C70: - Knocking / banging sound from front left over bumps, bushes?

StatusRed · Jan 10th, 2021, 13:20

A problem I've had with my C70 for a while is thing banging / knocking sound as you go over bumps from the front left (passenger) side of the car. This goes away gradually as the car is driven then comes back after it's not been used for a day or two. The sound is quite noticeable but was checked over at it's MoT, deemed to be entirely safe (spring and strut are fine) it's just noise.

I'm thinking it's noise caused by the subframe bushes being worn out or the the control arm bushes. The driver's side control arm was replaced about 1 year ago and there's no noise from it.

At first I was thinking of asking the garage to replace all the subframe, passenger side control arm and anti roll bar bushings, but do you think this is all necessary - I'm trying to keep costs down? What do you think the most likely culprit is? Is it maybe worth just replacing the passenger side control arm bushings first?

Cheers.

Derek UK · Jan 10th, 2021, 13:29

The ARB drop links might be the culprit although the MOT should have found that problem. I had an advisory on my last MOT, 1999 V70, for play on one side. They are a rather long rod on mine and may be the same on yours. Cheap replacements not recommended. See sirobb on YT.

Baffler · Jan 10th, 2021, 19:04

Not sure on the coupe but I'm led to believe all C70's have solid aluminum subframe bushings so you can probably rule these out.

Check the steering rack, on the LH side, where it sits on its mounting bracket. I've seen a few of these separate. Not sure how they're bonded at time of manufacture, no evidence of a weld, so may be a friction fit with a metal adhesive. The bracket is mild steel whereas the rack is aluminium.

My C70 failed its test on this very problem so, to remedy this, I removed the two screws for said bracket, leaving the bracket in place, and fitted a U-Bolt over the rack and through the bracket (with some PVC pipe fed over the U section to minimise metal to metal contact). Getting it to sit correctly, without applying to much downward force on the casing of the rack, is a case of adjusting the 2 upper nuts (bracket side) then tighten 2 lock nuts from underneath the subframe. Sounds like a bodge repair but has worked for three consecutive tests and saved an otherwise perfectly good steering rack

StatusRed · Jan 10th, 2021, 20:56

Quote:

Originally Posted by Derek UK

The ARB drop links might be the culprit although the MOT should have found that problem. I had an advisory on my last MOT, 1999 V70, for play on one side. They are a rather long rod on mine and may be the same on yours. Cheap replacements not recommended. See sirobb on YT.

I don't think it's this because I'm pretty sure the droplink got replaced last February when a pothole too out both my passenger side wheel and tyres.

Quote:

Originally Posted by Baffler

Not sure on the coupe but I'm led to believe all C70's have solid aluminum subframe bushings so you can probably rule these out.

Check the steering rack, on the LH side, where it sits on its mounting bracket. I've seen a few of these separate. Not sure how they're bonded at time of manufacture, no evidence of a weld, so may be a friction fit with a metal adhesive. The bracket is mild steel whereas the rack is aluminium.

My C70 failed its test on this very problem so, to remedy this, I removed the two screws for said bracket, leaving the bracket in place, and fitted a U-Bolt over the rack and through the bracket (with some PVC pipe fed over the U section to minimise metal to metal contact). Getting it to sit correctly, without applying to much downward force on the casing of the rack, is a case of adjusting the 2 upper nuts (bracket side) then tighten 2 lock nuts from underneath the subframe. Sounds like a bodge repair but has worked for three consecutive tests and saved an otherwise perfectly good steering rack

I think I'll jack up the wheel and take a good look at all of this, cheers! If I can identify what's perished should save me some cost, don't want to replace things which seem OK.

sam1 · Jan 10th, 2021, 21:06

Dont know how similar the C70 is in terms of front suspension to a V70... but my 07 V70 had a similar problem which turned out to be the top spring seat - the bit where the shock absorber went through right at the top was worn and the shock was just wobbling around. pic attached

acshortt5 · Jan 10th, 2021, 23:05

For reference it's only the C70 convertible that has the solid subframe bushings. The coupe has the same rubber ones as the other models.

StatusRed · Jan 10th, 2021, 23:46

Quote:

Originally Posted by sam1

Dont know how similar the C70 is in terms of front suspension to a V70... but my 07 V70 had a similar problem which turned out to be the top spring seat - the bit where the shock absorber went through right at the top was worn and the shock was just wobbling around. pic attached

Ah, very well could be. This will be evident with no dismantling? I'm guessing if that is the problem I may as well get new shocks / springs while the garage are at it due to the labour?

StatusRed · Jan 13th, 2021, 16:41

Checked the strut mount and it seems fine, tried rocking the car to see if it pops out and it doesn't. It's going into the garage next Thursday for them to investigate (they said the cost of changing subframe bushes will depend on how easily they come out lol).

SteveSarre · Jan 13th, 2021, 18:53

Hi StatusRed

Did you "Check the steering rack, on the LH side, where it sits on its mounting bracket ..." as suggested by Baffler?

If you hit something hard enough to take out droplinks or wheels, it wouldn't surprise me if that broke the steering rack mount.

It is a fairly common problem.

The subframe bushes seem to last quite well so I wouldn't expect them to go unless you have high mileage.

These inserts are really easy to fit, and could be all you need if your subframe bushes are a bit worn
https://www.ebay.co.uk/itm/293042915727

Steve

StatusRed · Jan 14th, 2021, 00:06

Quote:

Originally Posted by SteveSarre

Hi StatusRed

Did you "Check the steering rack, on the LH side, where it sits on its mounting bracket ..." as suggested by Baffler?

