940 knocking from underneath !!!

besidetheseaside · May 7th, 2019, 14:39

Hi Guys, Need your help again....... Knocking from underneath somewhere, seems to be middle of car ?? more often on braking or accelerating, had it on a ramp and could not find anything untoward, passed the MOT recently, might not do it for days then it will do it all day, really bad today, clunk, then double clunk then an almighty bang which feared me a bit. Exhaust is new, brakes have been re-furbed, been using a pry bar on suspension but no movement anywhere, bushes look a bit old but so is the car lol, just cannot pin it down........

Are there any places I should be looking at specifically, realise that this is absolutely impossible to diagnose but any help/pointers/advice would be gratefully received.

Booked in on my mates ramp for 6 so fingers crossed I find it then.

griston64 · May 7th, 2019, 14:57

Could be propshaft. But if that I would've thought it would do it all the time

360beast · May 7th, 2019, 15:27

New exhaust could have been fitted in a way that when you brake the engine moves forwards on the mounts and knocks on something.

Check the calipers/carriers have been tightened properly.

Sicnarf · May 7th, 2019, 18:29

Its your brake discs that are bad. Check them inside and outside to see if there is damage.

besidetheseaside · May 7th, 2019, 19:30

So an hour on the 2 poster and here is what we found,

Propshaft center bearing shot, the rubber doughnut part is actually separated from the steel outer, 6-7mm of vertical and horizontal movement.

Rear gearbox mount worn ?? 5mm of vertical movement, not sure if that is within limits.

Gear lever rod linkage bolt is flopping about in the bracket, I have an auto gearbox.

Running from the front numbers 1 and 3 heat shields were loose and have now been secured.

Nut missing from exhaust to turbo manifold, new one fitted and all now secure.

Checked all brakes, calipers and brackets, all perfect.

I had a pry bar under there and found no movement in any bushes, track rod end rubbers are cracking, (noted on MOT) but no excessive movement.

So just about to order the centre bearing and will probably make up a bolt and spacer for the gear lever linkage.

Hopefully my car will soon be as quiet as the proverbial church mouse wearing velour slippers.

griston64 · May 7th, 2019, 19:40

I now feel like the Lairds apprentice as I think I kind of got it right

May 7th, 2019, 14:39	#1
besidetheseaside Senior Member Last Online: Jan 26th, 2024 05:55 Join Date: Dec 2013 Location: Liverpool, now residing in North Wales.	940 knocking from underneath !!! Hi Guys, Need your help again....... Knocking from underneath somewhere, seems to be middle of car ?? more often on braking or accelerating, had it on a ramp and could not find anything untoward, passed the MOT recently, might not do it for days then it will do it all day, really bad today, clunk, then double clunk then an almighty bang which feared me a bit. Exhaust is new, brakes have been re-furbed, been using a pry bar on suspension but no movement anywhere, bushes look a bit old but so is the car lol, just cannot pin it down........ Are there any places I should be looking at specifically, realise that this is absolutely impossible to diagnose but any help/pointers/advice would be gratefully received. Booked in on my mates ramp for 6 so fingers crossed I find it then.

May 7th, 2019, 14:57	#2
griston64 Premier Member Last Online: Yesterday 18:50 Join Date: Jul 2012 Location: Lenzie	Could be propshaft. But if that I would've thought it would do it all the time __________________ V70 D5 SE Geartronic 215bhp Saville Grey 2012MY 940 LPT Manual 1996 740 SE 1990

May 7th, 2019, 19:30	#5
besidetheseaside Senior Member Last Online: Jan 26th, 2024 05:55 Join Date: Dec 2013 Location: Liverpool, now residing in North Wales.	So an hour on the 2 poster and here is what we found, Propshaft center bearing shot, the rubber doughnut part is actually separated from the steel outer, 6-7mm of vertical and horizontal movement. Rear gearbox mount worn ?? 5mm of vertical movement, not sure if that is within limits. Gear lever rod linkage bolt is flopping about in the bracket, I have an auto gearbox. Running from the front numbers 1 and 3 heat shields were loose and have now been secured. Nut missing from exhaust to turbo manifold, new one fitted and all now secure. Checked all brakes, calipers and brackets, all perfect. I had a pry bar under there and found no movement in any bushes, track rod end rubbers are cracking, (noted on MOT) but no excessive movement. So just about to order the centre bearing and will probably make up a bolt and spacer for the gear lever linkage. Hopefully my car will soon be as quiet as the proverbial church mouse wearing velour slippers. Last edited by besidetheseaside; May 7th, 2019 at 19:31. Reason: omission

May 7th, 2019, 19:40	#6
griston64 Premier Member Last Online: Yesterday 18:50 Join Date: Jul 2012 Location: Lenzie	I now feel like the Lairds apprentice as I think I kind of got it right __________________ V70 D5 SE Geartronic 215bhp Saville Grey 2012MY 940 LPT Manual 1996 740 SE 1990

May 7th, 2019, 15:27	#3
360beast Go redblock or go home Last Online: Yesterday 21:21 Join Date: Feb 2012 Location: UK	New exhaust could have been fitted in a way that when you brake the engine moves forwards on the mounts and knocks on something. Check the calipers/carriers have been tightened properly.

May 7th, 2019, 18:29	#4
Sicnarf New Member Last Online: Dec 2nd, 2023 15:46 Join Date: Jan 2013 Location: London	Its your brake discs that are bad. Check them inside and outside to see if there is damage.

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