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Knocking from N/S Rear #1155801
13/01/2011 02:52
13/01/2011 02:52
Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Kelv27 Offline OP
Club member 7239, Regional Rep., Malaysia
Kelv27  Offline OP
Club member 7239, Regional Rep., Malaysia
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Posts: 4,650
Malaysia..Glasgow at heart
Has anyone had any problems with knocking after fitting solid rear subframe bushes?

I've been looking for the root of this problem for quite sometime now but i'm still stumped on what it could be. It sounds like its only coming from the nearside..so can't really be the solid bushes right?

The shockers are ok. Thought it would be faulty trailing arm bearings but i've jiggled the trailing arm and can't find any play.

Ideas please!

Re: Knocking from N/S Rear [Re: Kelv27] #1155838
13/01/2011 09:39
13/01/2011 09:39

P
proccy
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can't help Kelv, but good to see you still about here! how's things mate?

Re: Knocking from N/S Rear [Re: ] #1155850
13/01/2011 10:04
13/01/2011 10:04
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Jimbo Offline
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Kelv, are the rubber bushes in the ends of the dampers in good condition, top and bottom (what dampers are on the rear)?

Any movement at all, ANY, will cause a knock with solid bushes so everything has to be 100% fitted correctly and tight!

I've never liked the idea of solid bushes on a road car, where is all the energy those bushes absorbing being transferred to?
You can't remove energy, you just move it on to the next point in the chain.
I'm guessing the only bushes left in the rear are now the damper mounting bushes so they will have to be the weak spot.

Re: Knocking from N/S Rear [Re: Jimbo] #1155873
13/01/2011 10:47
13/01/2011 10:47
Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Kelv27 Offline OP
Club member 7239, Regional Rep., Malaysia
Kelv27  Offline OP
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Malaysia..Glasgow at heart
Haha no worries Steve smile Yeah still around..although not as much as I would like. They make people work like dogs in this part of the world tongue

Thanks for the reply Jimbo. Good point about the rubber bushes at the end of the dampers. I only unhooked the trailing arm end of it. It looks good on this side. I think the bushes at the top is ok too as i jiggled it to see if there was any play..everythings solid. They are Bilstein dampers.

If the knock is caused by solid bushes, it would be one of the biggest mistakes i've done when it comes to modding the car. The bolts that go through the bushes and hold the whole subframe to the chassis are also on tight. Because the bushes are smooth, is there a possibility that it might be sliding on the surface of the chassis (ever so slightly)?

No one else with solid bushes seem to be having the same problem?

Re: Knocking from N/S Rear [Re: Kelv27] #1155990
13/01/2011 15:40
13/01/2011 15:40

N
Nazo
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I am having a similar knocking noise, but unsure which side. Certainly seems nearside. However I have bought new top mounts and will get new bushes put on my old wishbones, and changing the springs.

Will see the outcome

Re: Knocking from N/S Rear [Re: Kelv27] #1155992
13/01/2011 15:43
13/01/2011 15:43
Joined: Dec 2005
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mattB Offline
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Originally Posted by Kelv27
No one else with solid bushes seem to be having the same problem?


Yes. But I dont notice it so much in amonst all the other knocking, banging and rattling noises.


Death-rattle-tastic
Re: Knocking from N/S Rear [Re: mattB] #1156010
13/01/2011 16:48
13/01/2011 16:48

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sparco
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I hate knocking from the rear, it smarts!


Re: Knocking from N/S Rear [Re: ] #1156018
13/01/2011 17:01
13/01/2011 17:01

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Nobby
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You sure its not a rogue socket that has been dropped through the hole when you remove the rear struts (that wouldn't be a first).

When does it knock? over bumps, hard acceleration, braking, corners etc..?

I haven't noticed any knocks from my coupe.

One thing which I had to be very carfull of was when fitting the rear subframe to make sure that all the pipes were out of the way otherwise they would get squashed. Did all the big bolts go in ok? You haven't dislodged any captive nuts?

Other than that there are plenty of things at the back that could cause a knock. Rattly exhaust, fuel filter not secured, fuel tank not bolted on properly, spare wheel/tools or anything behind the storage bits in the boot.

