The BMW Brake FAQ

22 Mar 2015 | Author: | Comments Off on The BMW Brake FAQ


If you asked me what I most about the BMWs I there is no doubt that I answer the brakes. The brakes are the reason I own my cars, one of the reasons I sell the cars, and the most safety system in my car. BMW have helped me stay

That’s not bad for a system that was some time in the late

This article discusses aspects of the brakes in your BMW. It was known as the E28 Brakes FAQ, the 1982-88 5-series. All of the information relates to the E28. However, of it also applies to all the other BMW

While each model somewhat different suspension and brake technologies, the design are the same – to provide a and responsive suspension with brakes.

Most of the information is directed to owners that are in learning more about car’s brakes. If you are using BMW like a conventional automotive this FAQ is for you. If you are using BMW at the racetrack (BMW CCA driver schools, for you may require further suspension and more advanced solutions to problems due to the additional stresses you on your car.

But start so that you can rule out the obvious spots.

Due to changes in the laws what materials may be used in pads, brake technology has Nonetheless, BMW owners (and of every other make and have discovered that advanced brakes can be considered to a double-edged sword. They beautifully. However, the rotors can and cause the steering wheel to

If you want to avoid repeat your mechanic to resolve brake problems, read FAQ. I believe it is the most information, to date, regarding BMW If you find anything in this FAQ is incorrect or misleading, I would it if you would contact me so that I can this article.

My knowledge of the E28 from about ownership of one E28 since 1988 that, had nearly 320k miles being prepared as a dedicated ice and ownership of a 1987 E28 since Both eta engines. I am a do-it-yourselfer, and my is from driving and working on cars, and from the advice of outstanding BMW CCA friends.

If you have updates, or any additional information you feel can improve this please send e-mail. If you to reproduce any part of this all I ask is that you get my permission first, and mail me a copy of your where my FAQ appears to the address at the end of page.

FAQ Questions

The 82-88 as well as the E34 and E39 5-series and the E30,E36, and E46 while popular cars BMW people, all have the reputation for a shimmy upon braking. shimmy becomes more over time and mileage. are many proposed solutions, but no one BMW AG has spent the research dollars and to figure out the best solution, and in my they have found it.

has been some conflicting on the Internet and amongst some parts suppliers about the solution. The intent of this FAQ is to up some of these questions.

In a why does the front end shimmy braking?

This is a two-part first . these cars’ was intentionally designed to be responsive and unlike large American which allow heavy to rest on the front wheels. As a suspension, it is more prone to vibrations through the steering In the 3-series and 5-series, these are caused by deteriorating components in the

As these various components the evidence of their wear apparent through vibrations in the wheel most noticeably braking, and particularly between mph (80-105kph). Second . the other of the problem rests with the used in the brake pads and how it with the rotors. In the mid-80’s, was outlawed in the USA.

After the of that era had already been and produced, BMW had to search for a semi-metallic pad for parts (scheduled maintenance), they couldn’t sell the pads once the asbestos law into effect. The asbestos were originally selected they were able to acceptable levels of heat, it was much more difficult to similar specifications with pads.

In time, the additional generated caused the rotors to During this period, BMW many updates. They a number of rotor and pad manufacturers, Textar and Jurid.

They did until they felt got the proper pad-rotor combination. It was common for dealerships to replace set set of warped rotors and ruined in some customers’ cars can fish for an answer, too). The were often replaced under the 12-month parts

Unfortunately, although this was known while the E34 and E36 were in development, these cars the same problem to a lesser The E46 and E39 have been reported to the same susceptibility to shimmies, but the suspension components are stronger older models. Again, brakes with new ones solve the problem (for too unless the suspension is in good

What parts should be

If you experience the symptoms mentioned your rotors are most warped. If you get the shakes at different speeds even prior to you definitely have one or more suspension components. Whether or not need to replace suspension is a question based on the car’s age, and mileage. You should not replace the brake components examining the rest of the suspension.

It is to need additional suspension in addition to the brakes, particularly on with over 100k

Replace all four rotors and with stock pads. a dealer. They’re relatively ( cheaper than American and cars!!). So do all four.

ALL FOUR . The is so bloody easy that you be sorry. Besides, after you do it, and insured the rest of the suspension is you’ll be really happy.

