Braking in New Handbrake shoes and Disks

How long to brake in new handbrake shoes and rear disks? (E46 330D)


The rear drivers side disk on my car is rubbing on the bottom shoe on the
side facing front of car. I've stripped the brake down and checked
everything else and by putting some tip-ex onto the shoe I discovered where
it's rubbing. Doesn't seem to drag all the time, just once per rotation.
It's been about 1000miles now since they were installed on the car but I can
still hear it rubbing sometimes. Used genuine BMW dealer disks and ATE
shoes. Will the rubbing go away as they bed in some more or have I a
problem here ?

Thanks

MC

"M C" > wrote in message
...
> How long to brake in new handbrake shoes and rear disks? (E46 330D)
>
>
> The rear drivers side disk on my car is rubbing on the bottom shoe on the
> side facing front of car. I've stripped the brake down and checked
> everything else and by putting some tip-ex onto the shoe I discovered
where
> it's rubbing. Doesn't seem to drag all the time, just once per rotation.
> It's been about 1000miles now since they were installed on the car but I
can
> still hear it rubbing sometimes. Used genuine BMW dealer disks and ATE
> shoes. Will the rubbing go away as they bed in some more or have I a
> problem here ?

I'd say you have a problem.
Sounds like the discs are not running true. Either the discs are faulty,
which is unlikely as they're new, or the hub mounting flange is damaged, or
there's a foreign body trapped between the disc/hub mating faces.
Check the mounted disc for runout with a dial guage. It should be true
within a thou or two. If it's more, it should give an indication of where to
look for the problem.
If nothing is apparent, check the disc mounting face on the hub. If that's
OK it could be a faulty disc.
Mike.

In article >,
M C > wrote:
> The rear drivers side disk on my car is rubbing on the bottom shoe on
> the side facing front of car. I've stripped the brake down and checked
> everything else and by putting some tip-ex onto the shoe I discovered
> where it's rubbing. Doesn't seem to drag all the time, just once per
> rotation. It's been about 1000miles now since they were installed on
> the car but I can still hear it rubbing sometimes. Used genuine BMW
> dealer disks and ATE shoes. Will the rubbing go away as they bed in
> some more or have I a problem here ?

The handbrake shoes should be bedded in using the procedure described in
the owner's handbook. From memory, you just drive at moderate town speeds
with the handbrake applied gently for a couple of miles.

However, it's most unusual for the handbrake shoes to *ever* need
replacing in normal use.

--
*Does fuzzy logic tickle? *

Dave Plowman London SW
To e-mail, change noise into sound.

You're probably right but I (perhaps unwisely) decided to replace them when
replacing the rear disks, together with the spring kit from the dealer.
I've driven loads with the handbrake applied and the problem persists. I
think it may be something more serious. I've booked it in to be checked
out.

MC


"Dave Plowman (News)" > wrote in message
...
> In article >,
> M C > wrote:
>> The rear drivers side disk on my car is rubbing on the bottom shoe on
>> the side facing front of car. I've stripped the brake down and checked
>> everything else and by putting some tip-ex onto the shoe I discovered
>> where it's rubbing. Doesn't seem to drag all the time, just once per
>> rotation. It's been about 1000miles now since they were installed on
>> the car but I can still hear it rubbing sometimes. Used genuine BMW
>> dealer disks and ATE shoes. Will the rubbing go away as they bed in
>> some more or have I a problem here ?
>
> The handbrake shoes should be bedded in using the procedure described in
> the owner's handbook. From memory, you just drive at moderate town speeds
> with the handbrake applied gently for a couple of miles.
>
> However, it's most unusual for the handbrake shoes to *ever* need
> replacing in normal use.
>
> --
> *Does fuzzy logic tickle? *
>
> Dave Plowman London SW
> To e-mail, change noise into sound.

This question is counter intuitive. I would not have thought that the break
in period for a parking brake would even exist.

I have to wonder if the parts were installed correctly. I would be looking
to see if the shoes are on straight, that sort of thing. My inclination is
that a parking brake is something that would work right out of the box if
everything was done correctly.




"M C" > wrote in message
...
> How long to brake in new handbrake shoes and rear disks? (E46 330D)
>
>
> The rear drivers side disk on my car is rubbing on the bottom shoe on the
> side facing front of car. I've stripped the brake down and checked
> everything else and by putting some tip-ex onto the shoe I discovered
where
> it's rubbing. Doesn't seem to drag all the time, just once per rotation.
> It's been about 1000miles now since they were installed on the car but I
can
> still hear it rubbing sometimes. Used genuine BMW dealer disks and ATE
> shoes. Will the rubbing go away as they bed in some more or have I a
> problem here ?
>
> Thanks
>
> MC
>
>

"Jeff Strickland" > wrote in message
...
> This question is counter intuitive. I would not have thought that the
break
> in period for a parking brake would even exist.
>
> I have to wonder if the parts were installed correctly. I would be looking
> to see if the shoes are on straight, that sort of thing. My inclination is
> that a parking brake is something that would work right out of the box if
> everything was done correctly.

My owners manual states the procedure from bedding in the drum emergency
brake, and also as a different item the procedure for the main 4 wheel disc
brake system. Does yours?

-Russ.

In article >,
Jeff Strickland > wrote:
> I have to wonder if the parts were installed correctly. I would be
> looking to see if the shoes are on straight, that sort of thing. My
> inclination is that a parking brake is something that would work right
> out of the box if everything was done correctly.

