Where's my 4WD?!?

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mrwoppit

New Member
Posts
103
Location
Didcot, Oxfordshire
Hi All,

Encountered an unexpected problem today, I got stuck in a wet muddy field. No problem I thought, 4WD it is.
Nope, only the back wheels are turning.
OK then, low box, that HAS to be 4WD!
Again, no, just the back wheels turning.

YIKES!

Took me a while getting a run up and trying various approaches but finally got unstuck. Not something I'm keen to repeat :S

I have free wheel front hubs and while they appear to be locked,I'm wondering if they aren't. OK, I'm hoping it's the free hubs rather than the half shafts or something more dire.

I've read the advice about jacking the front end, putting it in gear and 4WD and turning one wheel to see if the other counter-rotates but surely if the free hubs aren't locked this wouldn't happen anyway?

How do I go about stripping down the free hubs and once I have, how do I tell if they are locking or not?
Is it as simple as removing the 6-7 bolts around the edge of the hubs and pulling off the protruding "cap" and "free/lock" disk?

Thanks in advance
 
first question is what FWH's have you got ??

if they are MAP's then there is always the possibility they've froze disengaged, good looking hubs but not the best in my opinion

other makes "may" have the same failing
 
OK, I've done a little more investigation and have more info.

They are ORA free hubs, I've included a picture below.

Some tests and results...

In neutral I can manually rotate the front prop shaft, there's no "nasty" noises I would associate with a knackered diff or anything else in the drive train being broken.
Can still rotate it manually in 2WD in gear.

In 4WD (high or low box) I can no longer manually rotate the prop shaft, other than for about 1/4" which I'll put down to play in the system.

With one wheel jacked up, 4WD engaged and in gear I can't manually rotate the prop shaft (yes, I know, redundant test but I like to be thorough :) ).
Still jacked up and in gear/4WD I spin the wheel by hand and there's no movement on the prop shaft at all. Not even to take up the 1/4" play.
The wheel moves easily with very little resistance. Everything sounds fine, no nasty noises I would associate with something having broken.

So, from all this I think I can conclude that the most likely problem is the FWH, though it is of course still possible it's something else.

Does that sound plausible? Sensible?

In which case, are FWH difficult to replace?
Is it worth replacing them with new FWH or should I revert to standard hubs?
Anyone know what parts I need on an '84 series 3 88" to convert back to normal hubs?

Any advice and suggestions very much appreciated!
 

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i'll agree that it's a fault in the hubs, it might just be the nut on the end of the halfshaft missing

late axles often have 24 splines on the shafts but to be sure you need to open the FWH up

i have a pair of 24 spline AVM's here if you're interested/in need
 
OK, I thought I'd try unlocking and relocking the FWH but they won't budge. Even with excessive force :S

Again, to me points to the FWH being the problem. I realise this may be wishful thinking.

So, how do I get them off?
Just undo the bolts around the base and pull?
Will I be able to see how many splines there are from that?

Nitemare, the offers much appreciated but timing's the issue.
I kind of need them ASAP so was going to order them online (once I know how many splines).
These look identical in style to my ORAs (and being AVM's are the same as yours Nitemare?):

Bearmach Free Wheeling Hubs at www.rimmerbros.co.uk

Thanks for all the advice guys, more appreciated than I can say being a long term aspirant and very short term owner!
 
they are the later versions than mine, on appearance alone i prefer my ones (i have three sets) which are constructed with less aluminium

here's a picture of one of mine waiting for me to clean it up and fit it to my '65 109
TinTent.jpg


edit
jesus, just noticed the price of them on that website link, think i'll keep my spare ones and look for another pair of inserts to suit the 10 spline shafts ready to go on my other 88" when i get round to building it
 
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From the look of yours off the vehicle, it suggests I do just remove the 6 bolts round the edge and pull. Is that right?
If so then surely fitting them is simply the reverse and therefore a blindingly easy job.
 
OK, I thought I'd try unlocking and relocking the FWH but they won't budge. Even with excessive force :S

Again, to me points to the FWH being the problem. I realise this may be wishful thinking.

So, how do I get them off?

Undo the screws on the outer cover 1st (the bit that turns) and the guts of the f/w/h comes out. Undo the nut on the end of the half shaft, remove bolts into hub around the outside and the whole thing comes off.
 
Jamesmartin, there's one on a previous post, but here are a few more...
 

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somewhere in the dim recesss of my memory either ORA or AVM were a copy of the other (maybe a licensed copy) so as directed earlier

undo the six little screws (can be a bugger to undo, may need a little shock with a hammer and drift) and lift the cover off complete with the bit you rotate to engage (

under that you'll see a castellated nut with pin arrangement that needs removing

once that is done then all you need to do is undo the six bigger bolts that attach the body to the hub itself, a little tap on the side of the casting will ensure it falls off

the AVM hubs are pretty forgiving but do stick with age/corrosion/muck if not operated reasonably frequently, my first pair had to be stripped and cleaned, yours possibly have the same problem
 
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