Brake Creep / Soft Pedal After Pad Change

**jim_tdi** · 17-12-2012,12:06 PM

Hi all, pads were low so changed the backs first a few weeks ago, all good, then the fronts this weekend. I swapped them out as I have done many times, just eased the piston back into the calliper and put the new pads in etc. After doing this (forced a little fluid out of the master cylinder), I have a soft pedal that needs pumping once to get a pedal and then it creeps down if compressed. I suspected air but can't see how it could have got into the lines.

After researching, it seems that I should have un-done the bleeder whilst pushing back the piston, but again, I haven't had an issue before. So I have bled the brakes, and quite a bit of air came out. However, I still have the soft pedal. I suspect there is still air in the lines, and am hoping that I haven't screwed the master cylinder....

Any thoughts appreciated.

**mikeybutch** · 17-12-2012,05:17 PM

How did you take fluid out of the m/ cylinder?I have usually remove any excess from the res

**jim_tdi** · 17-12-2012,05:40 PM

I didn't - I didn't notice and a bit spilled over the top - forced out of cap. Not too much so easy to wipe down the top of the MC.

**Danny-boy** · 17-12-2012,05:42 PM

That's the way I do it on all my cars, although with the cap removed so as not to over-pressurise.

**jim_tdi** · 17-12-2012,05:52 PM

Yes, I've not had this problem before - I can't see how air has got into the lines, and so am worried that the MC seals maybe damaged - maybe as I forced the piston back in this way?

**Danny-boy** · 17-12-2012,05:56 PM

If I'm honest, I have forgotten to remove the cap a few times in the past and not caused any problems.

Can't be sure if the fluid was 100% full though, so there may have been some slack there.

I don't understand where your air has come from either. Maybe a problem with the piston seals?

**audia4qts** · 17-12-2012,06:26 PM

is it diesel or petrol?

When you say pedal creep. Do the pads bite and then if you keep the pedal pressed hard the pedal will creep slowly to the floor?

I've never bothered to remove the cap and never had any issues before.

**Alan02** · 17-12-2012,09:15 PM

If this is the pedal having further travel/soft feel when driving, it would be best to bed the pads in then see if it improves. A slight lip on the discs will cause this `soft pedal` feel.

**Danny-boy** · 17-12-2012,09:33 PM

Very good point Alan.

Although OP noted his brakes bled a fair bit of air out after the work, so unless it was already in there it's a little strange.