New type of reverse only handbrake.

[Monkeyfeet]

Thought I had the dreaded handbrake / caliper sticking issue, but no -
(C5 Mk1) Front passenger side, inboard pad. The pad has come away from the backing, could move forwards but would wedge in place to stop reverse.

Anyone had this before?

[Stickyfinger]

Age and/or overheating due to sticking caliper

[Monkeyfeet]

Sticking caliper - thats what I was afraid it was, I've got some new pads on their way tomorrow, I'll see how it goes.
Hopefull be warm again tomorrow. Couldn't do it yesterday, 1C and bit of a stiff breeze...

[Stickyfinger]

It is always the inside first, it gets all the kerb side rubbish and puddles thrown at it.

[Monkeyfeet]

Nail on the head! Thanks.
Drivers side was the same, ie inside pad material had come away from the backing plate. Caliper all covered on crud too.
That pad plate shows signs of overheating - paint all bubbled up and layering off. I've put it more down to the build up, as the handbrake cables move freely, the mechanism moves and easily goes back to its stop. Pad still have plenty of meat on.
New pads and cleaned up.
I'll keep an eye on.

[Monkeyfeet]

Afraid I'd appreciate some more advice now please!

I've changed the pads & cleaned up the calipers.
Handbrake cables not sticking, in fact moving quite freely.
Handbrake levers on the back of calipers return to their stops, no sticking here either.
Hubs both spin freely.
Her indoors went for a spin in the car yesterday, but came back with sticking brakes. I took the wheels off to take a look. It had cooled down by then and, again, both wheels span freely, but I could see (and smell!) that the pads had got very hot. In fact they'd melted the plastic covering on the low-pad warning doobrey and brought the indicator light on.

Right, well, to me it seems strange that they're both doing it at exactly the same time. I'm about to get those replacement calipers, but could it be something in common, causing the pads to drag enough when driven to stick? I'm thinking engine-on so servo running, possible master cylinder problem. If so I must admit I've not come across this before.
One thing I've noticed is that if pressed for long and hard enough the brake pedal will nearly go the floor (when on the drive - brakes work fine otherwise, I tested after fitted new pads, it'll pull up quickly and in a straight line)
Any thoughts please??

[ekjdm14]

I've seen failed flexible hoses act as a one way valve before now causing the brakes to drag, but the fact that both sides are doing it added to the sinking pedal I would suggest servo or master issues as you say.

[Monkeyfeet]

Well I've just nipped out and pressed in the pedal engine on / off for comparison. Pedal is hard at first but will definitely sink if pressure kept on, only difference with motor running is its easier to push it further down. As kind of expected I suppose...
We're assuming master cylinder here but what about ABS block?
I think the master cylinders more likely though?

[Monkeyfeet]

Just had a thought. (amazing) I've not bled the rears yet, and I can't rememeber the last time I did. That could partly explain squidgy brake pedal. Not the front binding though.
And i've just looked up price of a master brake cylinder. £350, with ESP (at Mister Auto)