Simon's new Xantia V6 and Leaf blog

[Mandrake]

The plot thickens!

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:

As far as I can remember, the top one with the anti rattle spring is the inside pad and the bottom one is the outside facing pad. There's a clear difference in width of pad material on the order of 5-10mm there. More importantly, the wider outside pad when fitted is riding up over the edge of the rust shoulder on the wear lip on the inside edge of the disc by at least 5mm. 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! )

And predictably, this rusty lip is not perfectly symmetrical around the disc so when you apply the brakes hard at speed it does definitely introduce a vibration. 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:

Anyone have any thoughts on why one side has a metal only pin and the other side has a nylon (?) bushing ??? I wonder which is factory and which has been replaced ?

[Stickyfinger]

Not seen those nylon bushed pins before....not on any of the Xantia brakes I have ever worked on anyway. My money is on that being a replacement for a lost or corroded one......."that will do, it is about the right size"...... job done !

The "lip" on the disk is easy to remove with an abrasive disk on an angle grinder. I keep the grinder at one position & at the correct angle and turn the disk to get an even edge.

[white exec]

Very odd to see different areas of lining on each side of a disc, which is usually equally clamped and supported, to avoid lateral stresses.

You could also remove the outer rust lip from the disc: jack up and rotate while carefully applying a supported grinder. The loss of the lip will have no deleterious effect on braking, which attacking the pads might have.

Might be a good idea to buy a set of proper new pads, and take a look at how much rusty lip needs removing, if any.

Apart from the anti-rattle springs, should there be any anti-squeal shims there too?

[RichardW]

Discs and pads can be had for not too disastrous a price: e-bay; never heard of APEC though!

Those pads don't look like a matched set, bit difficult to say without seeing them in flesh. Having different pins is not unknown; sure at least one of mine has different ones top and bottom - hard to believe they are not original on what was a <30k mile car when you got it. I'm a bit pre-occupied with boilers, but you're welcome to borrow the grinder if you want to de-lip the discs. I don't think I will need it to fit a new boiler

[CitroJim]

APEC stuff is OK... I've used it in the past as it's one brand often flogged by our local motor factors...

Simon, this is getting interesting... Reckon you're onto it now with the front discs...

I await good news

[RichardW]

Pins look to be original, the one with the sleeve should be at the bottom:

[Mandrake]

Very odd to see different areas of lining on each side of a disc, which is usually equally clamped and supported, to avoid lateral stresses.

You could also remove the outer rust lip from the disc: jack up and rotate while carefully applying a supported grinder. The loss of the lip will have no deleterious effect on braking, which attacking the pads might have.

The lip the pad is riding over is actually on the inner edge of the disc not the outer - and although Richard offered to loan me his grinder I have no experience using one so I'm not keen to try grinding the inside edge of a disc as my introduction to grinding to be honest!

Apart from the anti-rattle springs, should there be any anti-squeal shims there too?

Don't know - none fitted at the moment... And yes the brakes are squealing again, but I reckon that will be the pads touching the disc lips again... and there are no wear light wires either even though they're shown in the new ebay set Richard found.

Discs and pads can be had for not too disastrous a price: e-bay; never heard of APEC though!

£52 for new discs and pads together is actually really reasonable! I always worry about the prices of parts for this car - on the one hand its a small, simple car so many parts such as tyres and apparently brake parts are a lot cheaper than the Xantia, but because its a very rare car some dealer only parts (like a new A/C compressor) are eye wateringly expensive! Looks like I lucked out this time.

Those pads don't look like a matched set, bit difficult to say without seeing them in flesh.

They're not even remotely matched in width, but to be honest looking at the photos again I wonder if the narrower one has already been chiseled back by somebody ?? The pictures in the disc/pad set you found show the pad areas to be identical and to the full width with the only difference between inner and outer pad being one has an anti-rattle spring and the other doesn't. So my bet is someone already did the bodge on one side that I'm contemplating!

I can't afford to buy those pads and discs this pay day as I have a number of other expenses to catch up on first, 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.

Pins look to be original, the one with the sleeve should be at the bottom:

ion brakes.JPG

Aha! I see what has happened now. Someone has had them out and mixed them up, and ended up putting both nylon shimmed pins on one side of the car and both metal pins on the other side, instead of one of each on each side as depicted. I'll make sure to put them back how they should be when I'm next doing something to the brakes.

I wonder why the one with the sleeve goes at the bottom in particular ? Is that used as a crude form of pad bias so that when the caliper squeezes it squeezes slightly more at the bottom (trailing) edge ? If so, that might explain squealing pads...or perhaps even unnecessary drag...

[Stickyfinger]

Pins look to be original, the one with the sleeve should be at the bottom:

ion brakes.JPG

Well I never.....that is one for the memory

[harryp]

Going back a little

10mph the car actually rocks side to side slightly in a slight wiggle!

Have seen this before on a friends car in the '70's.

It's due to the tyre carcass not being placed correctly, i.e. flat in the mould, so that when the mould closes the tyre sits at a slight angle so that the tread is not in line with all the reinforcing belting underneath. After cure the underlying (inflated) carcass tries to assert its proper shape and the tread "wobbles" from side to side. Not very common!
If you unroll say a roll of lining paper and roll the wheel down it, a low down view should reveal the read performing a shallow sine wave!!
Only a replacement will cure this. Have you tried contacting the manufacturer? Not really what you want to hear .
HTH

[white exec]

Harry, would you be able to see this sideways tread movement by slowly rotating the wheel with a pointer aimed straight at the thread?

[Mandrake]

With the threat of heavy snow next weekend I decided I better have another quick go at the front brakes - a threat that was later downgraded to only rain afterwards.

