Handbrake ratchet removal

motoroller · Post by **motoroller** » Wed Dec 28, 2016 2:52 pm

Back in a Z4 after many years! Had the 2.0i back in around 2010, bought the 2.5i recently.

It failed its MOT on the handbrake and airbag light. I'll get a friend with INPA to look into the airbag light.

The handbrake mechanism is worn - I've taken out the centre console and can see the ratchet bit is worn. Do I need to take the diff out and remove all this from underneath the car? Advice would be appreciated.

Also has anyone re-ground a new set of teeth into the mechanism or is a full one from BMW the only way?

GuidoK · Post by **GuidoK** » Wed Dec 28, 2016 3:17 pm

Are you sure the ratchet is worn? or is it just a bad adjustment (bad adjustment: ratchet works but you have to pull the brake lever up too high to get any bite on the handbrake). The handbrake has a semi automatic adjuster; it has to be clipped in a non automatic position, then adjust the rear handbrake shoes by turning the little expandable thing between the brake shoes (through a wheel bolt hole) to the point that it just grabs and then a few turns back (there is a specific setting for that), and then engage the automatic adjuster.

To remove the hand brake lever is a pain: exhaust has to come off and propshaft has to be removed.
The handbrake lever mechanism sits in a tray that is bolted from underneath.
I've never heard anyone regrinding the teeth on the lever by this car. BMW TIS recommends a new lever mechanism.

motoroller · Post by **motoroller** » Wed Dec 28, 2016 3:23 pm

It's not adjustment - I can see the worn teeth. This picture doesn't show it too well but you can see teeth ~4-8 worn and these are the ones the handbrake would normally be on, I can't pull it up past 3 - it slips back down.

GuidoK · Post by **GuidoK** » Wed Dec 28, 2016 7:08 pm

indeed if it slips back, its def. worn

You've got an interesting job ahead

I'd recommend if you dont have a car lift, to rent one.
And you need quite a bit of tools, apart from the ordinary: probably some oxyacetylene to get the front exhaust bolts off, and e10 or e12 sockets to remove the rear bolts from the propshaft
And a transmission jack to lower the (complete) exhaust. it's quite heavy.

Ewazix · Post by **Ewazix** » Wed Dec 28, 2016 8:39 pm

Feel for you, what a PITA job for a handbrake ratchet!

http://workshop-manuals.com/bmw/z_serie ... nting_pan/

MrPT · Post by **MrPT** » Thu Dec 29, 2016 11:30 am

Ahh what?! Need to do mine at some point too.

Mine's not terrible though (no issue with MOTs) - might try adjusting it to bite with the lever a bit higher up.

motoroller · Post by **motoroller** » Thu Dec 29, 2016 12:06 pm

Well due to the airbag light I've taken most of the interior out (seats, carpets etc) and the roof mechanism. Almost down to a bare shell!

paddy wright · Post by **paddy wright** » Thu Dec 29, 2016 1:34 pm

Had mine done under warranty in September, they had to drop the prop etc. Might be worth replacing the prop donut W like the probs off as well.

MrPT · Post by **MrPT** » Thu Dec 29, 2016 2:29 pm

paddy wright wrote:Had mine done under warranty in September, they had to drop the prop etc. Might be worth replacing the prop donut W like the probs off as well.

Yeah, probably lots of little things worth doing, e.g. brake line refurb, diff flange re-grease, loose heatshields, re-torque cross braces etc.

motoroller · Post by **motoroller** » Thu Dec 29, 2016 9:48 pm

MrPT wrote:
paddy wright wrote:Had mine done under warranty in September, they had to drop the prop etc. Might be worth replacing the prop donut W like the probs off as well.
Yeah, probably lots of little things worth doing, e.g. brake line refurb, diff flange re-grease, loose heatshields, re-torque cross braces etc.

Diff flange and donut W, will look into those.

Are there any common jobs to do when the interior is out? Any places to add dynamat to improve road noise / audio quality, I'm already thinking of adding rear cubby subwoofers or components.

paddy wright · Post by **paddy wright** » Fri Dec 30, 2016 11:59 am

motoroller wrote:
MrPT wrote:
paddy wright wrote:Had mine done under warranty in September, they had to drop the prop etc. Might be worth replacing the prop donut W like the probs off as well.
Yeah, probably lots of little things worth doing, e.g. brake line refurb, diff flange re-grease, loose heatshields, re-torque cross braces etc.
Diff flange and donut W, will look into those.

Are there any common jobs to do when the interior is out? Any places to add dynamat to improve road noise / audio quality, I'm already thinking of adding rear cubby subwoofers or components.

Sorry for the typo- autocorrect changed while to W like?? The diff donut is just called the diff coupling donut.

motoroller · Post by **motoroller** » Sat Dec 31, 2016 6:57 pm

I'm about 75% of the way to having the blasted mechanism out.

Exhaust is out and the front of the driveshaft is off, but the rear diff end isn't coming off. It's stuck on there. I've left some maintenance spray on there to loosen it up a bit. Any tips for removal? Then I should be able to get the handbrake mechanism out.

GuidoK · Post by **GuidoK** » Sat Dec 31, 2016 7:25 pm

I always stick a tyre iron through the joint (to block the propshaft from rotating, I usually set it so that its wedged against the petrol tank so I have both hands free), and just take out the inverse torx bolts.
Never had any problems with it, but my car is a garaged car for most of its life, so there's hardly any rust.

motoroller · Post by **motoroller** » Sat Dec 31, 2016 7:32 pm

Does it have any internal "pin" / notch to keep it centred?

GuidoK · Post by **GuidoK** » Sat Dec 31, 2016 7:34 pm

Yes, there is a small centerflange on the propshaft joint (maybe 5mm or so) that slots into the diff flange. About 4cm in diameter.
you can get the tyre iron or prybar between the diff flange and propshaft flange on a few points (maybe at one of the joint protrusions) and pry the propshaft back from the diff (only a few mm necessary)

I always mark the position the propshaft sat in the diff. I dont think its a completely balanced assembly (only the propshaft is balanced), but that way you're assured of the same balance as you set off with.

Here you can just see on my car the little flange that fits into the diff:

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