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MAC 6000 Hydronic Heater
Trailer Axle Manual
2106 East Indiana Ave., Bismarck, ND 58504 U.S.A. • www.macheaters.com • +1-800-272-4604
4
Rev: 07.25.2013
BREAK-IN PERIOD FOR ELECTRIC DRUM BRAKES
The break-in period is a typical phenomenon with drum brakes and especially electric
drum brakes. Electric drum brakes will require a break-in period to achieve full
performance. This break-in period applies for new axles and any time new brake shoes
and/or magnets are installed as part of regular maintenance.
Lippert Components has found through extensive brake testing that the break-in
period for our drum brakes can range from 20 to 50 brake applications.
Brakes can be seated in by applying approximately 8-10 volts to the trailer brakes at
an initial speed of 40 mph and allowing the truck/trailer combination to slow down
to 20 or 25 mph. For best results do not use truck brakes during this procedure. The
trailer brakes will seat in faster by using them to stop both the truck and trailer. The
easiest method is to apply the trailer brakes using the manual activation lever located
on the in-cab brake controller. Care must be taken to not overheat the lining material,
therefore brake applications conducted at one mile intervals will suffice. The driver
should feel a noticeable difference in the brake performance during this period,
sometimes in as few as 10 applications. After 50 applications, the brake lining material
will be fully cured from the heat and develop close to 100% contact with the brake
drum surface.
This break in period not only seats the shoe lining material but also seats in the brake
electromagnets. During the break-in period, the linings will wear at a faster rate than
they do after they are seated in.
NOTE: Brakes should be manually adjusted after the first 200 miles of operation and
periodically thereafter, approx. 3,000 mile intervals.
HUBS/DRUMS/BEARINGS
HUB REMOVAL
To remove the hub assembly for inspection, maintenance or service, follow the six (6)
steps below:
Lift unit by the frame and never the axle or suspension. Do not go under unit
unless it is properly supported by jack stands. Unsupported units can fall causing
serious injury or death.
1. Lift trailer and support it per manufacturer’s requirements.
2. Remove the wheel.
3. Remove the grease cap by prying the edge out of the hub. If equipped with oil
lubrication, unscrew oil cap using a 2 1/2” socket, let oil drain into pan.
4. Pull the cotter pin from the castle nut and remove the outer spindle nut.
5. Remove the spindle washer.
6. Pull the hub off the spindle. Do not let the outer bearing cone fall free of the
assembly. The inner bearing cone will be contained by the seal and will not fall
out.
NOTE: Brakes may need to be adjusted or backed off to remove drum from spindle.
NOTE: A gear puller may be necessary to remove hub from spindle.
Brakes/Hubs/Drums/Bearings
