Brake Upgrade



Brake Upgrade

Contained in this document:  Brake Upgrades - E28,  Brake Upgrades - E34.  

See also:                              Rotor Warp - Prevention,  Brake Upgrade - Master Cylinder.  

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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 535 302mm 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:

E28 535 284mm x 10mm solid

E34 535 300mm x 10mm solid

E34 540 300mm x 20mm vented 

E34 M5 300mm x 20mm vented

E34 M5 328mm x 20mm vented from 6/94

    Unfortunately these don't work, but are here as a size reference

    E32 735 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 master cylinder 

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 E34 M5's and 

have the same brake reaction times as the M3 Lightweights, 

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.  

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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.

[pic]

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: : 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

>m6bigdog@

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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 master cylinder, calipers, 

and rotors, from the 735/750 E32 cars.  Straight bolt-on operation.  

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,

E30 M3'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)

[]=****=[]

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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: 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

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Date: Wed, 24 Feb 1999 

From: "Rodney Moore"

Subject: RE: 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

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Date: Thu, 25 Feb 1999

From: "Jake Steijn"

Subject: Re: 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

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Date: Thu, 25 Feb 1999

From: "Rob Levinson"

Subject: Re: M5 brake rotor options?

>From: "Curt Kiser"

>Subject: RE: 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

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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

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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

[pic]

Date: Thu, 25 Feb 1999

From: Jerry Chyo

Subject: Re: E28 M5 brakes

Rod wrote:

>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'm not sure I agree with this. Many have had very good results changing

to the E32 rotors, and the venting issue is real. Frank Fahey (of ///M

fame) has even developed a cover for the hats that effectively changes the

flow of air to do what the E32 rotors do.

>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!!

This is a great upgrade, albeit a little more expensive. It's harder to

find used E34 rear brake setups than you would think (there were only a few

K imported into the US). Do the regular E34's have vented rotors in the

back? Would this be another alternative? Something not mentioned is that

the fronts have 4 pistons and the rear have two. The E34 M5 calipers

pistons are pretty big compared to the stock E28 calipers. I would also

change the pads to Deluxe or Metal Master. They stop better than stock,

cost about the same and don't dust as much.

>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.

I can further comment on a full E34 M5 brake upgrade (at least the earlier

E34 M5's. The later ones had HUGE front rotors). This setup will stop you

on a dime. I have better brakes on my M5 (E34 M5 rotors & calipers w/Metal

Master pads) than my 6000 lb. Explorer. I feel very confident that I can

make any stop needed with this setup. It would probably be a great track

setup if I ever took this car out, although the cost of the rotors is a lot

higher (can you say TWICE what the E28 M5 rotors cost, and the E28 stuff is

a lot more than the E32 stuff).

Sorry for the length. Hope it's helpful though.

Jerry Chyo

'88 M5

'72 tii

[pic]

Date: Thu, 25 Feb 1999

From: Sherman Koo

Subject: Re: M5 brake rotor options?

------- Rodney Moore's email included: -------

>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.

Actually Rodney the problem with e28 M5's IS the front rotors. M5

rotors have holes in the hat to reduce weight. As stated by others,

these holes allow air to escape horizontally rather than flow through the

rotor. It has little to do with high-speed driving, brake bias, sweep

area... as others have guessed.

But I do agree that the rear brakes are undervalued. I have four piston

front calipers with 345 mm rotors on my M5. With the stock 284 mm rears,

the car stopped very well. But when I went to vented 300 mm, it stopped

absolutely flat; it was wonderful. So good that I'm hoping to install

328 mm rotors and calipers. 

Sherman Koo

______________________

Facilitecture (sm), Inc.

(510) 653-7151

[pic]

Date: Tue, 13 Apr 1999 

From: "Gilbert, Clark"

Subject: RE: E28 Brakes

Now we find that a host of brakes will fit onto an E28 with little or no

modification. The major variables then become rotor diameter, pad area, the

number of pistons in the caliper, and cost. Larger diameter gets more 

stopping leverage, but going from 284 mm dia to 302 mm dia increases the

lever arm by only 6%. More pistons look cool, but I don't know the effective

area of the setups, so I can't compare the reduction in pedal force required

for the same pad application pressure. Therefore, the E32 brakes get my vote

because of the larger swept area, especially if you factor in cost: used E32

calipers can be had for $75, used M5 or M6 4-piston calipers go for $500.

