I recently changed rear brake pads. Unfortunately, callipers started to brake but they got stuck.

 

Another issue is disc overheating - I recently returned from Glocknerstrasse and to my surprise rear discs overheating like hell.

 

As you can see from the link above by, rear disc reached very high temperatures. OEM pads, even premium ones have heat capacity up to 300 deg C.

 

I wonder if anyone tried rear calliper carriers upgrade. I know that if you change front ones - you can upgrade from 288 to 312mm discs. Is it same with rear ones?

 

Did anyone do it already?

 

I believe everything is same on 103kW and 125kW Octavia II, except sizes )

Didn't your rear discs overheat because the calipers are knackered?

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Sadly not, it was my first thought. If you check out pictures in my post, another side has got slightly lower temp but still very high.

 

It is caused by unbalanced brake system - front is Ferodo DS2500, which brake very well and rear Ferodo Premium pads.

 

It is fact that I had a boot full of gear but my car is still heavy on front. It doesn't make sense :-D

Edited 22 October, 201510 yr by sniper29a

I had a knackered handbrake cable and in about 3 miles one of the rear discs got so hot I could feel the heat coming off it just standing near it.

 

It's common for the pads to stick in the sliders on the back and cause the pads to drag, on my old Octavia the back would get hot enough you could hear it "pinking" as it was cooling down.  That or the pistons get gummed up.

yep, common issue is that people rarely use heavy braking. You can see rusted rear discs and also rusted thread on pistons. Once, you try to make it work...it never works again.

So you know for a fact that the calipers were 100% when you were flying round the alps, but had degraded to the point of replacement in the intervening period.

I know they were "ok" because they were stuck in one position and didn't break at all.

 

After I forced callipers few times back and forth - they started to work.

 

Unfortunately, the left rear one got stuck in one position again.

 

I've bled brake again. Pumped pedal. It was just temporarily solution.

 

After consultation with my friend car-mechanic..he said "change it, nothing you can do about it. It gets rusty on the thread and rarely works again..."

So you know they definitely were not sticking or dragging whilst up an alp?

Sadly guys, it all appeared ok. It needed just few times of hard breaking and callipers were stuck :-D

 

Only stupid thing was to change pads and then drive right away for 3000km trip :-D Never mind, nothing happened and I've got reason to change rear brakes...finally.

 

Mega high mileage was Fabia. This one is Octavia and it has got just 170k km on ODO. It is a new car except rusted rear brake callipers :-D But it is normal, I haven't seen many cars with working rear brakes.

Edited 23 October, 201510 yr by sniper29a

It is great polemics as usually but nobody answered my question so far ;-)

Did you change the discs when you did the pads? If so did you have to remove the carriers to get the discs off?

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no, discs were still ok - 11mm thick; limit is 10mm.

 

yes, you have to take carriers off during discs replacement. I like some Audi constructions, you can take off disc with ease.

What's the PR code for the rear brakes. If you have to remove the carrier it suggests you have larger discs to start with.

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my discs are 255mm. Larger discs = better cooling. Ideal would be an inner cooling discs, which are on VW Transporter for example.

Mine are 256mm too.  You can get 272mm rear discs but they're not vented.  But what size are your front discs, 280mm?  Fitting almost identical size discs front and rear may cause problems.

Front ones are 288mm for now. Once, Ferodo DS2500 and discs are gone - upgrade to 312mm. Of course, sport suspension is next because it is nightmare.

 

I'm not aware of any issue since car is not balanced anyway. Skoda Octavia WRS used to have 366/300 with 6/4 piston front/rear brakes. And that was custom built balanced racing car.

 

Stock cars are heavily unbalanced, especially large size engines - stock car is designed to be balanced at full load. You're nose heavy unless you put your whole family into car and boot full of luggage.

 

If I'm mistaken based on too little of information about balance of car...well ABS/ECU will assist me despite I don't like late assistance/intervention of all electronic assistants in modern cars. 

If you want vented rear rotors then the only factory fit I'm aware of is the Audi S3 / TT / R32 310mm x 22mm setup.  They are a straight bolt-on for the TRW style caliper with 260 / 282 / 286 mm rotors.  You'd have to double check the fitment with the 255mm setup - especially the brake pipe connector. 

 

The other alternative is stick with solids & go with the 282mm setup.  There's no point going with the 286 unless you can get it cheap or you really want the extra fraction of heat sink mass as the pad area is the same and doesn't come right to the outside edge.

 

There are many aftermarket rear BBKs available.

