Sailsbury Diff removal.

Austin Shackles wrote:

> what I don;t know is why people don't, instead of ****ing around with
> stretching the casing, take and angle grinder to the edges of the hole and
> make it the mm or so wider that it needs to be. Is there any good reason
> not to?

It's a matter of a few thou, but it's what puts the preload on the main
carrier bearings so it's fairly vital.

And the design works bloody well in terms of being strong - I've yet to
smash a salisbury pattern diff without being incredibly stupid (silly
amounts of horsepower and serious abuse of the vehicle), but have had
some interesting failures with banjo style diffs whilst being relatively
sensible in the same vehicle.

--
EMB

Austin Shackles wrote:
> On or around Fri, 30 Jun 2006 12:17:47 +0100, "Huw"
> <hedydd[nospam]@tiscali.co.uk> enlightened us thusly:
>
>>> and you permanently distort the housing, converting it to scrap.
>>> JD
>> And what a crap idea it is. The responsibility for this abominable creation
>> is the Dana Corporation of America. What WERE they thinking of? Why did they
>> not make the hole a few millimetres bigger?
>
> have to agree with Huw, there. There's no good reason for making an
> aperture which is fractionally too small. and IIRC the difference is really
> small, not more than about 1 or 2mm.
>
> what I don;t know is why people don't, instead of ****ing around with
> stretching the casing, take and angle grinder to the edges of the hole and
> make it the mm or so wider that it needs to be. Is there any good reason
> not to?

The stretching is NOT to get it OUT its to load the bearings properly -
which is why its so bloody tough. The MAXIMUM deflection permissible is
only 15 thou.

Steve

"Huw" <hedydd[nospam]@tiscali.co.uk> wrote in message
news:[email protected]...
>
>
> I have many tractors of many brands with diffs in front and back axles,
all
> of which have cast iron housings and none of which need expanders
> [obviously] and all of which are reliable. There is no reason that Dana
> could not make a reliable axle that didn't need the case stretching to
> service certain components.
>
> Huw

And look at the physical size difference, of course the tractor ones don't
break! If they were smaller due to the physical space constraints of the
design, they'd need to be made to a better, tougher design to be reliable
long-term. As it stands, they have more space available and also they don't
rotate anything like the same speeds, which as long as cleanliness is
observed, increases the lifespan considerably.
Gimme enough space physically and I could design a diff that would handle
4,000,000 bhp reliably from basic materials (no fancy metallurgy), but ask
me to design it to fit in a certain space, I'd fall flat on my face!
The Salisbury (Dana) type of diff mounting has been around for years, it is
a good, strong and well-proven design that has been used in many forms by
many vehicle manufacturers. It was designed by people (engineers) that knew
what they were doing, not by people who merely thought they new what they
were doing.
Anyone who grinds clearance into a salisbury case is going to suffer
premature bearing failure and possibly lunch their diff, it is designed to
run with a certain preload, no preload = imminent failure!
Badger.

On or around Sat, 01 Jul 2006 16:38:01 +0100, steve
<[email protected]> enlightened us thusly:

>Austin Shackles wrote:
>> On or around Fri, 30 Jun 2006 12:17:47 +0100, "Huw"
>> <hedydd[nospam]@tiscali.co.uk> enlightened us thusly:
>>
>>>> and you permanently distort the housing, converting it to scrap.
>>>> JD
>>> And what a crap idea it is. The responsibility for this abominable creation
>>> is the Dana Corporation of America. What WERE they thinking of? Why did they
>>> not make the hole a few millimetres bigger?
>>
>> have to agree with Huw, there. There's no good reason for making an
>> aperture which is fractionally too small. and IIRC the difference is really
>> small, not more than about 1 or 2mm.
>>
>> what I don;t know is why people don't, instead of ****ing around with
>> stretching the casing, take and angle grinder to the edges of the hole and
>> make it the mm or so wider that it needs to be. Is there any good reason
>> not to?
>
>The stretching is NOT to get it OUT its to load the bearings properly -
>which is why its so bloody tough. The MAXIMUM deflection permissible is
>only 15 thou.

ah. Mind, I'd have thought you could load the bearings by other means -
other diffs do. The strength of the diff is in how it's designed, mostly,
not in the axle casing. Older rover diffs were not designed to take all
that much power and/or torque, so if you overload them with a big engine
they tend to fail. That's not an inherent design fault, simply that the
diff was designed for a give power. The Dana ones are obviously designed
for more power, but if LR set out now to design the rover-type axle, then
the diff and half-shafts would be designed to take the load of the current
engines.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"Pereant qui ante nos nostra dixerunt"
(confound the men who have made our remarks before us.)
Aelius Donatus (4th Cent.) [St. Jerome, Commentary on Ecclesiastes]

On or around Sat, 1 Jul 2006 17:37:25 +0100, "Badger"
<[email protected]> enlightened us thusly:

>Anyone who grinds clearance into a salisbury case is going to suffer
>premature bearing failure and possibly lunch their diff, it is designed to
>run with a certain preload, no preload = imminent failure!
>Badger.

