L320 EPB screech with video

2008 RRS V8 petrol

Hi I’ve been doing research and it seems like this EPB screeching sound always follows after the latch is disconnected within the EPB module. The solution being to remove the 8 torx screws and manually unjam while leaving module in place. I’ve attached a YouTube url showing the movements of the gears within my module and the threaded rod making contact with the stopper leading to the screech. It also shows my cable still attached. I’ve adjusted the cable tension behind rotor with no success. Hoping somebody with experience can diagnose with the video provided. Thank you for reading

Either the cables are stretched, the shoes are worn or badly adjusted and also the backing plates eventually fold in towards the disks and give scratching sound with low speed manœuvres.
My advice would be to get into the rear disk/drums and check the brake shoes before the epb module goes on a permanent holiday

Mark Piercy said:

Either the cables are stretched, the shoes are worn or badly adjusted and also the backing plates eventually fold in towards the disks and give scratching sound with low speed manœuvres.
My advice would be to get into the rear disk/drums and check the brake shoes before the epb module goes on a permanent holiday

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Thank you! Ordering parking brake/shoe kit will update after install. They are definitely old but appeared functional. The arm behind the shoes that extends back and forth via cable is not seized on either side. If no improvement I’ll replace the cables. Again thanks for help.

Check the new brake shoes for an Allen bolt, if there is then there is a specific way to adjust the shoes.
I'm not sure if your model needs a shoe bedding in process as well

Also check the backing plates for handbrake shoes for any signs of distortion

Wind the adjusters up so the brakes are on, do your test again.
I think the cables are stretched and I don't think there is adjustment to take up the slack on cables, from what I see.

There is a bed in process but as Its a park brake if it holds the car I wonder if its needed, If you have diagnostics to do it then fine.

But dont use it till its sorted.

J

marjon said:

Wind the adjusters up so the brakes are on, do your test again.
I think the cables are stretched and I don't think there is adjustment to take up the slack on cables, from what I see.

There is a bed in process but as Its a park brake if it holds the car I wonder if its needed, If you have diagnostics to do it then fine.

But dont use it till its sorted.

J

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Funny you say that about the bedding in process... I did a d4 with new disks pads and shoes. Did the bed in process to the T and it tore the new shoes apart ...
After the second set were put in I refrained from doing it again.....
It held even still

Try adjusting them 1st iv never done the bedding in procedure on either of my D3s or L320

Notguilty said:

Thank you! Ordering parking brake/shoe kit will update after install. They are definitely old but appeared functional. The arm behind the shoes that extends back and forth via cable is not seized on either side. If no improvement I’ll replace the cables. Again thanks for help.

Click to expand...

Check that the backing plate mounting points for the shoes are not corroded - there are three pressed 'high spots' per shoe, these need to be as smooth and corrosion free as possible, additionally, apply some brake grease (not copperslip - it's the work of the Devil!) with the end of a cable tie once the shoes are installed between the shoes and the mounting points, this will reduce the force required to move the shoes during the adjustment process and the application / release of the park brake.

Stopped using copperslip a while back as it attracts break dust and then hardens

Mark Piercy said:

Check the new brake shoes for an Allen bolt, if there is then there is a specific way to adjust the shoes.
I'm not sure if your model needs a shoe bedding in process as well

Click to expand...

The current shoes and new shoes definitely have the Allen bolt. I played with it a bit but really didn’t know exactly what I was doing. A chunk of one of the PB shoes broke off during my 2nd attempt. I’ll try again with new shoes installed following the tips provided on this thread. Maybe they’re so old/corroded they don’t function.

I noticed extremely minimal movement from the passenger side PB shoes during the modules attempt to apply brake. Driver side really didn’t move. I could see the cable extending back and forth behind the rotor on both sides. The cables being stretched sounds very plausible. PB kit comes in Tuesday, hopefully I make progress otherwise I’ll order cables Tuesday night. Thanks

Graculus said:

Check that the backing plate mounting points for the shoes are not corroded - there are three pressed 'high spots' per shoe, these need to be as smooth and corrosion free as possible, additionally, apply some brake grease (not copperslip - it's the work of the Devil!) with the end of a cable tie once the shoes are installed between the shoes and the mounting points, this will reduce the force required to move the shoes during the adjustment process and the application / release of the park brake.

Click to expand...

Will definitely pick up the brake grease thank you for info. I’ll be sure to post the results

SOLVED! (Still getting very short screech upon engagement) it’s working so I’m kindve ready to move on, maybe I need slightly more adjustment? I can’t believe it but its otherwise working as it should. After many attempts and this and that and using launch tool to try and manipulate the cables the following procedure worked. There’s a chance I had so much trouble from trying to make the adjustments with the disc rotors removed.

1. With rotors installed, adjust star cable tensioner until so taught it will not budge no matter the effort. Rotors will not spin anymore as they are engaged by the PB shoes.

2.back off star cable tensioner 8-10 clicks. Spin rotors till you can access the Allen bolt.

3.loosen Allen bolt significantly.

4. Rubber mallet all around the disc rotor HAT, plenty of smashing all around.

5. Tighten Allen bolt.

6. Look up and say please, then engage the PB using interior switch.

If it works go ahead and drop a few tears, if not working and your situation is similar to mine, my guess (credit to previous replies) would be replace the PB cables. Might be silly but I couldn’t turn rotors without being in neutral. All the videos I watched didn’t mention putting in neutral to rotate for access to adjustment/allen bolt. Maybe common sense but maybe not when you’re a rookie.

Thanks so much everyone for the suggestions and tips. I’m off to more projects.

Also I did replace the PB shoes/hardware so there’s a chance that contributed significantly. Wouldn’t be surprised if the set I removed were original.

Nice one