Clark

87 535is

[pic]

Date: Wed, 26 Jan 2000

From: Gary Bossert

Subject: [uuc] Re: Audi (warning, not a lot of BMW content)

Steve,

Snip...

>(6/99- SportAuto did a comparative test of stock vs Movit brakes on

>an Audi 1.8TT. They did consecutive high speed stops with each setup, cold

>and warm from 200km. With the stock brakes, the first stop from 200km/h

>yielded rotors temps of 417C front & 278C rear.....the Movit brakes were

>150C front & 97C rear. By the time they did the 5th stop from 200km/h, the

>stock rotors were at 600+C both front and rear with flames coming front the

>front hub assembly...testing was suspended. With the Movit brakes at the

>10th consecutive 200km/h stop, rotor temps were only 356C front & 169C

>rear. Now this really doesn't mean much here in the states as there's

>little chance these cars will be driven at drivers schools where you'd be

>doing this kind of high speed braking. It is significant in Germany.)

It's not even significant in Germany. Who makes consecutive stops from 

124mph time after time ANYWHERE?

Five stops from 124mph without a chance for any cool down time, you don't 

even have those extremes on the track (at least any track I've been to).

Big brake kits are great for the track but a total waste on the street 

unless the motive is to look cool. I've yet to see anyone use up stock 

brakes while out for a drive on public roads, if so, they should be locked up.

The brakes on both my '95 M3 and my S4 are both fantastic on the street 

with the edge going to the S4's twin piston 4 pad units. They are fantastic.

On the track I'm sure they both need upgrading with Pads at a minimum and 

possibly a big brake kit to get the last little bit of performance.

Snip...

Gary Bossert

Many BMW's a few Audi's

[pic]

Brake Upgrade - E34

Date: Tue, 26 Sep 2000

From: "ra rabmw"

Subject: Re: [uuc] Calling the big brake experts....

Felix;

Based on Rob L's experience with E39 brakes for E34's,try this:

On my E34 535i, I had original size rotors gas slotted in a race shop 

(NOT bought from someone who may know how, but someone who did), 

added  super blue fluid, and installed a street/track carbon-kevlar pad set. (or use similar)

My car out-braked 540's at NHIS, and was the only 5 series, up thru E34 

M5's, of any year, that had the same brake reaction times as the M3 

Lightwieghts at O'fest '96 trials run by The Car Guys there.

It also outdid the M3's at the April '97 Instructor's school run down 

here at Moroso Park.

You don't need E39 brakes on your sister's car.

o/______\o "RA"/Bob G.

(Oo=00=oO)

[]=****=[]

  ( Note:  This may not be suitable for the street due to the pads not

               working well until they've had enough time to warm up.  Ed. )

[pic]

Date: Mon, 3 Jul 2000

From: "Rob Levinson - UUC Motorwerks"

Subject: [uuc] dammit - big brake conversion didn't work.

As some of you may know, I have a brake upgrade fetish:

my '85 535i Turbo got E32 750 front brakes.

my '88 M5 Turbo has 850CSi brakes front, E34 540i brakes rear.

my '90 Miata (stop laughing) has larger '95 front brakes.

I wanted something more interesting for my '94 M5 Touring (stock front brakes are 315mm,

single piston). The opportunity presented itself and I acquired a set of front brakes

from the 2000 E39 M5. These use 345mm rotors (same size as the '94-'95 M5 Nurburgring

brakes) and larger single-piston calipers.

As apparently all BMW "big car" brakes since 1982 (E24, E28, E31, E32, E34) are

interchangeable, I bet that there was a good chance these E39 brakes would also.

Today was the day I was going to fit them. Took one side of the E34 apart and compared

the parts. It was immediately apparent there were minor differences and fitment brought

to light major differences. BMW has deliberately made no part of the E39 brakes

retrofittable. Bastards!

Differences:

1) Hex-head screw that holds rotor to hub is in different spot.

