Brass caliper guides? What is wrong with the stock ones? I think at some point we have all run across these little things on our favorite BMW aftermarket website. Have you skimmed over them? Have you wondered what they were? Well in all honesty, you probably should skip right over them...unless you track your car!
The solid brass caliper guide kit eliminates the caliper from twisting under hard braking from the rubber guide pin bushings in the stock caliper. The new guides will replace the mushy (most likely worn out) rubber bushing (BMW PN# 34111157038.) The precision machined brass guides allow your calipers to squeeze evenly on both sides of the brake rotor. This emulates the more expensive multi piston big brake kits. So, what are the results of all this? You will see a significantly longer brake pad life and more consistent brake pedal feel.
So why did I tell you in the beginning you should skip right over this unless you have a track car? Easy. Most people in street applications will not ever be braking hard enough to get the same amount of deflection that is seen with track driving. Moreover, the brass caliper guides require attention. At least once or twice a year, you will be required to remove the caliper pins from the brass guides and re-lube them with high temperature ceramic brake lubricant. This is because the original design was a floating pin with a rubber bushing. The brass guides are machined to a very tight tolerance. If the guide pins are not lubed regularly, then friction will build on the pins and the caliper could seize up.
Sounds like a hassle huh? Well it kind of is, which is why I would not recommend this mod for a street application. We track our e30 a lot, and this modification has proven to be very beneficial. Although brake pedal feel does feel slightly better, the main advantage of this system is even brake pad wear. Our track pads are not cheap, ranging from $100-$400 for two wheels. The more life I can achieve from the pads the better.
Build It. Race It.
**Note: These brass caliper guides will only work on ATE branded calipers. These will not fit the girling calipers found the front brakes of most e30s. Although, some e30s did come with ATE front calipers and is a very common upgrade in the SPECE30 community. These brass guides will also fit more than e30s. The following models will be applicable. E30, E23, E24, E28, E36, E46, E31, E32, E38, E39, E52, E53, E61, E62, E63, E64, E92, Z3, Z4. Please contact the manufacturer to verify if these will fit your car before purchasing.
Please enjoy the installation pictures below. Be careful when installing. Because of the tight tolerance of these bushings, your calipers should be very clean, with no nicks or burs to prevent the bushing from sliding in. Use ceramic high temperature brake lubricant when installing the caliper guide and pin. BE CAREFUL NOT USE ANYTHING STEEL TO POUND THE BUSHINGS IN. THESE ARE BRASS AND VERY SOFT. I WOULD RECOMMEND A BRASS OR PLASTIC PUNCH TO HAMMER IN. USING STEEL PUNCHES OR PLIERS COULD RESULT IN THE BUSHING BEING DEFORMED, WHICH WOULD RUIN THE TIGHT TOLERANCES OF THE BUSHING.