Braking Noise and Parking Brake issue

[JohnDavo]

Hi everyone.

I have a brand new XC40 B4 AWD purchased in March.

I have two issues maybe someone could help with

Occasionally it makes a slight squealing noise on braking . It will only do this when car is in freewheel mode and no other time . My dealer has said they believe it to be something to do with the regenerative braking system rather than the brakes themselves . This makes sense to me as the noise appears to come from the centre front of he car rather than the side of the car. The dealer have said they have looked at another XC40 with a similar issue, have reported to Volvo and are awaiting a fix. I am still waiting to hear back from them..

Has anyone else had a similar issue??

Secondly, recently I had a message appear on the dash saying "parking brake wont hold car". There is no actual fault and the parking brake works fine.

This is my second XC40 B4 and my first XC40 also had this issue. Again the dealer was unable to identify the fault.

If anyone could help me with either of these issues it would be much appreciated.

Thanks in advance

John

[Felindre]

Parking brake won't hold car, had this intermittently up until first service, they did something and it went away. Had it again recently twice. I've noted that when it happens and you operate the PB manually, they don't sound like they're working together but one coming on behind the other. May be sticking pads I guess.

Re squeal and regen. Regen actually works by increasing the load on the generator to increase engine 'drag' whilst increasing charging. It's nit actually linked to the brakes as such. On the B's there is a whopping great motor generator at the front, belt driven off the engine and connected to the 4i volt battery in the boot, which I guess also acts a a motor to help start launch. It's also why the engine starts so silently, because there's no starter throwing engagement, this motor just turns the engine.

This could be where the noise is coming from. I'd just check this belt is tight, not showing signs or rubbing on anything, and that you cant turn the pulleys under the belt.

[Deleted User 3359]

Parking brake won't hold generally comes up when on a gradient, and the car doesn't believe that you have pressed the footbrake hard enough. When the PB applies it only applies to the rear brakes, but footbrake applies to all 4 wheels, hence the need to apply more brake force to the rear wheels for the PB

[JohnDavo]

Parking brake won't hold car, had this intermittently up until first service, they did something and it went away. Had it again recently twice. I've noted that when it happens and you operate the PB manually, they don't sound like they're working together but one coming on behind the other. May be sticking pads I guess.

Re squeal and regen. Regen actually works by increasing the load on the generator to increase engine 'drag' whilst increasing charging. It's nit actually linked to the brakes as such. On the B's there is a whopping great motor generator at the front, belt driven off the engine and connected to the 4i volt battery in the boot, which I guess also acts a a motor to help start launch. It's also why the engine starts so silently, because there's no starter throwing engagement, this motor just turns the engine.

This could be where the noise is coming from. I'd just check this belt is tight, not showing signs or rubbing on anything, and that you cant turn the pulleys under the belt.

Many thanks for this. What you say all makes perfect sense. I will have a look although you would like to think the dealer has checked this but nothing would surprise me. Thanks again

[JohnDavo]

Parking brake won't hold generally comes up when on a gradient, and the car doesn't believe that you have pressed the footbrake hard enough. When the PB applies it only applies to the rear brakes, but footbrake applies to all 4 wheels, hence the need to apply more brake force to the rear wheels for the PB

Thanks Larry. Unfortunately the gradient has no bearing on when this message appears. It can appear on a flat gradient as well as a hill. It sometimes comes on when on my drive which is pretty flat. I will try using more brake force in future!. The fact that my previous XC40 did this makes me think it is nothing significant, hopefully! Cheers

[Felindre]

Agreed, my driveway is flat as a pancake, I've had it a couple of times there. The PB applies the rear brakes with motors that wind them onto the disk. My guess is occasionally the pads might stick or the motors are 'lazy' and the motor feedback indicates it's not wound on fully.

Had the same system on a Passat and Tiguan, never a problem. So just the Volvo implementation.

Generally I turn the ignition back on (full on hold on button for 5 secs), then release and reapply PB manually with the switch.

[JohnDavo]

Agreed, my driveway is flat as a pancake, I've had it a couple of times there. The PB applies the rear brakes with motors that wind them onto the disk. My guess is occasionally the pads might stick or the motors are 'lazy' and the motor feedback indicates it's not wound on fully.

Had the same system on a Passat and Tiguan, never a problem. So just the Volvo implementation.

Generally I turn the ignition back on (full on hold on button for 5 secs), then release and reapply PB manually with the switch.

Thanks for this.

On my previous XC40 the dealer ended up changing the motors and also the discs in an attempt to rectify this to no avail!
I am seemingly not the only person with this issue so you would think Volvo would have had this sorted by now.
Thanks
John

[Felindre]

You would think... Depends how many dealers escalated the issue, and how many owners learned to live with it like me

[gaughey]

John,

I have a 2023 XC40 dark B3P.
I have had a similar problem since day 1.
I would describe the noise as a "whooping" noise when I brake during regenerative braking.
I have recorded the noise and visited 2 main dealers who have not heard of a similar problem. They sent the recording to Volvo technical who said it was caused by the gearbox actuator which is a "characteristic" of the B3P.
I wouldn't except this as the dealer says its only my car that does it so Volvo won't authorise a repair.
Its embarrassing when passengers hear the noise and want to know what's wrong with it.
Customer services have been useless saying it is a feature of my car. (I don't remember ticking the extras box for a noisy brakes gearbox).
I can only see it getting worse before the car breaks.
This is my 2nd xc40 and 3rd Volvo.
I won't ever buy again.

[JFDIT]

I've noticed a similar noise when touching the brakes. Very intermittent and only lasts a second and sounds like you've gone over a rumble strip, but higher frequency sound.