2) E34 rotors have two large holes with corresponding posts on hub - E39 does not have

holes so rotor cannot sit against hub.

* Normally #1 and #2 would not be a problem as correct 345mm E34 rotors could be

substituted. BUT...

3) caliper carrier holes for bolts that hold it to back of hub are about 2mm further

apart. No chance of getting it to fit.

So the search continues for big brakes. Hmmm, doesn't the E38 7-series use 340mm rotors?

Anybody got a spare set of E38 brakes I could try?

Rob Levinson

'94 M5 Touring

'88 M5 Turbo

[pic]

Date: Mon, 3 Jul 2000

From: "Rodney Moore"

Subject: RE: [uuc] dammit - big brake conversion didn't work.

Rob,

The E-38, 740 has 324x30mm rotor w/single piston floating caliper front,

324x12mm solid rear rotors and the 750 has 334x32mm rotor w/2 piston

floating caliper front, 328x20mm vented rear rotors.

Not only that the calipers on the E38 & E-39 mount rear of the strut.

Previous models have the calipers mounted in front of the struts. This

would cause the E-38 & E-39 caliper bleed and flex-line holes to be on the

wrong end of the calipers for the early model application. Also, if the 4

piston calipers have small lead pistons (common on fixed 4 piston calipers)

they can not be swapped left to right because then the lead pistons will be

the bigger ones and that will cause the pads to wear at a taper.

Maybe BMW anticipated the up-graders and made the mounting changes to

prevent an inappropriate use of these parts on the earlier models?

Rod...

[pic]

Date: Wed, 05 Jul 2000

From: "ra rabmw"

Subject: Re: [uuc] Re: big brake conversion - too much brakes?

I don't know, guys...Spending a lot of time with E28's, most driven 

very hard need the 7 series update to work well, but the E34 cars start with 

a far better system, not far off the E32 brakes added to the E28's.  I have 

found in 80% of the cases, just gas-slotting the harder rotors and better 

pads is plenty of brakes for most hard E34 drivers.

Of course, that doesn't apply to Rob, myself, or similar 

fanatics, who continually will try for 110% of a car's limit's in all 

categories. Still, my E34 535i would run The Glen for three days, and NHIS for 

two, never running out of brakes set that way (track pads for schools) at even 

my lead-footed braking maneuvers.  And I only use the PBR Deluxe pads for the 

street.

o/______\o "RA"/Bob G.

(Oo=00=oO)

[]=****=[]

[pic]

From: "Steve D'Gerolamo"

Date: Wed, 30 Jul 1997

Subject: E34 Brake Upgrade

>From: "Jeffrey R. Taylor"

>Date: Tue, 29 Jul 1997

>Subject: E34 Brake Upgrade

>

>Hi all

>

> It is getting about that time where I need to replace my brake pads and

>turn the calipers. I am considering upgrading my braking system while I

>was at it. I called Dinan, but the only upgrade they had available was a

>complete replacement of the entire system to the tune of about $5k.

>

> I decided that is definitely not the way I want to go. I was looking in

>the Bavarian Autosports catalog and they have some cross drilled rotors

>that will evidently fit my car. They say for off-road use only, which

>doesn't seem like it would matter. I suppose I should just be happy with

>what I have (which is actually pretty darn good).

>

> Does anyone have any experience with this, or any suggestions?

I'm in the process of upgrading the brakes on my wife's 89 535i with new 

front & rear 750i calipers and rotors. This will give the same braking as the 

540i (E34)...the booster and brake m/cyl are no larger in the 8-cyl car. 

Not only are the rotors thicker but the piston diameters are larger in the 

750i/540i calipers. The rotors are also vented in the rear. Appears to be a 

direct bolt on (you will need to buy the braker carriers as well). I'll follow-up 

with a racap of all of the parts, tools and fasteners needed to do the job once 

I've gone through the installation. SD

(BTW...I'd avoid the cross drilled rotors. They do not offer any significant 

performance improvement, mainly cosmetic appeal. The ATE slotted rotors 

would probably be just as effective at removing gases as the more expensive 

drilled rotors.) 

Steve D'Gerolamo 

The Ultimate Garage, 

Emerson, NJ Tel 201-262-0412



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