Master cylinder

How To Bench Bleed a Step Bore Master Cylinder

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• published: 12 Jun 2014
• views: 57884

We will walk you through 2 different ways to bench bleed a Step Bore Master Cylinder (SBMC). NOTE: When installing master cylinders, it is important to get all the air out of the system. If not, it could result in poor brake performance. Step Bore Master Cylinders are more difficult to bench bleed than conventional master cylinders. Learn more here: (0:34) CARDONE recommends using a brake syringe when bleeding a SBMC Method 1: Syringe 1) Mount the master cylinder in a vice by clamping on he mounting flange (1:03) Make sure the mount is level and avoid clamping onto the casting body to prevent damage 2) Place a drain pan under the master cylinder to catch any fluid expelled during the bleeding process (1:15) 3) Remove the protective caps in the primary brake line port and fill the reservoir with fresh, clean brake fluid at least halfway. (1:23) 4) Draw some fluid into the syringe and purge the air from the syringe (1:31) 5) Starting with the primary inlet in the reservoir, inject brake fluid until clear, non-aerated fluid flows from the primary brake line port. (1:36) 6) Refill the syringe, purge the air again, and inject the fluid into the primary brake line port until no air bubbles are visible in the reservoir. (1:45) 7) Do the same for the secondary inlet and secondary brake line port (1:57) 8) Complete the install following your OE Approved Service Manual. (2:00) Method 2: Piston Stroking w/o Syringe *This method is much more time consuming 1) Mount the master cylinder in a vice, keeping it level (2:22) 2) Install the supply plugs into the primary and secondary brake line ports of the master cylinder and fill the reservoir half way with fresh, clean brake fluid (2:27) 3) Using a blunt tool to press the piston using a short stroke of an inch or less and hold for 20 seconds (2:37) *Make sure the stroke doesn't exceed 1 inch, you could damage the seal (2:43) *Keeping the piston depressed is the key to getting all the trapped air out of the Quick Take-Up Valve (2:50) *It's important to wait 30 seconds between strokes to allow the larger primary bore to refill with fluid (2:56) 4) Repeat as necessary until no air bubbles are visible and the piston travel is less than 1/8 of an inch when stroking (3:02) 5)Complete the install following your OE Approved Service Manual. (3:10) Was this video helpful? If so, make sure to like it, and be sure to subscribe to our channel. For technical bulletins regarding steering click here: http://cardone.com/tech-help/ - Website: http://cardone.com/ - Facebook: https://www.facebook.com/CardoneIndustries/ - Twitter: https://twitter.com/cardoneparts **Disclaimer** At CARDONE we cannot guarantee against improper interpretation or application of the information we present in this video. You should always follow the enclosed safety guidelines, consult your OE repair manual for correct specifications when performing any install or repair procedure. Any injury, damage or loss that may result from improper use of tools, equipment, or from the information contained in this video is the sole responsibility of the user, and not of CARDONE Industries.