Stratman
MB Enthusiast
The problem. You press the pedal to engage the parking brake and it won't stay down. This may or may not have been preceded by the brake sticking on, needing a helping foot to release it, coupled with a floppy release handle.
The fault. One end of the spring has come out of the plastic lever which provides the friction to hold down the pedal. This is how it should look:-
When you press the pedal the spring, the other end of which is fixed to the pedal, pushes up in the slot on the plastic lever which is fixed on its pivot. This winds up the spring which then wants to unwind, pushing the plastic lever against the friction drum of the pedal jamming it in position and holding the parking brake on.
Pulling the release handle pulls the cable upwards and releases the friction, letting the brake release. The small release spring returns the pull handle to its retracted position.
Pushing the pedal too hard, perhaps because the main mechanism is stiff, causes the spring to pop out of its slot in the plastic lever. This can cause the brake to fail to stay on as there's no force pressing the lever against the friction surface, or it can make the whole lot jam. The release handle goes floppy because the plastic lever sometimes gets wedged in the 'up' release position and can even cause the little return spring to become detached.
Remove the three screws holding the lower fascia panel (T20 torx) and move it aside. You can get away with leaving the bonnet release and OBD socket attached, just be careful. Pull out the foam insulation and limber up for the next bit.
By moving the driver's seat back as far as it will go then reclining it all the way down, you can lie on your back on it and get your head in the footwell where all will be revealed. Reading glasses and an inspection lamp may be needed.
I used a large negidrive (not posidrive ) screwdriver to lever the spring back into position and gave it a tiny bend with pliers to hopefully prevent it jumping out again. The small return spring was put back with long nosed pliers.The top hook end goes into the plastic lever from the rear.
The release cable may still be loose because it's dropped out of its slot in the pull handle. Prise off the panel at the right hand end of the dashboard and undo the T20 screw holding the fuse panel. Move it to one side bearing in mind it may be live. If you're worried just put it in a plastic bag. You can now see and access the handle quite easily. Just pop the cable back and you're nearly done.
The last thing to do is lubricate the mechanism under the rear seat. I have an estate so I just lifted the base and removed the cover in the middle. A good sloshing with WD40 and 3-in-1 should keep it sweet for a few months. The nut is used to adjust the main cable. Take out the slack but don't overdo it.
Put it all back together and make an appointment with your osteopath
Note that when replacing the under dash panel, there are matching ventilation ducts which must engage. I've no idea which way round the foam insulation goes, I just jammed it in until it held.
The fault. One end of the spring has come out of the plastic lever which provides the friction to hold down the pedal. This is how it should look:-
When you press the pedal the spring, the other end of which is fixed to the pedal, pushes up in the slot on the plastic lever which is fixed on its pivot. This winds up the spring which then wants to unwind, pushing the plastic lever against the friction drum of the pedal jamming it in position and holding the parking brake on.
Pulling the release handle pulls the cable upwards and releases the friction, letting the brake release. The small release spring returns the pull handle to its retracted position.
Pushing the pedal too hard, perhaps because the main mechanism is stiff, causes the spring to pop out of its slot in the plastic lever. This can cause the brake to fail to stay on as there's no force pressing the lever against the friction surface, or it can make the whole lot jam. The release handle goes floppy because the plastic lever sometimes gets wedged in the 'up' release position and can even cause the little return spring to become detached.
Remove the three screws holding the lower fascia panel (T20 torx) and move it aside. You can get away with leaving the bonnet release and OBD socket attached, just be careful. Pull out the foam insulation and limber up for the next bit.
By moving the driver's seat back as far as it will go then reclining it all the way down, you can lie on your back on it and get your head in the footwell where all will be revealed. Reading glasses and an inspection lamp may be needed.
I used a large negidrive (not posidrive ) screwdriver to lever the spring back into position and gave it a tiny bend with pliers to hopefully prevent it jumping out again. The small return spring was put back with long nosed pliers.The top hook end goes into the plastic lever from the rear.
The release cable may still be loose because it's dropped out of its slot in the pull handle. Prise off the panel at the right hand end of the dashboard and undo the T20 screw holding the fuse panel. Move it to one side bearing in mind it may be live. If you're worried just put it in a plastic bag. You can now see and access the handle quite easily. Just pop the cable back and you're nearly done.
The last thing to do is lubricate the mechanism under the rear seat. I have an estate so I just lifted the base and removed the cover in the middle. A good sloshing with WD40 and 3-in-1 should keep it sweet for a few months. The nut is used to adjust the main cable. Take out the slack but don't overdo it.
Put it all back together and make an appointment with your osteopath
Note that when replacing the under dash panel, there are matching ventilation ducts which must engage. I've no idea which way round the foam insulation goes, I just jammed it in until it held.
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