E39 M5 Elusive Vibration...
Discussion
Dear //M People,
The old girl now has one, troublesome issue.
Bearing in mind that this week saw new drop links, control arm bushes, comprehensive suspension appraisal (yielding clean bill prognosis), all new tyres and the alloys 100% ito there being no imperfections and balanced up, the continuing, unwelcome prescence of the 70-80mph shimmy has us all quite bemused.
The poise of the car in general is fabulous, the suspension feeling 'refreshed' and below and above this range, it is the model of stability I always knew the thing to be.
And yet, in 90% of 70-80 cruise scenarios, there is a most definite tremor through the wheel, felt too through the seats. The chief tech is nearing full bemusement and is investigating further this coming week.
Is there anything from the category labelled 'bleedin' obvious' that needs ticking?
The old girl now has one, troublesome issue.
Bearing in mind that this week saw new drop links, control arm bushes, comprehensive suspension appraisal (yielding clean bill prognosis), all new tyres and the alloys 100% ito there being no imperfections and balanced up, the continuing, unwelcome prescence of the 70-80mph shimmy has us all quite bemused.
The poise of the car in general is fabulous, the suspension feeling 'refreshed' and below and above this range, it is the model of stability I always knew the thing to be.
And yet, in 90% of 70-80 cruise scenarios, there is a most definite tremor through the wheel, felt too through the seats. The chief tech is nearing full bemusement and is investigating further this coming week.
Is there anything from the category labelled 'bleedin' obvious' that needs ticking?
Cheers guys but what about this, maybe?
http://www.ca-automotive.co.uk/products-Y2FyX21ha2...
I just have this inner feeling it's a frequency/resonance somehow connecting transmission and chassis...
http://www.ca-automotive.co.uk/products-Y2FyX21ha2...
I just have this inner feeling it's a frequency/resonance somehow connecting transmission and chassis...
Chaps, I don't know why but yes, the propshaft cum mounts side of things feels like a distinct poss: it's the way it 'comes on' under certain loadings: it's most prevelant in the 70-80 zone but it can be felt to a lesser degree elsewhere and often during a charge, it just feels like something's out of kilter, out of synch - and a rotating shaft which isn't quite true of axisional perfection I can imagine emanating the distortive frequencies which would resonate accordingly.
Oddly, it always feels worse when cold although M5 'breathing' generally is a documented issue so I spend a fair while warming her juices (ahem) and eventually trickling along very genteel like until temps are nicely up.
Unfortunately, the specialists are all southerly and I'm stuck with main agents and (hopefully
) salvation via what you guys are suggesting. 
Re the wheels - I dunno but I just don't think it is them. Current rubber is nearly new Dunlop Sports but believe me, I tried all the others, it makes no odds and the dealer's chief tech bod assures me the wheels are 100%.
I'm going to mention all the 'arm' related possibilities but I suspect these have been checked over.
So annoying because 95% of the time it's fine (well, more than fine) and the whole way the heel n' toe/blip for sheer effect repertoire flows so naturally makes every journey utterly beguiling.
Don't worry I have some more tablets due at 11...
Oddly, it always feels worse when cold although M5 'breathing' generally is a documented issue so I spend a fair while warming her juices (ahem) and eventually trickling along very genteel like until temps are nicely up.
Unfortunately, the specialists are all southerly and I'm stuck with main agents and (hopefully
) salvation via what you guys are suggesting. Re the wheels - I dunno but I just don't think it is them. Current rubber is nearly new Dunlop Sports but believe me, I tried all the others, it makes no odds and the dealer's chief tech bod assures me the wheels are 100%.
I'm going to mention all the 'arm' related possibilities but I suspect these have been checked over.
So annoying because 95% of the time it's fine (well, more than fine) and the whole way the heel n' toe/blip for sheer effect repertoire flows so naturally makes every journey utterly beguiling.
Don't worry I have some more tablets due at 11...
belleair302 said:
That E34 would have been a much better acqusition than spending cash on an E39....you cannot beat a handmade, low volume limited edition car.
Ooh, I dunno, there's still an illicit thrill in smiting VW CGTs and their ilk! 
(Not to mention pesky E46 320d bods who are genuinely stereotypical and clueless in equal measure!)Hello Jesmondacles of The Lower Palatine.
Old girl in yesterday for one last go, thence to the specialists for which referencing I'm grateful to Messrs ASBO and V1xpy.
Drop links, done; thrust arm (bushes), done; control arms being done; sub frame mounts being done; gearbox mounts being done and propshaft 'doughnut' bush being done (where 'done' = checked and replaced if necessary.)
If none of this works then (a) I'll resume my affectation with Scottihs distilleries and (b) try some other wheels up front.
Charlie's man suggested something to do with the brakes but I'll look at that one via said specialist if all else fails.
Biff may have hated manure but I hate untraceable vibrations!
Old girl in yesterday for one last go, thence to the specialists for which referencing I'm grateful to Messrs ASBO and V1xpy.