All service bulletins from BMW on replacement recommend replacing and rear rotors as well as when servicing brakes.

Replacement Parts list:

pads (1 set – usually 506EE for older E28s)

pads (set)

Factory rotors x 4

Front left sensor

Rear right sensor

Hex key screws x 4 (provide of your BMW mfg.)

1-2 quarts fluid (per mfg.

As I said, the brake job is quite At this point, I don’t see a to go into excruciating detail the procedure for replacing brakes, because the Bentley, as well as the BMW manual, are very clear on

Why can’t I simply turn the

Warped rotors cannot be (cut). The excessive heat has caused the rotors to warp the composition of the metal so that cannot be cut properly, and the problem virtually immediately. New rotors a BMW dealer, with a BMW CCA discount, are so particularly on the older BMWs, it is economically foolish to turn old

Another comment on turning – when you buy new rotors BMW, they have a on the brake surfaces. Clean before installation. Take brake cleaner and clean off surfaces of the rotor (where the make contact).

Then, assembly, don’t touch the with your greasy

I’m trying to get the old rotors and I’m afraid of stripping the hex key holds them on. What I do?

Whatever you do, don’t strip the hex key that holds the rotor to the Use a fine dentist-type tool to out the vertices of the hex key, so that a hex can be completely inserted into the Give it a shot of Wurth fluid if you’ve got it. Then (I do before I remove ANYTHING with someone pressing the (or handbrake, if rear), apply a torque to the screw.

These shouldn’t be too tight, although and corrosion can make it more If you strip it, get the easy-outs. I have removed these screws easy-outs.

It requires patience. drill out the head of the screw and the rotor. If all else fails, a (seriously) can be used. One or two whacks to the of the rotor (be careful not to hit anything will, in fact, remove it.

it is only a set screw. The wheel firmly attach the rotor to the

Is there some trick to the rear rotors on a BMW?

On the rear the inside of the rotors act as a drum for the brake shoes. You must the emergency brake so that the back away from the walls of the rotor. Loosen the brake, left and right by loosening both nuts at the brake handle. Further, the brake’s internal adjusting are accessible through the lug holes in the

Then remove the rear

Should I flush the brakes?

You ALWAYS be flushing the brakes per year. Read your owner’s manual for manufacturer And check out the article, Bleeding BMW’s Brakes, and Fabricating a Bleeder Pressure Kit for more on how to build your own brake

Can I use a pressure bleeder to flush the

In most cases, you can. In models, you have to. A couple CCA members have developed a grown tool for this since so many commercially bleeders are inadequate to the task.

the article mentioned in the last

Any other nebula to consider, Mr.

Yes, I’m glad you Make sure you torque the to 85 ft-lbs. No more, no less. it or not, this torque insures the proper heat between the brakes and the wheels.

means every time you get new every time you have the rotated, every time you put on the make sure the monkeys at the shop use a torque wrench to put on the lug not an airgun.

I replaced the rotors and with the OEM stuff you suggested. only 5k later, and they’re again. Why??

This is a sign that you find the root cause of the Yet. Assuming that warped in less than 1 and you got them from a dealer, the are under warranty. You can replace for free.

But you have to examine the components in the suspension, one by one. one must examine each each tie-rod assembly, and the Bushings should be checked for cracks; specifically look at the control arm bushings and thrust arm These can be disconnected in order to them.

Tie-rod assemblies, rod, and idler arm (in the E28) be checked for play, and can be checked by Ball joints (in lower arm or thrust arm) can be checked by the test, usually, and should be checked for visible signs of deterioration. Shock diagnosis is since the bounce-test is useless.

the type of driving and mileage be considered, as well as how tires how well the car tracks at high and how much the car leans on cornering. My E28 lasted with shocks 150k, my newer one seems to them after only Finally, a four-wheel alignment be performed so that the rear alignment can be measured (there are no here) and the front wheel can be measured and adjusted.

In my older the front strut bearings a serious culprit, in addition to the This made sense, worn-out strut bearings are not to properly hold the strut in upon braking, and the result was a of BADLY shaking strut

One other thing – forget that your and tires are also suspension and MAJOR ones. I have both the stock 14 rims and 15 rims. Some have +2 and even +3 sizes. The difference in feel between 16 and 18 wheels is and unless you live in a part of the with perfectly smooth may find that larger can exacerbate brake problems. must not be dented or out-of-round.

