Pothole damage and locked electric parking brake

[Mazdaq]

Hi

I've got a C4 Grand Picasso 2014 model.

Just over a week ago, I hit a pothole that I couldn't see as it was below the surface of a puddle. It burst my tyre and I later discovered that it had also cracked my alloy. I have now had a new alloy and tyre fitted at home and decided to take it out for a test drive as I suspected there was also possible damage to the suspension. However, I can't move it off the drive as it appears the electric park brake isn't releasing from the wheel, which I had replaced.

From what I can tell, the brake is releasing from the other 3 wheels, just not from the one that was damaged. Any idea how to get it to release? I have it booked into a garage on Wednesday but obviously I can't get it there at the moment!

Any help, gratefully received.

[GiveMeABreak]

The handbrake only acts on the rear wheels, not all 4. So there may be some other damage. It would help if you popped your VIN up (please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff) so I can determine the specific system employed on your calipers.

[Mazdaq]

Thanks Marc

My VIN is VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

Ok, so confirmed this a C4 Picasso (B78) and you have rear motorised calipers.

Is there any warning light on the dash or message when you start the vehicle and try to release the parking brake? Do you have any other warning lights on. What happens when you push the control to release the parking brake?

[Hell Razor5543]

Are you sure the new alloy is the right spec for your car? I have heard of an occasion when an incorrect spec wheel was fitted, and it fouled on the brake calliper (which meant the wheel could not turn).

[Mazdaq]

Are you sure the new alloy is the right spec for your car? I have heard of an occasion when an incorrect spec wheel was fitted, and it fouled on the brake calliper (which meant the wheel could not turn).

Now you say that, you might be right. The new alloy pattern isn't an exact match with the others as I couldn't find an exact match at a reasonable price. It's similar but I just assumed the only difference would be the aesthetic look of the alloy.

I will have to double check when I get home.

[Mazdaq]

Ok, so confirmed this a C4 Picasso (B78) and you have rear motorised calipers.

Is there any warning light on the dash or message when you start the vehicle and try to release the parking brake? Do you have any other warning lights on. What happens when you push the control to release the parking brake?

No warning lights when I try to release the brake.

I put my foot on the brake and release the parking brake with the control and the red light goes off. But when I then put it in gear and try to move, it won't budge.

I will double check the compatibility of the alloy when I get home.

[GiveMeABreak]

It's the size of the alloy that is key. The wrong sized wheels can cause instability and upset the ESP ECU, but if you have fitted the incorrect wheel, then expect issues as James has said.

[Ross_K]

You need a wheel with an offset of 47 (ET47 will probably be stamped on the inside of the wheel) for a 2013 onward C4 Grand Picasso

Citroen - C4 Grand Picasso (2013 - )
PCD: 5x108
Center bore: 65.1
Offset: 47
Mounting: Bolt - 12 x 1,25
Wheel torque steel: 100 Nm / 74 ft-lb
Wheel torque alloy: 100 Nm / 74 ft-lb
Possible tire sizes:
205/60R16
205/55R17
225/45R18
225/40R19
225/35R20
245/30R20

[GiveMeABreak]

He has these on this model for 17":

7 J17 CH5-50

The 16" factory fit are:
6.5 J16 CH5-47

[Mazdaq]

You need a wheel with an offset of 47 (ET47 will probably be stamped on the inside of the wheel) for a 2013 onward C4 Grand Picasso

Citroen - C4 Grand Picasso (2013 - )
PCD: 5x108
Center bore: 65.1
Offset: 47
Mounting: Bolt - 12 x 1,25
Wheel torque steel: 100 Nm / 74 ft-lb
Wheel torque alloy: 100 Nm / 74 ft-lb
Possible tire sizes:
205/60R16
205/55R17
225/45R18
225/40R19
225/35R20
245/30R20

Thanks for this Ross. The new wheel I bought was off eBay and it had come off a 2016 C4 Picasso (not Grand). It takes the same size tyre as the other wheels (205/55R17) so I, probably foolishly, assumed that it would fit my car. I'm contacting the seller to see if he can confirm whether it is compatible. Do you know what the offset is for a Picasso?

[Ross_K]

Do you know what the offset is for a Picasso?

Sorry I don't, but maybe someone who has one could chime in.

You didn't say whether this is a front or rear wheel that's giving trouble?

[Mazdaq]

Do you know what the offset is for a Picasso?

Sorry I don't, but maybe someone who has one could chime in.

You didn't say whether this is a front or rear wheel that's giving trouble?

Rear wheel, it's the electric park brake. It seems to release OK on the other rear wheel, but not on this one that was replaced.

[Mazdaq]

He has these on this model for 17":

7 J17 CH5-50

The 16" factory fit are:
6.5 J16 CH5-47

Yep I've just checked the old, cracked alloy and I can see 7J17 CH5-50 printed on it. I'm pretty sure the replacement alloy was also a CH5-50. And I've had a 205/55R17 new tyre fitted to it, and that wouldn't fit a 47 offset, as I understand it.

So I'm guessing the issue is with the brake caliper not releasing? Are there any temporary solutions for this so I can get it to the garage to be looked at without having to call out a car tow?

[Mazdaq]

I seem to have resolved it - engine off, put my foot on the brake and pressed the ignition button, then I pressed the parking brake button and I heard the brake release. Then clutch in, pressed the ignition button, engine on, into 1st gear and pulled away absolutely fine.

Turned it all off and went through the normal start procedure and this time the handbrake seemed to automatically release as you would expect, without needing to press the parking brake button.

I will take it out for a proper test drive in the morning.

Thanks for all the help on here.