Knocking over bumps

[matty_doh]

Hi all,

Recently my car ('09 133 with cup pack, 24000 miles) has started knocking from somewhere within the front suspension when going over bumps, though not all the time - it seems to be more frequent when the front wheels aren't straight (IE, turning a corner)

Any recommendations for what to look at here? I'll take it down to Renault anyway but it'd be nice to have some idea of what to tell them! I've heard that drop links can sometimes be the cause?

 

[matbry01]

might be you sure it isnt a creek or something like that ?

but saying that it might be the lower balljoints as i hade one go on my previouse car.

 

[matty_doh]

might be you sure it isnt a creek or something like that ?

but saying that it might be the lower balljoints as i hade one go on my previouse car.

Cheers for the swift reply.

Definitely not a creak no - it's a banging/knocking noise and has been going on for a couple of weeks.

I'm going to get the jack out and take a look later I think, stuck at work for now though!

 

[Karl]

Or could be top mounts on the suspension

 

[matbry01]

no probs.

so it doesnt do it under steering then or anything like that just specficly over speed bums and normal bumps in the road ?

 

[matty_doh]

no probs.

so it doesnt do it under steering then or anything like that just specficly over speed bums and normal bumps in the road ?

It does it no matter if the steering is straight or turned, just more frequent with the steering turned.

And yep, any bump - no matter if it's a pothole or a speed bump. Probably worst over rumble strips.

 

[matbry01]

could be what karl has posted or what i said bottom ball joints.

 

[Sharpy]

Try the drop links

 

[matty_doh]

Blimey you're a helpful bunch!

20 minutes after and three different people helping, much obliged gents.

Going to drop if off at Renault on Friday, at least I have a couple of ideas to put forward (and I can take a look tonight)

 

[Anonymous]

my mounts have gone after 50k, very very loose
kamracing got a few aftermarket ones on their site if you wish to go that route, as well as BC on here developing one

 

[matty_doh]

Well, it's booked in to Renault for this Thursday to hopefully be mended - whilst having a look at the suspension I noticed the inside of the front nearside tyre is virtually slick! Whether it is related or coincidental I don't know but this is getting expensive already and it's not even been in yet!

On the plus side, I've been offered a courtesy car. Any ideas what I'll get? Cooperative Renault Blackpool!

 

[singlespeed]

Well, it's booked in to Renault for this Thursday to hopefully be mended - whilst having a look at the suspension I noticed the inside of the front nearside tyre is virtually slick! Whether it is related or coincidental I don't know but this is getting expensive already and it's not even been in yet!

The inside edge being worn, implies your running a shed load of camber or the tracking (toe angle) is out. Guessing your not intentionaly running increased camber with a top adjustable mounts or offset bolts between the hub carrier and shockabsorber, so this would imply something is worn or loose.

Strut top mounts (bush and bearing assembly at the top of the shockabsorber), wishbone mounting bushes (two bushes mounting the A-arm onto the subframe) and the bottom ball joint (ball joint between A-arm and hub carrier) all control the toe and camber angles of the front suspension. Whilst the toe is also controlled by the track-rod end which is the ball joint on the end of the steering rack.

The knocking could be unrelated to the tyre wear, which may just be the steering out of allignment due to a pothole type impact, but more than likely the it will be related.

 

[matty_doh]

Again, thanks for the reply - the car is completely standard so no intentional camber adjustment. I am now suspecting either the drop links or the top mounts as they've been mentioned whenever I've mentioned it to anyone.

Is there an easy way to test if the fault lies with either of these?

At the moment I am just hoping it's covered by warranty after paying a small fortune for 4 new tyres, if not I'll be living on beans for the rest of the month!

 

[singlespeed]

Heres the left hand side of the arb and the bottom end of the drop link. The top of the drop link has a bearing going onto the strut

To check for any play, the arb needs to be unstressed, or any play will be hard to detect... so you can't get away with jacking one side. So it is either on the ground or ramps, or both sides on axle stands of a 4 point lift.

The strut top mounting is actualy under the wheel arch, where the top of the shockabsorber/spring is located into the inner wing. so you can't see much of it. Essentialy it is a rubber bush which sits in a recess in the wheel arch and locates the strut whilst the rubber stops too much noise and vibration coming into the car. A thrust bearing transfers the weight loads from the top of the spring/damper into the rubber bush, whilst allowing the srtut to rotate freely.

In the engine bay, theres a mushroom like assembly which prevents the strut dropping out of the inner arch if it is jacked up or unloaded. Heres mine with 8500 miles and the wheels pointing straight

If the strut top bush has worn, or collapsed, the gap between arch and mushroom may be larger, or the mushroom may be off to one side so the shinny metal part which drops down through the wing has been knocking against the wing.

 

[matty_doh]

Thanks again for the helpful posts, those pictures were very helpful Singlespeed!

Dropped the car off this morning, got a phone call a bit later to say they *think* they've found the problem and are going to replace both bottom arms next week, hopefully that should solve it. I've not much idea what I'm looking at if I'm honest so no idea what that actually is!

 

[singlespeed]

Thanks again for the helpful posts, those pictures were very helpful Singlespeed!

Dropped the car off this morning, got a phone call a bit later to say they *think* they've found the problem and are going to replace both bottom arms next week, hopefully that should solve it. I've not much idea what I'm looking at if I'm honest so no idea what that actually is!

The bottom arms will be the triangular shaped arm which goes between the subframe and the bottom of the hub carrier.

On the inner end, theres two metalastic bushes (metal/rubber) pressed into the arm to locate it onto the subframe. These allow the arm to pivot up/down without too much fwd/aft movement, although the rubber will flex a bit.

On the outer end of the arm, theres a ball joint (spherical bearing) to allow the suspension to rotate and also move up/down. Being as the 133 has the balljoint manufactured into the arm, theres not the option of simply unbolting and replacing the joint.


Is this a waranty fix, and if so, is the worn tyre being replaced foc?

 

[matty_doh]

Cheers! You learn something new everyday - this is part of the reason I want a project car, to pull apart and understand how it works.

Yes it is a warranty fix, and no the worn tyre is not being touched, partially down to they think it is unrelated, and also as I'm running 205/40/17 tyres up front instead of the manufacturer spec 195's.

Hmm-ho, the tyre is almost ready for replacement anyway and I've got new tyres ready and waiting to go on, and I want the car laser aligned anyway so I'm not unduly bothered.

 

[singlespeed]

Cheers! You learn something new everyday - this is part of the reason I want a project car, to pull apart and understand how it works.

Yes it is a warranty fix, and no the worn tyre is not being touched, partially down to they think it is unrelated, and also as I'm running 205/40/17 tyres up front instead of the manufacturer spec 195's.

Hmm-ho, the tyre is almost ready for replacement anyway and I've got new tyres ready and waiting to go on, and I want the car laser aligned anyway so I'm not unduly bothered.

That's ok then. I had read you had just bought new tyres, but also the inside edge was worn bald, hence thinking this was a brand new tyre thas was knackred due to the suspension.