Brake Upgrade
Contained in this document:Brake Upgrades - E28,Brake Upgrades - E34.
See also:Rotor Warp - Prevention,Brake Upgrade - Master Cylinder.
Brake Upgrades - E28
( Note: The following is a compilation from many posts .Ed. )
The brakes listed below bolt on without any modification. This requires
calipers, carriers, guide bolts, rotors and pads. You need the carrier for
each brake system, usually included if you buy used.
Front brake assemblies that will fit any E28:
(some numbers may be slightly wrong, I misplaced my table)
E28 535 282mm x 25mm vented or E28 M5 300mm x 30mm
E34 535302mm x 22mm vented
E34 540 302mm x 28mm vented
E34 M5 315mm x 28mm vented
E34 M5 345mm x 32mm vented from 6/94
E32 735 302mm x 28mm vented
E32 750 302mm x 28mm vented
E31 840 324mm x 30mm
Rear brake assemblies that fit any E28:
E28535 284mm x 10mm solid
E34 535 300mm x 10mm solid
E34 540 300mm x 20mm vented
E34 M5 300mm x 20mmvented
E34 M5 328mm x 20mmvented from 6/94
Unfortunately these don't work, but are here as a size reference
E32735 300mm x 12mm solid
E32 750 300mm x 20mm vented
The E34 Rear Brake Part Numbers to use:
E34 540i / E32 740i Calipers:
34 21 1 160 399 ( part number - left )
34 21 1 160 400 ( part number - right )
E34 540i / E32 740i Carriers:
34 21 1 160 384 ( part number x 2 )
E34 540i / M5 300mm x 20mm rotors
34 21 1 159 659 ( part number x 2 )
E32 calipers need the E32 master cylinder to work properly.
If you install SS lines without bigger-volume piston'ed front calipers (IMO)
the pedal ends up unacceptably 'sharp'. However, ABS equipped cars
can loose some of the spongy pedal feel by using SS lines.
The E32 brakes will fit under 15" wheels. These are your best choice for
economy... and will be capable of handling just about anything you would
do with your 535i. E32 750iL front rotors are vented from the inside
rather than outside around the "hat".
The 540i/6 fronts may be considerably cheaper the E34 M5 and are the same
size. The stock E28 ///M car brake bias is calculated at 73% front and 27%
rear. The upgrade to E34, M5 rear brake will change the bias to 66% front
and 34% rear.
the E28 M5 used the same rear rotors as the 535i. Which should tell you how
important rear brakes are in the big scheme of things.
An increase in pedal firmness can be gained by installing the mastercylinder
from the E-32, 750 that has a 25mm cylinder bore.
Brake Pads - E28
To make an E34 535 out brake 540's, be on par with E34M5's and
have the same brake reaction times as the M3Lightweights,
The E34 rotors can be gas slotted, but needs to be done by an
experienced race shop. You then add super blue fluid, and install
a street/track carbon-kevlar pad set, (or similar) but this is only
suited to the track, as the pads take time to warm up.On the street
the pads will wear out 15% quicker.
Personally I would change the pads to Deluxe or Metal Master.
Metal Masters handle harder driving, but don't stop as well cold as the Deluxe.
Deluxe don't dust, are good when cold and don't chew out the rotors
like Metal Masters.
Date: Thu, 31 Aug 2000
From: Jerry Brown <>
Subject: Re: [uuc] WNT e-28 big brake kit
Rob,
While it's true the stock brake master cylinder will *function*, I can
tell you from experience, that replacing it with the E32 750i piece
*greatly* enhanced pedal feel and reduced pedal travel on my
E24 with the E34 brakes.
But I suppose it's one of those preference things. ;^)
jerry
Rob Levinson - UUC Motorwerks wrote:
> No, the E28 master cylinder is just fine. On my ex-535i Turbo, it's been running those
> brakes for over two years and as far as I know the new owner still likes the brakes.
> The E28 M5 master cylinder, as a comparative example, has no problem running the 850CSi
> 324mm front brakes and 540i 300mm rear brakes as in my car.
> Rob
______
In the first upgrade iteration, I installed the E34 540i fronts and rears;
the 300mm X 28mm (front) and 300mm X20mm (rear) is a *huge*
improvement over the stock 284mm units. FWIW, the E34 540i calipers
are the same as the E32 740i/750i, but differ in the rear rotor.
Recently, I went to E34 M5 fronts (same caliper, 315mm rotor).
For the track, this setup is great, but probably not worth the extra money
on the street, as the M5 brakes are very hard to find.
As I mentioned below, the E32 750il master cylinder is also highly
recommended.