The is true for tires. I have worn tires make a car like it was on its last leg. You may to purchase new tires to fix brake but that’s the subject of another

Whatever you do, don’t be a cheapskate considering tires. A poor may cost you a lot more money the road.

I consider this to be others say it’s subjective, so disclaimers apply. First, the CCA discount, the price can’t be Second, all parts (excepts and brake pads) come a 12-month, unlimited mileage As long as you have a valid from a dealer, they allow you to replace warped – for those do-it-yourselfers, the cost is your time to do the You should not take advantage of policy, but use it when necessary.

I check with the dealer, at the of purchase, what procedure use to replace rotors under BMW policy requires dealers to them for you even if you bought at another dealer, but some will give you a hard so don’t count on their One year I went through 4 of rotors until I isolated the suspension part that was the problem (see previous

I have known the service of some dealerships to have experiences. Since I posted the version of the FAQ, I confirmed Eurasian can also get the Jurid at reasonably competitive prices as to BMW dealers (with a 20-30% CCA I would ask specifically for the model pads.

Also, see the next question for a of stock vs. aftermarket rotors.

what’s the difference between the rotors and the same rotors an aftermarket?

Well, aside the warranty, which is important, the rotors are spin-balanced at BMW after the OEM (Brembo, Ate, Balo, ships them to BMW. manufacturers claim to spin their rotors, but they may use reliable clip-on or glue-on whereas BMW shaves metal off the to achieve the proper balance.

My is that from a reputable BMW with an aggressive parts you can buy rotors CHEAPER from the The aftermarket dealers that in Roundel have been, in case, MORE expensive (to my as well), and there is rarely a with their products.

OK, now replacing suspension parts. Do bushings help?

Not really, you are planning to modify the springs, and sway bars. Some have claimed to use the 750iL successfully, but my feeling is that the in its stock form, wasn’t to run with these, and these bushings will put more on the rest of the suspension, which not designed to work with Also, on the later E28 models some have claimed only the 750iL bushings work.

I am still investigating

Needless to say, any new bushings help, if your existing are worn. The stock bushings are cheap – the labor is unless you can remove the ball without damaging it, and have a to carefully press out the old bushings and in the new.

OK, I’m using the pads and I’m happy. But the pads generate a lot of brake Can I use dust shields?

General has been that using shields are the WORST thing you can do for the of your suspension. While do appear to keep the dust off of the some people have that the heat from isn’t dissipated properly, and have empirical data of fast rotor warpage their use. More use of a good wheel cleaner is the solution.

I happen to prefer due to its overall excellent design and (it won’t kill your it won’t ruin your it won’t destroy your Admittedly, it requires a bit of elbow-grease. like Zymol Wax, the speak for themselves.

There has some speculation about the side effects of Armor QuickSilver wheel cleaner, but I know much about except to say that anything should not be sprayed near any components. Period.

What cross-drilled rotors?

If you’re driving schools monthly, probably in a different realm of pad/rotor/fluid than most of us. possibly using Cool pads, and maybe even brake fluid. In this cross-drilled rotors may make for you to dissipate gases and to prevent fade. You might even air ducts to provide extra to the brakes.

But if you’re not pushing the with this type of cross-drilled rotors are a waste of Better spend it on some school to learn how to drive. also seen some of stress fractures developing in rotors that eventually the brake pads.

I don’t if the manufacturers of these parts know what they’re

Speaking of driving habits, can my habits cause my brakes to

This is a tough question, I have some firm here, which all may not agree I don’t believe in automatic because I believe they much car control to mechanisms don’t have eyes. I that with automatics, one use the brakes much more since they have control over the drivetrain.

people claim that with the engine (ie. is wrong because brakes are to replace than a clutch. one of my E28s had gone 220k before requiring clutch and I downshift all the time. Some claim brakes are cheaper to than a clutch, and while may be true, it’s a safety I’d much rather a clutch than play with my front suspension.

worn suspension parts can be an frustrating, iterative process.

