Wednesday, August 3, 2016

Brake Preventative Maintenance and Caliper Rebuilding

It goes without saying that the brakes are probably the most important system in your car, but often times they seem to receive little attention (until they do not work of course!). Most people know that fresh fluid is always a good idea but often times we pull fluid from brake systems that looks like this.
Brake fluid is hygroscopic, meaning that it absorbs moisture from the air. This moisture combined with repeated heating and cooling cycles breaks down the fluid. This contaminated fluid will boil much sooner than fresh fluid and also tends to eat away at the brake system components. We recommend bleeding your brakes before every track event and doing a complete flush at least once a year Motul RBF600 is our favorite fluid and Torque RT700 is recommended for those who see extreme brake fluid temperatures.

In addition to keeping your fluid fresh, it is also necessary to realize how old some of your brake components are. Most critical are any bits made of rubber or synthetic rubbers like your stock brake lines and caliper seals. With most Lotus Elise/Exiges now at over 10 years old, replacing brake lines with stainless versions like our innovative QWKbleed lines is not a bad idea from just a safety perspective alone. There are also rubber parts inside the calipers themselves, the piston seals. These little rubber rings are the critical bit that lets you transfer force from the brake pedal to the pad. We are currently track testing our replacements to ensure they are of sufficient quality to survive track abuse. We worked with a manufacture that makes seals for many applications (including Lotus) but we strive to do our own testing and validation, especially for safety critical items.

We have also rebuilt several calipers here in the last few months and are exploring the possibility of offering it as a service. I bought some nasty black calipers for my own Elise, stripped, painted, and rebuilt them with new hardware. 

Another interesting thing we have tried is cleaning calipers cryogenically. This is similar to sand blasting, but rather than sand, frozen CO2 (dry ice) is used. You can see the results below. These calipers had 52,000 miles on them. 
Before Cyro
After Cryo
Art Car v2 caliper with Ti Bolts
  Another interesting thing we are looking at is Titanium caliper bolts. We are currently track testing these to see how they hold up but they are certainly cool looking and are worth about 0.36lbs of unsprung weight.
Ti Bolts vs Stock

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