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Sandringham 6x6


bill van snorkle
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A mate of mine rang to tell he is thinking of buying a Stage One V8 based Sandringham 6x6 from the early 1980's that is currently for sale over here. This apparently has some problem with the thru drive diff on the forward rear axle. I had a look at a Sandringham (probably the same one) about 15 years ago. the chassis modification and rear suspension was an abortion, but I can't recall too many details of the special diff . Does anyone know of any web links that give a schematic view of this component, and just as importantly know if spare parts are still available ?

Bill.

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I was chatting about this with Stumpy2268 the other month as I think his mate had a through drive diff or was looking at doing this. ISTR he diff if it went pop was in the region of 5K sterling :o :o :o :o .

Be carefull what your mate buys

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I was chatting about this with Stumpy2268 the other month as I think his mate had a through drive diff or was looking at doing this. ISTR he diff if it went pop was in the region of 5K sterling :o :o :o :o .

Be carefull what your mate buys

5k for the thrudrive ? That is outrageous. He won't be buying the POS at that rate. Thanks for the warning.

I just remembered I still have my homemade thru drive under what remains of the skeleton on my old 6x6. I wonder if it has rusted into a solid mass in the 15 odd years it has been lying dormant ? I'm seeing dollar signs before my eyes.

Bill.

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Bill may i ask how you built your throughdrive and from the short clips i have seen the rest of your 6x6, articulation was very impressive, do you have any pictures of the rear axle setup?

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Bill may i ask how you built your throughdrive and from the short clips i have seen the rest of your 6x6, articulation was very impressive, do you have any pictures of the rear axle setup?

I hope this long winded explaination is not too difficult to follow.Thru drive is not too accurate a description of what I had. They, meaning both thru drives, as there was one on each rear diff, consisted of a slim gearcase with a train of 3 gears bolted on to earlier diff housings through the 6 oil seal housing bolt holes, drilled out and retapped to 7/16'' unf, similar I suppose to the Foley Special Vehicles or Ashcroft 6x6 power dividers. I fabricated the gearcases from steel and had them jig bored on a milling machine. For gears I used 2 high gear wheels and the helical intermediate gear from series Landrover

transfercase. The top shaft of the forward power divider was made from a transfer case output shaft and had a dog clutch from a centre pto to permit drive down to the diff pinion to be disengaged. The gear that fitted on to the diff pinion was bored out and a 4 spline pinion flange pressed in and welded to it.

The top shaft of the rear power divider was also made from a t/case output shaft, but the dog clutch did not have a selector to disengage the drive down to the pinion.

Both rear axle assemblies were turned back to front so that the pinions faced the rear of the vehicle, The propshaft from the vehicles transfercase went over the top of the forward axle housing and connected to the top shaft of the first power divider, the train of gears took the drive down to the diff pinion. A second prop shaft connected to the other end of the top shaft of the forward power divider and then went over the top of the rearmost axle and connected to the top shaft of the second power divider. This arrangement permitted a very large amount of bogie articulation due to the relatively long and level propshaft for the closely coupled axles and the double slip jointed propshaft to the forward axle was also reasonably long and level even though the axle centre line was placed only 10 inches from the handbrake drum for a wheelbase of 74 inches plus 39 inches . I found a photocopy of an article in a mid 1980's 4x4 Australia magazine that I was certain had photos of the power divider but those seem to have vaporised. Next time I go to the vehicle graveyard on my land I'll take the camera.

Bill.

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Thanks bill, I have drawn this diagram of what i think you descibed although it could be totaly wrong :lol:

Bills6x6.jpg

Which axle did the dog clutch prevent drive to? i presume the rear one?

What type of suspension did it use? coils or leafs and i presume the axles were independantly sprung rather than being mounted in a bogie type arrangment?

Thanks, Will.

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5k for the thrudrive ? That is outrageous. He won't be buying the POS at that rate. Thanks for the warning.

I just remembered I still have my homemade thru drive under what remains of the skeleton on my old 6x6. I wonder if it has rusted into a solid mass in the 15 odd years it has been lying dormant ? I'm seeing dollar signs before my eyes.

Bill.

There was also a story in LRO I think. Not sure what edition but at least 12 months ago. HTH

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Thanks bill, I have drawn this diagram of what i think you descibed although it could be totaly wrong :lol:

Bills6x6.jpg

Which axle did the dog clutch prevent drive to? i presume the rear one?

What type of suspension did it use? coils or leafs and i presume the axles were independantly sprung rather than being mounted in a bogie type arrangment?

Thanks, Will.

Yes Will the diagram is quite accurate except of course that the drop boxes were further back and bolted to the pinion housings,and that the intermediate gear was the larger of the 3 gears in the train. The dog clutch disconnect was on the forward axle. In practice, after a trial period I realised that windup didn't occur due to the vehicles relatively light weight, so I generally had both rear axles engaged.

It had a proper load sharing bogie suspension with an inverted centrally pivoted leaf spring on each side and torque rods like many 6x6 and 6x4 trucks. You may be able to pick that up on a couple of the short video clips. I'll try to find the video clip of a 6x6 converted 101 making hard work of climbing a small sand dune, which illustrates what can happen when not enough thought is given to designing a 6x6 with adequate bogie articulation. 6X6 Pinzgauers have similar problems under certain conditions, and Sandringhams had no articulation whatsoever.

Try this http://video.google.com/videoplay?docid=2431106815226648783

bill.

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Thanks for those pics Grem. That thru drive looks quite complex. Too much re engineering for a weak Rover diff. Gold tooth on a rat springs to mind.It would have been far preferable to rework a Salisbury.

Bill.

Is it not as "simple" as cutting the bowl off the back of a rover diff and mounting another diff nose+pinion on the back (upside down)? Getting the backlash right is likely to be a bit tricky - but not impossible.

Si

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Is it not as "simple" as cutting the bowl off the back of a rover diff and mounting another diff nose+pinion on the back (upside down)? Getting the backlash right is likely to be a bit tricky - but not impossible.

Si

I wpould not even consider doing it that way for two important reasons. Crown wheel and pinions are matched pairs that are lapped together to produce a satisfactory contact pattern . One would have to be extremely lucky to find a second pinion that gave the same contact pattern with the crownwheel and if it didn't that diff will howl and wear out very quickly. It would also be difficult to have 2 pinions lapped to one crownwheel ,even new ones.

A pinion flange measures around 270 mm from the axle centreline. two diffs facing each other equals 540mmIf you space the 2 rear axles 1 metre apart, that leaves you with an interaxle propshaft only 460mm long. with wide angle universal yokes this would only permit interaxle articulation of around 210mm which is nothing like enough for good crosscountry performance.

Bill.

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I've never seen it done - but it's something I've heard discussed - but for the reasons you've mentioned, probably BS. I guess you could fill the casing with grinding paste - it would soon lap itself together! ;)

Si

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Ok found it

Grem

He has gone to an enormous amount of trouble to convert that Salisbury.Aside from the shortcomings I previously mentioned, the other problem is that he has kept a Rover diff in the back, and with a rear suspension like that he will have very little articulation to equalise the torque loading in rough terrain.

In my own experience and also possibly that of Sandringham, due to the fact that they fitted Salisburies at the rearmost axle, the rearmost diff cops a harder time in cross country operation than the forward rear diff, so if you are only going to have one strong diff on the bogie then it should be at the rearmost axle.

Bill.

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