VRS partially worn disc

[Dave71]

Hi All,

looking for some tech advice. I hve a 2014 VRS combi diesel. My right rear brake disc has alot of rust on it ~70% of the surface. It looks like the pad is contacting only the inner part of the disc closest to the hub.

While still  under warranty I mentioned this to Skoda who said it was a wear part and not covered. I maintain that the caliper is seized which is causing the issue.

Anyway, in order to fix it myself, would I be right in saying that the caliper is seized or pad stuck to the slider? In terms of repair I was planning to remove caliper and activatee the brake to check for movement.  For pressing the piston back is it one of those that need to be rotated back into position?

Thansk for any tips,

Dave

[mk4gtiturbo]

Don't know for certain but I wouldn't suggest applying the brake with the calliper removed, you are likely to pop the piston out.

 

Take it apart and have a look at it and clean it up.

[nidza]

Dave, can you show us photo? I would like to see it, if possible of course.

 

[flybynite]

To check if your calipers is seized you do not need to strip the brakes. Simply  jack the rear up turn the wheel by hand and get someone else to press the brakes. If it locks and then rotates again when the pedal is lifted the caliper is working.

 

My money is on the disk being left wet for periods and rusting, then the pad collecting the rust bedding it into the pad. You can usually hear that as it is metal on metal.

 

If you are comfortable stripping brakes rub the pads on some coarse sandpaper to clean the face and clean the disks with a power wire brush. That should give them a bit more life. If that doesn't do anything then probably best replace them.

[CCTaylor]

A tip to prevent future problems and worth trying before you start stripping the brakes.

 

Back in the day i had LR Discoverys, as a gentle braker I had problems with the rear callipers seizing and the pads operating only on one side of the disc. My solution was when waiting in traffic every so often i would press the brake pedal as hard as I could. This helps prevent the calliper sticking. This is worth doing on any car with rear discs especially if you are gentle on the brakes.

 

I used to do this once a month.

Edited 13 April, 2017 by CCTaylor

[Spudey]

I had the same issue with my 2014 vRS. Outside of the rear disc were pitting and corroding badly and noisy under braking. I flagged it to the dealer at 1st service but they said it was normal wear.

 

it got to the point where it was grinding under normal driving at 17k miles so I booked it into another dealer for rear discs and pads and asked them to check for anything unusual and keep the old parts. They told me calipers were slightly sticky but when I looked at the old parts it was clear the inner pads were worn down to the metal and outers were like new, with the groove still visible.  All braking was being done by inner pads.

 

I was not happy having malfunctioning calipers from new and having to replace discs and pads at 17k miles. 

 

Dealers agreed it was unusual but brakes are wear and tear, so I took it up with Skoda customer services who also gave "wear and tear" defence. 

 

I raised it further with the motor codes ombudsman but an independent inspection would be required at more than the £120 the new brakes cost me so not cost effective and with no guarantee of success so I had to accept defeat at that point. 

 

Edit: just re-read the op and it seems he has a different issue with break wear uneven across the outer face. My issue was uneven wear between inner/outer pads. 

Edited 14 April, 2017 by Spudey

[HeavyMetalRich]

I think you will find that the section where the surface is rusted won't be getting any contact from the pad at all. I would suggest that you check the operation of the caliper as described by @Flybynite checking operation of the foot brake and the hand brake in turn.

 

If you find they are working properly then you can move on to stripping the brakes down. If the calipers are working, the pads might be stuck but also check that the slide pins have nice clean, wet grease on them (preferably a silicon based grease).

 

If you get as far as replacing them, then yes you will have to wind back the pistons and make sure they line up with any pegs on the back of the inner pad (I don't think there are any to worry about on the Octavia though).

 

Good luck and check back if you need any more advice.

[banksie]

It's a fact of life that OEM discs will rust! They are C**P! Not just on the disc face but on the hub as well! You can argue/discuss with your dealer, but with a car at 3 years old, I'd be surprised if you got them changed free/warranty!

 

its just easier and less hassle to get some new discs, non Skoda (EBC or other etc etc), a rewind tool set off Amazon and change them yourself, assuming you fancy doing it and your keeping the car!

[nidza]

Interesting. Our RS is still very new, but our Elegance TDI is little over 4 years and not a dot on discs. They look brand new still, with contact surface bright as mirror. 

 

On the other hand, rear discs on RS look more worn on 3m old car then on 4y old. So many deep scrapes. 

[Black_Sheep]

In response to the OP and Spudey:

 

I very much doubt that the calliper (piston) has seized. From my experience it is most likely that the rear brake pads have seized in their runners. Whilst all cars are prone to this to some extent, the VAG cars I have owned (from Mk5 Golf / Mk2 Leon onwards) are particularly prone to this.

 

In order to prevent this I usually remove the brake pads from the carriers and service as described below, usually when swapping to/from summer/winter wheels.

 

As others have said, clean the pads with a wire brush (including the pad surface / groove to prevent gas build up under braking) and then spray with brake / clutch cleaner to degrease. Next clean the machined surfaces on the calliper runners (easier to see on the VRS painted calliper) first with wire brush and if required with a square or flat file. Again degrease with brake / clutch cleaner. Once cleaner has evaporated, apply a non-metallic brake component grease (Pagid Ceratec at Euro Car Parts), graphite grease (OEM pads come with a sachet of this in the box) or high temperature lithium grease to the machined surfaces that you have just cleaned taking care not to get any on the brake disc - whilst some recommend copper slip, I would not recommend this due to the fact that if you jet wash the car a lot, the jet wash washes away the lubricant leaving copper fragments in contact with the ferrous brake components, which in turn creates dissimilar metal (galvanic) corrosion and accelerates the chance of the pads seizing.

 

Next remove the carrier pins, spray with brake / clutch cleaner and wipe clean. Again apply some grease to the pins before reassembling. 

 

If you are worried about the calliper (piston) you can push back the protective rubber boot around the piston, clean with a cloth and reapply a liberal amount of grease.

 

Finally reassemble in the reverse of removal. Once complete, turn on engine and give brake pedal a couple of pumps to take up any slack in the system before driving, especially if pads were seized. 

 

One of the the major problems that you will find is that a poorly functioning rear brake is still able to pass the roller brake tests under MOT conditions / hold the vehicle using the handbrake. Hence what Spudey experienced where all of the braking had been completed by the inner pad only. 

Edited 16 April, 2017 by Black_Sheep