Technical Brake disc, a ring of rust

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Technical Brake disc, a ring of rust

We are all on the same page Andy, any rust on the pad contact area the rust will always win, gradually expanding to the point the pads have no shiny contact area to even try to function on, long before that time, the Mot tester or service mechanic should have picked it up.
It is amazing to see the poorly functioning brakes on some cars. Over 30 years ago when my two youngest (twin girls) were being born my wife talking to the lady in the next bed to hers mentioned I was a motor engineer and arranged for her father to drop her Austin Maxi car to me to check the brakes as they were pulling to one side. Once the wheel was off I couldn't believe what she had been driving on, the brake disc had broken away from the driving flange completely, so the pads could grip the disc tight but not affect stopping one iota, consequently the car pulled violently to one side on braking. I showed this to her father/grandfather of new baby shortly to be driven in the car and he refused to have the work done, even though I was so concerned I offered to fit the parts free, just the trade price of the materials. He then took the car away, I issued him my normal invoice stating exactly what was wrong with the car and how dangerous it was, with no charge for my time , purely for my records if there was a subsequent accident and it was suggested it had been to me for repair. I also got my wife to tell the new mother how dangerous her car was!!!:mad:
I think all of us who've worked on cars for our living have come across this sort of situation Mike. We always issued a written confirmation of work recommended and got the customer to sign it, if possible, retaining a carbon copy for our records. You really need to do this for your own protection.

I think there are two factors at play when a customer so blatantly disregards advice like this. The first, and for me most disturbing and disappointing, is the deep suspicion many people hold towards the garage repair trade. This comes about, I think, because of the relatively small number of rip off outfits who, by their heinous activities, contaminate the rest of us. It saddens me greatly whenever I hear, perhaps from a neighbour, of an incident such as this. The second is that vehicles, which were complex enough in my youth, are today humoungously complex bits of kit. It can be almost impossible to, after a quick look over, which the customer often expects for free, to definitively give a price to "sort" it. Even after a quite in depth inspection, often involving the use of an expensive diagnostic piece of kit which you are having to pay out on for regular updates, the best you may be able to come up with is "All the indications are that it's this, this and/or this which seems to be the problem but I won't really know for sure until I start dismantling and working on it". Although it's often possible to accurately quote a price for a repair, so many fall into the "trap" of quoting when the action you are committing to is far from clear. Then, when more work, or additional parts, are required, the customer feels ripped off and unhappy with the additional cost, which these days can be considerable. In this sort of situation I always had a "conversation" with the customer so they were in no doubt that additional costs might be incurred. Yes, I occasionally lost work by doing this but in the long run I think we gained from this policy as we gained a reputation for honesty and once overheard a customer in the pub saying "well, they're not the cheapest but if they fix your car you can be sure it'll stay fixed" and I'll take that all day long thank you very much.

A last comment is that many don't appreciate the implications of ignoring faults/symptoms with their vehicles. Trouble is because they have no technical understanding of what you're saying they don't grasp, and perhaps lack the imagination to appreciate the possibly cataclysmic outcome of failing to rapidly rectify the problem you're alerting them too. All they see is the cost/inconvenience - and it's difficult to not sympathize on that. I remember Mrs J's Dad saying "if Jock say's there's something needing done on the car you can guarantee you can go on driving it for another 6 months before it's going to let you down" - He was an accountant and hardly knew how to even check his oil and water levels.
 
I remember Mrs J's Dad saying "if Jock say's there's something needing done on the car you can guarantee you can go on driving it for another 6 months before it's going to let you down" - He was an accountant and hardly knew how to even check his oil and water levels.
This is the difference between preventative and reactive maintenance.

Only an idiot would continue to drive a car knowingly that something is wearing out and will fail and they are going to keep on driving it, till the point that thing fails.

You break down on the side of the road, you have to pay a break down company or recovery company to get you back to the garage. The thing has broken as you were told it would. In the mean time the price of that thing has gone up. you want the job rushed through. maybe in the mean time some bolts have rusted or the failing part has damaged something else.

Yes you might have been able to eek another 6 months out of it but the job has now cost you 3 times as much. Not exactly a cost cutting money saving exercise.
 
