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-   -   940 Knocking on front UK drivers. (https://www.volvoforums.org.uk/showthread.php?t=289343)

mhuk Dec 5th, 2018 08:54

940 Knocking on front UK drivers.
 
Hi,

My 97 940 turbo has a knocking sound when turning left at speed knocks when I slow down in a straight line. Turning right it does not knock.

I replaced all the bushes on the front end and it continues to knock. The ball joints are not worn. I have no broken springs.

Could it be a bad damper?

bit lost at what it could be.

Cheers

Martin

Laird Scooby Dec 5th, 2018 10:25

Is the knock coming from the front or back of the car? Also what sort of knocking, is it one tap or thud , is it rhythmic and related to road and/or engine speed? Have you checked the wheel bearings? Likely to be the right hand wheel bearing if it knocks on left hand corners and vice versa but say it knocks on left hand turns.

When you say it knocks when you slow in a straight line, is that by using the brakes or just letting it slow naturally?

Have you checked the wheel nuts for tightness? Also, jack the front up so a wheel is in the air, grab the wheel at the 12 and 6 o'clock positions and try rocking it, then repeat at the 3 and 9 o'clock positions - can you recreate the knock?

Could be so many things and sadly, your description is a bit vague - without hearing it or a better description, it's going to be hard to pin this down! ;) :D

GreenBrick Dec 5th, 2018 12:18

On my first 940 the damper came loose inside the strut as it looks like it had not been tightened down properly. It was finally found that by holding the strut and pulling it in and out with weight still on it.

I could have just tightened it back up through the spring, but I opted for new shocks and put new ball joints on at the same time.

All the knocking went, as you would guess.

You could also look at the control arm bushes. Sometimes things only show up slop with the full car weight on the wheels.

lnparry Dec 5th, 2018 12:52

Hi Martin,

Open the bonnet and rock the car up and down / side to side to see if the bushes at the top of the dampers have worn. I had to replace mine to get rid of an annoying knock. Doesn't sound too likely given your symptoms but worth checking to eliminate anyway.

Good luck,
LeeP

mhuk Dec 6th, 2018 09:18

Quote:

Originally Posted by Laird Scooby (Post 2473109)
Is the knock coming from the front or back of the car? Also what sort of knocking, is it one tap or thud , is it rhythmic and related to road and/or engine speed? Have you checked the wheel bearings? NO Likely to be the right hand wheel bearing if it knocks on left hand corners and vice versa but say it knocks on left hand turns. Yes on left turns.

When you say it knocks when you slow in a straight line, is that by using the brakes or just letting it slow naturally? Using brakes

Have you checked the wheel nuts for tightness? YES Also, jack the front up so a wheel is in the air, grab the wheel at the 12 and 6 o'clock positions and try rocking it, then repeat at the 3 and 9 o'clock positions - can you recreate the knock? I need to do this

Could be so many things and sadly, your description is a bit vague - without hearing it or a better description, it's going to be hard to pin this down! ;) :D

Thank you :-)

mhuk Dec 6th, 2018 09:24

Thanks guys.

I replaced all the bushes with poly on the front. Only the ARB/ufo and those funny cones where worn.

I'm also getting wheel skip hop when turning on full lock and looking yesterday it looks like the tyre has touched the inside of the wheel well. I also had a read of this...

https://www.volvoforums.org.uk/showthread.php?t=200534

Quote from that page (I had a problem years ago with an old van I had. It clonked when turning full lock and it was the bearing in the top mount that had failed. It also on a random basis didn't return to straight ahead when turning full right.
The front wheel skipping may be related to the front suspension bushes. Mine did the same and also wore unevenly. It past the MOT but I reckon it was the rust that was holding them in place. When I removed them the large ones that attach to the chassis had separated from the steel core. As said it was the rust that made them seem solid. My MOT centre has a vibrating unit on their ramp that moves the car from side to side to check play but they didn't pick the worn bushes up.
Theres also bushes I think called top hat that were really bad on mine as well. I did the lot and it made a huge difference to handling etc.
If your doing them yourself you may have to take the arms into your local garage to have them pressed out and the new ones pressed in. I managed with a hydraulic puller set and a big vice but it was some job.)

Laird Scooby Dec 6th, 2018 09:52

Quote:

Originally Posted by mhuk (Post 2473418)
I'm also getting wheel skip hop when turning on full lock and looking yesterday it looks like the tyre has touched the inside of the wheel well.

That suggests wheel alignment and/or track rod ends as previously suggested. If a T/R/E is worn, they can make a hell of a clonk - again, if it happens when going round left hand bends, suspect the right hand T/R/E because the weight transfer is all onto the right.

mhuk Dec 7th, 2018 11:30

Thank you. I have some new steering rod arms on order.

mhuk Dec 17th, 2018 13:18

OK this is what I have.

Make sense?

http://i66.tinypic.com/30d7xid.jpg

Cheers

lynns hubby Dec 17th, 2018 18:57

I know this is going to sound strange but I had the same as you describe years ago in our first 940. It turned out to be the downpipe from the exhaust was knocking on the chasis rail. It does it when cornering at speed because the engine moves slightly as its on rubber mounts which means the downpipe moves with it.
I just nudged the downpipe over from the chasis rail with a long bar and nipped up the nuts securing it to the turbo as they had "relaxed" a bit.
It did it again a few years later but I knew what to look for then.
Just see how close your downpipe is running to your chasis, you need a good inch (25mm) clearance.
As I said, it sounds a long shot, but it was my problem twice.


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