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[paulhide]

Can anyone give the definitive answer as to why my P4 shudders round tightish corners even though I've changed the viscous coupling with good bushes?? The car does not do this with the 4WD switched off. And can the two sides of the propshaft on either side of the coupling be fitted 180 degrees out of alignment? The propshaft to the rear can only be fitted one way because the four fitting bolts connecting to the coupling aren't symmetrical, but the front propshaft could be fitted one way round or the other. I just remember reading something about balancing somewhere? If this is true how would you know if you'd got it wrong way round??
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Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

[Deano]

The viscous coupling allows rotational slip between the front half of the propshaft and the rear half. Therefore, the front and rear sections of the propshafft are never going to be fixed in relation to one another. So it shouldn't matter how you put it back together as long as you put all the bolts back in! If the propshaft is out of balance then you will experiene vibration whilst driving in a straight line. Both of my P4's suffer from "shudder" when manouvring at low speed on full lock, and so do all the other ones I have driven, so welcome to the P4 club!

[Matt Stolton]

I know the shudders you are talking about, as mine had them terribly.

However, after replacing both the rubber mounts on the viscous coupling, and reinforcing the tunnel to which the viscous bolts too, ALL p4 shudders went. We had to reinforce the tunnel, as I ripped one of the rubber mounts out of the tunnel.

I think the larger bush was about £30, whilst the smaller one was more expensive, as it has a bearing already in it, at around £50, if memory serves, both through a Alfa Main Dealer (Desira).

I can't remember which way around they go, but it would make a huge difference to whether the viscous would work or not.

Anyway, I think each bush has different number of bolts to the tunnel wall, so that should help with working it out.

We also played with the alignment of the gearbox rear mount, and the arm that extends from the rear of the box and supports the base of the gear shift. By making sure that is aligned nicely to the rear shaft, it gives the maximum designed space for any deflections in the drive shafts.

Even if the rubber looks in good nick, I would replace them, as they do get soft, and lead to a lack of control on the drivetrain.
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Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

[LDA]

both of the p4's i've had do the low speed shuddering.
never worried about it and just put it down to not having a proper 4wd system.

Matt, could you give a little more detail on the extra reinforcement you added?
did you just weld in some extra plates and if so what shape where they etc etc..

L.
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A good workman allways blames his sh*t tools.