Knocking noise from front left

GreenTech

Hi All,

Just wondering if anyone could give me some idea as to what might be wrong with this. I have a Volvo S40 diesel and for the last 3 weeks I've been getting a knocking noise from the front left wheel when steering. It's more noticable at lower speeds and when braking at low speed (in traffic or car parks etc). I have taken the front wheel off and jacked it up to check the CV joints, track rods etc. and there doesn't appear to be any play in them. I did notice that the brake disc has alot of movement in it, ie. it can rattle. There are 2 screw holes for holding the discs in place but I'm not sure are these required on the S40 as they aren't fitted??? ( I checked the drivers side and is the same). The discs were fitted in the last 12 months. Is this likely to be the problem or possibly ball joints or something similar?

Owen

Generally you need the discs to be bolted on with their specific bolts (Disc keys, most are normally allen nuts, or torx). The holes through the disc which are positioned over the normal wheel bolt holes are larger than the bolts that go through them, so you'd have radial movement with those.

Knocking though could well be your bushings. The only way to test those is get a nice big prybar and give them a good jiggle.

GreenTech

Thanks PaintDoctor. I was thinking the same about the discs as I noticed the radial movement you are talking about, which didn't seem right. It may never have been noticed if I hadn't been checking for another problem!

Buford T Justice

Check and see if the caliper has seized or partially seized. Happened to an old A4 that I had.....

Slidey

Does it make the knocking noise when stopped?

If so it is probably a top shock bearing.

If it knocking as you drive the most likely suspect is the anti-roll bar bushes or links. If you cannot find any obvious play in them just disconnect one side. If the noise immediately ceases you now have found your problem

GreenTech

If I steer when the car is stopped you can hear a bumping noise. Its like as if the more drag that is on the tires the more likely it is to happen. It doesn't consistently knock when steering, just once when I turn the wheel. Thats why I was thinking its not a CV joint. There didnt appear to be any play in the anti roll bar bushing either but I need to get under it properly and check all the above suggestions.

Thanks guys!

Buford T Justice

GreenTech wrote: »

If I steer when the car is stopped you can hear a bumping noise. Its like as if the more drag that is on the tires the more likely it is to happen. It doesn't consistently knock when steering, just once when I turn the wheel. Thats why I was thinking its not a CV joint. There didnt appear to be any play in the anti roll bar bushing either but I need to get under it properly and check all the above suggestions.

Thanks guys!

Check and see if you've a broken spring. up near the top of the coil or down the bottom. Could be it, and easy to spot....

no1beemerfan

Don't worry about the disks, the nuts that are missing just hold the disk in place so its easier to put on the wheel etc. Once you have the wheel on and tightened the disks are not loose. I'd get the nuts anyways and put them on.

As for the knocking it could be the track rod end, drop link, broken spring, top shock mount, ball joint, anti roll bar bushing gone etc etc!

What I did with my Laguna when it had a similar knock was drive it up on ramps and laid under the car and got someone to push down and shake the car on the corner the noise was coming from and I found out it was my drop link was gone.

GreenTech

Haven't been on here for a while but Slidey was bang on the money - Top shock bearing!