2014 Metropolis - I fitted new Delphi discs 18 months ago and recently noticed that the outer face of the front right hand side (or offside in the UK) disc was deeply pitted and rusty for the outer 20mm - see front pic 1. The other face is perfect as are both faces of the left hand side disc. There was no noticeable reduction in braking effect and no pulling to one side. Anyway, I decided to replace the discs again as the pitting was too deep and it would possibly fail the MoT in a couple of months.
I took everything apart, cleaned and wire brushed it all and fitted new discs and pads but after driving a few miles that section of the new disc is now doing the opposite, it’s wearing but the inner section is not, see pic front 2, now I’ve only done a few miles and it may bed in eventually but once again the other face of that disc is fine with full width pad contact showing, as is the left hand disc, so something is amiss.
Could this be down to the guide pins? I did clean them and put a dab of silicon grease on them, the caliper slides freely side to side but could they be the cause of this uneven wear? They are the only bits I haven’t changed but looked unworn.
Any suggestions or advice would be welcome.

But wait …there’s more…..the right hand side (again!) rear disc is badly rusted on the outer face, the inner face is fine as is the left hand side disc, any ideas as to what could cause this? Once again, braking is good and the electronic handbake appears to be working and holding fine. See pic rear 1

Strange wear patterns……from pics it looks like the car spends a lot of time parked-up….hence the rust on the discs. You say thé calipers slide ok…..so guide-pins not seized…..no wobble in the calipers ?
Caliper pistons ok …not rusted ?
My wife’s Mini has similar wear pattern on discs…i.e. not all the disc covered by pads…..this is caused by lack of use….not fully bedded-in…….after being replaced for MOT Test 3yrs ago…….hardly used since. FL2 SD4 HSE Lux Auto MY 2012— current
D2 TD5 HSE Man MY 1999 470kmls….gone 2014 ….lovely engine..chassis rotten
D1 300TDI Man MY 1996 56kmls….gone 1999…D2 much better
Wife’s FL1 1.8P MY 2001 32kmls …gone 2007…has Mini since.

I think both front & rears are likely to be as a result of the caliper guides, rather than the caliper pins. You need to focus on part LR043284 for the rear on a car with EPB. (not sure about the part number for the guides on the front). That picture of the rear disc shows the outer pad is not acting on the rotor - the braking effect being good & the EPB holding well means the inboard pad is doing all the work

I had something simillar on the OSR - the root cause was corrosion on the caliper guide. I removed the guide, mounted it in a vice, removed the stainless pad guides from guide & gave it all a thorough cleaning. Stainless steel guide plates/clips were quite distorted. Mounted it all back & problem was still there... To get around the problem I removed the stainless guide plates, leaving the discs to "float" in the channel in the caliper guide until the replacement guide arrived in the post. Replaced the caliper guide with the new one, problem resolved.

I have since used the corroded guide on the NSR of the car [they are interchangeable] after grinding back to bare metal, painting then replacing the stainless pad guides and the caliper guide pins. The pins were probably OK, but were changed anyway (cheap & easy to do). The pads moved really easily in the reconditioned guide with new stainless clips.

@Fatal Apathy :

Your diagnosis is entirely possible…..I had similar issues with wife’s FL1 years ago….effectively thé metal part of the brake pad (esp. outer pad) is possibly so corroded in the stainless steel guide that it won’t move & contact thé disc….or it wedges sideways à bit…hence the uneven wear. Worse on the rear of course with the EPB pulling the caliper inwards all the time thé car is parked. Thé pads must be free to move in the stainless steel guide before fitting the caliper over the pads. FL2 SD4 HSE Lux Auto MY 2012— current
D2 TD5 HSE Man MY 1999 470kmls….gone 2014 ….lovely engine..chassis rotten
D1 300TDI Man MY 1996 56kmls….gone 1999…D2 much better
Wife’s FL1 1.8P MY 2001 32kmls …gone 2007…has Mini since.

You probably need to use a different lubricant on the pins and guides. Ceratec was recommended to me. And yes, the guides themselves need to be as smooth as possible or the pads will hang up and not make full contact with the disc. That will cause the wear patterns you’re getting.

@Fatal Apathy

Thanks for that, on the fronts, that I've just done, there was a fair bit of corrosion in the guide slots where the pads sit, but I thought that I'd cleaned it all out, filed back to bright-ish metal (no ss guide plates in the front) and the pads were a rattling loose fit in the slots, but maybe there's a bit I missed, will have another look tomorrow when hopefully the new guide pins I've ordered will arrive.
As for the rears that I've yet to do, (I presume you meant "leaving the pads - not discs - to "float" in the channel" ??) when I changed the discs and pads last time, the pads didn't come with new ss guide plates but the new ones I have, came with new plates so we'll see if they or the channel is the problem.
Thanks for the info.


@OxonPete

You are right, the car doesn't do much, it's only got 26000 miles on now and sits in salt air most of the time, I have to shift the wife's car off the drive to get to mine, so if I'm just popping to the shops, I'll use hers.......

Seadog I can't but admire how clean and new looking the bits of your Alloy Wheels are.
At 26k miles, if the rest of your Metro is the same you will have a very sought after car in times to come.

Having read your post, and the replies, I will be looking closely at the wear/rust patterns of my discs. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 82k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Drive it like you stole it and use the brakes for their intended purpose - end of problem I'd say.

New guides in a kit are around £12 on ebay. Easy to fit.

eg
https://tinyurl.com/wspezanj

I use Ceratec grease on all my brakes. Jules

Aveling wrote:

Drive it like you stole it and use the brakes for their intended purpose - end of problem I'd say.

Aveling wrote:

Drive it like you stole it and use the brakes for their intended purpose - end of problem I'd say.

Pic 2 looks like it will bed in ok.
I've found various brands of pads poorly shaped recently meaning they didn't move freely in the carriers. Had to file excess paint and even metal to get them to fit properly without binding.
Sitting unused in salty air will definitely not agree with brake discs. Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

Quote:

(I presume you meant "leaving the pads - not discs - to "float" in the channel" ??)

Sorry. Exactly that - the Pads float in the caliper guide channel, not discs/rotors... I really should read the stuff I write sometimes...

My '84 Cavalier had floating front discs - they fell off everytime I removed the front caliper. i always forgot they were not fastened on

A tip on front discs/ pads. I replaced the fronts on my 2013 SD4 and found they are different part numbers on SD4's for all pads too. Rears are bigger, fronts too. I was a bit miffed as I had some for a 2009 Diesel, and they did not fit. A band on the disc not worn does suggest that some parts fitted are not correct. I use Copper Grease on guide pins, but dry Rocol spray would be an alternative, as it is not messy.

I thought the front pads were the same on all FL2. With the I6 having bigger disks and caliper carrier but same pads (I did that conversion).

All the part numbers are here

https://parts.jaguarlandroverclassic.com/p...and-rover/ Jules