Oil on rear axle

[mof]

The area where the rear axle and U bolt and rear damper meet on my saloon is coated in oil of some sort. I have checked the damper fluid and none has been lost, so i assume it's coming from the axle. The only way to tell 100% is to take all the bits off at this point, but before I do, has anyone any experience with this problem? Could I have a pinhole in the axle? It seems unlikely. It doesn't seem to be obviously coming from the area of he back plate either.

[rayofleamington]

If the damper leaks, the entire area can look oily. Try nd rule out the damper first.
If you still think it might be axle oil I would recommend to strip it and have a look at the axle! The axle can corrode around the u-bolts as this area is a trap for dirt etc..

[les]

I have cut an axle in the past to see the thickness of metal used, it is about an eighth of an inch thick, although the area you mention is prone to corrosion it is usually restricted to the welded bracket. The 'u' bolts can leave grooves in the axle case if the bump stop metal has rusted, but they would have to be pretty excessive to cause a leak.

[Peetee]

The area where the rear axle and U bolt and rear damper meet on my saloon is coated in oil of some sort

Do your brakes feel OK? It could be the union on the back of the drum

[Scott]

I would suggest that you clean the area thoroughly first to try & trace the leak. As Ray says, oil leaks can spread & cover the whole area.
Try & soak degreaser/kerosene over the area & use a brush to loosen the residue. Access to a pressure washer is even better for cleaning this off when well & truly soaked. If not a normal garden hose jet should clean it off OK.

REAR AXLES CORRODING !!!!!!
We might not get too much rain here but at least not EVERY part of our cars rusts.

See how you go tracing the leak, it could be anything previously mentioned & it's a lot easier to see/trace an oil leak with everything clean & still assembled.

[Chris Morley]

Scott,

Rear axle corrosion isn't normal even here in the UK - I've never seen it. In fact the damp climate probably isn't the biggest factor in the rusting of cars- the salt spread on the roads each winter makes it far worse.

Unfortunately rust is now responsible for the scrapping of almost all Minors in Britain. This isn't to say Minors are / were prone to rusting as many contemporary 1960s cars rusted away years ago.

mof - is the staining on the rear axle present on both sides and are the oil patches of the same size?

[rayofleamington]

Rear axle corrosion isn't normal even here in the UK

I have only seen it on Minors which didn't have much TLC. The dirt build up around the U-bolts traps damp, not to mention the huge amount of salt we get over winter. If it is never cleaned over 30 years, then you'll get corrosion, in the same way the wings rot if they are not cleaned out in the mud trap areas.
The last car I worked on was quite bad. When wire brushing the axle after the U-bolts were removed the pits were deep and the welded bracket had nearly dissapeared.
A friend of a friend had their axle turn in the u bolts as the welded brackets had become too weak! They only noticed because the propshaft started rubbing on the crossmember.

Your point is correct on the influence of salt - The UK has a huge amount of salt due to gritting in winter. Hence the trend where people are garaging their 'nice' cars over winter. Not everyone has the option to do that, especially if your classic is also your daily transport.

A climate where cars don't rot? Over here, we can only dream of it!!

[mof]

Thanks gents.

I think I'll have to get to first base by clearing the oil away.

It seems to have coated the whole area, including the leaf springs.

I've fitted new rear wheer cyliders, checked the rear axle level, checked the damper level. No clue as to where it is coming from.

The only thing I can think of is that it may look spectacular, but the actual amount of fluid is too slight to be visible in either damper or axle, which are the likely candidates.

Steve

[Benjy]

I seem to remember finding oil all over that area on my car and panicing that it might be getting into the brake drums. I replace the half shaft gaskets on both sides and never saw it again, but there was only a drop on the end of the halfshaft inside the drum, and none had managed to get onto the braking surfaces. The car was off the road at the time, so no great danger, but glad I fixed it!

As for axles rusting, my handbrake anchorage point broke off recently due to rust! Some Chemical Metal soon fixed it and I have since had to replace the leafspring, so the whole lot got cleaned and thoroughly greased. The axle casing itself looked fine though, even the U bolt threads were still intact and all the nuts actually unscrewed!

Ben

[les]

If the leaf springs are oily you may find that the hub bearing oil seals are letting by.

[rayofleamington]

you may find that the hub bearing oil seals are letting by.

had that thought this afternoon - seems i'm a bit slow though ;-)

[washer-bottle]

My minor spent 30 years in a rural area and the gap between the axle casing and the U bolt mounting was full of "muck". This had actually rotted a hole right through the thick casing and there was very little oil left inside. I ended up fitting a another axle casing.

I always try to hose it down with the jet wash now.

If this is not the leak then its probably the rear axle hub seals - how are your brakes? When you take them apart don't get the half shafts mixed up - they are handed and should go back on the correct side.

If the oil is sprayed all around the propshaft joint then it may be the diff/prop shaft oil seal. If its around the bottom of the diff it may be the oil filler or the diff/axle casing paper gasket.

Check the oil level in the diff by sticking you finger in the filler hole and feeling for oil - you can just do it wthout jacking up the car. On the top of the diff is a plastic cap (like a toothpaste cap) which is the oil breather. If its blocked (rare) then the oil might be forced out - if its missing then muck will get into the diff.

Good luck

[elainemr]

I'm still new to all this, but as I have just acquired a pressure washer, what exactly should I be hosing down?

Elaine

[les]

It's the void between the axle and the bossed bracket that is welded to it at the point where the rear springs cross the axle. Dont be too keen to use your washer on this area unless you can be sure of removing all the mud etc, otherwise it will just contain the water adding to the problem. Poke it all out with some stiff wire and then squirt some waxoyl in.

[rayofleamington]

A good time to get at it is when the wheel is off to adjust the brake shoes (eg. during servicing).
As long as you make sure the car is well supported and safe when you take the wheel off, then this is a good opportunity to poke prod and clean the area.
Apart from getting wet knees, when the wheel is off to adjust front or rear brakes it is also a good time to clean out / hose the wheel arches / inside the wings. This is about the only time to get a good view of the areas but make sure the car is not just on a jack as that's not very safe.

[Kevin]

Steve I dont wish to ask the obvious question, have you had the car very long, its also possible the previous owner squirted some around, as some owners dont like the look of a rusty leaf spring and feel that their lifespan will be extended by oiling.