D Drive shaft question

L

leendert

Member
Tadpole
Joined
Sep 20, 2014
Messages
30
Location
melbourne
Hi Gents, can anyone pls explain what is the functionality of the two weights clamped on to the DS23 's drive shaft and do these need to be located in exactly the same position as they are ? These are not applied to a SM's drive shafts? Comments greatly appreciated. cheers lee
 
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I believe they are for vibration management. A bit like wheel weights
 
Yes, harmonic balancers.
They have inertia and are rubber mounted with a natural frequency much higher than any vibration resonance that might develop in the driveshaft.
So they dampen out any such vibration.

Their exact position is not critical, roughly midway on the shaft, so they can act on any vibration coming from either end.
 
Um............ they did....... often.
And GS as well.
Probably CX too....... Shane?
 
Buttercup said:
Um............ they did....... often.
And GS as well.
Probably CX too....... Shane?
Click to expand...

CX's ... I don't recall ever noticing them. The shafts are short, and quite strong given the modest power. The RHS shaft has a solid shaft over to the carrier bearing, then a very short outer shaft.... and the left hand side is short as that is where the gearbox is (east west engine).
 
My 1974 DSuper5 has them, my 1972 Safari doesn't.
Similar to those two big weights in the engine bay, do they make a difference?
 
Buttercup said:
Um............ they did....... often.
And GS as well.
Probably CX too....... Shane?
Click to expand...
Ok, I recall reading somewhere that the later models didn't have them. I seem to remember my first D (second nose) had them. My subsequent Ds ('74 and '75) did not. I refurbished my '75 D Special drive shafts a few years ago without them. I assume if you don't have them and are not experiencing any vibration, then no need. For those that do, there's a page from the DS manual on the Citroen Classics website which says there should be a gap of 159mm between the outer boot and the weights on the LHS side (longer shaft) and 91mm on the RHS (shorter shaft).
 
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It might be a case of "who really knows"

My '72 DS21 which has a known history since 1975........ has them!

I know the mixing and matching that has gone on with Dees over the last 65 years has made it impossible to base opinion about originality on current status.

I know of a 1 owner DS21 with an aluminium boot lid. The owner declares with certainty that it was so since the day he picked it up from the showroom.
But we also know there was shipping damage, quickly rectified by dealers using whatever parts were on hand, before new delivery.

I'm not saying that driveshafts are susceptible to shipping damage, but each these cars has a veeeeeeeery long history.

We also know that Citroen had a policy, that no 2 cars would ever leave their factory EXACTLY identical.
 
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Looking at the parts books, they were introduced for the '69 model year on all DS21 and ID21 F models.

Moving forward to the '72 parts book they don't mention specific models suggesting that all models got them from that point on.

For those playing at home, the LH one has a yellow marking and the RH one has a blue marking.
 
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