OK, I accept that now that I know about it.

doesn't mean that it has to be done that way. There are plenty of other
diffs which are not like the dana ones.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"Pereant qui ante nos nostra dixerunt"
(confound the men who have made our remarks before us.)
Aelius Donatus (4th Cent.) [St. Jerome, Commentary on Ecclesiastes]

"Badger" <[email protected]> wrote in message
news:[email protected]...
>
> "Huw" <hedydd[nospam]@tiscali.co.uk> wrote in message
> news:[email protected]...
>>
>>
>> I have many tractors of many brands with diffs in front and back axles,
> all
>> of which have cast iron housings and none of which need expanders
>> [obviously] and all of which are reliable. There is no reason that Dana
>> could not make a reliable axle that didn't need the case stretching to
>> service certain components.
>>
>> Huw
>
> And look at the physical size difference, of course the tractor ones don't
> break!

Oh but they sometimes do.

If they were smaller due to the physical space constraints of the
> design, they'd need to be made to a better, tougher design to be reliable
> long-term. As it stands, they have more space available and also they
> don't
> rotate anything like the same speeds, which as long as cleanliness is
> observed, increases the lifespan considerably.

I have no figures available but the front axles diffs are very compact, and
so are the rear ones considering the extreme duty they are subject to. The
front diffs are certainly more compact that the Salisbury and they probably
turn as fast or faster, the axles having epicyclic reducer gears on the
half-shafts as a rule to reduce the torque to which the diff is subject.


> Gimme enough space physically and I could design a diff that would handle
> 4,000,000 bhp reliably from basic materials (no fancy metallurgy), but ask
> me to design it to fit in a certain space, I'd fall flat on my face!
> The Salisbury (Dana) type of diff mounting has been around for years, it
> is
> a good, strong and well-proven design that has been used in many forms by
> many vehicle manufacturers. It was designed by people (engineers) that
> knew
> what they were doing, not by people who merely thought they new what they
> were doing.

Yes, it is an old design and it is generally reliable, but it is not unique
in being reliable.


Huw

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Sat, 1 Jul 2006 17:37:25 +0100, "Badger"
> <[email protected]> enlightened us thusly:
>
>>Anyone who grinds clearance into a salisbury case is going to suffer
>>premature bearing failure and possibly lunch their diff, it is designed to
>>run with a certain preload, no preload = imminent failure!
>>Badger.
>
> OK, I accept that now that I know about it.
>
> doesn't mean that it has to be done that way. There are plenty of other
> diffs which are not like the dana ones.

You've hit the nail on the head. Even Dana make axles that don't need case
stretching and they are perfectly good and reliable. Case stretching is NOT
a pre-requisite for reliable diffs and just one look at the Salisbury shows
that it does not have a particularly compact differential.

Huw

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Sat, 1 Jul 2006 17:37:25 +0100, "Badger"
> <[email protected]> enlightened us thusly:
>
> >Anyone who grinds clearance into a salisbury case is going to suffer
> >premature bearing failure and possibly lunch their diff, it is designed
to
> >run with a certain preload, no preload = imminent failure!
> >Badger.
>
> OK, I accept that now that I know about it.
>
> doesn't mean that it has to be done that way. There are plenty of other
> diffs which are not like the dana ones.

Very true, there are a lot of good designs out there, unfortunately some of
the diffs that get labelled as bad ones are usually labelled thus due to
failure after they were subjected to higher power/torque loadings than the
manufacturer intended, as has already been said by your good self I think,
further up the thread.
Series jag XJ's used a slisbury differential unit, a lot smaller than a
landrover one (I think the jag one was the 4HU and the landy is the 8HA?)
yet it could reputedly handle 1000bhp. Bet if you put it in something as
heavy as a landy it'd go bang long before that figure was reached. Lighter
vehicles will spin a wheel at a lower torque figure, thus unloading the
transmission.
Badger.

