I took the car back to Coopers to try to show them the distortion of the front tyres - they got the front wheels onto the balancer machines and spun them right in front of me and said they couldn't see anything wrong with the tyre. Well blow me down, I looked at it closely too and there was the tiniest little insignificant wobble up and down on the tread, not the big "dip" that I thought I was seeing before.
I was completely baffled and bemused by this after I thought I had seen a large dip when spinning them on the car, and was a little lost for words.So they decided to rebalance all the wheels including the rear wheels - which have not been rebalanced since they were originally fitted several months ago. They called me over to the machine when the rear wheels were on and pointed out one of them had an imbalance of 30/50 grams (inside/outside) and the other wheel I was later told was 20/40 out, both of which seem a lot. They seemed pretty confident that this would be the issue and that it wasn't the front at all... of course if the rear wheels were that far out it's probably only because they got it wrong initially as they did supply and fit them...
They did rebalance the fronts from scratch as well, and I noted that the poor placement of the weights on one wheel that I posted the photo of earlier was rectified.
So I went for a quick test drive with one of the wheel balance guys, and it seemed "OK" over a short drive but it was raining heavily, most of the road surface we drove over was rough and I couldn't really get up to a fast enough speed to verify the fix.One thing I had noticed over the last few months is that hard acceleration from about 30-50mph resulted in a slight "lumpiness" from the rear - I've had all kinds of theories about that ranging from wheel imbalance, a tyre fault, a faulty driveshaft joint or just a characteristic of the motor. Having not driven another Ion I have no comparison. I was pleased to note the following day driving to work that this rear lumpiness under hard acceleration seemed to have gone and I decided it must have been wheel balance all along...
or was it ??A couple of days later the lumpiness/vibration at the rear under hard acceleration is back, same as ever.
And predictably, the vibration at the front is there just as bad as ever, so basically all the rebalancing seems to have made no real lasting improvement at all. Meaning either it is balanced wrong again or balance was never the issue, despite the machine saying the rear tyres were a long way out... 
So what now ? Time to revisit the front brakes again. After carefully observing the symptoms over the last week I've now swung right back around to the front brakes being the cause of the vibration. Lets look at some of the clues and symptoms:
One thing I had been unhappy about with the front brakes was that they always made a rust grinding noise when applying them lightly at low speeds. When I had them apart the pads have plenty of thickness and so do the discs, but there is something fishy about the width of the pads. This is a picture I took of the front pads a couple of weeks ago - the right front I think, and you'll notice that the pad width (from inner to outer edge of the disc) is considerably different for the pad on either side of the disc:
This means the pad touches the rust lip before the flat surface of the disc and that is the source of the rust scraping noise when applying the brakes lightly.Here is the outside and inner side of the front right disc. (Not great pictures unfortunately - click them to get them the right way up!
) On the other hand the inside pad clears the rusty inner lip of the disc by about 2-3mm and seems to sit nice and flat on the active disc surface.So what's going on here ? Has someone fitted the wrong pads or a mismatched pair of pads ? How can that happen ? As far as I can remember the other side of the car had the same issue where the inner and outer pads were a different width, although the shoulder wasn't so problematic on that one.
Is it possible that the disc was worn down (creating a shoulder) on the original factory pads, and somebody then fitted an after market pair with a wider pad surface thus causing it to ride on the edge of the lip ? I still don't understand how inner and outer pads would be a different width though... why ?
I did chamfer the corner with the file quite a bit but it doesn't seem to have done much to help - if anything the scraping and vibration when braking is worse now. Which leads me to my next observation - there seems to be some drag all the time, and it seems to get worse after driving a while.
What I had noticed is that when cold the "vibration" at the front is very minor, but after the car has been driven a while it gets progressively worse so by the end of a 30 minute drive it is quite bad. It seems very likely in hindsight that as the discs heat up the pad is starting to drag on the lip on the inner edge of the disc, and drag enough to cause further heating and then drag even more, before you know it the pad riding on the rough lip on the disc is causing significant drag and vibration.
In fact this morning I even noticed at 10mph on the motorway that the car was lurching ever so slightly instead of rolling smoothly suggesting drag from the brakes that varies with rotation each time the wheel goes around.
Whether the brakes are the whole issue or not it is definitely a big part of the problem and needs sorting ASAP.The question is what to do. The obvious 100% long lasting fix is to fit new discs without lips, and new (hopefully equally sized!) pads... Problem solved. However I have no idea what new pads and discs might cost for this car, and even if they are reasonable it's not really an option at the moment financially.
So I was thinking, would it be an acceptable bodge to get me by for now if I were to carefully and neatly vertically chisel off (with a wood chisel) the excess pad material on the wide pad which is riding over the inner rust lip so that it sits properly flat on the flat part of the disc ?
I have vague recollections of doing this before on another car but my worry is that the edge of the pad material may have a glue or binder that helps hold it together, and if I were to chisel away the pad material at the edge right to the backing plate it might start to fall apart in use ? Has anyone done this before ?
Regarding the rattle of the brakes over rough surfaces, that is completely gone since I last did the front brakes. I found two things - one is that the anti rattle spring on the inner pad was lacking in tension on the right hand side and completely squashed flat and ineffective on the left hand side - which was the extra noisy side. I just retensioned the two springs (which are just U shaped) before refitting the pads.
The other thing I found was the the brake caliper pins had virtually no lubrication on them - it looked like hardly more than a drop of oil, and they do seem rather loose, yet not worn. I put plenty of copper grease in them with the hope of the sticky grease keeping them quiet and that may have helped too, but after a discussion in another thread about the suitability of copper grease in this application I'm probably going to rip it out again and replace it with silicone grease! (Hopefully it will still stay quiet then)
Interestingly the left and right side of the car has different design pins! So it looks like one side may have been replaced before, here are the two variations:
Looks like I lucked out this time. 
but because a full new set is only £52 I'm inclined to go ahead with a little bit of careful chiselling as a bodge knowing that I have the safety net of a £52 new set of everything as a fallback if something did go wrong. And then in a couple of months when finances have built up again I'll go ahead and order it anyway and fit the new pads and discs - it's worth it even if the bodge works I think as I do a high mileage in this car.
Well done and good work 