Can you solve the problem that Caterham cannot?

[Saltyhair81]

Evening,

My car is currently with Caterham under a warranty claim. It's been in once before for the same issue, and they could not find the problem.  Since then I have sent them this video;

https://streamable.com/0mjszf
 

When the weather was warm, the issue seemed to be more frequent but does happen in cold weather too. When coming to a stop, normally on mid to light braking, I get a vibration through the car/ brake pedal/ front left (I believe) side.  The noise goes when you let off the pedal, but comes back every time you dab the brake on that one braking cycle until you come to a complete stop. 

You could pull away and brake another 10 times and the issue would not show itself, likewise it may do it the next 10 times.  Apparently they have checked everything and cannot find anything wrong.  They also are struggling to get the noise to replicate itself.

My first impression would be calliper/ disks/ wheel bearing but as I've just also had a major service, this should all have been checked/ re-packed with them checking through warranty. 

I've had the car 11 months and it's been there since day one of purchasing. I'm now getting towards the end of warranty and the noise seems to be as loud if not louder. It doesn't inspire confidence braking and also it is bloody embarrassing coming to a stop at lights as it is so loud! 

Does anyone have any ideas? Caterham will have had my car 3 weeks next Monday (this is partly due to staff off due to covid isolation) but I'm worried they are going to say they cannot find it!

I have probably 10 witnesses to the noise, plus video evidence. It's extremely frustrating.

Any advice/ thoughts would be appreciated.

Joe 

[aerobod - near CYYC]

I would say it seems like a resonating panel, possibly the mudguard due to poor bonding between the stay or looseness of the stay to the upright. A lesser possibility is of noise transmission through the suspension or vibration due to movement of the suspension itself in the bushings, which could imply a bad bushing.

To diagnose this, I would securely tape a weight to the top of the mudguard and see if it changes the characteristics of the noise, or similarly to the suspension wishbones, It is worth putting a thin layer of rubber between the weight and the component to get better coupling, before taping down securely.

[SM25T]

Its a didgeridoo !! Very odd

[Saltyhair81]

Hi James,

The resonating panel is caused by the vibration under braking. You can feel it through the brake pedal. All the front panels were checked before including the nose cone and grill (a clip was actually missing which was replaced). I guess this means that theory is out. 
 

Suspension could be an option, I am not sure if this has been checked by Caterham so I will add this to a list if they say they cannot find it. I did report that in my opinion, steering feels a bit vague. They said it would benefit from a flat floor.  I am more inclined to do the tracking first as I'm sure there was a very slight pull to one side. 
 

Not sure if any of the above will help diagnosed the issue further...

[Wrightpayne]

Have you taken the pads out for a look? I wonder if the pad material has separated from the backing plate or contamination on pads / disc.

I wouldn't assume they stripped / repacked the bearing unless they specifically stated so. Most services now are engine oil and filter and lots of checking / plug the computer in.

[SM25T]

It almost sounds like the edge of the tyre tread rubbing on the wing stay.

[Saltyhair81]

On the service schedule, I think on the 2 year/ 24k service they are shown as repacking the bearings. Even so, you would assume they would have checked this but I'll add it to the list in case. 
 

The car has 12,300 miles on it for info as well and is a 2006. 

I haven't pulled the pads out, mainly as I purchased from CC as a select model, had 12 months warranty and had just been serviced. I have completed only 1500 miles in a year. It did cross my mind regarding the pads but you would assume it would happen more frequently. Sometimes you can drive for an hour and it won't happen. Other times it can happen within 5 minutes of a drive. Strange! 

[Saltyhair81]

I thought this as well, but you would assume it would be more dramatic depending on the speed you were travelling. If anything it's worse slower then faster.  
 

The only reason I'm assuming it's brake related is due to the vibration through the pedal.

[K7 VCT]

That's very odd.... the didgerido effect indeed

[BrettJ]

I would suggest removing the left-hand side suspension and checking the bushes.

[Wrightpayne]

I know of one owner who bought a rebuilt race car one of the sleeves was missing in the front lower damper fixing. That made a knocking noise.

I would look at everything on that corner.

have you got any video devices or an old phone you could mount and record the front corner as it happens?

 

Ian

 

[7 wonders of the world]

the slight pull you mention, which way..?

does this occur under drive or braking conditions..?

