Brake pedal sinking after new pads and discs fitted

[dara85]

Hi

I know I'm at wrong section of the forum but the brakes on Octavias are almost the same as on Fabias and over here more techs are hanging around.

Yesterday I've fitted new discs and pads all around, using Pagid from ECP. All went well but the brake pedal is now sinking to the floor. First depress goes all the way down, on second depress the pedal gets harder and you can feel a bite point but then pedal slowly sinks to the floor. Hand brake barely works.

Before I started I have undone cap on brake fluid reservoir and some fluid leaked when I pushed pistons back in (yes correct tool was used on rear calipers). Level is fine now.

NSR piston didn't want to go in easily. Had to use ratchet on the tool to wind it in.

What could be the problem? Damaged seal on the rear caliper? Master cylinder (can't see how this could get damaged)?

Going to drop it off at garage for bleed but want to know what it could be.

Thanks

[Tilt]

11 minutes ago, dara85 said:

Hi

I know I'm at wrong section of the forum but the brakes on Octavias are almost the same as on Fabias and over here more techs are hanging around.

Yesterday I've fitted new discs and pads all around, using Pagid from ECP. All went well but the brake pedal is now sinking to the floor. First depress goes all the way down, on second depress the pedal gets harder and you can feel a bite point but then pedal slowly sinks to the floor. Hand brake barely works.

Before I started I have undone cap on brake fluid reservoir and some fluid leaked when I pushed pistons back in (yes correct tool was used on rear calipers). Level is fine now.

NSR piston didn't want to go in easily. Had to use ratchet on the tool to wind it in.

What could be the problem? Damaged seal on the rear caliper? Master cylinder (can't see how this could get damaged)?

Going to drop it off at garage for bleed but want to know what it could be.

Thanks

 

Fluid leaked from where???

I'm sure the garage will sort it...........

[dara85]

31 minutes ago, Tilt said:

 

Fluid leaked from where???

I'm sure the garage will sort it...........

 

From the reservoir when I was pushing/winding pistons back in - didn't notice it until brake fluid was dripping on the floor.

[Jrjg]

Any damp looking areas on any of the calipers? Symptoms of a possible leak from them? 

If your master cylinder was leaking surely you'd notice a drop in the level as well as fluid loss under the car. 

 

JRJG 

[KenONeill]

@dara85 Am I reading correctly that the OSR piston just pushed back into the caliper? If so, then I suspect that the handbrake thread on it has stripped, so part of your problem may be pad knockback.

[dara85]

2 hours ago, KenONeill said:

@dara85 Am I reading correctly that the OSR piston just pushed back into the caliper? If so, then I suspect that the handbrake thread on it has stripped, so part of your problem may be pad knockback.

Sorry if I didn't make it clear. No, both rear pistons were winded in with the tool but the NSR was hard to turn, had to use ratchet attached on the tool to have bigger leverage. Can't see any leaks anywhere.

[KenONeill]

14 hours ago, dara85 said:

Sorry if I didn't make it clear. No, both rear pistons were winded in with the tool but the NSR was hard to turn, had to use ratchet attached on the tool to have bigger leverage. Can't see any leaks anywhere.

OK.

 

In which case, did you re-adjust the handbrake "pre-load" after setting the pads against the discs with the pedal?

[dara85]

Lack of time and moaning from my partner forced me to take it to the garage. They said OSR caliper has small leak around seal and needs sorting out. Full rebuild kit isn't much cheaper then new caliper and because the NSR was really hard to wind in, I bought both rear calipers from Brakes International and it's sorted now. Amazing how new pads&discs&brake fluid improve braking. Plus hand brake works now incredibly well:).

Thanks

[Tilt]

On ‎09‎/‎05‎/‎2017 at 10:29, dara85 said:

 

From the reservoir when I was pushing/winding pistons back in - didn't notice it until brake fluid was dripping on the floor.

 

I believe it is quite corrosive? especially to paintwork.

 

I guess you mopped up as much as you could anyway??

[dara85]

Of course. I know what kind of damage DOT can do. Have flooded engine bay under the reservoir with water and some floor cleaner mix in a spray bottle. Not much access there. It's all good but thanks for checking.

[sepulchrave]

1 hour ago, Tilt said:

 

I believe it is quite corrosive? especially to paintwork.

 

I guess you mopped up as much as you could anyway??

 

It used to be, modern two-pack clearcoat is far more resistant to it (and everything else), two-pack is like an epoxy finish, it cures rather than dries, it's also so hard that old fashioned T-Cut will hardly touch it.

[KenONeill]

17 hours ago, sepulchrave said:

 

It used to be, modern two-pack clearcoat is far more resistant to it (and everything else), two-pack is like an epoxy finish, it cures rather than dries, it's also so hard that old fashioned T-Cut will hardly touch it.

And, of course, clearcoat doesn't contain any pigment to oxidise, and removes the cutting compound's direct access to and sun-bleached pigment under the clear.