Re: Knocking from N/S Rear [Re: ] #1156260
14/01/2011 04:07
14/01/2011 04:07
Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Kelv27 Offline OP
Club member 7239, Regional Rep., Malaysia
Kelv27  Offline OP
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Posts: 4,650
Malaysia..Glasgow at heart
The knock happens all the time..even when driving slowly. I did think about the possibility of a rogue socket in the hole. The bushes were installed by a mechanic so not sure if he actually dropped anything in there. However, the sound of the knock suggest that a socket trapped in there is unlikely.

The exhaust and things stored in the boot are some of the first things I checked. When cornering hard on roundabouts, i get rubbing/scraping noises too crazy

Think i'll have to lift the car up in a garage to see if theres anything obvious..

Re: Knocking from N/S Rear [Re: Kelv27] #1156277
14/01/2011 08:57
14/01/2011 08:57
Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Kelv27 Offline OP
Club member 7239, Regional Rep., Malaysia
Kelv27  Offline OP
Club member 7239, Regional Rep., Malaysia
Forum is my job

Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Just took the car in to an Alfa specialist. The guy seems quite confident that its the trailing arm bearings at fault. Getting it replaced tomorrow..so will see if it cures it.

Re: Knocking from N/S Rear [Re: Kelv27] #1156292
14/01/2011 09:49
14/01/2011 09:49
Joined: Dec 2005
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Jimbo Offline
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I'm wondering if these solid bushes will shorten the life of the trailing arm bearings?

Last edited by Jimbo; 14/01/2011 13:05. Reason: I meant bearing, not bush
Re: Knocking from N/S Rear [Re: Jimbo] #1156329
14/01/2011 11:00
14/01/2011 11:00

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sparco
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Weakest point Jimbo so it sounds sensible. I don't get that on my car as i don't do the same sort of mileage as guys with road cars but i'm sure i'll see increased wear on certain things. It's a fine line with a road going car of comfort and out and out performance where as i just want it to go where i point it.

Kelv i changed traileing arm bushes before and within no time had to change one again. They look easy to change but if you don't fit the plastic bits properly they just end up collapsing so be careful when getting them fitted.


Re: Knocking from N/S Rear [Re: ] #1156355
14/01/2011 11:32
14/01/2011 11:32

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Marco20valveT
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soild bush's on a road car is not a great idea in my eyes, as jimbo said, where is the energy going?

its going to put so much more stress on other parts.

fingers crossed its the trailing arm bearings Kelv!


Re: Knocking from N/S Rear [Re: ] #1156357
14/01/2011 11:36
14/01/2011 11:36

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jonone
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I have had solid rear bushes fitted recently,and when the car came back the knocking was really bad, so I got him to look at it again and it turned out to be something to do with 22mm whiteline arb and the modified std brackets.
After getting it back for the second time it still knocks, but know where near as bad, I don't know if its still to do with the arb or not.
I had same the 22mm on when I had std bushes and there was not a peep from the back end!

Re: Knocking from N/S Rear [Re: ] #1156757
15/01/2011 02:49
15/01/2011 02:49
Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Kelv27 Offline OP
Club member 7239, Regional Rep., Malaysia
Kelv27  Offline OP
Club member 7239, Regional Rep., Malaysia
Forum is my job

Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Thanks for the heads up Sparco. Will let them know smile

Marco.. Thanks. I'm hoping it's something simple too!

Now that jonone has mentioned, it might be a good idea to look at my ARB brackets too as I'm running the same diameter. When the ARB was first installed, it was running on standard subframe mounts without issues. The problem only came after fitting the solids... So it would mean that either the brackets weren't fitted back properly after fitting the solid bushes or the bushes have made some changes to the geometry And the ARB doesn't like it! Can't imagine the latter being the culprit though..

Re: Knocking from N/S Rear [Re: Kelv27] #1157180
16/01/2011 13:17
16/01/2011 13:17
Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Kelv27 Offline OP
Club member 7239, Regional Rep., Malaysia
Kelv27  Offline OP
Club member 7239, Regional Rep., Malaysia
Forum is my job

Joined: Jun 2007
Posts: 4,650
Malaysia..Glasgow at heart
Well got it all sorted now. Looks like it's neither the trailing arm nor the subframe bushes nor the ARB. It was the shockers afterall. It was ever so slightly bent. Not really obvious due to the rubber boot covering the piston rod..the shocks can still be compressed and retracted.. But did take abit more effort.

Fitted some new ones and the sounds gone! smile

Re: Knocking from N/S Rear [Re: Kelv27] #1157307
16/01/2011 18:01
16/01/2011 18:01

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jonone
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nice!


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