Front Huck to Bendix Brake Conversion Procedures

by: Mike Klepp

 

 

Pre-1951 Huck brakes, when in good condition are adequate.  So, why would you want to change your 3100 from Huck brakes to Bendix style brakes?  There are several reasons:  Huck replacement parts are scarce and expensive; you may desire to keep your truck stock looking; you want to keep the original single master cylinder; or you swapped out the rear axle with a newer GM unit with Bendix brakes.  The upgrade to 1951-1959 Bendix brakes should increase your stopping power.  Although both brake types are the same diameter (11 inches), Bendix shoes are 2 inches wide, while the Huck shoes are only 1 3/4 inches wide.  Additionally, Bendix parts are still readily available at most local parts stores.  The Bendix brake parts are easily adapted to the pre-1951 half-ton truck with only minor changes.  Follow these steps:

 

1.  First on the agenda is acquiring the all required Bendix parts necessary for the conversion.  You will need the backing plates with all mounting hardware, brake shoes with attaching hardware, wheel cylinders, and the brake drums.  All parts should be thoroughly cleaned and inspected to insure their condition.  As a minimum, shoes likely will need to be replaced, wheel cylinders rebuilt, and drums turned.  Some of the attaching hardware may also need replacement.  These parts can be procured from local parts stores as required.  Once all the parts are on hand, the disassembly of the old Huck components can start.  The old parts should be saved for someone doing an original restoration, if they are serviceable.

 

2.  Remove the old Huck parts from your axle.  Remove the hub and brake drum assembly.  Remove the brake shoes and attaching hardware, and pull the backing plate after disconnecting the brake hose.  Separate the brake drum from the hub.  Wheel lugs and/or rivets will have to be removed to separate these parts.  You will be using your old hub with the new Bendix drum.    Clean and inspect the spindles, bearings and races while everything is apart.  This is also the perfect opportunity to replace those worn king pins, bushings, and tie rod ends too.

 

3.  To install the Bendix parts, some preparation is required.  The old Huck backing plates were held in place with four 7/16 inch bolts, while the Bendix backing plate uses two 7/16 inch bolts on the top, but two 1/2 inch bolts on the bottom, where the steering arms attach.  The lower bolt holes through the spindles and the steering arms must be drilled out from 7/16 to 1/2 inch for a proper fit. 

 

4.  Mount the Bendix backing plates to the spindles.  (The center hole may have to be enlarged slightly to fit the old spindle).  Use new cotter pins after torquing the bolts.  Attach the new or rebuilt wheel cylinder to the backing plate.  Make sure that the correct cylinder is mounted, as there is a left and right cylinder unlike the old Huck cylinders.  Connect the brake hose to the cylinder.  Note:  The original brake hose length is adequate, but longer hoses are advised.  Now the brake shoes and attaching hardware can be mounted to the backing plate.  Make sure the adjuster is oriented over the offset slot in the backing plate, or you won’t be able to adjust the shoes.  Insure the primary (shorter) shoe is mounted toward the front of the truck and the secondary (longer) shoe is toward the rear.  The shop manual details this very well.  Install the hub and drum assembly after checking and repacking bearings and installing new seals if needed.  Replace any damaged wheel lugs when assembling the hub and drum.  Be sure to use a new cotter pin after torquing the axle nut. 

 

5.  The only remaining jobs are to adjust the brake shoes and bleed the brakes.  Again, the shop manual details these procedures clearly.  Mount front wheels and test the brakes.  Brakes may require adjustment after a few miles after initial shoe/drum seating.