E38 740i 1996 -- front end "shimmy" when braking. Could it be JUST the rotors?

Hi Folks

I recently changed the front pads on my 740 E38.

Strange thing although they were listed as E38 they were slightly different to the ones fitted in as
much that a grinding wheel was taken to each pad to chamfer the top and bottom to match the original
ones. However I digress, but since then I have gradually noticed a definite shake from the from
especially when braking. The harder I brake the more violent the shake is.

I know that the rotors are due for replacement but could it be JUST the rotors warped (gets more
noticeable the warmer the brakes get - like slowing in traffic minor wobble. Slowing from 100+ Ok
to start with but as the car nears 40 it shakes.....

Thinking of fitting Pagid Rotors + green Pads

Any comments - should it cure it or could it be shocks etc.


Sir Hugh of Bognor


Intelligence is not knowing the answer but knowing where and how to find it!

Hugh Gundersen


http://www.bognor-bill.co.uk
Bognor Regis, W.Sussex, England, UK

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Vyisder Asmeni
Orsisarsis Asderisorsis.
B.Cozderiz
Vunarz
PERORZ
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On Sun, 19 Sep 2004 16:13:16 +0100, Hugh Gundersen wrote:

> Hi Folks
>
> I recently changed the front pads on my 740 E38.
>
> Strange thing although they were listed as E38 they were slightly
> different to the ones fitted in as much that a grinding wheel was taken to
> each pad to chamfer the top and bottom to match the original ones.
> However I digress, but since then I have gradually noticed a definite
> shake from the from especially when braking. The harder I brake the more
> violent the shake is.
>
You definitely got the wrong pads. The correct pads would have been a
"drop in".

> I know that the rotors are due for replacement but could it be JUST the
> rotors warped (gets more noticeable the warmer the brakes get - like
> slowing in traffic minor wobble. Slowing from 100+ Ok to start with but
> as the car nears 40 it shakes.....
>
Were the rotors checked (with a dial indicator) for signs of warp? Were
they checked for being below the wear limit? Both of those checks need to
be done before replacing the pads and if either check fails the rotors get
replaced on both sides.

There are several things that could be the cause of the shake:

1) Worn suspension components (ball joints, control arm bushings, etc)
2) Incorrect alignment
3) Out of balance or out of round tires
4) A bad tire(s)
5) Warped rotors
6) "Grabby" pads

A BMW suspension is so highly tuned that it takes very little error in any
of those items to cause problems.

> Thinking of fitting Pagid Rotors + green Pads
>
Pagid pads are great! After fixing 1-4 above on a '90 E32 I still had a
noticable shake when breaking through the 40-30mph range. The rotors were
fine by a dial indicator check and well above the wear limit so I replaced
the OEM pads (still in good shape though a bit thin) with Pagids and the
problem went away. As a bonus the brakes were way more effective and
didn't cause the "dreaded black dust wheel disease".

--
The instructions said to use Windows 98 or better, so I installed RedHat.

On Sun, 19 Sep 2004 13:01:56 -0500, Jim Levie > wrote:

>On Sun, 19 Sep 2004 16:13:16 +0100, Hugh Gundersen wrote:
>
>> Hi Folks
>>
>> I recently changed the front pads on my 740 E38.
>>
>> Strange thing although they were listed as E38 they were slightly
>> different to the ones fitted in as much that a grinding wheel was taken to
>> each pad to chamfer the top and bottom to match the original ones.
>> However I digress, but since then I have gradually noticed a definite
>> shake from the from especially when braking. The harder I brake the more
>> violent the shake is.
>>
>You definitely got the wrong pads. The correct pads would have been a
>"drop in".

Yeah! - Emergency panic purchase ----------------
>
>> I know that the rotors are due for replacement but could it be JUST the
>> rotors warped (gets more noticeable the warmer the brakes get - like
>> slowing in traffic minor wobble. Slowing from 100+ Ok to start with but
>> as the car nears 40 it shakes.....
>>
>Were the rotors checked (with a dial indicator) for signs of warp? Were
>they checked for being below the wear limit? Both of those checks need to
>be done before replacing the pads and if either check fails the rotors get
>replaced on both sides.

Not checked but definitely on the wear limit as to thickness.

>
>There are several things that could be the cause of the shake:
>
>1) Worn suspension components (ball joints, control arm bushings, etc)

Just been fixed - have to check what was changed
>2) Incorrect alignment

Possible but unlikely

>3) Out of balance or out of round tires

Possible but "sudden" --- weights still in place and no scuffing

>4) A bad tire(s)

VERY unlikely -----

>5) Warped rotors

VERY possible

>6) "Grabby" pads

VERY possible
>
>A BMW suspension is so highly tuned that it takes very little error in any
>of those items to cause problems.
>
>> Thinking of fitting Pagid Rotors + green Pads
>>
>Pagid pads are great! After fixing 1-4 above on a '90 E32 I still had a
>noticable shake when breaking through the 40-30mph range. The rotors were
>fine by a dial indicator check and well above the wear limit so I replaced
>the OEM pads (still in good shape though a bit thin) with Pagids and the
>problem went away. As a bonus the brakes were way more effective and
>didn't cause the "dreaded black dust wheel disease".

Definitely will use Pagid stuff


Sir Hugh of Bognor


Intelligence is not knowing the answer but knowing where and how to find it!

Hugh Gundersen


http://www.bognor-bill.co.uk
Bognor Regis, W.Sussex, England, UK

-------------------------------------------------
Vyisder Asmeni
Orsisarsis Asderisorsis.
B.Cozderiz
Vunarz
PERORZ
-------------------------------------------------