What's the secret... how do I remove centre propshaft? '86 300G
Hi All,
Ok, so I know this is a well covered topic, although I have not been able to find any real clues (and admittedley most posts on this site were nearly 20 years ago!) - but how the hell do I remove the centre propshaft! Of the 16 nuts (8 each end) not even managed to loosen 1 
Can get spanner on, but as only partially and slight angle due to everything else in the way am merely 'rounding' nuts (and even made thinner spanner and cut to provide tighter fit than standard 13mm - can only use open end as nut so close to yoke).
Why? Am getting vibrations as speed up (feel them > 30mph), horrendous around 50 mph, then loosens but not away. No vibrations can be felt in gearstick, but transfer box (4WD selector) really vibrating. No steering damper issue (familiar with those), wheels balanced, tracking OK, no obvious suspension issues and bearings all done. OR is there something else I might be missing?
Managed to remove rear propshaft (only 2/16 needed angle grinder, at least had access compared to centre propshaft, see image) and had specialist check and no obvious issues, hence wishing to try prop linking gearbox/transfer case... and failing spectacularly. Can't feel or see anything wrong (so happy not to remove if can avoid), but is next on my search for cause as driving is not pleasant.
Grateful for any suggestions. Or stories of similar woe to make me feel better. Might be tricky as only now 28 licensed 300GD's, seems everyone is sticking them in a garage so need to keep my daily drive going (114 SORN).
Tally ho,
Stewart
They are awkward!
Good quality, tight fitting spanner that hasn't got splayed jaws is the only advise I can give
Febi do sets of 8 bolts and nuts at reasonabe price compared to MB although they have shot up like everything else!
If it has not been off in a long time, is well greased and no obvious play or damage and no sign of any missing balance weights on the prop you may well be wasting you efforts
Are the Panhard Bushes and Front Control Arm Bushes in good order? Is the Transfer Case Brace intact and Bushes in good order and Trasfer Case Mountings the same?
When the rear prop was off did you look at the rear vibration damper that sits immediatley behind the Transfer Case on the diesels that the long front bolts go through? Not sure exactly how it works or how to check it, but I understand it isn't just a metal spacer like it looks! The petrols don't have them, parts listing calls it a Damper so it must be there for vibration issues on the 5 cyl 460 diesel drive train as the 6 cyl 463's diesels don't have them fitted
Assuming from your description you're not getting vibrations through the steering wheel? Just the TC shift lever?
Incredible choice of 13mm spanners when you research them, or grind down a ring spanner to get on? Tho lots of plus gas 1st? Is vibration a recent thing? Nothing changed before you noticed it as in tyres etc?
Propshafts don't just go out of balance. Maybe it took a knock. I've never removed one, but surely applying heat once you get a good ring spanner on it will help?
Another random thought - could you try a spot weld on a best guess spot, to see if its worse or better (balancing). Completely hit and miss idea though.
Unsure how techy you are but if you could buy a cheap webcam and connect to phone, you can see vibration as you drive along, if you secure camera underneath?
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Hi Gav - thank you for all the points! Vibrations through the whole car, can feel it through seat. Am familiar with steering issues and this is very different. Was very disappointed when rear-prop checked out OK, means need to keep digging!
YES, have looked at damper (images attached - and yes, spot angle grinder damage required to remove 2 x rounded nuts). No service required, it is very heavy and basically 2 x large rubber washers encased in metal and held together with 6 x bolts and then the 8 x prop bolts.
And bit blimmin late letting me know about Febi bolts
, just ordered through MB after having tried elsewhere including fastener specialists - cost £70 for 16x bolts and 32 x nuts 
- decided to get full set if decide angle grinder is way forward to remove centre prop (costly, but s'pose saved money as repair on prop not required). For nut/bolt officiando's they're M8 with fine thread (M8 typically 1.25 mm, these 1mm) and with a 10.9 hardness (apparently harder than normal). And of course the bolts have shoulders sized to fit between the prop connecting plates.
Bushes all appear OK, and transfer box mountings.