Dexter Brake Repair

When I brought the old girl back to the house for winterizing, I noticed a serious delay in braking response.  Not good.

Our 2008 Classic uses a Dexter 1600 electric/hydraulic brake system. The actuator sounded like it was responding properly, but it had that ‘air in the line’ sound. That is, it takes much longer to reach the straining sound that happens under max compression.  Figured it was either the new actuator going bad, or some air bubbles had shaken loose somewhere in the system (it’s notoriously difficult to bleed this system).

So, I jacked her up on blocks, pulled the wheels and activated the brakes with the breakaway switch.  The problem was immediately apparent.  A small leak on the curbside front caliper at the cross-over line.  I can guess how that happened. These Dexter 6,000lb disc brakes are made up of two separate piston halves that bolt directly to an axle yoke.  Most disc brake assemblies have both pistons on a single casting, making it easy to manipulate when replacing pads.  The problem with this is, when replacing the pads, the only thing holding the two piston halves together is the little cross-over line; and it’s very easy to torque/twist it.  I figure a tiny fissure must have developed.

Since I didn’t have a replacement part, and she was up on blocks with the wheels off, I figured wrenching down the bolt some more might help.  Couldn’t hurt, right?  Wrong.  What was a tiny dribble under pressure, turned into a firehose. It’s amazing how much hydraulic fluid you can get out of a tiny opening under 1,600 psi.

Finding that little cross-over line part was challenging.  Finally, ended up ordering it directly from Dexter, part #071-517-00.  Installing it’s a snap.  Be sure to tighten both ends together and evenly.  Also, make sure you use a ‘line wrench’ to tighten (25 lb-ft) otherwise you’ll round those nuts over.

Now comes the fun part.  Bleeding the system.  Another set of hands makes it much easier, and always have more brake fluid than you think you’ll need.  Also, the actuator reservoir is much smaller than it looks.  I will only open the bleeder valve for about 2-3 seconds at a time, before topping off the reservoir.

My order of bleeding went like this: street side front, curbside front, street side rear, curbside rear.  I made two complete rotations, with 2-3 bleeds per caliper.  The last bleed having no trace of bubbles.  I’m confident all the air was eliminated.

See You Down the Road!

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