Sunday, July 27, 2008

Bleeding the brakes

I finished bleeding the brakes today and wanted to share a few new things I learned this time around. I've always done brakes in the past as a two man job. One guy pushing in on the pedal while the other guy is releasing the pressure at the caliper. The wife was with the baby and my neightbor was on vacation so I decided to purchase a brake bleeding kit. These start at around $25 and go up depending on quality and are well worth it.
First always make sure the reservoir is topped off before bleeding each wheel. You'll also want to check in the service manual for the order the wheels should be bled in. Yes there is a correct order. Before you bleed each wheel remove the bleed valve completely and wrap the threads with teflon tape. This will ensure that no extra air can enter the bleeding tool air lines making it hard to tell when the process is complete. Replace the valve and attach the bleeding kit to the end of valve. Pump the handle and build up the vacuum in the fluid catcher. If the vacuum doesn't want to build up or won't hold check your connections, find the leak and fix it before continuing. Once you have built up 15-20 in/hg you can crack open the bleeder valve and watch the system bleed itself. At first you should only hear the air moving through the system. You might at first see some dark/old fluid after which the air will come. Finally you should start to see the cleaner/new fluid coming into the tube. It doesn't take long and the bubbles will stop coming up the tub. Each wheel should only take 10 seconds or so. If it's taking longer you may still have a leak at the threads and need to redo the teflon tape or you haven't opened the valve very far making it take longer for the fluid to transfer. When the bubbles stop close the valve. Refill the resorvoir and repeat for the other wheels. Do these steps and you'll have your full system bleed in no time at all.

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