If you hit something hard enough to take out droplinks or wheels, it wouldn't surprise me if that broke the steering rack mount.

It is a fairly common problem.

The subframe bushes seem to last quite well so I wouldn't expect them to go unless you have high mileage.

These inserts are really easy to fit, and could be all you need if your subframe bushes are a bit worn
https://www.ebay.co.uk/itm/293042915727

Steve

Maybe at the weekend I can find time to jack it up and take a good look. Do you have a photo of exactly what I'm looking for? Cheers.

Jan 10th, 2021, 13:20	#1
StatusRed Premier Member Last Online: Apr 24th, 2024 19:28 Join Date: Jul 2015 Location: Glasgow	Knocking / banging sound from front left over bumps, bushes? A problem I've had with my C70 for a while is thing banging / knocking sound as you go over bumps from the front left (passenger) side of the car. This goes away gradually as the car is driven then comes back after it's not been used for a day or two. The sound is quite noticeable but was checked over at it's MoT, deemed to be entirely safe (spring and strut are fine) it's just noise. I'm thinking it's noise caused by the subframe bushes being worn out or the the control arm bushes. The driver's side control arm was replaced about 1 year ago and there's no noise from it. At first I was thinking of asking the garage to replace all the subframe, passenger side control arm and anti roll bar bushings, but do you think this is all necessary - I'm trying to keep costs down? What do you think the most likely culprit is? Is it maybe worth just replacing the passenger side control arm bushings first? Cheers. __________________ 2009 S40 SE Lux 2.0i \| 2022 Suzuki V-Strom 650 \| 2002 Audi TT 225 Previous: C70 Coupe 2.4i \| Saab 9-5 Aero \| Daihatsu SporTrak

Jan 10th, 2021, 19:04	#3
Baffler Premier Member Last Online: Yesterday 14:56 Join Date: Dec 2002 Location: Co. Limerick, Ireland	Not sure on the coupe but I'm led to believe all C70's have solid aluminum subframe bushings so you can probably rule these out. Check the steering rack, on the LH side, where it sits on its mounting bracket. I've seen a few of these separate. Not sure how they're bonded at time of manufacture, no evidence of a weld, so may be a friction fit with a metal adhesive. The bracket is mild steel whereas the rack is aluminium. My C70 failed its test on this very problem so, to remedy this, I removed the two screws for said bracket, leaving the bracket in place, and fitted a U-Bolt over the rack and through the bracket (with some PVC pipe fed over the U section to minimise metal to metal contact). Getting it to sit correctly, without applying to much downward force on the casing of the rack, is a case of adjusting the 2 upper nuts (bracket side) then tighten 2 lock nuts from underneath the subframe. Sounds like a bodge repair but has worked for three consecutive tests and saved an otherwise perfectly good steering rack __________________ Liam... '96 854 TDI SE, '99 V70 2.5D S, '05 C70 2.0T Collection, '05 S80 2.0T SE, '15 V70 D4 SE Lux Nav.

Jan 10th, 2021, 23:05	#6
acshortt5 Volvo Nutcase Last Online: Jul 14th, 2023 12:57 Join Date: May 2007 Location: N/A View Photos By: acshortt5	For reference it's only the C70 convertible that has the solid subframe bushings. The coupe has the same rubber ones as the other models. __________________ Andrew 1998 S70 T5 CD AUTO Previously a 1990 240 GLT-R

Jan 13th, 2021, 16:41	#8
StatusRed Premier Member Last Online: Apr 24th, 2024 19:28 Join Date: Jul 2015 Location: Glasgow	Checked the strut mount and it seems fine, tried rocking the car to see if it pops out and it doesn't. It's going into the garage next Thursday for them to investigate (they said the cost of changing subframe bushes will depend on how easily they come out lol). __________________ 2009 S40 SE Lux 2.0i \| 2022 Suzuki V-Strom 650 \| 2002 Audi TT 225 Previous: C70 Coupe 2.4i \| Saab 9-5 Aero \| Daihatsu SporTrak

Jan 13th, 2021, 18:53	#9
SteveSarre Premier Member Last Online: Apr 24th, 2024 15:16 Join Date: Oct 2004 Location: London/West Country	Hi StatusRed Did you "Check the steering rack, on the LH side, where it sits on its mounting bracket ..." as suggested by Baffler? If you hit something hard enough to take out droplinks or wheels, it wouldn't surprise me if that broke the steering rack mount. It is a fairly common problem. The subframe bushes seem to last quite well so I wouldn't expect them to go unless you have high mileage. These inserts are really easy to fit, and could be all you need if your subframe bushes are a bit worn https://www.ebay.co.uk/itm/293042915727 Steve __________________ V70 2.5 Turbo AWD Man. 1999 Red V70 2.5 10V Auto 1998 Green C70 T 20V Auto Conv. 2001 Blue, C70 T5 Auto Conv. 2000 Blue V70 2.5 Turbo AWD Auto 1998 Green, V70 2.5 10V Auto BiFuel 1999 Red (scrapped) V70 20v Auto 1999 Green (scrapped)

Jan 10th, 2021, 13:29	#2
Derek UK VOC Member Last Online: Yesterday 15:54 Join Date: Jul 2006 Location: Chatham	The ARB drop links might be the culprit although the MOT should have found that problem. I had an advisory on my last MOT, 1999 V70, for play on one side. They are a rather long rod on mine and may be the same on yours. Cheap replacements not recommended. See sirobb on YT.

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