I recently had all discs, pads, fluid and the rear calipers replaced on my 05 Octavia II Classic (estate).... I've just noticed the rear discs have uneven wear! It looks as though the pads are not making contact with the inner part of the discs.

Does this mean they were not fitted properly? Both rear calipers were replaced as one had completely seized and the bleed nipple had seized on the other and was about to snap off.

What could be causing this?

The insides never wear as much as the outer on single piston calipers. If they is large difference in wear between the two then it is usually a case of the sliders not moving and cleaning them up and a little grease will get them working again. Don't put too much grease on the sliders as this causes problems too.

Edited 16 September, 201510 yr by CWARD

The inner part of the rear discs are getting a light coating of rust where the pads are not touching (even though the pads are big enough to cover that part of the disc). I'd say the untouched rings left on the discs are almost and inch thick. the middle and outer edges of the discs are fine where the pads are making contact.

The pad material is probably warped on that description.

Brand new pads too. It might be worth a trip back to the garage who supplied and fitted all the parts (a VW specialist).

A couple of picture links showing the rear discs:

 

http://i799.photobucket.com/albums/yy271/PowerPie5000/IMG_20150917_090521.jpg

 

 

http://i799.photobucket.com/albums/yy271/PowerPie5000/IMG_20150917_090548.jpg

 

 

 

.... The pads, discs and calipers were all brand new less than 2 weeks ago. I have no idea where all the rust splatters came from on the rear drivers side disc (none of the others have this). You can see clearly in one of the pics that the inner edge of the disc is not wearing like the rest of the disc. It's like the pad is not making contact.

 

 

What do you guys think?

Edited 17 September, 201510 yr by Dan83

I thought you were talking about the inner disc surface not wearing like the outer hence my comments above. The rust splatter is normal and it is just brake debris.

 

The wear pattern is from the pad contact. It will never reach the hub due to the brake pads carriers they are located in. I would say this is normal and the pads aren't quite bedding in yet. If you apply the hand brake and shine a torch between the caliper and disk you will be able to confirm your pads are making full contact.

I had a look and the pads cover most of the disc (close to the hub), But there is a very tiny gap between the disc and the pad when the handbrake is applied (around the inner edge of the disc that isn't wearing). It's more apparent on the rear passenger side.

 

I've also noticed that the quality of both rear calipers look different! They were both replaced and are both were supposed to be new. The rear passenger side caliper metal looks clean, shiny and smooth. The metal on the other caliper looks clean, but the metal looks a bit rough and bumpy... I can't help thinking they cleaned up the old caliper and charged me for a new one! Or maybe used a refurb part? It cost me £500 for new pads & discs (front and rear) along with rear calipers, brake fluid and fuel filter to be supplied and fitted.

Edited 21 September, 201510 yr by Dan83

My brakes are now starting to squeal a bit! I'm pretty sure it's coming from the front... Guess i'll just see if it'll go eventually.

Before you start the car, press the brake pedal hard and release as if you were bleeding brakes.

 

It may be also rusted rear callipers, which is common issue.

Before you start the car, press the brake pedal hard and release as if you were bleeding brakes.

 

It may be also rusted rear callipers, which is common issue.

 

 

Pressing the brake pedal hard doesn't do anything really. The rear calipers are also new, but it sounds like the squealing/screeching is coming from the front. It doesn't squeal if I brake hard.

Pressing the brake pedal hard doesn't do anything really. The rear calipers are also new, but it sounds like the squealing/screeching is coming from the front. It doesn't squeal if I brake hard.

it forces rusted pistons back ;-)

 

If you have racing pads, squealing is normal. Cold pads do it all the time. If you heat them up to around 500deg C, they are ok.

it forces rusted pistons back ;-)

 

If you have racing pads, squealing is normal. Cold pads do it all the time. If you heat them up to around 500deg C, they are ok.

Sorry, I meant it didn't do anything with my car (nothing noticeable anyway). It's using the standard VW OEM discs & pads all round as far as I know. They still squeal a bit even after they've warmed up... I guess I'll just put up with it until I get my next car . I also noticed the rear pads have copper grease on the back of them, but the front pads don't.

There's your problem then, lack of copper grease on back of pads, squealing will undoubtedly occur.

There's your problem then, lack of copper grease on back of pads, squealing will undoubtedly occur.

I doubt that is the issue.

 

I never had any copper on back of my pads.

If I remember correctly what my master taught me. There is many reasons:

 

• run out of discs is off - they need to be perfectly balanced
• as you have written uneven wear - I've recently replaced brakes of my friend's parents and they had same issue. Cause was, damaged master brake cylinder with booster.
• air in brake lines but you wrote it has been replaced

 

Check all vacuum hoses - there is usually problem with main hose from tandem pump. It tends to pop out of brake booster. Check out if there is even any vacuum from tandem pump !!!

 

In case of the car I mentioned above by - pedal was jamming in certain positions (master cylinder gone). I replaced discs and pads - they weren't worn evenly even after 200km and brake performance was poor (master cylinder gone)

 

It is hard to suggest something, I would need to see it.

I doubt that is the issue.

 

I never had any copper on back of my pads.

 

Lack of lubrication on the back of pads does often lead to squealing though.

Lack of lubrication on the back of pads does often lead to squealing though.

I wonder what is the science behind the copper grease on the back of the pad ??? It sits there and doesn't move forward/backward from car direction point of view. One possible movements of pad is back and forth from piston point of view. Between disk and pad is about 0.1mm space.

 

I know in my case it is burnt friction material on pads because I have no drilled discs yet.

As I understand it the copper grease helps to stop minute vibrations of the pad in the calliper which is one of the things that can cause squealing.