Brakes not working right

new2me

friends 2004 2.0 dti zafira needed new front brake disc so he had a go at changing it .
All done but now the brake pedal feel spongy when engine is running but fine when engine is turned off. also the brake is kinda sticking on too...
vehicle has been sitting up for 11 months

any help appreciated

biko

I assume he pushed the piston back in?
After a brake job the brakes will feel a bit odd for a day (often less). It usually rectifies itself.

lavelle15

You will need to bleed the system if they are soft (there is air in the line)

biko

Is brake noisy?
If the brakes pads sounds/feels like they are sticking inside the caliper you may have to file away old rust from the caliper. Perhaps also file the contact surfaces on the pads too, just a tad mind.
The pads should move freely inside the caliper, if they're really hard to move by hand they will probably stick in action.
Add copper grease as lube (not to brake surfaces of course).

Sure, bleed the system too - particularly if you can't remember when it was done last.

new2me

biko wrote: »

I assume he pushed the piston back in?
After a brake job the brakes will feel a bit odd for a day (often less). It usually rectifies itself.

what the correct way to bleed the brakes on these please?
We notice the the piston rubber boot has a small cut in it too

biko

It's the same way for all cars - you force the old fluid out the brake caliper nipple and add fresh fluid in the brake fluid cylinder in the engine bay.
Google "bleeding brakes". It's easier with 2 people but you can do it yourself too.
http://www.youtube.com/watch?v=V5O_pbC8R2E

But I'd address the piston rubber too, it's possible that it's somehow connected to spongy feeling. Buy and replace the rubber.

Couple vids on how the brakes work.
www.youtube.com/watch?v=9EIVWoYy0ug

www.youtube.com/watch?v=Kb8-0RcyFpc