[Saltyhair81]

As I said, Caterham still have the car and I really want it done under warranty as it's been an issue since I purchased it/ plus that's the point of buying with a warranty. 

If I do get it back and it happens again, I can probably get a go pro set up with camera and audio. I will then do a much longer drive and see what the exact characteristics of the noise are. Suspension does seem a good place to start I guess if the braking system is in good shape.  You would think with the volume and how severe the noise/ vibration is, the issue would be quite obvious from checking round. It does make me think how thoroughly they are looking 

[Saltyhair81]

I think it was pulling slightly right from memory in normal driving conditions, again I can't remember under braking as I haven't used the car much in the last few months - but I believe it was pulling a bit of everywhere due to how severe the vibration is.

[Tony Whitley]

Different sound and it was all the time but my car had an awful loud rattle that I couldn't track down. It was caused by quite a small amount of play (less than a mm from memory, not easy to spot) in one of the steering rack joints which was transmitted through the chassis and manifested itself just about anywhere you listened so I thought it was on the right side of the car while passengers reported it was on the left.

[Seabea23]

Warped disk perhaps?

[ScottR400D]

Discs very rarely warp, though you do get deposits on them that can lead to vibration. 

It certainly seems like a vibration caused when the pad hits the disc, if that’s not stating the obvious. I’m surprised they haven’t just changed the pads and then discs if necessary. 

Worn bushes, loose panels, wing, could all be amplifying the noise but hard to see other than pad/disc vibration as the root cause.

 

 

 

[elie boone]

The vibration the brakes produce should be addressed but the sound seems to come from the scuttle area,  could it be something that is slightly loose that is fixed on the scuttle ?

[David_Long]

I would look at the left engine mount. I suspect the mount (or possibly gearbox) it is touching the the chassis as the engine moves around under braking. Loosen it and lever away to give more clearance.

[Seabea23]

The loose engine mount is an interesting thought, if it’s a K could the exhaust manifold be touching the side skin under breaking.

[Simon.Rogers]

Always difficult to assess from video but like a couple of others above I think you have two issues and one is masking the other.

I suspect pad pick up on the disc as the intermittent feel you get through the pedal.  It can really feel like normal under a firmer press of the pedal but more of a light braking or trail brake action can make you think the front is going to fall off!

I think that the sound is clearly a panel vibrating. Although I am not sure that they are linked.  Do they always 100% occur concurrently?

I don't suspect the suspension.  Not to say it should not be checked.  I very much doubt the lack of the inner ali sleeve on the front damper would produce that sound.

[WobblyWeb]

If it's not the most probably brake pads, shims, pins, sticking caliper pistons, caliper-to-upright bolt-check, and the same bolt-check on the front suspension - my left-field suggestion is..... the engine mount has failed!

I had something similar a million years ago on my Triumph Herald. Rubber split/un-bonded (mount looked fine visually) allowing intermittent metal to metal (engine to chassis) vibration under braking or turning. Suggest Caterham substitute a new engine mount on the LHS or frankly, both. Check the Gearbox one too I would suggest. Easy to do, just need a jack and a socket set.

ww

[Saltyhair81]

A few answers;

• Yes they happen together that's the braking vibration and panel noise
• Car is a Sigma
• It is definitely not coming from the scuttle area
• It can happen regardless of brake pressure and speed
• I considered the engine mount/ gearbox mount and this is possible 
• I also thought the steering rack 
• The car was sat for years doing back and forth to the MOT station once a year. I assume this could be linked to that
• Vibration also seems to feed a bit through the tunnel 

This thread is great as I'm going to list everything in an email to Caterham if they say it's not found. Obviously I will report back what the issue is if they find it.  It's also interesting that no one else seems to have had the noise, means I'm not being led astray by CC's! 

 

[Paul Deslandes]

I'd bet money on that noise being the wing resonating.  If you tap the wing quite hard you'll get the same noise/pitch.

The video/audio clip is a bit short but it sounds as though the modulating frequency, rather than the pitch, drops as you slow down, which might suggest something rubbing the tyre tread.

I appreciate that the wheel and wing move together so the clearances shouldn't change with braking but check that there's nothing under the wing touching the tyre, like lump of Sikkaflex or similar that holds the wing on.  Also check the brake hose movement.  Mud flaps?

Paul

 

[Mrp]

When mine had a random noise and vibration I finally tracked it down to the bonnet and foam stripped all the surfaces where it touched. 

Mrp