So yesterday the front brakes came out again and I did what I could to bodge it. You can see how much the pad overlaps the rusty part of the disc:

So I chiselled off a good 5mm of pad facing the centre of the disc on all 4 pads - here is one half done to show how much I took away:

I tried to get them all as even as possible. I also put a file across the caliper support and turned the disc by hand as was able to remove quite a bit of the rusty lip. I noticed that on the inside edge of the disc (facing the centre of the car) there was a big flakey rust lip that I hadn't noticed before - the file held in place while I spun the disc made short work of the loose flakes of rust - they were probably a good part of the problem too.

I removed the 4 pins and sure enough found the two with nylon sleeves were on the right side of the car while the two all steel ones were on the left - I know I didn't do that as I didn't have both sides apart at the same time last time I had the brakes apart.

When I went to refit them to their correct locations with the nylon sleeves at the bottom I made a discovery - they aren't nylon! They're actually rubber, and pretty soft rubber at that... In fact when I went to refit the one on the right and side of the car it wouldn't go back in - because the rubber was too soft and was just sliding out of position up over the shank of the pin jamming the hole instead of staying on the machined down section. I'm going to guess that mineral grease has indeed softened the rubber to the point where it no longer wants to stay where it should be, however some grease probably got between the rubber and the pin as well making it slippery on the pin as I did put a lot in last time to try to cure the caliper rattle.

So I cleaned out all the grease from the hole and discovered at the bottom of the hole there was quite a bit of yellowy/green grease - which looks to me just like bog standard all purpose lithium grease. So if I made the mistake of using a mineral based grease, somebody else did before me as well! (And also mixed up the locations of the pins...)

So I cleaned out all the grease in the hole and on the pin under the rubber and put just the slightest wipe of grease on the pin and with a bit of fiddling was able to get it back in without the rubber riding up over the pin - but the pins with the rubber sleeves definitely need replacing now as the rubber is buggered. Whether it was heat, the previous monkey's lithium grease, my copper grease or a bit of all of the above I don't know.

I put it all back together and gave it a drive (and have subsequently driven to work today as well) and it is a major improvement. The grinding when coming to a stop is all but gone, the squealing of the brakes reversing at low speeds is gone (but for how long..) and I'd say 90% of the vibration at speed is gone now. It's not completely gone but there is none at all when I first start driving and then after 20 minutes on the motorway there is a just detectable vibration instead of a fairly bad one that was there before. I think previously the disc would heat up and the flakey rust would expand and start rubbing against the edge of the pads making it grab and introduce a vibration.

Also greatly improved is that hard braking at speed before would cause a lot of vibration - there is hardly any now. What I did also notice when I had the brakes apart is that there IS a small amount of runout/warpage of the disc, so I don't think it will be 100% vibration free until the discs are replaced.

The caliper rattle has also returned on the right hand side - clearly the extra grease I had stuffed in the pin had quietened it right down as there was NO rattle whatsoever the last few weeks with plenty of grease on the pins, but this time because of the swollen rubber I cleaned all the grease out and only put a slight wipe back on - not enough to quieten it down apparently.

So this should hopefully last me a few months but ultimately I need to fit the new discs and pads, and also get new pins - I definitely need the ones with the rubber sleeves and if there is rattle I might as well get all 4 of them as the others may be worn. And this time I will assemble them with a good dollop of high temperature silicone grease to keep them quiet but without upsetting the rubber...

And then shake my head and ask myself who designs brake caliper slide pins with a rubber bushing/sleeve on them!

By the way, when I got to work this morning I thought I smelt a wiff of brake smell exiting the car (probably paranoia) so I checked the temperature of the discs - not even warm to the touch, they were almost cold... just goes to show how little work the brakes really do with regenerative braking available! Most of the time they only slow you from about 10mph and hold you stationary, unless you are doing an emergency stop...

[CitroJim]

Simon, that's excellent news Well done and good work

[white exec]

Simon, looking at that top photo, I'd say that either wrong pads are fitted to the car, or there is something wrong with the caliper position. It may be a trick of the photo, but the pad just doesn't seem to line up with what looks like the swept (polished) area of the disc.

I find the photo quite worrying.

[Zelandeth]

I'd say something has been well messed up with these brakes...which given the mileage is really quite worrying.

I'd say new discs, pads and pins then see where we are from there. That photo makes it look like that pad isn't even the correct one relative to the disc.

One thing springs to mind: I'm pretty sure that (in Japan at least) Mitsubishi offer what is essentially the same car but with a small rear mounted petrol engine. Is it possible that some of the braking components are different between the two? Expect given how much of the work the regen system does in an EV...

[Mandrake]

I'd say something has been well messed up with these brakes...which given the mileage is really quite worrying.

I'd say new discs, pads and pins then see where we are from there. That photo makes it look like that pad isn't even the correct one relative to the disc.

I agree - it looks to me like the car originally had narrower pads so wore the disc down over a reduced sweep width, and then wider pads were substituted, now overhanging the rusty untouched lip on the inside of the disc... but how that could have happened at 35k when they should still be the original discs and pads I can't fathom.

Seems like someone has botched something up with the front brakes some time in this cars history, we know they put the pins back in the wrong locations at the very least, hence why even though it is working well now, I still want to put new matching discs, pads and guide pins in to start fresh and erase any prior botch ups that persons unknown might have done...

One thing springs to mind: I'm pretty sure that (in Japan at least) Mitsubishi offer what is essentially the same car but with a small rear mounted petrol engine. Is it possible that some of the braking components are different between the two? Expect given how much of the work the regen system does in an EV...

Yes the Mitsubishi i-Car is what the Ion is based on with a 650cc turbocharged petrol at the back...and 272 did find their way into the UK as well. As you say the specific dimensions of the discs or pads may differ between the petrol and electric version of the car, but I haven't tried to look up the differences.