------
The 540i calipers, carriers and rotors - both front and rear - are a
bolt-on for the E28/E24.
In addition, the E34 M5 calipers, carriers and rotors - both front and
rear - are a bolt-on for the E28/E24.
The only differences between the two are the front carriers and rotors.
The M5 carriers must be used with M5 rotors, to accommodate the larger
diameter.
------
While it's true the 540i/740i/750i front brake calipers are the same,
the caliper bracket and rotor are different. The bottom line is, you'll
need to get a complete M5 kit, since the brackets are very difficult and
expensive to get separately.
My recommendation is to go with the 540i brakes, new Balo rotors and
good quality stainless steel brake lines. Don't forget to upgrade to the
750i brake master cylinder.
Date: Fri, 02 Jun 2000
From: "ra rabmw" <>
Subject: Re: [uuc] Date: Fri, 2 Jun 2000
Congradulations, Rod;
The VERY last sentence.
After all that space, you and others finally got to the solution;
the E32 calipers need the E32 master cylinder to work properly on
most BMWs. Period. Write it down.
>From: "Rodney Moore" <>
>Subject: [uuc] Date: Fri, 2 Jun 2000
>Jerry,
>Since the upgrade you performed has been extensively reviewed and road
>tested by many BMW enthusiasts, I would not think the upgrade caused the
>brake performance difficulty you perceive. Yep, bleeding the brakes can be
>tricky and I suggest multiple brake bleedings. I use the pedal bleed method
>first followed by the pressure bleed method. Caution, pedal bleeding causes
>small bubbles in the brake fluid that will take time to settle out. Pedal
>bleeding will also make the master cylinder travel into normally unused
>areas of the master cylinder. Pressure bleeding a system with an ABS, on
>the other hand, may not expel bubbles trapped in the horizontal brake lines
>going to the calipers. It's a tough life!!
>My diagnostic suggestions are the same.
>It you think you have effectively bleed you brakes? Test for master cylinder
>internal leaking with the boost accumulator discharged. Master cylinders
>can leak internally(inner piston seal) and that will cause the brake pedal
>to move toward the floor with time and there will be no indication of a
>problem such as a brake fluid leak. Have the brake boost pressure regulator
>tested. You may also want to have someone press on the brake pedal while
>you investigate the flexible lines and other possible brake system components.
>I have no experience with the ABS causing this pedal feel issue.
>My M6 has the same Master cylinder as your 635, 23.81mm cylinder bore. I
>have upgraded to Euro 1995, E-34, M5 BIG brakes. The brake pedal has always
>had an appearance of wanting to depress to the floor with boost, however, I
>will not press the brake pedal as hard as I can because it is possible to
>damage components with maximum hydraulic pressure generated by the brake
>systems under boost. Also the brake pedal support has been known to fatigue
>and or fail under excess pedal application force. IMHO, Since the road
>performance of my brake system is outstanding, I thing that is the ultimate
>test and I personally refrain from suggesting, that the pedal feel when the
>vehicle is stopped is an indication of a system failure.
>An increase in pedal firmness can be increased by installing the master
>from the E-32, 750 that has a 25mm cylinder bore.
>Regards,
>Rod...
>------original Message------
>Date: Thu, 01 Jun 2000
>From: Jerry Brown <>
>Subject: Re: [uuc] RE: <E24/E28>: soft brake pedal
>Rodney,
>You make some thoughtful observations. However, one thing I didn't
>mention is that the brakes in my 533i don't exhibit the same behavior:
>the pedal is rock hard at all times. Also, this behavior was present
>before I upgraded the calipers.
>Thanks,
>jerry
>Rodney Moore wrote:
> > Jerry,
> > It is possible the boost pressure regulator(on top of the accumulator/bomb)
> > is faulty allowing excess boost. It is possible the master cylinder is
> > bad (test by discharging the accumulator and holding the brake pedal
depressed firmly until your leg hurts and if the pedal hasn't moved down
toward the floor it's good).
>------snip------
>Rodney Moore
>BMW CCA #86830
>Golden Gate Chapter
>
Date: Tue, 29 Aug 2000
From: "ra rabmw" <>
Subject: Re: [uuc] WNT e-28 big brake kit
HOWARD:
The "big brake kit" best used is simply the mastercylinder, calipers,
and rotors, from the 735/750 E32 cars. Straight bolt-onoperation.
Calipers and perhaps master cyl. you can find used. Have the new
rotors (for all four wheels) gas slotted by a BMW or other repair/raceshop
properly, add a good track/street pad set, and you can out-brake E28 M5's,
E30M3's, 540i/6's, small Porches, and just about anything else that isn't a newer
"P" or BMW "M" car. Those you can keep up with, but not out-brake.
