What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
Volkswagen Polo III - Brake disc badly corroded - csgmart

At the last MOT (November) I had an advsisory that the front brake discs showed evidence of corrosion but not serious enough to fail. Due to problems with the health of my mother I only got around to replacing them yesterday and boy am I glad I did.

The brakes have evidently got much worse since the MOT was carried out and to be fair they still worked OK, although I had noticed a slight tailing off in their sharpness recently.

From the outside of the disc nothing was untoward; a little bit of surface corrosion and they were getting down to their minimum thickness but otherwise OK. Having replaced the drivers side I then moved over to the passenger side. On removing that disc from the hib I turned it over to reveal that the inner face of it was in a shocking state. There was little more than a 2cm portion of the disc that was making contact with the pad and either side of that was a wide band of corrosion.

I am of course entirely to blame for letting the brakes get into this state and this serves as a reminder that certain things (brakes and tyres particularly) are all that keeps you from having an accident.

Moral of the story, check these things regularly....

Volkswagen Polo III - Brake disc badly corroded - gordonbennet

Good reminder that, for non DIY types the modern version of garage servicing doesn't help where brake maintenance too often comprises of a technician peering through or from behind the wheel and squirting brake cleaner in the general direction of the caliper.

And thats where people have their cars serviced, in many cases the MOT test is the only inspection the car ever gets.

Wheels have to be removed, then the pads/drums removed to inspect properly, IMO this should be an annual event, and it pays for itself as properly cleaned inspected and correctly lubed braking systems often last the life of the vehicle with only friction parts needing renewal.

Coincidentally i'm just about to attack the Subaru while the weathers nice thismorning, wheel change to summer set and full brake and underbody inspection, might give it a spring blast over underneath with the pressure washer while it's up in the air and hope the highways mob didn't take advantage of treble time early hours to lay some not needed salt again.

Volkswagen Polo III - Brake disc badly corroded - csgmart

Thanks GB. I do all my own servicing on the Polo (still basic enough for the DIYer) and get satisfaction from that.

Will make sure I keep a closer eye on these things in future.

Volkswagen Polo III - Brake disc badly corroded - Wackyracer

I had the drums off the Astra this afternoon and gave them a clean out and inspection. It's something I had been meaning to get around to for a while.

Volkswagen Polo III - Brake disc badly corroded - gordonbennet

Well done lads, some good money saving work there.

Realised it's been 5k miles since the last engine oil change so treated the Scoob to new oil and filter whilst down under, always got oil and filters in stock.

Incidentally, i had a good look at the subframes where i treated them with Bilt Hambers finest, sure enough no sign of any rust poking its ugly snout out, standing up to normal road grit abrasion well.

All looked good otherwise, then washed the fleet to finish off, all covered in dust, gawd nose where that came from.

By the way CSG, part of my car buying ethos is that they must be simple enough (or well enough designed to be simple) to maintain or mercs which i leave to my indy, keep that Polo serviced and looked after and keep away from moderns..:-)

Edited by gordonbennet on 06/04/2015 at 21:17

Volkswagen Polo III - Brake disc badly corroded - Wackyracer

Funny that GB, I only intended on changing the engine oil and ended up giving the brakes a looking at.

Did you give the open areas a light coat of cavity wax before applying the UB wax? I'm not going to treat the Astra to rust protection, when it gets rusty I'll have an excuse to get rid of it then.

Volkswagen Polo III - Brake disc badly corroded - gordonbennet

Funny that GB, I only intended on changing the engine oil and ended up giving the brakes a looking at.

Did you give the open areas a light coat of cavity wax before applying the UB wax? I'm not going to treat the Astra to rust protection, when it gets rusty I'll have an excuse to get rid of it then.

The open areas were well rubbed/wire brushed down and the heaviest rusted areas (subframe), sprayed with zinc primer then painted with that 2 pack epoxy paint, then an overcoat of proper UB wax...the cavity wax only went in the cavities.

Opposite for me, didn't intend to change the oil in the Scoob, but then saw the mileage writ in indelible under the bonnet from last time, so oil change it was.

