Hi, can anyone help me? I have a '51 Octavia 1.9 tdi. I am really clueless about cars but I recently changed the brake pads (all round) but I had to remove one of the rear calipers as the pad had worn right down and the piston was jammed out . I sorted that and put everything back on, bled the system and the brakes work fine. The only problem is if I keep my foot on the brake pedal it slowly creeps down. Does anyone have any idea why this is ? I have checked for air in the system and there is no fluid leak.

Cheers

It soumds to me like the seals in the master cylinder. When you are bleeding the brakes a lot of people push the brake pedal right to the floor. This pushes the piston in the master cylinder further than it normally travels when you nornmally use the brakes. This 'area' inside the master cylinder because its not normally swept by the seals can corrode or develop a lip inside the cylinder. When you push the pedal to the ground during bleeding the seals run over this lip or corrosion and can get damaged. The end result is that fluid can push past the seals when you press the pedal and the pedal will , in worst cases go right to the floor.

The other possibility is damage to the ABS system, Its better to crack open the bleed nipple on the calipers when installing new pads in order to prevent fluid pushing back into the ABS pump and possibly damaging the seals in the ABS solenoids. Although most cars will have the solenoids actually defaulting to the open position in 'safe mode' when the ignition is not on so I don't think its the ABS , i think you may have damaged or flipped over the lip of the seals in the master cylinder if you do not have any leaks anywhere.

It could be air in the master cylinder but this would more than likely give spongy brakes rather than a 'flat' pedal. I 'm not sure if the master cylinder on the octy has a bleed nipple but someone may be along who knows, this might let you bleed the master cylinder before comdeming the seals.

Agree with the above, this is why we use pressure bleeders and do not pump the pedal.

Thanks all,

like I said I am clueless about cars so the help is really welcome

How old is the brake fluid?

Master cylinder does have two bleed nipples on it - one for brakes, and I guess the other is for the clutch....

I don't know how old the brake fluid is as I have only had the car 6 months. I tried the bleed nipple on the master cylinder but it made no difference. I guess it is just time to hand it over to the experts. Can anyone recommend a reliable garage in the Bridgend area of South Wales?

Thanks for all your help guys.

Thanks all,

like I said I am clueless about cars so the help is really welcome

if you changed the front pads are the discs worn ie lipped on the outside edge you need to file the edges of the pads top and bottom to fit.

Master cylinder does have two bleed nipples on it - one for brakes, and I guess the other is for the clutch....

No the clutch has its only bleed nipple on the slave cylinder. The only common connection between the two systems is the reservior.

The second bleed nipple is required as you have two seperate brake circuits.

If you want to eliminate the front brakes that you have changed clamp off both the front brake flexi pipes and try the pedal again, if you still have travel its not down to them.

if you changed the front pads are the discs worn ie lipped on the outside edge you need to file the edges of the pads top and bottom to fit.

My disks are lipping yet my independent just told me to brake carefully after he fitted new pads - after 680 miles I still get a creaking sound from the front, or I find stopping takes for ever! this is scary so will take it back to him and get them to do the job properly.

I have never filed the edges of pads in all my life as a tech. If the discs are that knackered then replace them. If there are still above min thickness then it shouldnt take more than 100 max of carefull braking and they should be matched again.

Just been out for a quick "test" problem seems to have gone.