Ask me how I know.
Unless you have a turbo, or hot cam
set-up (Hartge, Alpina, etc.), and/or run something at or over 300hp, that's all
the brakes you should need. You can upgrade the rears, but shouldn't find it
necessary past the gas slots and pads.
The Brembo system is terrific, but unnecessary for most E28's
without the euro 296hp engine or better.
o/______\o "RA"/Bob G.
(Oo=00=oO)
[]=****=[]
Malcolm Reitz wrote:
> The front brake rotors on my E28 M5 need replacing. I've been told
> that the factory M5 rotors aren't necessarily the best option and
> there are other BMW rotors or 3rd-party rotors that will work better.
> However, I don't have the specifics on what other rotors will work.
> Can anyone pass along more info or suggestions?
> Thanks,
> Malcolm Reitz
> '88 M5
Date: Wed, 24 Feb 1999
From: Jim Moran <>
Subject: Re: <E28> M5 brake rotor options?
Use E32 750iL front rotors. They're 2 mm larger in diameter and 2 mm
less thick and are a direct fit. They are vented from the inside rather
than outside around the "hat". I have them on my M6 and have yet to
warp them. Finally, they are cheaper than the stock pieces.
Jim Moran
'88 M6
Date: Wed, 24 Feb 1999
From: "Rodney Moore" <>
Subject: RE:<E28> M5 brake rotor options?
Malcolm,
The problem with the E24 & E28 ///M brakes is not the front rotors it is
that BMW left the undersized rear rotors from the non-motorsport cars in the
rear. Hence the front brakes do most of the stopping. This can cause the
front rotors to warp under hard braking. I also don't believe the use of
302x28mm, 750 front rotors is a good idea because you are effectively
installing rotors warn by 2mm your car and the 2mm increase in diameter is
of no consequence. Also since the rotor wear limit is a combination of
rotor and caliper design you will experience reduced pad or rotor wear
limits. The claimed advantage of front vs rear rotor venting is a myth.
I believe the best upgrade is to keep the stock OE front rotors &
pads (Energit 582EE) and also replace the 284x10mm rear rotors &
calipers(35mm pistons) with the 300x20mm vented rear rotors, pads (Jurid 547
FF) and calipers(40mm piston) used on the E34, M5. A bolt on job!!
The stock E24 & E28 ///M car brake bias is calculated at 73% front and 27%
rear. The upgrade to E34, M5 rear brake will change the bias to 66% front
and 34% rear. While the numbers don't seem significant, let me tell you,
this is a big braking performance upgrade. Just ask some one that has an
E34, M5. This is the same bias that the E34, M5/ E31, 840 uses. The heat
load in the rotors will be better distributed front/rear and applying more
torque into the rear suspension will reduce the amount the rear end lifts
under hard braking.
Believe me, you won't regret the additional expense!!.
Also installing just larger front rotors and calipers from an E34,
M5(315x28mm) or E31, 840(324x30mm) rotors will only further increase the
front bias and increase the likely hood of warping the front rotors.
Regards,
Rod...
M6, with the E34, M5 rear rotors & calipers.
E34, M5
Date: Thu, 25 Feb 1999
From: "Jake Steijn" <>
Subject: Re: <E28> M5 Rotors
Malcolm,
The 750 rotors fit and are a good replacement, slightly lower cost, slightly
thinner (for better cooling) and with a different air flow (again, better
cooling). The M5 rotors are better for prolonged high-speed (100MPH+)
touring due to air flow directed over bearings - not an issue in the US.
You can get them from the Ultimate Garage. I know, I just got mine.
Jake Steijn
88 M5
Date: Thu, 25 Feb 1999
From: "Rob Levinson" <>
Subject: Re:<E28> M5 brake rotor options?
>From: "Curt Kiser" <>
>Subject: RE:<E28> M5 brake rotor options?
>I like this idea. And it's a direct bolt-on?
>I'd like to hear more about this from folks that has done it. Pro's &
>cons to this mod. TIA.
Curt, buddy - where have you been? This is the upgrade you saw on
Helen!
These brakes listed require no modifications and are completely reversible.
You need calipers, carriers, guide bolts, rotors, pads.