My is that you shouldn’t ride the You should be aware of your so that you don’t use the brakes you need to. That may sound but if you think about it, and practice it you drive, you can drive smoothly and your brakes for when you need them. Short, braking, combined with allows far more cooling riding the brakes for a hundred before a stoplight, tollbooth,

Your brakes need the to cool. I also don’t sit my foot firmly on the floor at a pressing the pads against hot but this probably isn’t an on an automatic.

Can I attend driving at a race track with a or will it warp my brakes?

The to this is completely subjective. My would be yes, but to be fair, the on your car during a school are high, so you shouldn’t complain things break. As Richard W. schools do wonders at exposing in your car.

You can surely rotor warpage during a day of driving at a school.

Are BMWs the cars that warp

No. In fact, due to asbestos being by the US government, all cars now use non-asbestos One reason that this as much of a problem with cars is that they … long before the warped. On my old E28, they after 130k miles. reason is that these cars are designed to provide soft rides, which means very heavy suspensions, which masked out vibrations until the vibrations quite serious.

Now, CabForward designs and more suspensions, I commonly hear those new Chryslers warping in only 25k miles of driving!

are you this … retentive all your automotive repairs?


In my E28 M5 the factory replaced the front with 750 hydraulic bushings. the larger wheels and tires are stock on the M5 (225/50/16ZR tires), is the only thing which the shimmy from recurring 8k miles (on a new car, with worn).

There is available a stainless steel hub cover, redirects air flow, and GREATLY the incidence of rotor warpage. can be obtained from Carl at CNPR 1-800-466-8184.

For track if you wish to engage in spirited and do not want warped rotors, Carbon Pads are a MUST, They are the only way I have the problem. At a BMWACA drivers at Laguna Seca, the Instructor me why my rotors weren’t warped, as all the E28 M5’s he had been that day

For the answer, see above.

Front Upgrade Kit Addendum, courtesy of Magee :

The stock E28 brakes are They even stood up to use at Sears Point. However, are entirely inadequate for track use at Seca (Laguna has a tremendous of elevation change.

Turns 2, 5, 8, 10, and 11 a significant amount of braking four hot laps can cook the brakes).

I went with a front brake upgrade It uses 850i rotors and but not the same calipers. I believe the calipers are two piston, whereas the calipers have one piston (I have heard that no longer sells the kit I have, but has it with two other kits).

I recommend this setup. pads, crossdrilling rotors, gave less improvement, greater side effects track pads are often on the street and may not work well at low the cross drilled rotors very quickly).

I also stainless steel braided hoses, which improve feel. And I installed air ducts a company called Berlinetta. ducts are specific to the E28 M5 air dam (shared by the iS) and to provide an extra measure of *Fresh* brake fluid a high boiling point a big difference.

The brake upgrade a wheel upgrade. The stock TRX do not accommodate the big brakes (besides, TRX are lousy). The original M5 wheels 20 mm offset) fit.

850i (16×7.5 10 mm offset) fit. But require trimming or bending the inside lip of the rear fender factory trimmed the M5 fender; body shop recommended because it leaves all the metal in The tire to use is 225/50 16 . This is exactly the same diameter as the tire (BTW, the Tire catalog has some useful information, including a formulas for diameter, wheel offset,

Other 16 wheels may or may NOT fit the Dinan I highly recommend a test fit any oversized brakes. The wheel is very critical with the E28 More than 20 mm means against the front strut.

than 10 mm means rubbing the rear fender (the numbers change with width; consult the Tire catalog for formulas). The opening the rim is critical also. The distance the Dinan brake caliper to an M5 is on the order of 1 mm.

Dinan sells big for the E28 chassis. I think they are and can be fitted with 235/45 17 (if I correctly). These wheels are pricey, and require spacers in the (to keep the wheel away the strut) and fender adjustment in the

I chose not to go for that size 16 tires are cheaper and more For example, I don’t believe the A008 is available in 17.

A word of about wide tires. The ball steering in the E28 is famous for on center. A sloppy front end to wear of ball joints, tie rod etc.) combined with wide tires will matters significantly worse.

told me that E28 M5 brakes can be on a regular E28. I have not this. I do know that the strut [inserts] are different, so I was that this is a bolt on

1997, 2002, 2004 Steven J. Bernstein All rights

Comments to:

Steven Jay

updated Monday, 23 February 2:23:11

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