Drop links, done; thrust arm (bushes), done; control arms being done; sub frame mounts being done; gearbox mounts being done and propshaft 'doughnut' bush being done (where 'done' = checked and replaced if necessary.)
If none of this works then (a) I'll resume my affectation with Scottihs distilleries and (b) try some other wheels up front.
Charlie's man suggested something to do with the brakes but I'll look at that one via said specialist if all else fails.
Biff may have hated manure but I hate untraceable vibrations!
Usual brand of not quite Lexian service: Von ASBO's excellent diagnosis was acknowledged by the dealership yesterday in a moment of self-confessed, Homer 'doh-ness,' propshaft doughnut duly ordered and yours truly had been looking forward to a paragon of moorland schnleted solidity only to be told several times that bits and pieces were lying around and eventually, some clips which should have accompanied the parts hadn't been in the pack and...well, you know BS when you smell it.
Even so, I've been assured it will be ready on the morrow so will be expecting it's delivery at some point. Thence to Fearnsport for the brake saga: assuming the vibe itself is done for if not, the great man can sort that, too.
RS6 for sub £25k, anyone?
Even so, I've been assured it will be ready on the morrow so will be expecting it's delivery at some point. Thence to Fearnsport for the brake saga: assuming the vibe itself is done for if not, the great man can sort that, too.
RS6 for sub £25k, anyone?
Squire, it's already on it's 2nd AP 6 pot system (up front, std at t'rear) which have been a model of utter dross to date.
Lord ASBO's researchers have cited the works of renowned Beemer race fettlist, Jeff Steel whose theory on this surrounds the relative lack of floating (if any, in extreme circs) for these discs caused by heat expansion relative to the bell housings.
Apparently, the boltholes may need reboring... A Farewell To Vibrations. We shall see - this is certainly a job for our man at Silverstone.
Lord ASBO's researchers have cited the works of renowned Beemer race fettlist, Jeff Steel whose theory on this surrounds the relative lack of floating (if any, in extreme circs) for these discs caused by heat expansion relative to the bell housings.
Apparently, the boltholes may need reboring... A Farewell To Vibrations. We shall see - this is certainly a job for our man at Silverstone.
belleair302 said:
It is worth doing both front and rear if serious about Vmax...
Er...Well the propshaft doughnut was knackered and replaced: I'd say it has made a big difference, especially in the sub 70 zones although a trace wobble can still be suffered - albeit less frequently - when obeying m-way speed limits. Ish. There is also still, a distant and very low level 'knock' somewhere in the bowells when traversing certain ridged imperfections - this is a real swine because it is something I am 'tuned' into - the average techy simply cannot fathom this one...
Will ask about the diff but nobody's suggested that hitherto and all bets are leviatating towards a disc imperfection and resultant troubled relationship between caliper(s) and/or bell housing.
My problem is that I am a perfectionist and I'm sure 95% of folk wouldn't notice but I know it's slightly off and like the Spartan King, compromise is not really on the menu.
Ok, dowager update...
+ve news, by the sounds of it.
Andy Fearns has been kindly teaching the roundabouts of Bicester the meaning of Herman Does Oxon this last week and in conclusion has pretty much stripped and rebuilt the brakes.
The AP discs weren't warped but a coagulation of fetid, socialist, road bourne detrius had caked the surface so severely that lunarscape rather than mill pond described the interface suffered when pad made contact, a surefire wobble guarantor.
He changed the disc holding bells and the seals (12 off) in the calipers where seizing was an issue. (This was a bit of a prob astern, too, so these have been attended accordingly.)
A softer compound pad has been inserted and first reports are both wholesome and smeared of baby lotion. Let's just hope trafpol are in the correct frame of mind for the post collection journey...
Von Fearns has also concluded that the front shocks and strut tops need replacing which might account for a low level, barely perceptible but 'hone-inable' ocassional knocking from the lower decks so I'll get that seen to by the dealer next week when the PDC sensors are replaced.
It would've been more cost effective to relaunch Cornwall's tin mining industry but common sense went some way west of wonder a long time ago.
Onward...
+ve news, by the sounds of it.
Andy Fearns has been kindly teaching the roundabouts of Bicester the meaning of Herman Does Oxon this last week and in conclusion has pretty much stripped and rebuilt the brakes.
The AP discs weren't warped but a coagulation of fetid, socialist, road bourne detrius had caked the surface so severely that lunarscape rather than mill pond described the interface suffered when pad made contact, a surefire wobble guarantor.
He changed the disc holding bells and the seals (12 off) in the calipers where seizing was an issue. (This was a bit of a prob astern, too, so these have been attended accordingly.)
A softer compound pad has been inserted and first reports are both wholesome and smeared of baby lotion. Let's just hope trafpol are in the correct frame of mind for the post collection journey...
Von Fearns has also concluded that the front shocks and strut tops need replacing which might account for a low level, barely perceptible but 'hone-inable' ocassional knocking from the lower decks so I'll get that seen to by the dealer next week when the PDC sensors are replaced.
It would've been more cost effective to relaunch Cornwall's tin mining industry but common sense went some way west of wonder a long time ago.
Onward...
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