Changing Brake Pads

[Hightower]

Changed the pads on our Astra 1.9CDTi this morning without issue.

However, upon testing them, the brake pedal is very soft on the first press, giving almost no braking. Second press of the pedal gives the usual sharp response that I have been used to.  Fluid is new and clear, no leaks visible.

What have I missed please, as this has never happened to me before on any other car that I have worked on . . . . . .

[V8MoneyPit]

I have come across this from time to time. As long as you are getting correct braking, use the car for a while and you may find the pedal gets better. I can only think it's the caliper seals pulling the pistons back. Once they settle in again, it improves.

[dxmedia]

Only the first time?


You've moved the pistons back into the cylinders when fitting new pads.

The first time you press the pedal the pistons self adjust pushing the pads to the disk.

If it happens every time, you've air in the system behind the pistons.  You'll need to bleed the brakes.

[Hightower]

Thank you for the thoughts, but 'tis now sorted.

Turned out that I'd put the retaining springs back in slightly incorrectly which allowed the caliper to flex away from the pads  :doh:

[V8MoneyPit]

Only the first time?


You've moved the pistons back into the cylinders when fitting new pads.

The first time you press the pedal the pistons self adjust pushing the pads to the disk.

If it happens every time, you've air in the system behind the pistons.  You'll need to bleed the brakes.

But it wouldn't improve if it was air in the system. I'm convinced it can be related to the seals pulling the pistons back. Obviously not the case here though.

[Range Rover Blues]

|When ever I fitted new pads to my Cavalier I had to bleed the brakes and this was recomended in the workshop manual too.