C4 Picasso sticking brake

[RichardW]

As noted elsewhere, the C4 has suddenly decided that the NSF brake wants to stick - it was OK only a few weeks ago when it was MOTd, no comment about it dragging (and it's proper dragging now!). I cleared away the snow, and in between the snow showers stripped it down this afternoon.

I love working on cars in these conditions. Not...

Anyway, pads are free, so it seems to be something else. It took a fair bit of levering to get the caliper off. I tried to squeeze it back but it wouldn't go; only way I could get it back on was to remove the anti squeal backing on one of the pads to make a bit more room Bleed screw is now somewhere between 8 and 9mm and doesn't look like it is going to come out anyway - couldn't find an imperial spanner that was a snug fit. So either the caliper has just decided to seize up, the hose has collapsed, or the ABS block is having a fit, and holding the brake on. I might plug in the computer to see if it shows line pressures in the brakes, but my thoughts are it's most likely to be the caliper at fault? New ones are not too expensive, but I've got plenty of other things to be doing; it might be going to the garage if he can fit it in.

[GiveMeABreak]

Are you sure the extreme cold hasn't been a contributory factor - My bonnet catch wiring cables seized solid, causing the plastic to snap on the handle, the starter was really sluggish and everything was generally groaning when we had the -10 plus winds and drifts here. I've just replaced the cable yesterday now it is milder.

[Michel]

My C4 GP has been disliking the cold. Sticky handbrake and "parking brake faulty" message on the screen. We've had -9 and a real-feel of -18.

It warmed up yesterday and today, and it's been fine.

[Eddie Nuff]

Madam's C4GP just keeps chugging on. Her lead boots keep the egr clean, the grandkids test everything inside, the middle row of seats spend as much time down as they do up, and the bloody thing just keeps ploughing on.

[Mandrake]

As noted elsewhere, the C4 has suddenly decided that the NSF brake wants to stick - it was OK only a few weeks ago when it was MOTd, no comment about it dragging (and it's proper dragging now!). I cleared away the snow, and in between the snow showers stripped it down this afternoon.

IMG_20180304_142255166[1].jpg

I love working on cars in these conditions. Not...

If I recall I changed the front discs and pads on the Ion in amongst the snow as well, not fun!

Anyway, pads are free, so it seems to be something else. It took a fair bit of levering to get the caliper off. I tried to squeeze it back but it wouldn't go; only way I could get it back on was to remove the anti squeal backing on one of the pads to make a bit more room Bleed screw is now somewhere between 8 and 9mm and doesn't look like it is going to come out anyway - couldn't find an imperial spanner that was a snug fit. So either the caliper has just decided to seize up, the hose has collapsed, or the ABS block is having a fit, and holding the brake on. I might plug in the computer to see if it shows line pressures in the brakes, but my thoughts are it's most likely to be the caliper at fault? New ones are not too expensive, but I've got plenty of other things to be doing; it might be going to the garage if he can fit it in.

Does the car have full active stability control / traction control or just ABS ? Standard ABS can't apply the brakes, only release them. Only full active stability control / traction control systems can apply the brakes without you pressing the pedal. (The Ion has this) So I'd say ABS block is probably at the bottom of your list of candidates.

Seized caliper or failed hose I'll bet...

[RichardW]

It does have ESP, but I'd have thought if it was holding brake pressure at the wrong time it would have flagged a fault. It was pretty hot by the time I got here this morning, and I am away with it at the weekend, so I've managed to book it in for Thursday to see if a new caliper will sort it.

[MikeT]

Don't the caliper pistons need to be rewound to retract them? They do on my C5 and if I found I could push them back without rotation would assume something's broken inside?

[Mandrake]

I regret to inform you that your tax disc is 3 years out of date Richard... oh, wait....

I also can't help thinking that either the wheel shrunk or the car has just had a large meal. Proportions look a little off...

[RichardW]

Calipers only need winding back if the handbrake acts on them - which is on the rear on this car.

Yes, tax due up at the end of the month - trying to work out if I can manage to transfer the Reg Keeper to me without having to pay an extra month's tax. There's no real hassle with it not being 'mine' except I don't get driving others cars on my insurance.

[RichardW]

Garage fitted a new caliper yesterday which has cured it. The MPG has now recovered from 37 to 45 on my commute! And, as a further bonus, the noise I thought was a wheel bearing has gone, so it must have been the brake vibrating. Winner!

[Mandrake]

Garage fitted a new caliper yesterday which has cured it. The MPG has now recovered from 37 to 45 on my commute! And, as a further bonus, the noise I thought was a wheel bearing has gone, so it must have been the brake vibrating. Winner!

Same improvements here when I fitted new discs/pads to the Ion and replaced the swollen rubber bush on the caliper slide pin that was sticking - the noise and vibration I thought was a wheel bearing went away and the range went back up!