New brake discs cost £60 something, less than the £75 Arnold Clark charged to resurface the discs at the last main service I let them do.
I remember disc resurfacing machines were all the rage at one time. a bit like on car wheel balancing. We never bought into resurfacing discs prefering to just fit new when needed. However, a "clever" salesman managed to get the boss to buy an on car balancer on the grounds that it did a more accurate job because, by spinning up the wheel and hub assembly together it achieved a "better" balance. We found that was very occasionally true but it would be defeated completely by even the smallest amount of play in either the wheel bearing or suspension. and it took considerably longer to set up and use than just taking the wheel off and balancing it on a conventional floor mounted machine - Most of the time you're needing to balance a wheel after fitting a new tyre so the wheel is going to be off the car anyway. The biggest problem with it was that it only really worked well on rear wheel drive vehicles as the drive train caused the wheel to slow down too quickly on FWD vehicles - Of course you could spin it up using the car's engine, but we found that didn't work very well (and now a days would be impossible with ABS). Anyway, with FWD becoming the norm, it wasn't long before this expensive piece of equipment went to "rest" at the back of the shop and gather dust.

Getting back to the subject of discs. I haven't seem anyone using a resurfacing machine in years and I don't think it's worth it unless you're talking about very expensive setups. Coated discs? For me it falls into two camps. On a wee cheap runabout where saving immediate cost is a priority then "bare" uncoated discs do the job just fine. However if you're going to spend money on coated discs, and there are definite advantages like making it much easier to work on because the disc won't corrode to the hub and the outer rim won't develop a rust ridge until the disc is very old, Then go the whole hog and buy a "fully coated" product. This may help with understanding what I'm talking about: https://www.delphiautoparts.com/en-... as rain, snow,by fitting Delphi coated discs.

Just don't expect the actual friction face to be protected by this because the pads will still rub the protection away so you'll see some light rust on the disc face first thing in the morning after it's stood outside on a rainy night.
 
All the OEM discs on my Golf are Coated from VW and as I generally only use OE parts I don't actually know if there are non coated versions but I presume there are from budget brands at the local motor factors.

The discs when coated last incredibly well, with the ones on the back of my golf only being replaced after 95k miles and 8 years and that was only because the MOT was due and I knew it would get an advisory. the edges and middle of the old discs were only just beginning to rust and the braking surface had only just the beginnings in the last year of rust creeping into the braking surface so it was worth doing.

I think car owners are told so frequently that their brakes need doing, at MOT time and at services. They take the car for a tire and someone tries to upsell them on new brakes. That people no longer believe it when told they need the brakes doing and then decide to get them done when they feel they are sufficiently old enough to warrant it.

If you go back in time on here I documented in detail the issue I had with VW insisting I had my brakes changed as they were 85% worn or something like that, but I insisted on having the old parts left in the car and measured the old parts against the new with a set of calipers. I then sent pictures to the manager of the dealership basically telling them that their 85% worn claim was BS and they had inappropriately insisted on a change of brakes (which at VW is a £300 job) in they had initially agreed to only charge for the parts but then backed down and agreed to refund me on that as well, as basically they didn't need doing and were only about 5-10% worn.
 
I remember disc resurfacing machines were all the rage at one time. a bit like on car wheel balancing. We never bought into resurfacing discs prefering to just fit new when needed. However, a "clever" salesman managed to get the boss to buy an on car balancer on the grounds that it did a more accurate job because, by spinning up the wheel and hub assembly together it achieved a "better" balance.

I agree Jock re disc resurfacing, not a fan!
I recall using the Repco on car wheel balancer at college, the only time I had use for it was after catching some rocks in a lane as a teenager and damaging both wheels on one side of a 1950s Wolsely 1500, after beating the rims straight I managed to balance them successfully , but it involved weights nearly a third of the way around the 14inch rim, it was over fifty years ago. ;)
 
I agree Jock re disc resurfacing, not a fan!
I recall using the Repco on car wheel balancer at college, the only time I had use for it was after catching some rocks in a lane as a teenager and damaging both wheels on one side of a 1950s Wolsely 1500, after beating the rims straight I managed to balance them successfully , but it involved weights nearly a third of the way around the 14inch rim, it was over fifty years ago. ;)
Absolutely pointless on a solid disc that costs £15 and is made out if steel forged from the cheapest chineesium.

but you have an expensive floating disc set up on say a Porsche 911, where they are made from the highest grade materials and designed to be resurfaced with exacting tolerances of how much can be taken off.
and maybe one disc is £300 - 500.

