I have a major oil leak from my escort axle. The whole drum on the right side was full of oil.
Does anyone know if there should be any gaskets between the axle casing and the half shaft/bearing/flange?

This explains why the rear brakes worked so bad.

ho gasket afaik but the bearing has seals and has an o ring bearing around the outside that seals against the casing. So its half shafts out and new bearings I guess.

IIRC The seal is in the brg. I have changed a few on a cortina axle on a tiger for a bloke because it kept blowing the seal.

ok thanks.

I'll have to change the bearing then

When you get a bearing make sure the retaining collar comes with it.

These bearings are quite easy to change without a press --- do a search and you should find one of several threads in which I have given the procedure.

I have now changed bearing on one side. It wasen't that hard. The bearing itself was a tight fit, but not to hard. The collar slide right on after i had heat(red) it up with my gas welder.

I had to use the anglegrinder to remove both the old bearing and the collar.

If you're going on track its worth putting a small tack weld on the retaining collar to ensure it can't move as all the race / rally boys do. The press fit of the bearing is the only thing that holds the halfshaft (and therefore the wheel) in place and in high load cornering it has been known for the bearing / retainer to slip on the halfshaft (ie your rear wheel goes AWOL!) when subjected to high cornering forces and rough treatment.

good idea! will do that.

Is there any risk that the heat from the weld weakens the halfshaft?

Don't touch the shaft with a welder it will cause failure due to local stress raiser and undoing heat treatement.

I have seen shafts on racing escorts fail due to this --- failure at the outer end of a half shaft isn't good.

I bet theres been many more failures due to not doing it though, and we're only talking one or maybe two small tack welds, not MIG'ing it all the way around!

[Edited on 31/7/07 by ChrisGamlin]

quote:

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Originally posted by ChrisGamlin
I bet theres been many more failures due to not doing it! We're only talking a couple of small tack welds, not MIG'ing it all the way around!

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I have now put two tack weld on each shaft. Time will tell if it was a good choice or not.

The theory is sound, but considering breaking halfshafts seems to be a pastime in itself in rally circles when putting big power outputs through live axles, Im not sure without proper analysis of each break that you could categorically say that a shaft broke on a rally car directly because of a weld, rather than simply being stressed beyond its working limits due to the terrain or excess torque applied etc. I did do a quick google to see if I could find any mention of Escort halfshaft failing due to welds though or for competitors recommending not to, but couldnt find anything.

Anyway, Im happy to accept the theory and will leave it to Micael to decide what he wants to do, but I will will say that Im perfectly comfortable with my tack welded half-shafts, a mod that was recomended to me by my uncle who preps cars for Alan Mann amongst others, and considering his 40 year racing history with live axle'd Fords he should know more than most what does and doesn't work, with these particular axles at least.

cheers

Chris

No investigation required, generally its really easy to identify a fatigue failure and pin point the the exact feature it started at.

Every failled halfshaft I have examined displayed very clearly the the classic shore line striations which start from a single point at a stress raising feature.
With axles and torsion bars great attention has to be payed to surface finish and the detail design of fillet radi at features such as splines.


Illustration taken from this url http://www.sv.vt.edu/classes/MSE2094_NoteBook/97ClassProj/anal/kelly/fatigue.html

More here http://materials.open.ac.uk/mem/mem_ccf4.htm
Rescued attachment img00007.jpg

Thinking about it though, a failure induced by a weld on the inner most edge of the retaining flange will occur inboard of the bearing, meaning it is no different to breaking a halfshaft at any other point along its length inboard of the bearing (ie within the axle tube). Even if the halfshaft did break at that stress raiser, the outer half of the stub axle will still be retained by the same press fit into the bearing and the retaining cap as it was before the failure, and if it tried to twist in the bearing under the weight of the car, the drum / disc would prevent it moving out of alignment significantly.

Its only if you create a stress point outboard of the bearing and it fails at that point will a failure likely culminate with the loss of a wheel, so to me it seems by welding the flange on the inside the trade-off for a reduction in the chance of the driveshaft being pulled out of the bearing causing a criitical failure is the possibility of increased inboard driveshaft failure which in 99% of circumstances is far less dangerous.

cheers
Chris

Halfshafts unmolested by welding 99.9999% of the time only fail at the splined end. This is because of the stress raising effect of the end of splines. In days gone by this type of halfshaft failure was a very common roadside mechanical failure until about 1960 when manufacturers got wise to reducing the stress concentrations by under cutting the end of the splines with very a generous radius, if you examine an Escort Engish axle you will see the designer has taken great care to do this.

The surface layer of halfshafts and torsion bars must be defect free or they will fail apart from the stress raiser effects of the weld halfshafts are normally made from a molybenium alloy steel contain significant % of nickle, manganese and chromium, not that different from the sort of grade of steel used to make spanners.
Tack weld the with a MIG welder and a mild steel filler rod and it is anybodies guess what the hardness and compostion of the heat affected zone will be but it is a safe bet will at some point be brittle because of the rapid cooling caused by the the heat sink effect of of the material thickness and the small size of the weld.

As mentioned previously Im happy to take what you say about the meallurgy as read, but from my point of view in the real world many many race and rally cars have had this mod done over the last 40 years, if it was as dangerous and as likely to lead to failure as you seem to be suggesting then it simply would not still be done today (by the very same people that did it 40 years ago no less), so I can only assume that although yes maybe it does add a potential stress raiser, on an Escort halfshaft this is not sufficient to cause failure in all but the most extreme of circumstances, and as I mentioned even if it did fail Im not convinced it would be any worse than a failure at the splines which as you mention, is/was much more common and doesn't usually cause any catastrophic loss of running gear.

cheers

Chris