"Huw" <hedydd[nospam]@tiscali.co.uk> wrote in message
news:[email protected]...
>
> "Badger" <[email protected]> wrote in message
> news:[email protected]...
> >
> > "Huw" <hedydd[nospam]@tiscali.co.uk> wrote in message
> > news:[email protected]...
> >>
> >>
> >> I have many tractors of many brands with diffs in front and back axles,
> > all
> >> of which have cast iron housings and none of which need expanders
> >> [obviously] and all of which are reliable. There is no reason that Dana
> >> could not make a reliable axle that didn't need the case stretching to
> >> service certain components.
> >>
> >> Huw
> >
> > And look at the physical size difference, of course the tractor ones
don't
> > break!
>
> Oh but they sometimes do.

I was referring to your comment about tractor diffs being reliable, I didn't
mean that they never, ever break. They probably suffer less failures than
landrover ones though?

> If they were smaller due to the physical space constraints of the
> > design, they'd need to be made to a better, tougher design to be
reliable
> > long-term. As it stands, they have more space available and also they
> > don't
> > rotate anything like the same speeds, which as long as cleanliness is
> > observed, increases the lifespan considerably.

> I have no figures available but the front axles diffs are very compact,
and
> so are the rear ones considering the extreme duty they are subject to. The
> front diffs are certainly more compact that the Salisbury and they
probably
> turn as fast or faster, the axles having epicyclic reducer gears on the
> half-shafts as a rule to reduce the torque to which the diff is subject.

Right, I see. I must admit to not having a great knowledge of 4wd tractors,
my involvement with tractors stopped (thankfully!) with the MF135 /
International 474! I cut my teeth doing clutch changes on Majors and
Dexta's!! My comments were directed towards the rear axles, I should have
made that clear. I understand your comments re. higher speed and lower
torque by using the epicyclic reduction, it's quite possible that they had
to be designed that way to be compact enough to physically fit the
application? Another consideration has to be NVH (noise, vibration and
harshness), on a tractor you can design the diff helix angles etc of the
gears for maximum strength, automotive design tends to be a compromise of
strength v's NVH, even on landrovers!

> > The Salisbury (Dana) type of diff mounting has been around for years, it
> > is
> > a good, strong and well-proven design that has been used in many forms
by
> > many vehicle manufacturers. It was designed by people (engineers) that
> > knew
> > what they were doing, not by people who merely thought they new what
they
> > were doing.

> Yes, it is an old design and it is generally reliable, but it is not
unique
> in being reliable.

Absolutely. I can think of lots of makes of vehicles with very reliable diff
units, BMW and Merc spring to mind, even Ford granada/sierra ones are pretty
reliable if kept within their design criteria for power handling.
Badger.

In message <[email protected]>, Huw
<hedydd@[nospam].invalid> writes
>
>Yes, it is an old design and it is generally reliable, but it is not unique
>in being reliable.
>

I think the Salisbury axle on the back of Land rovers is a Dana 60.
American dragster folk love it because it doesn't break. Some dana axles
don't have to be preloaded and these tend to be swapped in favour of
60's.
They must have something going for them..

--
Mark Roberts

On or around Sun, 2 Jul 2006 06:45:43 +0100, mark <[email protected]>
enlightened us thusly:

>In message <[email protected]>, Huw
><hedydd@[nospam].invalid> writes
>>
>>Yes, it is an old design and it is generally reliable, but it is not unique
>>in being reliable.
>>
>
>I think the Salisbury axle on the back of Land rovers is a Dana 60.
>American dragster folk love it because it doesn't break. Some dana axles
>don't have to be preloaded and these tend to be swapped in favour of
>60's.
>They must have something going for them..

It's undoubtedly a good axle. point is that you don't have to make one like
that to make a good one.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"Would to God that we might spend a single day really well!"
Thomas À Kempis (1380 - 1471) Imitation of Christ, I.xxiii.

Austin Shackles wrote:

> if LR set out now to design the rover-type axle, then the diff and
> half-shafts would be designed to take the load of the current
> engines.

Much like Toyota have done with their Hilux diffs - similar design and
size to the Rover unit but a heap stronger - I'm successfully running
550BHP (and LOTS of torque) through one in my race car and have broken 2
half shafts in 5 years. When I get a supply of tuits I'll have a go at
marrying one into a LR diff housing.


--
EMB