Anyone have any advice on pinning down a noise that seems to be coming from the front wheels ... I think.

 

It sounds a little like the title sort of Grrrrrrrrr sound. Very similar to driving on those old concrete motorways with the fine ripples seeting up a resonance vibration in the tyres. Or maybe starting to spin up one of those old air raid sirens, though obviously not as loud.

 

It starts at 35 and gets louder up to legal speeds and seems unaffected by road surace or water. It's speed related and makes exactly the same noise if I knock the car out of gear and coast. The note changes in tone on turning the front wheelswhen in a corner.

 

I have Bilstein B4 shocks fitted (possibly extra stiffness changes the harmonics?) and front mud flaps fitted (maybe they interfere with the air flow?) but would like to keep them on in this weather.

 

Am having the car checked for bearings, but they feel OK to me. Strangely, I've mentioned it to two Octavia owners and they both say they have the same thing.

 

Any ideas please?

Your tyres have gone zigzaggy. Had the same on my old Cinturato P7s.

Taken car to Skida dealer thinking u had a major issue. They said tyres shot. I was thinking what the heck it's a reputable brand and only done 20k miles. They shrugged shoulders. Then took car to specialist. They said shocks are at fault. Legal but borderline. So changed the shocks to B6 Billies. New Barum tyres all round. Apparently some brands of tyres are more sensitive than others. Also regular tyre rotation helps. So now rotating tyres every 3-4k miles, and with news shocks too no probs at all. If you run your hand on the tyre you will be able to feel more resistance to hand movement in one direction than the other. I wa also able to see the zig zag clearly with naked eyes. Probably about a millimetre from one tyre block to the next.

Forgot to say that I'd wondered if it was the saw tooth effect that seems to effect rear tyres on these, and as my two rears were getting pretty old (though no sign of an saw toothing) I put a new pair of Hankooks on the back to see if it got rid of the noise.

 

It didn't, so I swapped the rears to the front and now have almost new Hankooks on the front and 5mm tread Neutons on the back.

 

If anything, the noise is getting louder and I'm "as convinced as I can be" that it's mainly coming from the drivers side front tyre, which, incidentally, is the shock that seems to make most noise when going over the numerous potholes .... seems to be a "double noise" on that one.

 

Have had the top arms checked for play and will check them again, but can't quite see why that would cause a noise that seems to be related to the rotational speed of the tyres.

 

I think it's fair to say that I only started noticing this noise after the struts were changed, but can't be exactly sure.

 

Puzzling.

 

PS Did your static timing advance solve the starting problem?

Actually, I've just been outside and rubbed by hand round the outside edges of the rear tyres and I think you might well be right.

 

If I start at the 12 o'clock position looking at the back tyres, there seems to be more hand resistance moving clockwise to the 3 o'clock position than moving anti-clockwise to the 9 'oclock position, which would indicate that the blocks are higher on the leading edge of the block than the trailing edge.

 

Tyres are rotational so it means I can't swop from side to side which is a shame.

Cold starts are still lumpy for 5 seconds. I think I may have a dead glow plug. Need to check. Now all are 4 tears old. Thats when 6 genuine ones were installed.

Warm starts i have not had to try yet, will let you know as soon as i have checked this. If its the pump itself for some reason I have a year to confirm / resolve until the pump warranty runs.

What if the ABS sensor is touching the cv joint ring? Got disturbed when the strut / shock was changed?

Turns out it's a very rumbly front wheel bearing on the drivers side, so it's 10 tonne press time soon :think:

Bearing now changed, but thought I'd post a few things that were learnt during the process ...... doh!!

 

Bought a new bearing and hub as the old hub can be damaged extracting the old bearing .... around £40 for the bearing and hub together so no big deal.

 

Don't even bother trying this without at least a 10 tonne press and a very good seletion of different diameter press pieces as these are really tight. After a bit of cleaning up and some penetrating fluid, the bearing finally started to emerge at just around the 10 tonne point, with a fairly startling bang as it broke the stiction. Pushed out fine from then on and no problems extracting the bearing from the hub.

