Brakes driving me mad!!!!

[STU3Y]

So got car back from garage. Amazingly they said it still had some air in it.

A small amount from both rear lines and even less in one front.

Not really had a proper chance to test it but on first drive it seems slightly firmer.

They stated it all appears to be working as it should although the pedal is slightly soft. They believe it could be due to the new brakes all round.

They used a pressure bleeder and said they did furthest calipers to nearest and then back again.

I explained that I had literally used 3.5 litres of brake fluid and done manual bleeding, vizi bleed, vacuum bleeder and pressure bleeder and on each occasion done every caliper until no air came out. And after the first couple of bleeds there was no air anyway. I mentioned the symptoms of the pedal sinking and original level of travel.

On that basis they told me to monitor it and if i discover while driving it the symptoms I describe are still present then one of two things will be wrong.

The internal seal in the master cylinder will probably have reversed itself under pressure of the pedal during bleeding.

Or

The rear calipers have the wrong size pistons.

I know the calipers are the same so it won't be that.

As it stands I will have to get used to driving it again without analysing every press of the pedal and see how it is. I'll report back when I know more.

Still doesn't explain. How I didn't get any air out myself. Must be something to do with having one corner up at a time and air going back up the line maybe

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[jonnybravo]

as dan says it sounds like master cylinder

 

[STU3Y]

as dan says it sounds like master cylinder

I would agree. I will monitor it over the next few drives and see how it responds

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[Dan FR]

Must be something to do with having one corner up at a time and air going back up the line maybe

Bingo

Car needs to be level else you'll trap a tiny little bit of air. It doesn't take much at all to give you a horrid pedal. Fingers crossed this was the issue rather than needing a new master cylinder

 

[STU3Y]

Bingo

Car needs to be level else you'll trap a tiny little bit of air. It doesn't take much at all to give you a horrid pedal. Fingers crossed this was the issue rather than needing a new master cylinder

It's strange cos I've never experienced it before and I have bled the brakes twice before on this car. Once when I did a fluid change and once for a new caliper on the front.

I've only ever done it one wheel at a time due to uneven ground

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[whitie]

Did you end up solving this issue?

I've just recently had a scraping noise start on my o/s/r disc, wheel gets red hot but the caliper sliders and piston are all moving smoothly.
Thinking of the mk4 chassis fix of handbrake return springs that I carried out on my '54 Toledo:-

1k0 615 295 left spring
1k0 615 296right spring

But can't find many people using them on this chassis, plus with this one being an '12 Octavia VRS I'm not even sure if I have the same rear brakes as golf 5/6 or Leon 2...

As for your sinking pedal, the pedal does always sink when the engine is started. Did you have the clutch system bled in the end?

 

[STU3Y]

Have been driving car now for a while and have got used to the pedal again. Still doesn't seem as good as it was but everything seems to be working well enough

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[STU3Y]

Did bleed the clutch myself no air. Yours sounds like the piston is sticking especially of the disc is getting Red hot

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[whitie]

Cheers for the follow up!

Turns out my rear callipers already have those handbrake helper springs!
Think I will just resort to checking the sliders and winding back the pistons every six months when I swap my wheels over anyway... Seems to be fine after doing that this time.

Good luck with your's!

 

[joeljackson]

Have been driving car now for a while and have got used to the pedal again. Still doesn't seem as good as it was but everything seems to be working well enough

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I feel your pain, did both rear calipers and after many liters of brake fluid and many choice words over several attempts they are usable but no where near as good as they used to be.