Banging and vibration in drivetrain

[d215yq]

Hi all,

Today I was going up a steep hill in 2nd and suddenly there was a loud metal tapping/thudding/drumming at 20mph in drive train... Seemed to be from rear right. And if I put my hand on transmission tunnel I could feel vibrations.

In third at higher speed it went away and full throttle on the flat it was fine. It was also fine slowly over uneven ground to my house. But came back uphill at around 20mph. I managed to get 4 km home but am not sure what to do and if it's safe to drive above 30mph. Certainly very loud tappkng/banging/drumming you can't drown out from the radio...other than vibration felt on drive train tunnel no vibrations through the car were felt and still accelerated smoothly.

The noise went away with clutch depressed at all engine speeds.

Not sure what to do...is there Anything I can look for underneath or should it even be driven at speed incase. It sounds more serious than the usual whines or characterful sounds - like a loud thudding somewhere at the back.

Any advice appreciated... In two minds to drive slowly tomorrow and see or just call the breakdown. I'd thought if it was in the drive train it would affect the smoothness of the drive which it doesn't. The parking brake suddenly doesn't seem as effective so not sure if that's broken in the drum though not sure if that would only happen in second and uphill and how it would cause vibrations...

Any advice appreciated.

 

[Uncle Benz]

Sounds like propshaft centre bearing problem to me

 

[d215yq]

Sounds like propshaft centre bearing problem to me

Thanks. Does that mean it's OK to drive about to the mechanic etc or should not be driven at all?

 

[John Laidlaw]

Fine until it drops off

 

[bembo449]

personally id jack it up and give it a wiggle , it should be obvious if it is the prop thats gone

 

[d215yq]

Well it went from doing it the first time only up steep hills to constant banging in all gears under any acceleration in 4km. Nursed it to the mechanics, in the end at 20mph...

Rubber centre bearing is shot and the metal clamp on the rubber had one fixing fail completely so the whole thing had 3 inches play...

I can't fault the village mechanic who has ordered the new part for 8.00am tomorrow (85€) and says 1-2h to fit so 125 to 160€ all in Inc labour.

I'm surprised how quickly it failed but can't complain if it's all fixed by tomorrow. If I was in Valencia city I'd be waiting 3 days for someone to look at it!

 

[d215yq]

Well it's fixed per sé for 120€ (1h of labour + new centre bearing rubber and bracket) but will it take sometime for the drivetrain to adjust to the new part? The banging has gone and the car accelerates and decelerates more positively than it did before any of this happened but there is now a small but persistent vibration/very feint rumble in the whole car at 52-62mph that I've never had before.

Is this a case of the prop shaft/doughnuts/other drivetrain has been knocked out of balance by the garage, or that it was more likely out of balance anyway and now it's more noticeable with a new centre bearing rubber. It arrived 100 miles back home not gettign worse, unless I just got used to it it seemed to be gettign better....so I'm not too bothered and can pop into the garage next week when I'm back in the village to see what they say.

Does anyone here have any thoughts if this would be expected or not? Is there something obvious they may have missed out I can point them towards?

 

[grahamcol]

If the propshsft hasn't been put back in the exact same position relative to any u/j's etc then this can happen. Garage should have marked their relative positions before any disassembly.

 

[Uncle Benz]

If the propshsft hasn't been put back in the exact same position relative to any u/j's etc then this can happen. Garage should have marked their relative positions before any disassembly.

exactly this. I bet its a spline out

 

[d215yq]

If the propshsft hasn't been put back in the exact same position relative to any u/j's etc then this can happen. Garage should have marked their relative positions before any disassembly.

Thanks for this, though I'm not sure of the consequences...will it get better as the rubber bits adapt or is this something that needs changing quick or somethign I can live with - though not sure how they will fix it if they forgot to measure/mark it in the first place?

 

[grahamcol]

I can only speak personally but l'd want it right. I can't see it self curing and l think you should complain and get it rectified. Good luck.

 

[oigle]

Not sure with yours but normally the rear uni joint can only be attached to the diff in 2 positions. Try undoing it and attaching it 180° rotated. More likely than being out by a spline.

Ian.

