New discs fitted - handbrake now sticks

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wonkydonkey
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New discs fitted - handbrake now sticks

Post by wonkydonkey » Fri Jul 06, 2018 11:06 pm

I fitted new discs and pads at the weekend, drove the car 20 miles or so with no problems, but drove it again today and the handbrake is sticking on a bit each time I release it to pull away. I get squealing as I roll to a halt without using the brakes, and it'll hold itself on a gentle hill without the foot brake or handbrake applied.

I did a full adjustment on it when I got home today:

Depressed and retained the spring underneath the handbrake lever.
Adjusted the handbrake shoes each side until they gripped.
Backed off 10 clicks at the adjustors.
Released the spring underneath the handbrake lever.
Operated the handbrake a few times.
Three clicks on the handbrake ratchet held both wheels, and releasing the handbrake allowed the wheels to turn freely in the air. Good, right?

The test drive gave the same behaviour as before. I didn't have this issue prior to fitting the new brakes. BMW handbrakes seem pretty dire in their operation in general, which doesn't help! Any tips, anyone?
2003 3.0i E85 Z4 Roadster in Sterling Grey
<My name is James>

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Grumpyowl
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New discs fitted - handbrake now sticks

Post by Grumpyowl » Sat Jul 07, 2018 8:27 am

Have you tried using the handbrake while the car is moving to align the brake shoes ?

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wonkydonkey
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New discs fitted - handbrake now sticks

Post by wonkydonkey » Sat Jul 07, 2018 8:44 am

Grumpyowl wrote:
Sat Jul 07, 2018 8:27 am
Have you tried using the handbrake while the car is moving to align the brake shoes ?
I've done three or four drives with the handbrake on and dragging a bit, for 50 metres or so each time, but perhaps that wasn't long enough or hard enough?
2003 3.0i E85 Z4 Roadster in Sterling Grey
<My name is James>

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charlie8
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New discs fitted - handbrake now sticks

Post by charlie8 » Sat Jul 07, 2018 9:06 am

Odd, if wheels spin freely in air but sticks when driving, almosts suggests the disc is moving around when driving with all the weight/momentum so its not concentric. But I'm sure that cant be right if everything is tight

DOes the call always push easy in the morning when left overnight and then tighten again when driving ?
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wonkydonkey
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New discs fitted - handbrake now sticks

Post by wonkydonkey » Sat Jul 07, 2018 11:10 am

charlie8 I agree, it is odd! The wheels spun freely in the air, the disc locating screw was fitted on each side, wheels torqued up etc.

As it happens I pushed the car out of the garage this morning. Gave it a gentle nudge... quiet squeal and resistance...allowed it to rock back against itself and then pushed again and it rolled fine. It didn't do this before I fitted the new discs.
2003 3.0i E85 Z4 Roadster in Sterling Grey
<My name is James>

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wonkydonkey
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New discs fitted - handbrake now sticks

Post by wonkydonkey » Sat Jul 07, 2018 3:09 pm

I've been out and popped the sticky nearside disc off. There were some flakes of old crud in there so I blasted the inside of the disc and the entire handbrake/shoe assembly with brake cleaner. Re-fitted everything, adjusted up again, but it's still happening. The smallest rock backwards in reverse gear frees it off :roll:
2003 3.0i E85 Z4 Roadster in Sterling Grey
<My name is James>

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charlie8
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New discs fitted - handbrake now sticks

Post by charlie8 » Sat Jul 07, 2018 9:12 pm

Wonder if direction matters given the handbrake pads are on a pivot. Do wheels turn in air both ways after h#brake on/off ? Does it stick in reverse at all

I presume all parts were exactly the same size when compared, wonder if something is not quite the exact fit
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wonkydonkey
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New discs fitted - handbrake now sticks

Post by wonkydonkey » Sat Jul 07, 2018 9:26 pm

charlie8 - I had a wiggle of the handbrake assembly and was pretty surprised by the amount of radial movement I could generate. This would explain that nasty BMW handbrake "rocking" that occurs, where you apply the handbrake but the car can still rock backwards and forwards a bit.

Having released the handbrake lever on a very slight downward incline, the car will hold itself. Just bringing the clutch up to biting point in reverse gear is enough to free off the handbrake and the car will roll down the slope. I did that five times in a row today.

The wheels turn nice and freely backwards and forwards in the air, yeah. It's as though being on the ground is affecting the handbrake operation, but the handbrake cable routing looks really good on this car. I don't think it can be put under tension with suspension compression.

I haven't measured the internal diameters of the old and new discs but I've been adjusting the shoes each side anyway, and they're not reaching the end of adjustment or anything.

I think I'll put it down to the old shoes bedding in to the new drum surface. I'm off for a 200 mile jaunt around Wales tomorrow so that might help them settling in! Thanks for your input today :thumbsup:
2003 3.0i E85 Z4 Roadster in Sterling Grey
<My name is James>

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