New Front Discs and Pads, but...

[PoloGIT]

Just swapped out my front discs and pads. Now the install instructions for the Remsa pads say "At a constant maximum pedal force, the pedal travel must not change even over a prolonged period of application." Well mine does change - it continues to go down slowly towards the floor. So is this just a case of bleeding the brakes (air in the line maybe?), or swapping out the fluid completely, or do I have a more serious problem? Maybe my master cylinder is letting the fluid back past the seal?

I didn't break the seal on the lines at all during the swap, but am intending to replace the fluid in the next week or so anyway. The braking performance is no worse now than it was before the swap, but the spongy pedal feel remains, which I really want to sort out.

Thanks in advance for any advice.

[h100vw]

Pretty sure you want to bed the brakes in a while after the change mate.

Then look at the fluid afterwards.

Don't be panicking about it if they are hauling you down.

Gavin

[brad]

bed the brakes in - contact Remsa or Brakes Direct for advice.

If still spongy after that then the next obvious bit is to flush the brakes - properly with a pressure bleeder - preferably after cycling the ABS with VCDS or similar (lots of black stuff will come out).

I assume you took the cap off the master cylinder before pushing the pistons back in?

[PoloGIT]

I assume you took the cap off the master cylinder before pushing the pistons back in?

Sure did. Thanks for the tips. I suspect the pedal was doing that prior to the disc and pad swap though, just never tested it.

[brad]

Sure did. Thanks for the tips. I suspect the pedal was doing that prior to the disc and pad swap though, just never tested it.

Is the sinky pedal in the workshop or under normal stopping? If it feels good when driving "as you normally do" then I wouldn't worry.

[PoloGIT]

Pretty sure you want to bed the brakes in a while after the change mate.

Then look at the fluid afterwards.

Don't be panicking about it if they are hauling you down.

Gavin

Hi Gavin, yeah, hauling it down fine. Will let it bed in and see where we go from there. Cheers

[PoloGIT]

Is the sinky pedal in the workshop or under normal stopping? If it feels good when driving "as you normally do" then I wouldn't worry.

Workshop. Stops fine but it feels a bit crap when I'm driving, like it always has. But then I've come from a E61 530i Motorsport that had awesome brakes, so maybe I've been tainted...

[PoloBlack]

How old is the brake fluid? I think water contaminated or degraded fluid can give spongy brake feel


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[PoloGIT]

Have cycled the ABS pump ( thanks Gavin) and it's feeling a little better. Suspect it's a good bleed that or complete swap of fluid that's in order. What's people's recommendations on the fluid front? For what it's worth, the writing in the reservoir implies that it was done 2 years ago but this car has done about a 100k in that time. Thanks for everyone's help so far.

[brad]

Pentosin Dot 4 LV

ATE SL.6

Anything else that is Dot 4 class 6 (complies with ISO 4925)

[seangti]

I run the penrite racing brake fluid in both cars. It's good for street and track work.

Any good dot 4 should be adequate, I've ran Castrol Dot 4, it's fine too. I wouldn't bother with dot 5.

RACING BRAKE FLUID

[brad]

I only mention Low Viscosity because the VW brake fluid specification 501 14 calls for a low viscosity fluid. Most Dot4 and DOT5.1 fluids don't meet the spec but I would think that in Australian ambient temperatures it might not be an issue.

Dot 5 is silicone based and not compatible with glycol based brake fluids.