brakes keep seizing :(

[f11rfn]

hi guys i have a 320i convertible 1990, i had issuethe front brakes kept seizing i had it checked by a mechanic he said was a bad caliper, so i have replace front calipers/discs/pads and brake lines to braided ones, After driving for 20 minutes the brakes seized up again! after you leave the car for a while to cool of brakes are ok, drive it for 20 minutes and use brakes they seize up again? brakes have been bled twice, any help would be appreciated thanks

[flybynite]

hi guys i have a 320i convertible 1990, i had issuethe front brakes kept seizing i had it checked by a mechanic he said was a bad caliper, so i have replace front calipers/discs/pads and brake lines to braided ones, After driving for 20 minutes the brakes seized up again! after you leave the car for a while to cool of brakes are ok, drive it for 20 minutes and use brakes they seize up again? brakes have been bled twice, any help would be appreciated thanks

When they did the calipers did they change the sliders if they are corroded or have a step a new caliper won't help

If you have done the calipers etc and it is still not the issue then my guess is master cyliner as a seal cold be inverting. Servo could be sticking on but that would do all 4. Lastly could be the ABS unit gunked up but that tends to be loss of brake pressure not locking brakes

I know you have bled the brakes but have you flushed the fluid through and given it a full fluid change.

[f11rfn]

hi thanks for reply, they didnt change the sliders, if was sliders car is left for 20 minutes then brakes work again, more then likley master cylinder? not done complete fluid chnage but will do just incase

[fixedwheelnut]

I would check that the pads slide freely in the carrier part of the caliper as rust build up can cause the pads to stick regardless of what the caliper is doing, if all that is OK check the pedal to servo adjustment, make sure that there is a small amount of free play and that the pedal is not pressuring the servo/master cylinder at rest.

Also check for kinks in the brake pipes I have seen new calipers fitted with twisted brake lines before too.