Thread: Salisbury diff housing failures

Originally Posted by uninformed

hahaha, Pat you missed my sense of humor. I wasnt poking fun at you, rather joining you. A few pics get posted and now people are running out to check their sals and sort out getting them beefed up or swapped out....got to love the internet hey.

BTW, Im not a fan of the sals either, I dont hate them and they do the job fine, but if I had the choice it would be a full steel housing. And yes it would not be a rover diff, something more towards the ford 9 or a Sixty9. Heck, if ENV were more common they would make a good diff IMO

The ENV in the FC,s were not much good.Pinion Bearings too close together and the tiny inner was in a fragile bit of casting that usually cracked. I swapped mine for Sals back and front. Maxied but not reinforced.

Originally Posted by 123rover50

The ENV in the FC,s were not much good.Pinion Bearings too close together and the tiny inner was in a fragile bit of casting that usually cracked. I swapped mine for Sals back and front. Maxied but not reinforced.

Yeah, but they had way more potential than the Sals, and have the all steel housing. Atleast they were 4 pin diffs and certainly an improvement over the Rover diff.

Originally Posted by Bush65

From what I can see in the first pic, it looks more like protection for the diff lock actuator and is not what I would call bracing.

Having never examined a sals with maxidrive, I might be missing what you are describing.

John, see my ammended pic. A sals tube doesnt have any weld seem along its length. Im guessing this is an external lamination.

Originally Posted by PAT303

Hello,someone has rubbished the holey of holies,the mighty Sals diff.Sorry Serg,never like them,never will.I'll have a rover full of Ashcrofts gear or the P38 with the same anyday.My Sals has 450k by the way,only ever changed the pinion seal,still don't like it. Pat

But IMHO has rubbished the wrong culprit.

The only reason for an axle tube pulling out of the diff housing is plane bad workmanship.

Originally Posted by uninformed

John, see my ammended pic. A sals tube doesnt have any weld seem along its length. Im guessing this is an external lamination.

Thanks, I see what is meant now. But I don't like what I see.

The mode of failure that should be expected from too many overload cycles is as seen in the first pic from the OP. A fatigue crack at the point where there is a large stress raiser due to the abrupt change in stiffness.

IMHO the only satisfactory way, if the axle is required to handle worse loading conditions, is to increase the wall thickness of the axle tube and thus reduce the magnitude of the cyclic stress, in the region of the stress raiser.

That lamination is outside the region of the stress raiser, so doesn't help at all there, but in addition has added a weld that is too close to the stress raiser and therefore increases the stress raising effect, i.e. 2 stress raisers combined.

Designing for fatigue is often difficult and it is not unusual to see changes made with good intentions backfire. The nature of fatigue is that failure is hard to predict because of the large statistical variation in the fatigue life over a number of seemingly identical components and loading histories.

Originally Posted by djam1

I know there was a lot of failures with the Jeep J20 when they were released in Australia back in the 1980s.
They had a Dana 60 in the rear that nearly always failed if it was used.
Its not exclusively a Land Rover issue if it is an issue

A few failures worldwide by overloading or abuse is to be expected.

compared to the thousands of Banjo housed diff failure numbers, keeping the Sals under my 110 is a no brainer.

I used to fit MaxiDrives for club members, never had any such failures, not sure that the failure in the early post can be attributed to the MD.

I could only find one folded Jeep rear end on google, and it turns out it failed because of a DIY axle swap, (the guy actually swapped left for right tubes so he could turn his diff over for a SOA conversion

Originally Posted by Bush65

Thanks, I see what is meant now. But I don't like what I see.

The mode of failure that should be expected from too many overload cycles is as seen in the first pic from the OP. A fatigue crack at the point where there is a large stress raiser due to the abrupt change in stiffness.

IMHO the only satisfactory way, if the axle is required to handle worse loading conditions, is to increase the wall thickness of the axle tube and thus reduce the magnitude of the cyclic stress, in the region of the stress raiser.

That lamination is outside the region of the stress raiser, so doesn't help at all there, but in addition has added a weld that is too close to the stress raiser and therefore increases the stress raising effect, i.e. 2 stress raisers combined.

Designing for fatigue is often difficult and it is not unusual to see changes made with good intentions backfire. The nature of fatigue is that failure is hard to predict because of the large statistical variation in the fatigue life over a number of seemingly identical components and loading histories.

even this is frought with potential issues if worked 'hard'. i have seen a ( fitted to the front) tru track'd D44 in a CJ J**p with thicker tubes fitted go on to break the casting housing where the tubes go in.... had a heavy cast iron engine over the top of it and was spending a bit of time getting air.

Not everyone drives sympathetically, maybe that is most of the problem.


jc

If you are breaking Sals housings, probably best not to bandaid them and step up to a real housing:

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