Then there is a strong case for paying £75 for someone to skim it, and I wouldn't have any problem with that.
 
Absolutely pointless on a solid disc that costs £15 and is made out if steel forged from the cheapest chineesium.

but you have an expensive floating disc set up on say a Porsche 911, where they are made from the highest grade materials and designed to be resurfaced with exacting tolerances of how much can be taken off.
and maybe one disc is £300 - 500.

Then there is a strong case for paying £75 for someone to skim it, and I wouldn't have any problem with that.
Agreed.
My concerns were related to "Fastfit" mechanics on bonus pressurising customers into having an indifferent job undertaken by an alledged "Brake Engineer" which was often the case down our way in the mid 1980s.:(
 
When the discs rust like that, there is usually a corresponding chunk missing from the pads, so even if you remove the rust from the surface of the disc you still need to replace the pads.

Discs and pads wear together the rust tends to be harder for the pad to remove and wear away and the rust then gouges a chunk out of the pads.

You can resurface discs as long as they stay in the thickness limits of the disc (usually written somewhere is a minimum thickness) but very little point in doing this on cheap cars with cheap discs. far cheaper and easier to replace them, but resurfacing is much more common on expensive sports cars and super cars that use steel brake discs.
Pads can easily be reflatted by gently rubbing them on a sheet of emery paper taking care to ensure they are evenly reduced and flat. Can be done in just a few minutes. Makes it possible to get some wear out of them. Has the benefit of removing glaze at teh same time.
 
Pads can easily be reflatted by gently rubbing them on a sheet of emery paper taking care to ensure they are evenly reduced and flat. Can be done in just a few minutes. Makes it possible to get some wear out of them. Has the benefit of removing glaze at teh same time.
Used to have to deglaze squealing pads when they first did away with asbestos and material was too hard in many cases.
 
Pads can easily be reflatted by gently rubbing them on a sheet of emery paper taking care to ensure they are evenly reduced and flat. Can be done in just a few minutes. Makes it possible to get some wear out of them. Has the benefit of removing glaze at teh same time.
I'd maybe do that to remove a bit of glazing but if they're scored it doesn't have to be by much before you need to remove a lot of material, and when I say a lot, 2 mm off a pad can equal many thousands of miles of driving for me as I am so light on brakes.

Also when the discs rust up, and the pads get scored like this, it's usually towards the end of the pads life anyway.

Also I don't really want to breath brake dust even if it hasn't got asbestos in any more, the fine particles are probably not very good for my lungs (says the ex 20 a day smoker)

Pads are generally quite cheap. GSF was doing some Panda Brake pads in another thread on here recently for £6
 
Also I don't really want to breath brake dust even if it hasn't got asbestos in any more, the fine particles are probably not very good for my lungs (says the ex 20 a day smoker)
As an apprentice in late 1960s it was common practice to blow out the brake drums with high pressure airline, the whole workshop would be full of it.:(
 
As an apprentice in late 1960s it was common practice to blow out the brake drums with high pressure airline, the whole workshop would be full of it.:(
To be fair given pollution in the 60s with factories, cars and trucks with no anti pollution measures, everyone smoking. Everything being made of asbestos. Houses being heated with open fires...... that brake dust was probably the least of your worries, its amazing that more people don't have severe lung conditions now.
 
As an apprentice in late 1960s it was common practice to blow out the brake drums with high pressure airline, the whole workshop would be full of it.:(
I well remember the metalic taste at the back of your throat and, when you blew your nose the result looked like black paint! Never understood why we haven't all died of emphysema or lung cancer?
 
My beautiful new disc and pads. I can use this as a reference for how long it takes to start to rust again.

53203561463_59d38ab31f_c.jpg
 
The new discs have made zero difference to braking performance. How odd.
 
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