Got a week off next week so hoping to make a start on the Landcruiser rustproofing, now it's all serviced up to date.

Took the old MB to work today, filled up with LPG (60ppl eat yer heart out Osborne..:-)), then came home via the long sweeping bends on the back road with all the windows and sunroof open, most enjoyable.

I'm quite heavy on my car brakes, so they don't last everso long, but to put that in context and if anyones intersted my lorry tractor unit had its first new set of drive axle pads @ 280k kms, the steer axle renewed @ 300k ish kms, the mid lift axle still has 60% @ 330k kms, all original discs.

Volkswagen Polo III - Brake disc badly corroded - Wackyracer

Sounds like you did a good job on it, I only asked as the Dinitrol I bought a while back suggested spraying a light coat of cavity wax on open surfaces before going over with the UB wax. The instructions said the cavity wax contains some active rust inhibitors that the UB wax does not have.

Warm weather is coming so I might buy a Sealey pressurised pot gun and a couple of gallons of Bilt Hambers finest.

Volkswagen Polo III - Brake disc badly corroded - John F

Wheels have to be removed, then the pads/drums removed to inspect properly, IMO this should be an annual event, and it pays for itself as properly cleaned inspected and correctly lubed braking systems often last the life of the vehicle with only friction parts needing renewal.

Spot on, gb. Replacing brake kit unnecessarily is one of the biggest garage scams. 'oh, and you must replace the pads as well, squire'.

With care, discs should last 100,000m and pads 50,000. Mine always have. I have just had a happy time hammering rust off our 106,000m Focus discs (eye protectors a must and ear plugs recommended!) and then smoothing them off with a carborundum wheel. My service record shows I did this in 2010 and 2006. They were new in 2004 at 29,000. The pads, not yet half worn, were renewed at 83,000. Real obsessives should loosen the bleed nipple and squeeze out a few mls of brake fluid.

Not only an immediate profit for the garage, there is also a possible long term gain because if the caliper pistons don't use their full travel, the unused cylinder walls will corrode and cause them to seize if disc/pad wear ever allows them to travel any distance.

Volkswagen Polo III - Brake disc badly corroded - skidpan

With care, discs should last 100,000m and pads 50,000.

Not that simple is it.

If you use the car only on the motorway that is possibly true but people who use their cars mainly in town with the frequent braking that entails will be lucky to get 1/2 that.

Take an old Golf I had. I mixed use the fronts would do 35,000 on a set of pads and the discs would be down to the minimum in 70,000 miles. Yet the wife had a Golf which had less town usage, the pads lasted 60,000 miles and the discs were OK to do the same again.

More powerful heavier cars tend to get though brakes quicker as you would expect.

Real obsessives should loosen the bleed nipple and squeeze out a few mls of brake fluid.

Sensible people bleed their brakes every 2 or 3 years.

Volkswagen Polo III - Brake disc badly corroded - galileo

With care, discs should last 100,000m and pads 50,000.

Not that simple is it.

If you use the car only on the motorway that is possibly true but people who use their cars mainly in town with the frequent braking that entails will be lucky to get 1/2 that.

Take an old Golf I had. I mixed use the fronts would do 35,000 on a set of pads and the discs would be down to the minimum in 70,000 miles. Yet the wife had a Golf which had less town usage, the pads lasted 60,000 miles and the discs were OK to do the same again.

More powerful heavier cars tend to get though brakes quicker as you would expect.

Greatest factor is how the vehicle is driven. "Gears to go and brakes to slow" as is currently taught is producing drivers who will cheerfully ride the brakes all the way down a long hill instead of dropping a gear or two to regulate speed.

Not to mention muppets who accelerate toward red lights and then stand on the anchors.

Volkswagen Polo III - Brake disc badly corroded - gordonbennet
Greatest factor is how the vehicle is driven. "Gears to go and brakes to slow" as is currently taught is producing drivers who will cheerfully ride the brakes all the way down a long hill instead of dropping a gear or two to regulate speed.

