Soft brake pedal after new discs & pads

[Kiwirst]

Just finished putting new Brembo rotors & ceramic pads in the hope of fixing a highway rear brake shudder and a soft brake pedal.

Haven't checked the shudder yet, but the pedal is still soft in my mind. Bite is much better, but I'm wondering if I can firm up the pedal more.

Bleed?

New brake fluid?

Any help much appreciated

[howardc64]

Fairly common and happened to quite a few of us. Outer caliper spring incorrectly installed. Here is what it should look like

http://cdn4.pelicanparts.com/techart..._med/pic03.jpg

Take a look through your wheel openings and the spring ears are surely sitting on the other side of the caliper bracket applying no spring tension. Caliper then twist under braking and pads don't get full contact.

[Astro14]

+1

What Howard said. Put the spring on properly and they'll firm right up.

[kutcht1]

Do the rears have the same spring on the outside of the caliper? Kiwirst says he did the rears and I thought those were different. Anyone have a rear brake issue and cause a shudder?
TomK

[Kiwirst]

I did front and back, I'll check the springs again tonight and try to post pics to see if I didn't get them right.

[howardc64]

Do the rears have the same spring on the outside of the caliper? Kiwirst says he did the rears and I thought those were different.

I believe rears is the same design with outer spring. The floating caliper design needs to stay perpendicular to the rotors under braking to squeeze the pads evenly. Thus, outer spring tension is necessary to maintain this geometry in this particular design.

I have seen Toyotas with a different design. Their caliper sliding pin is beefy and very little play. This alone can keep the floating caliper from twisting under braking pressure without an outer spring. But this design has other problems, the twisting pressure is still there wears down the sliding pin slightly and creates metallic mud. With tiny tolerance, this freezes the caliper from sliding. So these designs need to be relubed every 30k miles or so to prevent freezing.

[AutosDirectFlorida]

Assuming the spring isnt the problem - I believe stainless lines could help pedal feel as well.

http://www.stoptech.com/technical-su...rake-lines-q-a

https://www.ipdusa.com/products/1044...2-s60-v70-xc70

[Kiwirst]

Uploaded pics as best I could of the springs.

Pedal seems a little firmer but still softer than I would like.

Also have a knocking noise when applying heavier brake pedal application when stopping, almost sounds like the rdige between the two pad contact points is hitting something.

[Forkster]

Did you try bleeding your brakes? Also - when was the last time you replaced the brake fluid?

[Kiwirst]

I have not bled the brakes, that was the next thought. I have only had this car a few months now, so at the 180k service the shop said the brake fluid was ok but I'm thinking if I'm going to bleed I may as well replace the fluid to go with the shiny rotors & pads.