 

At the front, you can upgrade straight away using your existing brake pads & calipers.  You just need the 312mm rotor and the 312mm caliper carriers - change the slider rubber while you have it apart or fit a stiffener kit.  I'd regard this as a minor upgrade (but it's cheap to do) and if you drive as hard as you say you do then I'd look at a mini-BBK with porsche multi-piston calipers  or a proper BBK kit with 340mm+ hatted rotors.  You need to be aware of wheel sizes / clearances if you start going BBK.

 

NB: the vRS with 312mm rotors has a 1mm larger master cylinder.  This appears to be fitted to give a "sportier" pedal feel (less pedal travel) but in reality it doesn't make a whole lot of difference to braking capacity as the piston size on the calipers is about the same size no matter what diameter rotor you are using.

 

Brake fluid - try & find the proper factory spec low viscosity fluid.  Pentosin & ATE make it but Genuine VW isn't expensive & Jaguar & Land Rover spares have the right formula too.  It's only DOT4 but helps the ABS react quicker (both on & off the brakes) - especially in cold climates.

Thanks sir, finally some good answers.

 

If you want vented rear rotors then the only factory fit I'm aware of is the Audi S3 / TT / R32 310mm x 22mm setup.  They are a straight bolt-on for the TRW style caliper with 260 / 282 / 286 mm rotors.  You'd have to double check the fitment with the 255mm setup - especially the brake pipe connector.

Thanks for info, I wondered if there is rear upgrade as well. I believe D312mm on front and max 280mm on rear is optimal balanced setup. At the moment, I'm working on project how to upgrade Skoda Octavia 1Z3 for as little as possible. There is so many custom solutions but what is point to pay twice a much for Skoda if you can buy proper racing car such as my all time favourite Subaru Impreza - that's a decent platform to start with; AWD, proper fixed callipers; low centre of gravity and infinite options to modify this car from engine to seats ;-) Still, it will cost less that highly modified Octavia with price tag around 50k € (crazy people).

 

The other alternative is stick with solids & go with the 282mm setup.  There's no point going with the 286 unless you can get it cheap or you really want the extra fraction of heat sink mass as the pad area is the same and doesn't come right to the outside edge.

That is next step I wanna try - Drilled Brembo Sport Line

 

 

There are many aftermarket rear BBKs available.

 

At the front, you can upgrade straight away using your existing brake pads & calipers.  You just need the 312mm rotor and the 312mm caliper carriers - change the slider rubber while you have it apart or fit a stiffener kit.  I'd regard this as a minor upgrade (but it's cheap to do) and if you drive as hard as you say you do then I'd look at a mini-BBK with porsche multi-piston calipers  or a proper BBK kit with 340mm+ hatted rotors.  You need to be aware of wheel sizes / clearances if you start going BBK.

 

NB: the vRS with 312mm rotors has a 1mm larger master cylinder.  This appears to be fitted to give a "sportier" pedal feel (less pedal travel) but in reality it doesn't make a whole lot of difference to braking capacity as the piston size on the calipers is about the same size no matter what diameter rotor you are using.

I'm aware of BBK upgrade - I've read a GolfMkV thread from Romanian guy. He has basically same driving style but does circuit racing.

To be honest, I don't really want to increase size of discs because G-forces kill the handling and 190HP is too little for such a large discs! Large discs are "tuners" domain - it's all about balance and optimal setup. Less is more.

So far I'm happy with stock setup with Ferodo DS2500 - they are good enough for alpine spirited driving. I can make them burn but it just need some braking style adjustment. If you brake few meters earlier, you won't lose time because you're not racing right ;-) And it takes long time to heat up even standard discs (around 20km of alpine roads with racing style downhill braking)

I also managed them to burn because rear brakes didn't brake at all. Now, right rear side brakes but it's unbalanced setup!!! It's interesting how rear brakes actually brake despite nose heavy unbalanced car.

The NsBBK would be next step

 

 

Brake fluid - try & find the proper factory spec low viscosity fluid.  Pentosin & ATE make it but Genuine VW isn't expensive & Jaguar & Land Rover spares have the right formula too.  It's only DOT4 but helps the ABS react quicker (both on & off the brakes) - especially in cold climates.

Once upgraded to high-carbon steel cast discs, I'll use Castrol SRF Racing Brake Fluid and brake ventilation system. I already had ATE Powerdisc with "ceramic" pads - they never overheated but I boiled stock brake fluid several time. High-carbon disc have large thermal capacity!

If your going to change everything at the wheel end of the system I would change the handbrake cables at the same time, just as a precaution.