15 month lucky streak over - propshaft coupling/ exhaust query

Hi there people
My lucky streak (Nov 2011 until now) with no mechanical problem presenting itself is officially over, though my car is still running OK.

The diagnosis of the problem involves some parts/ terms i'm not familiar with, please excuse me if jargon I'm using isn't quite right.

The car is driving fine but i started noticing a metallic 'ding' noise recently, originating from underneath the middle of the car, which would only ever occur once just after shifting gears between "D" and "R". If I was parking, i notice this little ding noise just after D or R was selected. I wasn't much worried .. its hardly noticeable.

The diagnosis is that the driveshaft joint ( universal coupling) has some play in it (i think its the part in the middle of the driveshaft). The repair itself is apparently simple BUT, it requires access and so the whole exhaust needs to be dropped. Which is where the main problem lies -- if we drop the exhaust, some of the joins and stuff are real brittle, they are NOT going to make it.
The particular part identified as especially weak is a kind of flange/ collar thing below the manifolds - i think its the section circled here:

Is anyone familiar with this flange? Can it be repaired somehow?

Does anyone know any capable , not overly expensive exhaust fabricators with E31 experience? London / SE?

thanks..

Thanks for replies.
Yes indeed Graham. I'll never be more ready for a repair than I am currently, so no grumbles.

Pod - its possible that mine can be removed and stay intact, but unlikely. There are sections of my exhaust which look far more brittle.
Also, my garage man does not fabricate/ fit exhausts. so he has no financial incentive here, in fact he gave me his typical advice - don't worry, it'll probably last another year, he said! (half joking)
He also isn't very concerned about the play in the propshaft, although obviously we know it'll need fixing soon.

Right now, i'm a little unsure what the best sequence of tasks i should follow.

My garage guy basically told me to go start sourcing a reputable exhaust fabricator/ fitter, and he recommended one in Hayes in case i was stuck ['Longlife Exhausts' - if Stuart recommended them , its because they are genuinely good. He's a stand-up guy himself.

Zitat von Timm;109401

The last time I spoke to this Ebay seller:

http://myworld.ebay.co.uk/rall…ia?_trksid=p2047675.l2559

he had a propshaft from an 840ci - I was going to buy the front half (with the universal joint) until I found it was the other end (the CV joint) that was the problem. The Universal Joint is part of the propshaft and BMW do not sell it separately - although there are firms that do refurbish them.

Thajks Timm

Zitat von Timm;109404

I don't recognise the part the garage is describing as disintegrating - I can't remember any part above the cats at all - nor is there anything significant on the diagram:

http://www.realoem.com/bmw/sho…&btnr=18_0934&hg=18&fg=10

The parts above the cats (or around that area), are the guibo (rubber doughnut), gearbox mounts, and a bit further back, the centre bearing. Can you post the picture the garage gave you?

its this bit i think Timm, but there are other weak sections too... doesn't look like an easily fixable bit. What should i do? :O) [sits and hopes]

8er.org/forum/index.php?attachment/21604/

Zitat von Noggie;109405

The drive shaft coupling/bearing can be replaced. not a big deal.

Yep, my garage guy said the same.. 1 hours work tops, he said.

I'll bear in mind what you said about the manifolds. I think he reckons that as the sections come apart, the decay might be worse than expected.

Post #1 now edited to make more sense to anyone joining thread later:

Oh, and PS: I will be getting emailed the actual pix of the car tomorrow, so i will update the thread with those when i can.

Timm: i think i described the location of this collar/ flange wrongly in my OP, its this one:

8er.org/forum/index.php?attachment/21605/

Hi Reinhard, thanks for reply. I have noted and will repeat your words about checking guibo etc.
The metallic ding did not appear coming from the differential, it was apparently quite clear what was making it. Although i will now check this again.
In fairness, he actually said:
1 hour work excluding the time taken with the exhaust on/ off. In fact he said pretty much exactly what you said here. 'Its not complicated'...

I trust him completely. He is not hastening the end of the exhaust; but equally, he is not volunteering to remove it unless I'm ready for the potential consequences. Given the fact that he does not really undertake exhaust replacements, he simply suggested that i think twice before removing the exhaust.
As we don't have any parts handy or ready, he is correct - for the time being, no?
He also said that he intended splitting the drive shaft, and that a new one would likely not be necessary. He is a very creative and capable technician and his philosophy, 100% of the time, is to save money, re-use and repair where necessary.
The parts i've been shown are very rotten, so its possible i've mis-identified where this collar/ flange is, but thats not the only site where there is severe rot.
I'll get the pix off him and post them up.

Does it make sense to re-use the existing manifolds, with a new stainless steel exhaust?

One of my problems is really not being able to understand exactly what sections i'm likely to need.
I'll only know what sections once its removed and examined. But when that happens, i'll really need the parts in a hurry.. its an annoying Catch 22.

I would happily spend any needed money with Mr Engl -assuming they'll fit a V8. Price seems good, too.
Is it practical to buy those parts from him, and get them sent to me?
Is there a way of making a definitive decision of whats needed prior, or without, removing the exhaust first?

As a side note: the car has never leaked a drop of oil except when i tried to lubricate a squeaky brake pedal once...

I just had a word with him mentioning Reinhard's points and he was reassuringly aware of need to check Guibo, and marking the middle sections. I'll hopefully get some pix emailed to me soon, but I must dash out now. Will update thread ASAP.

Any further replies welcome

Update:
here is a pic of the rotten flange - its on the manifold downpipe. Obviously there are some other areas of concern, corrosion-wise.. In case anyone has a suggestion about a way to repair this flange, pls let me know.