Depends what you are expecting. The handbrake on my E39 - in perfect
condition - is what I'd describe as poor. The one on my 'classic' - which
is similar in performance and weight, and also RWD - will lock the wheels
on a dry road at 20 mph. I also had an older car, with inboard disc
brakes, where the handbrake worked on the discs, which would exceed 50%
efficiency on a brake tester, and lock the rear wheels at 30 mph with
moderate effort. So it can be done. But modern cars don't need an
emergency brake - merely a parking brake. I think it's a retrograde step.

--
*Be nice to your kids. They'll choose your nursing home.

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" > wrote in message
...
> In article >,
> Jeff Strickland > wrote:
> > I have to wonder if the parts were installed correctly. I would be
> > looking to see if the shoes are on straight, that sort of thing. My
> > inclination is that a parking brake is something that would work right
> > out of the box if everything was done correctly.
>
> Depends what you are expecting. The handbrake on my E39 - in perfect
> condition - is what I'd describe as poor. The one on my 'classic' - which
> is similar in performance and weight, and also RWD - will lock the wheels
> on a dry road at 20 mph. I also had an older car, with inboard disc
> brakes, where the handbrake worked on the discs, which would exceed 50%
> efficiency on a brake tester, and lock the rear wheels at 30 mph with
> moderate effort. So it can be done. But modern cars don't need an
> emergency brake - merely a parking brake. I think it's a retrograde step.
>

We have talked about this before, Dave. The "handbrake" is not a hand brake
at all but a Parking Brake. It is meant to hold a static load static, it is
not meant to bring a dynamic load to a static condition.

So, I was not aware that a parking brake had a break in period because by
design it only works when the car is already parked.

TO ANOTHER POSTER
Yes, I think they do discuss pulling the handle up a few clicks and driving
slowly (~25mph) to get the new shoes to mold to the drums. But, I was not
thinking that this procedure would alter the OP's experience that was
described.



> --
> *Be nice to your kids. They'll choose your nursing home.
>
> Dave Plowman London SW
> To e-mail, change noise into sound.

In article >,
Jeff Strickland > wrote:
> > Depends what you are expecting. The handbrake on my E39 - in perfect
> > condition - is what I'd describe as poor. The one on my 'classic' -
> > which is similar in performance and weight, and also RWD - will lock
> > the wheels on a dry road at 20 mph. I also had an older car, with
> > inboard disc brakes, where the handbrake worked on the discs, which
> > would exceed 50% efficiency on a brake tester, and lock the rear
> > wheels at 30 mph with moderate effort. So it can be done. But modern
> > cars don't need an emergency brake - merely a parking brake. I think
> > it's a retrograde step.
> >

> We have talked about this before, Dave. The "handbrake" is not a hand
> brake at all but a Parking Brake. It is meant to hold a static load
> static, it is not meant to bring a dynamic load to a static condition.

> So, I was not aware that a parking brake had a break in period because
> by design it only works when the car is already parked.

I'm not sure how you could design a friction brake that only worked to
hold the car stationary? Although you could mess about with the linings so
it had the very best friction under those conditions?. But if all it was
required to do was just this, then a mechanical lock - like you have on an
auto - would be perfect. But handbrakes are the same as the normal working
brakes in principle, ie friction. And do the job rather badly on the
average BMW.

> TO ANOTHER POSTER Yes, I think they do discuss pulling the handle up a
> few clicks and driving slowly (~25mph) to get the new shoes to mold to
> the drums. But, I was not thinking that this procedure would alter the
> OP's experience that was described.

--
*I have a degree in liberal arts -- do you want fries with that

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" > wrote in message
...
> In article >,
> Jeff Strickland > wrote:
> > > Depends what you are expecting. The handbrake on my E39 - in perfect
> > > condition - is what I'd describe as poor. The one on my 'classic' -
> > > which is similar in performance and weight, and also RWD - will lock
> > > the wheels on a dry road at 20 mph. I also had an older car, with
> > > inboard disc brakes, where the handbrake worked on the discs, which
> > > would exceed 50% efficiency on a brake tester, and lock the rear
> > > wheels at 30 mph with moderate effort. So it can be done. But modern
> > > cars don't need an emergency brake - merely a parking brake. I think
> > > it's a retrograde step.
> > >
>
> > We have talked about this before, Dave. The "handbrake" is not a hand
> > brake at all but a Parking Brake. It is meant to hold a static load
> > static, it is not meant to bring a dynamic load to a static condition.
>
> > So, I was not aware that a parking brake had a break in period because
> > by design it only works when the car is already parked.
>
> I'm not sure how you could design a friction brake that only worked to
> hold the car stationary? Although you could mess about with the linings so
> it had the very best friction under those conditions?. But if all it was
> required to do was just this, then a mechanical lock - like you have on an
> auto - would be perfect. But handbrakes are the same as the normal working
> brakes in principle, ie friction. And do the job rather badly on the
> average BMW.
>


A mechanical lock that used pins into a spline, or equivelent, AND if the
car was nudged for any reason, then the pins could sheer and the brake would
be rendered useless. If the parking brake was a pad of any sort that pressed
against a surface, and the car was nudged, then the pad and surface could
slip and set to the new position without destruction of the system.

All a Parking Brake has to do is keep a vehicle that is at rest at rest. A
parked car needs to remain parked. This is what a parking brake does.

Yes, they _could_ have linked it mechanically to the disc brakes and called
it an emergency brake, but they didn't They created a brake shoe and drum
that is minimally designed to keep a stationary load stationary. I don't
understand houw you could possible ask how to design a friction brake that
only worked to hold a car stationary.

BMW Parking Brakes work as good as they need to. They don't make very good
emergency brakes, but they rise to the challenge of keeping a parked car
parked, and that is all they need do by definition.