strange knocking

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strange knocking

Postby jebiga41 » 17 Feb 2018, 09:41

hi guys this one has stumped me for a while and has led to many changes and while I was in there upgrades and maintanence that Ive been meaning to do for ages but still seem to be chasing the ace as they say. I seem to be experiencing a kind of rotational knock vibration when moving, which is worse on rougher roads and almost fells like a twitchiness in the rear. I have run it under power and is there both on and off I have even switched off the engine and let her free wheel and is still there. Almost seems to be worse at low speeds ?I have dropped the prop so its not that I initially thought it was rear bearings but have changed them to no avail rear shocks been changed for disco 2 ones changed all the tyres and its still there changed all the brakes and upgraded rears to discs still there, refurbed cv joints with good used and still there theres no audible knocks so not ball joints. Am running out of things left to do trailing arm bushes tracking ??? any thoiughts guys
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Re: strange knocking

Postby silverbullet » 17 Feb 2018, 10:52

Rough roads...more suspension droop/twist...has front diff got its cv spacers fitted?
Clutching at straws but as you said, whats left to swap?
Where or how do you feel this snatching/drumming? The precise nature of it might tell us something.
Sounds a bit like the wbx syncro with the mystery vibe that Aidan had in a while ago.
A real head-scratcher, he and customer removed eveything and ran it up off the ground, it still shook the van without prop or driveshafts at anything over 40mph!
I suspect the engine had a bent rod or somesuch, but that was worse at speed.
Was the cause ever found?

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Re: strange knocking

Postby jebiga41 » 17 Feb 2018, 12:07

will try and investigate further today as the weather is quite nice here and report back initially thoiught it was the back but am now more inclined to think it may be the front can feel the vibrations throught the seat so maybe something there spacers are on the front diff which has been changed for a nice rebuilt one :) along with driveshafts will be doning more checks
:run
F*** your Syncro Westie I've a horse outside !
http://www.youtube.com/watch?v=ljPFZrRD3J8&feature=youtube_gdata_player
Time flies like an arrow; fruit flies like a banana
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Re: strange knocking

Postby footstuck » 17 Feb 2018, 12:55

I think it’s mostlikely to be the rear hubs are shot and you are hearing
the new bearing rocking due to a small amount of rim or tyre run out.
Cheap to have the rims balanced and observe to see if they run true
Or substitute the rear rims for known straight ones
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Re: strange knocking

Postby silverbullet » 17 Feb 2018, 14:30

Good point about bent wheels, they will balance but still cause vibrations. Been there.
Knackered dampers will cause wheel "patter", rougher roads would trigger an oscillation. Could that be the problem?

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Re: strange knocking

Postby jebiga41 » 18 Feb 2018, 18:22

footstuck wrote:I think it’s mostlikely to be the rear hubs are shot and you are hearing
the new bearing rocking due to a small amount of rim or tyre run out.
Cheap to have the rims balanced and observe to see if they run true
Or substitute the rear rims for known straight ones

yep kinda thinking it could be the rear bearing carriers have new tyre and even used a different set of wheels which were balanced when they fitted the tyres there doesnt seem to e any play in the bearings when i checkedd them ????? will have a proper look during the week week
F*** your Syncro Westie I've a horse outside !
http://www.youtube.com/watch?v=ljPFZrRD3J8&feature=youtube_gdata_player
Time flies like an arrow; fruit flies like a banana
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Re: strange knocking

Postby jebiga41 » 18 Feb 2018, 18:25

silverbullet wrote:Good point about bent wheels, they will balance but still cause vibrations. Been there.
Knackered dampers will cause wheel "patter", rougher roads would trigger an oscillation. Could that be the problem?

Sent from my S60 using Tapatalk

front dampers are old so may change them out this week to see if it makes any difference
F*** your Syncro Westie I've a horse outside !
http://www.youtube.com/watch?v=ljPFZrRD3J8&feature=youtube_gdata_player
Time flies like an arrow; fruit flies like a banana
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Location: dublin ireland
80-90 Mem No: 5654

Re: strange knocking

Postby Aidan » 18 Feb 2018, 18:53

Sounds a bit like the wbx syncro with the mystery vibe that Aidan had in a while ago.
A real head-scratcher, he and customer removed eveything and ran it up off the ground, it still shook the van without prop or driveshafts at anything over 40mph!
I suspect the engine had a bent rod or somesuch, but that was worse at speed.
Was the cause ever found?


the engine lost oil pressure on the way to the ferry week before last so customer has bought and fitted a replacement engine, I'm waiting for news on the smoothness or otherwise of the new one
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Re: strange knocking

Postby jebiga41 » 27 Feb 2018, 22:48

Ok so took out the front shafts and running stub axles from old front cv joints have changed the shocks and front wheel bearings (all jobs that needed doing in terms of preventative maintance ) and still there but may have located the cause looks either to be a dodgy cv joint or rear bearing will keep you posted
F*** your Syncro Westie I've a horse outside !
http://www.youtube.com/watch?v=ljPFZrRD3J8&feature=youtube_gdata_player
Time flies like an arrow; fruit flies like a banana
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