Independent examination of brake discs

liviboy

Tarambor wrote: »

This is what they'll most likely mean.



Don't bother. It is a common ruse to needlessly sell a brake disc change that isn't needed and often put as an advisory in MOTs as backside covering by the tester. A build up of dirt occurs around the outside edge of the disc and on the central hub area that looks like rust because it gets stained by the disc which has iron in it when the disc gets wet in the rain and it is that which they use to claim the discs are corroded and need changing. Once upon a time it was normal during a service to get a hammer and just chip that off the outer edge of the disc as a matter of course and get a wire brush to the hub area leaving a nice smooth surface instead of a rough one, I still do it on my cars.

In that image above which will be a bit more severe than yours there is absolutely nothing wrong with that disc other than it looking a bit shoddy compared to a nice shiny new one. Now if it looks like the one below then yeah you have a problem and it needs replacing.

My discs looked NOTHING like either of those pictures.

My disc looked more like this:

(courtesy of https://www.pistonheads.com/gassing/topic.asp?h=0&f=23&t=1648502).

foxy-stoat

Faulty pads or caliper.

I wouldnt waste your time with a small claim, it wont go anyway.

Good job your brakes are fixed now.

liviboy

foxy-stoat wrote: »

Faulty pads or caliper.

I wouldnt waste your time with a small claim, it wont go anyway.

Good job your brakes are fixed now.

So if faulty pads, surely that falls under consumer rights...not of satisfactory quality?

Or are we just to accept being ripped off? VW stated it was the DISCS that were faulty, not the caliper or pads...so at the least I have a claim against misdiagnosis (and ultimately trying to sell me a product to fix a non-existent fault??).

This is why I' keen to have them independently checked...

Mutton_Geoff

From memory Golfs have a brake distribution thing that moves more braking power to the rear if the car is heavily laden. Most often that not the car is driven without a full load, the distribution thing seizes and little braking action is applied to the rear brakes and they corrode through lack of use.


An occasional safe heavy braking from say 50/60mph to a stop or low speed keeps the back brakes clean.

liviboy

It doesn't help that I have an electronic parking brake...so can't even drive along with the handbrake applied to help clear them up...

Iceweasel

liviboy wrote: »

It doesn't help that I have an electronic parking brake...so can't even drive along with the handbrake applied to help clear them up...

I don't know about the rear brakes on a VW Golf, but most cars with rear discs have a separate hand-brake system which does not use the pads/discs.

Usually one finds drums and shoes integrated into the rear hubs
- so apply the handbrake doesn't affect the discs.

Deneb

liviboy wrote: »

Meant to add that nothing is seized, the pads etc are sliding freely and at nearly £200 for replacement parts I definitly think it's worth pursuing. I estimate around £100-£150 for an independent report but that is very ballpark.

Are you saying that you are considering spending £150 to try and get £170 back?


I used to carry out forensic mechanical examinations before I retired. I only received a salary from my employer, but if a third party requested a copy of my report a ball park figure would be anything from £1500 upwards, usually at least twice that.


I was once involved in a case where a report had been commissioned from an independent analyst before I became involved, which had cost £14,000 and basically said nothing.

Iceweasel

liviboy wrote: »

My discs looked NOTHING like either of those pictures.

My disc looked more like this:

(courtesy of https://www.pistonheads.com/gassing/topic.asp?h=0&f=23&t=1648502).

I would reckon that many infrequently used (or used for short journeys only) vehicles in the UK will have discs that look like that at this time of the year.

It's due to damp Winter weather and salt on the roads.

liviboy

Iceweasel wrote: »

I would reckon that many infrequently used (or used for short journeys only) vehicles in the UK will have discs that look like that at this time of the year.

It's due to damp Winter weather and salt on the roads.

I'm inclined to agree but point is, I have it on the service report that the discs REQUIRE replacement due to corrosion.

If this statement is false then surely something can be done?

Deneb

Iceweasel wrote: »

I would reckon that many infrequently used (or used for short journeys only) vehicles in the UK will have discs that look like that at this time of the year.

It's due to damp Winter weather and salt on the roads.

Agree. Fairly common. Rear brakes do not get the same use as front brakes in normal driving conditions. In wet conditions or if left standing for some time between journeys, rust that has formed on the unswept area of the disc starts to creep in across the friction area. Absence of heavy brake application on rear brakes in normal conditions fails to clear the surface corrosion under braking, and it gradually creeps inward from both edges of the disc face.