Seat Toledo 1.9TDI Brakes Calipers

Hello,

I have a strange issue that I am hoping someone can shed some light on.

My left rear caliper will effectively stay on when you use the brakes a few times and will release itself but only after a few minutes.

It is not a sticking piston. I have removed the piston, cleaned it, it is in very good condition and I replaced the seal.

The strange thing is that as soon as I open the bleed nipple a little the caliper will release. So the piston moves back when the pressure released and that is why I am saying it is not the piston.

I am not sure what is happening here. The caliper seems to be in good working order but pressure is building up in the caliper and slowly releasing.

Its as if something else is causing the pressure not to release, something further back the line. I have replaced the rear hose to eliminate that.

So what else is causing this? Can there be something else wrong with the caliper? There is not much to them.

Another thing I should mention is that when you remove the caliper the fluid will not flow. If you press the brake pedal it will spurt out, but without the pedal pressed there is nothing flowing. Could this be related?

It is as if something is making the fluid stay where it because you you cut the pipe, which I did, the cut section is full of fluid and it pours out but the section still attached to the car retains the fluid.

This is only affecting the left rear. All others calipers are fine.

I have never seem this on a car before and I have replaced a few dodgy calipers in my time.

Thanks

Barry

Replace the rubber hoses that lead to that caliper. I've seen behavior like this when they degrade or are damaged.

Hello,

In my quest for the solution, I have replaced the rubber hose and the full line but....

UPDATE

The brakes worked well but there was binding on one wheel but there was another issue where no fluid would flow to the rears when bleeding, (fluid would come out when the pedal pressed but not of its own accord), and indeed when you disconnected the two pipes coming from the MC to the ABS there was no fluid flowing from them either (again would flow when pedal pressed). This suggested a blockage of some type in the MC. The binding could still have been an ABS issue as it affected only one wheel? Or could it have been a return issue where fluid is not allowed return properly after the pedal is released but I read somewhere that this would have affected at least two wheels and not one?

Anyhow, I found the cause of the non flow. The bottom bolt on the MC was too tight against the servo and so pushing the piston in a fraction too much. As soon as I loosened it just a bit fluid started flowing. So one issue resolved.
I also removed the ABS and used compressed air and brake cleaner through the ports to blow out any crud and clean the valves.

I am hoping this will be my problem resolved but will not know until tomorrow.

My question is whether the problem at the MC could cause the binding at one wheel or did I indeed have two separate issues?

Barry

I state two issues as it has been suggest that a sticky valve in the ABS was causing the binding on one wheel, hence me pulling ABS and cleaning it