Re: Closed/Open Knuckle...Full/Semi Floaters...

[Tom Mandera <tsm1@domain.elided>]

alice@domain.elided wrote:
 
> kinda' new to all this stuff (remember, I mostly read the paper in
> my topless Scout with Volvo seats ...sometimes I take a nap
> there too), so...

I sit on the floor board of my '72 (no seats) and look around and
visualize what I need to do next.. and I make my apologies to it, and
promise I'm not going to let it just sit in the driveway without a heart
or seats or anything for too much longer..

> Old Land Rovers have a closed knuckle front axle.  They tend to leak,
> Please tell me what the advantage is of this design.  There may be

Advantage over open-knuckle?  Mud doesn't get inside.  The other big
advantage.. I think they designed the closed knuckle well in advance of
the open knuckle.. so the advantage is - it existed when open knuckle
didn't.. thus it's use in many older 4x4s.

> other vehicles with this design (perhaps IHC products).  I understand

IHC did.  Older Travelalls and Pickups used closed knuckle front ends..
I think the Dana 27 on the Scout 80 was closed knuckle.. and if you go
back farther, that's all you'll find.

> that turning radius is affected.  These vehicles also offer a "full
> floating rear hub" whereas, I am told, theIH Scout2 Dana 44 (which I
> have) is a "semi floating" type.  What does this mean?  Are my Dana

A semi-float axle has the vehicle weight supported by a single bearing
at the wheel "hub" area (weight transferred through the axle tube
partially) and weight is supported by the axle shafts themselves.  Think
about it.. with just one wheel bearing, you only have one pivot point..
you need a second to keep the axle shafts horizontal like they should
be, and that second point is the axle shaft itself, engaging the side
gears of the differential.

A full floater has two bearings and a hub assembly that supports all of
the vehicle weight.. the axle shaft does not support any weight.

There's a good write-up on the FourWheeler site, and an excellent
description done up by Bill Thebert for his FullFloater Axle Install
article in the Bulletin.. and at his tech seminar at Nationals.

> 44 axles prone to fatigue and catastrophic failure?  The Land Rover,

Dunno about that.. I think all axle shafts are prone to fatigue and
failure at some point when abused.

> as I am told, has a weak axle designed in as a "fuse" so as to not
> destroy other drivetrain components.  Does this make any sense?

It makes sense.  The lock-out hubs on a front-drive axle are designed to
be weaker than the differential and the axle shafts.. so the hubs blow
up before expensive parts do.  Some axle shafts have a deliberate taper
just before the splined section engaging the hubs.. this is another
purpose-built weak-link.. designed to fail before more expensive things
do.  U-joints, for that matter, in both driveshafts and in front drive
axle shafts, are a sort of weak-link designed in as well.

When I showed my step-dad my mangled rear driveshaft, his (somewhat
redneckish) response was, "When did you last change the U-joints" and
then "Stop keeping those joints in such great shape.. if you hadn't just
replaced 'em, the U-joints would've blown and not the actual driveshaft
tube".. which is an easier and cheaper repair.

> a periodic maintenance I should be doing?  I drive relatively few
> miles, mostly on paved roads, mostly in 2WD.  The Scout body rusts

I thought you said you sit in your Scout and read the paper?  Where did
this driving business come about? :-)

-Tom