Corroded Brake Discs & Warranty

N

northernbadger

Member
 Surbiton, Surrey
Hi guys,
Virgin poster here - need your help!

Bought my '57 Z4 Coupe in August from Bowker BMW in Preston and have done only 3,500 miles since then (the car has done £13k in total). I drive it only twice or three times a week and it sits outside. Over Chrstmas I didn't drive it for 2 weeks (holiday) and when I came back I noticed the brakes were unresponsive and there were vibrations under braking through the peddle and steering wheel. I thought this would fix itself after a few drives utilising the brakes but it didn't.

Taken it to Cooper Cobham to look at and they advised the brake discs are corroded and they'll need to change the pads at the same time. Quoted £490. They are effectively implying it's my fault for not driving it regularly enough and it wouldn't be covered under the warranty (used car or manufacturers). Bowker Preston are saying everything was fine when I bought it.

Have I got any legs to stand on here or do I have to accept it and put it down to experience (whilst promising to take the car out more often)?

Thanks in advance for any advice
Regards
Andy
 
If the brakes were ineffective through surface corrosion then I'd expect a 50 mile blast would sort them out - although you need to use the brakes robustly during that trip, as a 5 mile tootle to the shops and back won't put enough effort into them to clear the crap off.

Have you tried some really hard braking - i.e. until the ABS comes on?

Mine regularly sits outside for a week or so, picks up corrosion on the discs and then the inital braking is not good - but subsequent ones are better and better until they reach optimum performance again.

Depending how heavy these vibrations are then it could be that you've got something else wrong as a quick skim and new pads would sort it - assuming there's enough meat left on the discs to do the skim - and a dealer would prefer you pay for a full set of BMW discs instead.
 
either way - if the big blast doesn't fix the problem and BMW don't help out with the cost then get them done eslewhere, they really don't need to be done at a $tealer who will cost you WAY more (the root cost of discs and pads is far less than £490!)
 
Yeah id agree that you should try giving them a little abuse first. Make sure you let them cool (by driving sedately for a few miles) after also.

If they still vibrate the wheel, they are likely warped. Have you recently done any heavy braking to cause it, maybe with over worn pads, or doing through puddles with hot brakes?

Theyre having a laugh at £490 though. Its likely just your front discs and you could DIY them and new pads for around £120. :)
 
Hi Andy and welcome to the forum.
Sorry to hear about issues with your brakes. Agree with what the others have said - good blast and some heavy braking will normally clear the rust that has developed as a film over the disc surface. This is worse where water is retained between the pads and the disc and excessive rusting can occur over time - this can cause a juddering sensation under heavy braking but should soon clear. This can be fatal to the discs if the rusting has really started to bite into the disc surface and especially if the retained water is contaminated with salt as I imagine it would have been in your area over Christmas with the snow and gritting. As Ed says - they may be warped which has happened to others. £490 for replacement is nonsense easy DIY job for much much less.
 
Welcome :thumbsup:

My dics get surface rust all the time even after a wash but as said a few pumps on the brake pedal and all is well my car sat outside for 5 weeks this time last year through all the heavy snow and rain while i was on holiday came back jumped in the car and no probs at all.

Hope you get it sorted mate
 
BMW are holding my car as they didn't have parts available. I'm pretty sure the blast of the brakes won't work - I did 500 miles over the weekend and that didn't do the trick as I thought it might.

They are telling me corroded rather than warped (would warped discs be warranty?). It's beyond my talent to do anything mechanical so the option is to take it to a local garage and have them do the work? A cheaper option but could it be inferior work?

BMW will charge me for the inspection so I guess that's £150 already but perhaps taking it elsewhere will still save me some money on the £490 quoted. It still amazes me that it went through their "vigorous checks" just 6 months ago and now it's needing this work, didn't realise they were so fragile!

Thanks all
 
I'm still amazed that 2-weeks outside has corroded the discs to the point that they're useless items. I just can't see it myself. Appreciate you're saying you did a 500 mile drive and it still didnt work though, but really surprised...
 
Corrosion will have absolutley nothing to do with this problem if youve given them a good drive. The dealer is giving you rubbish.

Brake discs are made of a ferrous metal (Steel!) so they all corrode. After a good wash, mine will look completely rust coloured after 15 minutes. Especially with the current wet/salty road conditions. If the disc surface is indeed excessively corroded however, the pads are probably faulty to tell them to change everything because of that instead!
 
I think people are missing the point here. Yes brake discs rust, almost immediately when you wash the car you can see the rust develop across the face of the disc - soon cleared with a run and a short period of firm braking. Whats described here is a 'vibration' through the steering wheel and brake peddle under braking. This is not caused just by surface rust. There is a problem here which could be warped discs or where excessive rusting has been caused whilst the vehicle has been parked and where the pads sit against the disc and no doubt made worse by salt on gritted roads. Only one way to determine the problem and that is to physically look at the discs for damage and spin them and observe if they are warped or not. Simple method to determine warping is to use a toothpick (or similar) secured on the carrier with blue tack or plasticine with the point held just touching the disc face, gently then turn the disc and see what happens - not scientifically accurate but at least a cheap way to diagnose a warped disc. The dealers have adopted a common BMW repair solution - not properly diagnosing the issue but just repairing by replacement, an unfortunate sign of our modern times where true engineering and technical skills are being lost by this often expensive (for the customer) approach. If the problem is the discs then it is a sensible option to change the pads as well and an opportunity to improve over the original fit at a fraction of the cost of BMW OEM.
 
Do disks really warp? Discuss!

I've had vibration on a couple of cars one high performance and one not and it has been cured on the original disk and not by having them skimmed - vigorous scrubbing did the trick. The vibration on the high performance car was down to a pad imprint from holding the brakes on at the bottom of a hill after some particularly spirited driving. Clearly visible on both sides of the front disks The vibration on the Landy 90 was caused by it sitting idle for 3 months.

warped disk myth
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
 
2 weeks is a long time in this weather!

Pads can bind to the disc and leave big piles of rusty metal around where the pad was.

Drive em and it'll wear off but not sure on long term impact on life of pads after such use.

Just make sure it's driven or stored dry inside.
 
Spoke with AMC (BMW/Merc independant dealer) who confirmed he'd seen similar problems recently because of the harsh prolonged cold and excessive grit. They quoted £370 for original BMW parts (labour costs make the difference as they still have to buy the parts from BMW) and £263 for 'similar standard' from Durid(?).

As BMW had the car already the difference wasn't worth it. They gave me some money off so total came to £396. Expensive lesson learned!

Thanks for your help guys
 
northernbadger said:
Spoke with AMC (BMW/Merc independant dealer) who confirmed he'd seen similar problems recently because of the harsh prolonged cold and excessive grit. They quoted £370 for original BMW parts (labour costs make the difference as they still have to buy the parts from BMW) and £263 for 'similar standard' from Durid(?).

As BMW had the car already the difference wasn't worth it. They gave me some money off so total came to £396. Expensive lesson learned!

Thanks for your help guys
Click to expand...

Good to hear it's sorted.
 
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