tires and wheels '02 Brake Performance

[Teko1]

Recently replaced master cylinder on my '75 2002.  Also completely rebuilt rear drum brakes with new wheel cylinders and replaced front disk pads.  I've owned it for two years now.  It's the only one I've ever driven so I don't have a feel for how strong the stock brakes should be, but hard braking won't lock up the wheels.  Other cars I've owned w/o anti-lock systems would do so.  Not that I want or intend to regularly skid to a stop, but it seems that they should be able to so that you can get the most out of them.  Does this just indicate the typical performance of the stock system or have I not done a proper system bleed?  Work was done at the wheels first, which did show a decent amount of air removed during the bleed process.  The master cylinder bleed went well but didn't seem like it trapped a lot of air,  Looking for some input from the experienced '02 drivers out there.  If this is the stock performance, I can understand the reasoning behind the upgrades and why the TII had beefier systems.

 

Thanks!

[ray_]

Hmm, well...

 

How's the pedal feel? Is it going to the floor or?

 

What pads did you use? How sticky are your tires?

 

You should be able to lock them.

 

Cheers,

[Roland]

I agree about being able to lock the brakes.  I have both stock and upgraded brakes, and both are relatively easy to lock up in a panic stop

 

The advantage of most upgrades is the ability to better tolerate repeated hard use of the brakes -  without failure.  It provides an extra margin of safety for cars that handle harder use,  and higher speeds as well a potential competitive advantage in racing situations.  You didn't describe what pads you are using.  Certain friction compounds are not particularly effective when cold. Other softer compounds tend to work best when "relatively" cool but can be prone to fading when overheated.  Glazed and/or contaminated pads and rotors tend not to perform well.  While you may not have any issues with them, older rubber flex brake lines may hold pressure, but may also expand in the process providing a softer pedal feel.  This should not prevent you from locking the brakes in a panic situation, but just how old are your's?  Original hoses often carried a printed/embossed date or a band with a date.

 

hth

 

[TobyB]

 

You didn't describe what pads you are using

 

This right here.  Search around the site using the Google thingy- there are a lot of good recommendations for a good street

pad out there.

 

Most of what you get over the counter for the 2002 anymore isn't very good...

 

t

[m20powered1600]

Is your brake booster working? My booster wasnt/isnt really working because my vacuum line from my booster to my intake manifold was crimped close, so i bought a new emmisions hose and stuck it on....and my brakes still wont lock up on me either. I haven't tried the test again.. but ill try tomorrow

Try to see if you booster works or not. You can look it up on you tube. its very easy. Just type in brake booster test or something on the lines of that.

 

hope this helps

[Mike Self]

Josh--when you replaced the hose that runs from the manifold to your brake booster, I hope you used the specified factory hose--it's very stiff and steel-reinforced for a reason.  If you use "ordinary" hose (like vacuum or heater hose), the vacuum created by the engine will cause the hose to collapse, thus rendering your power brake booster ineffective.  Also, did you insure that the check valve was reinstalled correctly?  There's only one way it goes; install backwards and the booster won't work either.  

 

As an aside, if the hose between the check valve and the manifold cracks, replace with the same part from an E21 320i.  The 320 part has a  molded-in angle so it isn't constantly under stress like the straight hose used on the 2002.

 

cheers

mike

 

PS--neither of my '02s will easily lock up the brakes--and they've always been that way.  But they both stop just fine.  Good high pedal and equally good pedal feel.

[Roland]

If you want to get hyper-technical about your brakes, consider reading the shop manual which provides for several tests involving brake pressure and performance.  Being somewhat more pragmatic, I recall a friend who mentioned her '60s sports car (equipped with power brakes) had "bad" brakes because she was unable to lock the wheels as she easily could in her 68 Cadillac and other older US cars she drove.  I found nothing wrong with the car's stopping power, except that maybe it required a little more pedal effort than the typical full sized US cars of the period.  When she complained that the wheels wouldn't lock, I asked her if she was absolutely sure and slammed the pedal.  The wheels locked and produced tire smoke and four skid marks.  Most of us prefer to baby our vehicles and this typically prevents us from knowing the vehicle's true potential.  My 02s have tended to have sensitive brakes that are probably too easy to modulate and lock up.  I also have owned much older non-power brake equipped cars that required so much pedal effort that you might think the pedal could be torn from its mounts.  Nevertheless, the wheels could be locked when necessary.

 

The subject of pads and various friction compounds has been mentioned several times on this forum.  Same with "bedding" in new pads with new rotors.  Not all pads require the same bedding process to ensure good braking, but maybe yours do?

 

 

 

 

 

 

[peterschop]

Don't forget that your peak braking performance is right before they lock.

[M3M3]

stock 02 brake system is fully capable of locking the wheels.  even with sticky race tires.

[Teko1]

Thanks for all the great information.  Brake linings are all stock replacements (from BavAuto, I think), not sure of the compound.  The pedal feels firm and doesn't go to the floor.  I agree, Roland, about knowing a car's full potential and that is what led me to ask the question.  I've applied that to every car I've owned, however, your other comment about babying it may apply to this car for some illogical reason.  I'll take all the comments and investigate further.

 

Thanks!