UJs vc and proppy shafts

[robobobo]

Hi all, as a quite recent syncro convert i am learning fast there is a lot to learn about syncros. I have read up on a lot of tech pages but have some questions related to the removal of my prop shaft and it's effect on my good vc.

I was getting the occasional grumble from below when taking off at low speed usually just after the clutch has bitten(a low bell sounding rumble). I have removed the prop to check the cause assuming something was amiss. I found one of my UJ has a flat spot and the bearings are generally a bit worse for wear(the front one) the rear is fine and smooth.

1stly, are the bearings and shaft in the UJ any way serviceable

2ndly, if not can anyone suggest the best value for good product supplier for a new ujoint, can i still get one from mr vw !

3rdly, am i right in thinking that the front wheels are still turning the front plates in the vc thereby permanently locking the vc whilst i drive the van with no shaft. Does this not cause damage to a good vc by continually having the plates slipping and locking the vc having permanently frigid silicone.... I know it's prob ok as iv'e read many people remove their shafts and also fit decouplers but just dont understand the ins and outs

forthly, again thirst for knowledge, going from what i have just assumed (could well be wrong).. when a decoupler is fitted and decoupled, does the front gear still turn the prop shaft via the vc. Does this mean there is no fuel benefit during regular road driving being decoupled as mechanically everything is still in action??

I think that is probaly enough for now although i have many more questions in me somewhere i think. Thanks to anyone who looks or offers advice to a new kid.

On a nice note, whilst driving my goldy syncro the other day someone followed me. On the verge of thinking something was weird i pulled up at my destination to be accosted by a very eager and thoroughly nice man who told me he had owned the van for most it's life as his family vehicle. He told me the full life of the vehicle up to the trader i brought it off including a new vw gearbox halfway through its years. As a bonus he still has all the old manuals, service history, MOTs ,receipts and photos that he kept for the vehicle including a picture of the british soldiar stationed in Germany who got it new from the factory. How nice is that! Thanks Alan, ill try and keep up as good a record as you have. And sorry to the syncro gods for reversing into that fence ! Another job to fix

thanks for any advice offered syncroexperts
all the best, Robin in le manchester

[syncropaddy]

Someone will be along with the name of the guys who refurb propshafts in the UK.

When the prop is dropped the VC does nothing at all so wont be damaged

Some people report a fuel advantage when decoupled. I cant answer cuz I dont have one fitted.

[HarryMann]

That bell-ringing is common, it's not balance, it's a natural characterisic accentuated by:
Play in transaxle and front diff - main thing IMHO
A bush inside the rubber doughnut sleeve mount (though many say theres not a lot of difference when it's been done... ) can also make this worse, although I believe the main 'driver' is the prop responding to a crankshaft torsional vibration.

Aidans prop bush replacement article

What you are experiencing is when tthe revs drop back through the range that excites it, slip the clutch a wee bit longer, keeping revs above critical (1200~1400 rpm?).
You could also use high quality hose clips, balanced diametrically to clamp a damping material to centre of prop over a foot or so.. I bonded some bitumen panel insulation to prop, quietened it almost completely - until it got thrown off (props go slightly faster than engine speed in top gear!)
Also, can try turning rpop around, so doughnut is at other end

Prop vibes: CVJs (any of all ; trans mounts; engine mounts; diff mounts; wheel balance; prop balance, prop UJs, prop bent; prop alignment; doughnut shagged (uncommon)

1stly, are the bearings and shaft in the UJ any way serviceable

Yes, but the bearings are not often found on-the-shelf, and are staked not circlipped in.

A1 Props Bootle 0151-944-1586
£50 for one inc balancing (2 years ago)

https://club8090.co.uk/forum/viewtopic.p ... op#p183980

Also a Luton address I have which is much more expensive (the balancing seems to be overcharged usually..)

Another address (GKN Driveline) quoted here

2ndly, if not can anyone suggest the best value for good product supplier for a new ujoint, can i still get one from mr vw !

See that thread, but good 2nd hand VW one is better

3rdly, am i right in thinking that the front wheels are still turning the front plates in the vc thereby permanently locking the vc whilst i drive the van with no shaft. Does this not cause damage to a good vc by continually having the plates slipping and locking the vc having permanently frigid silicone.... I know it's prob ok as iv'e read many people remove their shafts and also fit decouplers but just dont understand the ins and outs

It is excessive long-term 'differential plate' rotation that causes problems

forthly, again thirst for knowledge, going from what i have just assumed (could well be wrong).. when a decoupler is fitted and decoupled, does the front gear still turn the prop shaft via the vc. Does this mean there is no fuel benefit during regular road driving being decoupled as mechanically everything is still in action??

All turns . As Andrew has intimated, the jury is out, SDP graphs for average surfaces suggest the Syncro system improves consumption!

[Aidan]

Baxter sells new trunions for our UJ's if you access to a press and a vice you can diy but it's not as good as having gkn or someone do it as they can actually adjust end float of trunion by using incremental size c clips whereas the kit just has one thickness supplied but they seem to work ok (normally that is Al make sure c clips are properly seated in grove - top tip)

[robobobo]

Thanks for that concise information, ill get on it and get that prop back on.
very helpfull cheers