Front brake assemblies that will fit any E28:
(some numbers may be slightly wrong, I misplaced my table)
E28 M5 300mm x 30mm
E34 5-series 284(?)mm
E34 M5 315mm x 28mm
E32 7-series 302mm x 28mm
E31 8-series 324mm x 30mm
Rear brake assemblies that fit any E28:
E34 5-series
E34 M5 300mmx20mm
Rob Levinson
Date: Sat, 22 Apr 2000
From: "Rob Levinson - UUC Motorwerks" <>
Subject: Re: [uuc] E28 Brake Options
(from memory but numbers should be accurate):
Stock E28 front brakes:
282mm x 25mm
E32 front brakes:
302mm x 28mm
Don't forget E34 M5 front brakes:
315mm x 30mm
E31 840i/850i front brakes:
324mm x 30mm
No tricks or pitfalls, all these systems bolt right up. You need the
carrier for each brake system as well, usually included if you buy
used.
The E32 brakes will fit under 15" wheels. These are your best choice
for economy... trust me, they will be capable of handling just about
anything you would do with your 535i.
The E31 brakes will fit under 16" wheels. These may be overkill but
if you can find a set cheap... well there's no such thing as too much
brakes! Actually, that's not entirely true. The E31 brakes will
unbalance your braking and you will be wanting to do a rear upgrade to
E34 540i brakes as well.
Rob Levinson
Date: Sat, 22 Apr 2000
From: Ethan Stock <>
Subject: [uuc] Re: [E28] brake upgrades
Chris said:
>The time has come to do the front brakes on my '86 535i...
>I'm looking to do a relatively affordable but beneficial upgrade without
>going overboard on aftermarket performance parts.
And Rob replied:
>(from memory but numbers should be accurate):
>Stock E28 front brakes: 282mm x 25mm
>E32 front brakes: 302mm x 28mm
>Don't forget E34 M5 front brakes: 315mm x 30mm
>E31 840i/850i front brakes: 324mm x 30mm
>The E32 brakes will fit under 15" wheels. These are your best choice
>for economy... trust me, they will be capable of handling just about
>anything you would do with your 535i.
>The E31 brakes will fit under 16" wheels. These may be overkill but
>if you can find a set cheap... well there's no such thing as too much
>brakes! Actually, that's not entirely true. The E31 brakes will
>unbalance your braking and you will be wanting to do a rear upgrade to
>E34 540i brakes as well.
My notes:
1) Stock 535i are 284x25mm front (vented) 284x10 rear (solid)
2) I believe that 540i/6 fronts are the same 315mm x 30mm as the E34 M5,
and may be considerably cheaper.
3) A front upgrade is all you really need, unless you're *very* serious at
the track (not likely with an '86 535i?) I had overheated the stock
fronts only once or twice on the street, in really hard-core situations
(racing down a twisty mountain road in Santa Fe... had to translate both
3000 feet of altitude and my excess enthusiasm into heat via the brakes...
they were fading fast!)
4) You may also find E28 M5 brakes around, at 300 x 30mm fronts... these
are often expensive because they are 4-piston calipers, one of the few that
BMW made. I know people that swear by the superior feel, but BMW itself
went back to single-piston calipers for the E34 M5 and the E36 M3. You
decide. Either way, the E28s are a valid upgrade. BTW, the E28 M5 used
the same rear rotors as the 535i. Which should tell you how important rear
brakes are in the big scheme of things.
5) Personal experience: E34 M5 fronts will indeed fit under 16" wheels,
but I recommend that you get SS lines to go with them. They have a larger
piston volume than the old fronts, and you will really notice the pedal
lagging a bit if you still have the old lines. Conversely, if you install
SS lines without bigger-volume piston'ed front calipers (IMO) the pedal on
the E28 ends up unacceptably 'sharp'.
6) These are indeed all bolt-up: E28, E34, E32, E31, and (pretty sure)
E39 brakes are all mix and match.
7) Just checked my database: The 8-series (E31) 324x30mm are also 4-piston.
8) If you really want to go nuts, the Euro 850Csi were for a long time
(pre-E39 M5) the biggest BMW brakes... 345x32mm. These also bolt stock to
an E28. Just ask Sherman 'big brakes' Koo here in the GGC. They do take
17" wheels, though, and (again IMO) you start making unacceptable
ride/handling tradeoffs on the E28 with 17" wheels because of the
relatively small overall wheel diameter.
9) Noting that the E28 M5 are 300x30 and the E32 are 302x28, if you do get
the E28M5 fronts, you can run E32 rotors... the extra 2mm of diameter fits
fine, and they just start out as if they were 2mm worn. There used to be
extensive debates back when the E28 M5 was newer about the different hub
construction of the two rotors, and whether one rotor or the other better
cooled (or insulated from heat) the front wheel bearings. Both were big,
fast cars... I don't think it really matters.
Also: Rob has a great web page out there somewhere where he details the
540i rear brake install... which I coincidentally just asked him for a URL
to... Rob? maybe move it under UUC projects?
Cheers,
Ethan
88 535is moderately tweaked