Amazingly thats been taught to new HGV and PSV drivers since the 80's, i won't bother to explain why this is so wrong as i expect the vast majority of the BR would instinctively think as you do Galileo.

Volkswagen Polo III - Brake disc badly corroded - galileo
Greatest factor is how the vehicle is driven. "Gears to go and brakes to slow" as is currently taught is producing drivers who will cheerfully ride the brakes all the way down a long hill instead of dropping a gear or two to regulate speed.

Amazingly thats been taught to new HGV and PSV drivers since the 80's, i won't bother to explain why this is so wrong as i expect the vast majority of the BR would instinctively think as you do Galileo.

Passed my test on a Morris Minor, in 1961. My first car was a 1936 Austin 10, cable brakes (and slightly oval drums!) so I early learnt the virtues of anticipation and not putting too much trust in brakes ( especially on routes like A6024 over Holme Moss) .

Volkswagen Polo III - Brake disc badly corroded - FP

"Real obsessives..."

Sorry. I had to smile.

Volkswagen Polo III - Brake disc badly corroded - FoxyJukebox

Surely an MOT should test for the roadworthyness of a vehicle for the next 12 months rather it's condition on the day of the test?

Volkswagen Polo III - Brake disc badly corroded - FP

"Surely an MOT should test for the roadworthyness of a vehicle for the next 12 months rather it's condition on the day of the test?"

You may think that, but practically it can't happen. Who knows what sort of conditions the vehicle will be subjected to? The mileage covered? At least the advisories flag up issues that should be attended to - mostly, though there can be some strange advisories sometimes.

The MOT is only a snapshot and should be treated as such by prospective buyers, for example.

Volkswagen Polo III - Brake disc badly corroded - FoxyJukebox

Yes indeed you are absolutely right--but it does worry me that many buyers of dodgy old cars or even shiny 3 year old models sold privately (or trade!) think they are as safe as houses with their juicy full MOTs which don't have to be renewed for another 12 months?

Volkswagen Polo III - Brake disc badly corroded - FP

"...it does worry me that many buyers of dodgy old cars or even shiny 3 year old models sold privately (or trade!) think they are as safe as houses with their juicy full MOTs..."

Then the problem lies with the buyers. The legal phrase that covers it is "caveat emptor".

Volkswagen Polo III - Brake disc badly corroded - hardway

2cm portion of the disc

Oh I've seen way worse than that!

CHUNCKS out of the face!!

Disk rotor seperated from the hub center!

Or last week the Mazda with one of the rear calliper retaining bolts unscrewed some 20mm out from the carrier,

Lucky for the owner it had rusted sollid and took cherry red heat to convince it to come all the way out.

I saved the calliper though so I didn't get accused of being a rip off garage!

A liitle troubling was it came in as an MOT failure on rear brake inefficiant,

More accurate would have been no braking on that wheel at all!!

Oh and just remebered a goody.

pads so worn the the piston had actually cut a curcular hole right through the steel backing,

the friction material had gone a loooong time ago,

Couldn't save that calliper.

what dropped my jaw was,

how didn't they hear the noise!!

They must have and ignored it for many,

many miles.

Though she swore she had heard nothing....................!!

And showing the carnage meant nothing to her!

No frame of refenence I guess.

Volkswagen Polo III - Brake disc badly corroded - John F

Oh and just remebered a goody.

pads so worn the the piston had actually cut a curcular hole right through the steel backing,

the friction material had gone a loooong time ago,

Hmm. Salt......pinch of?

Volkswagen Polo III - Brake disc badly corroded - Dave S M

Of course, fully in agreement that cars should be checked and maintained correctly, but I do wonder why VW Polo disks rust and wear so quickly. My 1993 BMW (FSH) has had two sets of front disks and one set of rear disks in 26 years and 218,000 miles.

I am looking for a newish Polo, but virtually every one I look at has high level of corrosion on the disks. If this is due to lower use by Polo drivers, would VW not realise this and fit disks that are fit for purpose?