 

[LostKiwi]

Check the propshaft markings line up (if they're there):

 

[d215yq]

Thanks everyone, I think I understand better now, so he's basically got to do 60% of the job again... to unbolt the joint and then remove the front half of propshaft/flexi disc and then reinsert it again correctly lined up with the rear one. I'll take it back and ask...

Though I'm not sure if I should expect it free. Assuming the parts are 85€ (they were delivered within 2h so not comparable to ECP etc) then he charged me 30€ labour for the whole thing. Is this an easy mistake to make (e.g. most cars it is not necessary) or a schoolboy error when replacing it? The guy was 50 years old or so and had ran the family mechanics and immeidately identified the prop shaft bearing from the original symptoms and seemed to know his stuff so I'm a bit confused if this is an obvious mistake to make

 

[peterws1957]

Thanks everyone, I think I understand better now, so he's basically got to do 60% of the job again... to unbolt the joint and then remove the front half of propshaft/flexi disc and then reinsert it again correctly lined up with the rear one. I'll take it back and ask...

Though I'm not sure if I should expect it free. Assuming the parts are 85€ (they were delivered within 2h so not comparable to ECP etc) then he charged me 30€ labour for the whole thing. Is this an easy mistake to make (e.g. most cars it is not necessary) or a schoolboy error when replacing it? The guy was 50 years old or so and had ran the family mechanics and immeidately identified the prop shaft bearing from the original symptoms and seemed to know his stuff so I'm a bit confused if this is an obvious mistake to make

If his labour charge was only 30 euros I personally wouldn't be complaining, but ask him to check the now obvious vibration. You can imagine what an MB dealer would have charged. (150 for "diagnostics" 150 for an hours labour 150 for parts etc and then given you a whole list of work which is required "urgently" with no guarantee that the work would have been done any better than your guy)

 

[oigle]

Thanks everyone, I think I understand better now, so he's basically got to do 60% of the job again... to unbolt the joint and then remove the front half of propshaft/flexi disc and then reinsert it again correctly lined up with the rear one. I'll take it back and ask...

Though I'm not sure if I should expect it free. Assuming the parts are 85€ (they were delivered within 2h so not comparable to ECP etc) then he charged me 30€ labour for the whole thing. Is this an easy mistake to make (e.g. most cars it is not necessary) or a schoolboy error when replacing it? The guy was 50 years old or so and had ran the family mechanics and immeidately identified the prop shaft bearing from the original symptoms and seemed to know his stuff so I'm a bit confused if this is an obvious mistake to make

If he has been in the game for many years, he should know better. It is common knowledge.

 

[DREAMER NO2]

If it was repaired with aftermarket replacment parts,, listen out for the noise you had before .Then when you hear it you will know just what it is .

 

[d215yq]

If it was repaired with aftermarket replacment parts,, listen out for the noise you had before .Then when you hear it you will know just what it is .

Thanks, though I'm not sure what you mean, the original centre bearing was fixed and now there is a different less important issue because the prop shaft was put back incorrectly. So I will go back and get it fixed and if I have to pay labour again so be it... it is worth it to stop the vibrations and if it's free all the better,.

I'm not even sure if an aftermarket centre bearing has been used though at 80€ for a 3" piece of rubber and piece of metal I hope so...but I have never used any Mercedes parts since buying the car, I always buy the cheapest recognisable brand from ECP/Mister-auto/autodoc etc (or even non recognisable if it is a fifth of the price), it's not a "nice" car, it's a tool so not worth spending any more than the minimum on, I only spent the 80€ this time as it was an emergency fix and the only one the garage could order within the day...

 

[DREAMER NO2]

d215yq This is a problem when others do the work fior you . I am like you and working on the car is so hard with pain from one joint or another . I think my spanner days are coming to an end very soon .. This is for other members that might come up against the same problem ..This is a diy on balancing the propshaft . With the use of hose clamps -you need 2 hose clamps the right size for propshaft. Then find a midle point of the propshaft about half its length,, mark it and then fit the hose clamps both together now lock them up .Take it for a spin see how things go .If still the same undo one clamp move it 1/4 of an inch clockwise keeping it next to the locked hose clamp lock it back up .This is trial and error . You can fit the hose clamps any place on the propshaft to get better results .

 

[matthew k]

TBH although I trust my mecanics there's no harm in marking the propshafts relative positions before you hand it over. Just in case they forget, also allows you to rule prop inbalance out if there's an issue.