The "big brakes" upgrade is probably the most-frequently asked question when it comes to upgrading an '02 for high-performance driving. In fact "big brakes" is really a misnomer because what we are really after here isn't necessarily a larger diameter brake rotor (although these upgrades below do give you a marginally larger rotor), but in fact rotors that are vented for better cooling.
Braking systems are basically heatsinks that suck kinetic energy out of a bunch of flying metal, plastic and glass, and convert it into heat: depositing it in the brake rotor itself. Then the rotor is supposed to shed it into the rushing, cool night air... Vented brakes simply allow this process to take place with more efficiency, in addition to having a higher basic mass which will by itself soak up more heat without failing.
Which option you choose to get your vented brakes will depend mostly on where you are starting. For tii owners, the best option is to use the brakes from the e12 early 5-series sedan or e24 6-series coupe. They will fit on the stock tii spindles and require no other modification of the car.
For non-tii '02s, really there are two major options. One is to go with all-BMW parts and buy a set of tii front struts. Then use the parts from an e12 sedan or e24 coupe as stated above. The other option is to just use the Girling Vented calipers from a mid-80s Volvo 240, and the rest of the parts from the e21 320i. This will save you some money if you are starting with a "regular" '02, and provide braking on par with the pure-BMW solution above.
Please note that Rob Torres, Jr. of 2002 Haus recommends the use of tii struts with their the larger spindles if you are running large-diameter (15"+) wheels, or else you will chew up wheel bearings at a rapid rate! Thanks to Rob for the tip!
Other options involve using racing brakes from people like Wildwood and the like. If you are considering operating at this level, the best advice is to find a vendor who will work with you to get the product installed on your car. Some vendors also sell other higher-end braking solutions such as lightweight aluminum calipers, and these kits will come with everything you need to adapt them to your car.
Because we are only worried about the DIY-type stuff at this point, here are the details for low-buck, big-bang brake upgrades:
Parts Required for tii upgrade:
- New 1977 e21 Vented rotors
- Used e21 hubs up through 1979 (junkyard)
- New or Used e12/e24 up through 1981 calipers (I'd just buy already-rebuilt ones but you could get good used ones or rebuildable ones from a junkyard for less $$)
- New brake hoses (unless yours are less than five years old, you might as well refresh/upgrade while its apart. Braided stainless ones will give you the best performance.)
- New wheel bearings
- Wheel bearing grease
- New performance brake pads
- Two pints of new brake fluid (might want to get a pressure bleeder too)
- If you are upgrading to the "pure-BMW" solution from a standard '02, then you will obviously also need a set of tii struts in addition to the above.
Parts Required for non-tii upgrade:
- New 1977(only) e21 Vented rotors
- Used 1981-83 e21 Hubs (just get these from a junkyard: dont buy new like I did... ;p)
- New or Used Girling Vented Calipers for a mid-80s Volvo 240 with VENTED brakes. (There are rumors of ATE Vented calipers also being available but the Girlings are far more available and that is probably for a good reason.)
- New brake hoses (unless yours are less than five years old, you might as well refresh/upgrade while its apart. Braided stainless ones will give you the best performance.)
- New wheel bearings
- Wheel bearing grease
- New performance brake pads
- Two pints of new brake fluid (might want to get a pressure bleeder too)
- Four 1" standard galvanized or stainless steel (why not, right?) washers
Be aware that certain 13" wheels will NOT fit over these upgraded calipers. In some circumstances, you can do a little grinding on the outside of the caliper to get them to fit, but you will need to start with a wheel with a good deal of offset amd should be as wide open inside as possible.
Project:
SAFELY raise the car and put it on jackstands. All the standard disclaimers apply. I don't want to get the FAQ sued because some e46 clownie wandered in here and decided to try this. (;p)
Basically, make sure the wheels are chocked behind them, its in gear, the e-brake is on (and working!), and your teeth are gritted. Put a floor jack under the middle of the front subframe with a block of wood between jack and subframe to protect and spread load. Raise the car and then put jackstands under the frame rails that are welded to the front floors. Again use some wood to buffer the stands and spread the load some.
Remove the road wheels, then remove the old brake lines and calipers. Theres not much to this, just some angry grunting with the aforementioned gritted teeth and possibly some flagrant cussing. Its also messy work, and you will need to drain the brake fluid, so get a pan or bucket too. Once you have the caliper removed, and the old brake lines (this part can be a nightmare in itself! Get out the vice grips and rhyming dictionary!), remove the cotter pin and big wheel nut, and then the old rotors and hubs (as a unit). Again, this is just dirty, messy but straightforward work.
Next is to clean the spindles, and inspect them for wear. IF you have a non-tii car and find that your spindles are shot/worn/etc., THIS might be a good time to think about upgrading to a tii strut-based setup (you didnt already order all the Volvo parts, did you!? - just something to think about before indeed placing that order.) If you have used hubs, you have to remove the old seals and bearings and clean them up. I bought new hubs like an idiot, which I immediately got filthy just by handling them. But, CLEAN them up so that you can put in the new clean bearings and grease.
Pack the new bearings with grease. If you've never done this before, the `word "pack" pretty much covers it. Do not OVERpack them because this will interfere with torquing down the main wheel nut. You will want to retighten the main wheel nut in 100 miles anyway, and you can put a wrench on the main wheel nut to give it a good squish, then back off and tighten the nut as described a little more below.
Install the new bearings into the hub and install the new seal with a flat piece of wood. As I recall, the seals go in flush with the edge of the hub, but I'm not totally sure about that. Then install the hub onto the spindle. Put the outer bearing, washer, and nut on, then spin the hub and finger tighten the big wheel nut until the hub stops. Then back it off a smidge and then put in the cotter pin. Make sure there is veryvery little to no play in the assembly when you rack it up and down, and that it also spins freely when you spin it with your hand.
Put the new rotor on, and then slide the new (rebuilt, etc.) caliper over it with the new brake pads installed. Make sure that the bleeder nipples are facing up, otherwise the system will be impossible to bleed correctly. Next install your new hoses. Some of you Volvo upgraders might want to think about using a tii or for tii people, an e28 master cylinder at this point too. The theory is that a larger set of calipers will require more volume of fluid to move the pistons a given distance. If you have a larger master, this will supply that additional flow. In my case, I used a 528 master cylinder. Im not exactly sure what the deal is with the rear proportioning systems in these various MCs, but since I am going to use rear discs eventually, I havent let it keep me up nights yet. Most people, however, simply choose to use the rear brakes from a 320i.
Once you have the rear brakes sorted, then bleed the brakes. Start from the passenger rear, drivers rear, then pass front, then drivers front. Make sure you flush all the old fluid out of the system. Some like to use a different-colored fluid each time they change it so they can tell when the old stuff is gone and the new stuff has taken its place. IF you do this, just make sure the two fluids are compatible chemically or else you can have a bunch of new problems on your hands.
Once you've got it all back together, it usually takes about 500 miles for the brakes to fully "seat," so don't go out and "test" them right away (oh, officer! see, i just got this new carburetor and i was just trying to test it..... ;p). Other than that, enjoy the new stopping power!
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