Thread: cracked housing

Originally Posted by JDNSW

1. 100,000km is low mileage.

2. Cracks will be where there are weaknesses not where the radius arms attach. (I suspect faulty welding accounts for why some crack and others don't!) If you visualise the stress distribution when you try to twist a housing, the diff holds the rear of the banjo rigid, and the torque is trying to distort the front section, resisted by the welded on pan. For the tubular sections the torque is applying shear to the longitudinal welds

3. Mileage is probably not a good indication of the repeated stress on axle welds due to torque - the stress is maximum for one wheel up and the other down, and this will happen when cornering or driving over very rough ground, but will be minimum for example on corrugated roads, which tend to lead to fatigue cracking just about everywhere else.

4. bent axle housings are a different kettle of fish - in most cases representing a single event.

John

100,000km may be low mileage to some, but if a problem hasn't arisen in 100,000km of testing then it's not likely to. It kind of rains on the parade of "x caused y" comments when x didn't cause y in 100,00km.

The radius arm bracket attachments are the highest stressed area in torsion. For these reasons:
1. Severe change in geometry at the transition from bracket to tube.
2. Welded transition.
3. The axle tube is the smallest diameter at this point.

The centre of the casing is bigger diameter (which resists torsion) and has a big cast diff head bolted in which greatly reinforces it.
Hence I don't believe torsion from poly bushes to be cause.

I know the bent axle tube is completely unrelated, I was simply stating why the axle was changed.

I have seen pics of broken trailing arms on UK landies (snapped bolt at chassis end) - attributed to hard poly bushes. I have never seen any front end failures attributed to poly bushes though.

I have never heard of any failures attributed to the (softer) superpro bushes though.

I've picked up a defender housing and trailing arms today and ordered some super pro bushes(52mm to suit the defender housing)my housing has 7 bolt swivels but is only 47mm between the plates on the housing where the bushes fit.I'll have to see how it all fits.

Originally Posted by yt110

I've picked up a defender housing and trailing arms today and ordered some super pro bushes(52mm to suit the defender housing)my housing has 7 bolt swivels but is only 47mm between the plates on the housing where the bushes fit.I'll have to see how it all fits.

I'm running skinny bushes with washers on a wider housing. Works fine.

Originally Posted by yt110

I've picked up a defender housing and trailing arms today and ordered some super pro bushes(52mm to suit the defender housing)my housing has 7 bolt swivels but is only 47mm between the plates on the housing where the bushes fit.I'll have to see how it all fits.

6 meters of 1/4 X 2, gas axe, a pack of 56S philips rods 2.5 mm, angle grinder, then give me a call

yt110 has a truetrack? but he probably sanded 1/2 the metal off the dif houseing when he painted it.

still the best looking county i have ever seen