 

Fitted the new hub and bearing, but when putting it back on the car, realised that though the diameters and splines on the new hub all matched up, the thickness of the hub flange is critical and the new hub (correctly marked Superb 2002 - 2008) had a 5 or 6 mm thinnner flange than the old one and wouldn't allow the disc carrier to mount correctly without hitting things. Also think that the shoulder that centres the disc carrier is the wrong diameter, so there would appear to be different hubs for the different Superbs.

 

Decided that it was best to re-use the old hub as it was fine, so pressed the bearing out again and extracted the hub .... only problem is that the thrust race has now separated  from the new bearing and is now stuck to the hub, so a clever hydraulic puller is now needed to get behind this bit and pull it back off the hub. Luckily we had one and it came off OK.

 

Re-assembled bearing and pressed easily into old hub. Disc carrier now fits correctly, all looks sweet and re-assemles fine.

 

Road test ... bearing sounds good but brakes are weird. Wheel with new bearing now seems to have a mind of its own and ABS is kicking in on that wheel whenever the brakes are applied. Decide that maybe the ABS sensor has picked up some swarf and thinks that the wheel is always locked, so try and pull the ABS sensor out to check and clean.

 

It really doesn't want to come out, so remove shaft and have a look and discover a bit of a design fault. When we torqued the drive shaft down, the ABS sensor was already pushed into the housing and be aware that it's possible to have the ABS sensor pushed too far in .... there's no stop to stop it in the correct position.

 

This meant that it was protruding too far in, and as the driveshaft was being pulled through, it caught on the ABS ring, pulled it off and broke it, while graunching the end of sensor. The moral is that you fit the drive shaft and then push the ABS sensor into place, not the other way round.

 

So car is now blocked up waiting for tomorrow to try and procure an ABS ring and a new ABS sensor. Seem cheap enough and readily available, just a bit of a pain. Still it's good for the soul ...... 

Edited 2 February, 201412 yr by CRC

If you forcibly separated the inner races of your new bearing changing the hub, I'm afraid you have wrecked it. Double row angular contact bearings are assembled cage last - just pushing a loose race back will score the running surfaces.

 

Removing and greasing the front ABS sensor bores is part of my annual maintenance. Unlike the Audis, the Superb uses an iron steering knuckle - hence rusty pinch bolts, stuck ABS sensors etc.

 

rotodiesel.

Ummm ... have thought long and hard about the bearing separating and think it's OK, though I fully appreciate your technical expertise on these matters.

 

From memory, the bearing consists of two sections. The inboard bearing and the outboard bearing. The outboard bearing is next to the hub flange and is pulled tightly into place by torquing up the nut that pulls the drive shaft through.

 

The part that popped out was right next to the hub flange, consisting of a lip seal and a "fluted shape" with balls attached at an angle. This only needed light pulling to pull it back off the incorrect hub. When off, it pressed easily back into the rest of the bearing using finger pressure only and the lip seal re-seated itself around the edge. No tools were needed for this .... just finger pressure.

 

Bearing has been fine for a couple of hundred miles or so, so I'm keeping my fingers crossed, but will heed your warning.

 

Regarding the ABS, new sensor and ring now fitted and no lights or fault codes showing. Brakes feel fine and powerful and ABS doesn't cut in under normal operation.

 

However, driving home tonight through the monsoon, I got caught up in a queue that involved some stop-start walking pace driving and I noticed that when the car is going very slowly and I apply very light brake pressure it almost feels like the ABS is kicking in on that wheel, as if the system thinks that when that wheel is going very slowly it has locked up and applies the ABS effect to that wheel only.

 

Which made me wonder if the system has re-adjusted itself to cater for the previous mangled ABS ring and needs a reset now that the correct ABS ring has been fitted. Vagcom shows no faults and I'm wondering if disconnecting the battery for a while might have the desired effect?     

Sorted the ABS problem .... some of the silicon grease that was used to re-install had created a black blob on the end of the ABS sensor.

 

Wiping it off cured the problem.

 

I like simple solutions.