Volkswagen Polo III - Brake disc badly corroded - Andrew-T

I am looking for a newish Polo, but virtually every one I look at has high level of corrosion on the disks. If this is due to lower use by Polo drivers, would VW not realise this and fit disks that are fit for purpose?

Like what - made of stainless? As long as disks are made of the same material (maybe they aren't - I don't know) cast-iron, the rusting will depend on the use they get and the environment the car experiences. As has been said, one good splash of rain or hose will leave a patina on the discs overnight. Unless you find that unsightly, and deliberately move the car with some heavy braking to dry them off afterwards.

Volkswagen Polo III - Brake disc badly corroded - focussed

I am looking for a newish Polo, but virtually every one I look at has high level of corrosion on the disks. If this is due to lower use by Polo drivers, would VW not realise this and fit disks that are fit for purpose?

Like what - made of stainless? As long as disks are made of the same material (maybe they aren't - I don't know) cast-iron, the rusting will depend on the use they get and the environment the car experiences. As has been said, one good splash of rain or hose will leave a patina on the discs overnight. Unless you find that unsightly, and deliberately move the car with some heavy braking to dry them off afterwards.

You don't want stainless steel discs on a road car. At first it sounds a good idea but modern motorcycle disc rotors are made from a grade of stainless steel. It isn't any old grade of stainless, it's a special grade that can be hardened but only has moderate resistance to corrosion - store a motorcycle in a damp atmosphere and the discs will show light rust in a week. Add some salt water to the situation and in conjunction with the sintered-type metallic brake pads you will get deep pitting of the discs where the pads sit- electrolytic corrosion. And they are expensive - around £80 to £100 a pop for 300 mm discs.

Volkswagen Polo III - Brake disc badly corroded - galileo

There are many different grades and hardnesses of cast iron, some more resistant to corrosion than others, one grade, known as Ni-Resist resists corrosion and high temperatures but is expensive and hard to machine.

It may well be that the discs for Polos are specified by bean-counters rather than engineers, a regrettably common practice these days

Volkswagen Polo III - Brake disc badly corroded - John F

It may well be that the discs for Polos are specified by bean-counters rather than engineers, a regrettably common practice these days.....

....especially perhaps at the cheap end of the model range. I think all the discs and pads on my 2005 flagship Audi A8 are original. There was no evidence of replacement in the service history when I bought it at 49,000 miles - but admittedly it is only at 68,000 miles in my five years of ownership. Front pads now down to about 3mm - at least another year or two's use left.

PS - update on my old post above - Focus front discs and pads replaced Sep 2017 at 125,100 miles. Rear drums remain uninspected since Jan 2007 when wheel bearing and brake cylinder (?damaged during bearing replacement) replaced. If it works, don't mend it.

Volkswagen Polo III - Brake disc badly corroded - gordonbennet

The OE discs on the 2007 Hilux we owned were more resistant to corroding than almost all aftermarket discs i've fitted, can't say as i'd want them by choice though, nowhere near the bite that normal cast iron rust-fast discs offer, i sourced anf fitted Mintex pads to it (the only aftermarket made as new model) with the vehicle not 12 months old which improved things somewhat.

Never had the extreme corrosion issues noted in this thread (though i've found horror stories lurking under vehicles i've worked on many times, full main dealer serviced vehicles included), and my brake fitments have almost always been aftermarket parts where known trusted makes available so chances are the same makers of OE Polo brakes have cropped up in my life without falling to pieces, its keeping that salt at bay as well as making sure everything works by regular proper servicing that i'm convinced makes all the difference.

Volkswagen Polo III - Brake disc badly corroded - edlithgow

Coke cans can make a difference too.

www.honestjohn.co.uk/forum/post/index.htm?t=110241

US Market Version: Less flak

www.bobistheoilguy.com/forums/ubbthreads.php/topic...s

Extended, updated US Market Version. Less flak, more pictures, including drum brake treatment.

www.bobistheoilguy.com/forums/ubbthreads.php/topic...1

Testing indicates that sunflower oil is a more effective binder on the rims than superglue, but I don't feel comfortable using it on the hub in case it gets spun out onto the disk surface.