubber flap now moves properly inside the cap against the spring, rather than being stuck up at the closed end as before.


Now it is refitted to the axle, the cap bounces on the spout against the spring with light finger pressure. Is that right?

However, I am still not sure how it is supposed to work. If it allows pressure to escape to atmosphere between the cap and spout, why doesn't water enter? The spring is so light that I can't imagine it withstanding much water pressure.

Thank you,
Roger

RogersJimmy wrote:

Now it is refitted to the axle, the cap bounces on the spout against the spring with light finger pressure. Is that right?

However, I am still not sure how it is supposed to work. If it allows pressure to escape to atmosphere between the cap and spout, why doesn't water enter? The spring is so light that I can't imagine it withstanding much water pressure.

That is right, it isn't supposed to be under water, only to resist the odd splash. The handbook warns that water that comes over the hubs or axle is too deep. For deep wading, people fit the extended breather tubes (and change the axle oil quite often).

There are also breathers on the transfer box, and gearbox that will let water in if you go too deep (which can be extended with tubes), but you'd likely have wet feet by the time you have to worry about them.