Choosing Replacement Trailer Brakes, Hubs and Actuator for 1978 Calkins Tandem Axle Boat Trailer


Hi, I need to rebuild the brake system on a 1978 calkins tandem boat trailer. It originally came with a 1979 21foot glasply boat which weighs about 5500lbs. I believe it was rated at 6900 lbs. i need to replace the actuator, all lines, drums brakes and hubs. The 14inch tires and wheels seem ok. Can you help me assemble a parts list? Soaps I dont leave anything out. Thanks.


Expert Reply:

You'll want to check a few details on the trailer so you can select compatible replacement parts.

First, you want to confirm the axles' rated capacity; this should be noted on a sticker or plate on the axles themselves. Based on the info you provided it may be that you have two 3500-lb axles. Your brakes and hubs must match the axle rating.

Next you'll want to take note of the size of the current brakes. You need to confirm the diameter and depth. You also want to note their mounting bolt pattern so you can match this as well. The linked page will show you all 3.5K hydraulic drum brakes; all of these happen to be the 10 x 2-1/4-inch size with a 4-bolt mounting pattern like left and right free-backing brakes # AKFBBRK-35-D. (Free-backing brakes allow for reversing your trailer without need for a lockout on the coupler.)

With free-backing brakes you can use a standard coupler (with no reverse lockout) such as 7.5K-rated # 099-175-00 from Dexter which is a fit for 2 inch hitch balls. It bolts to a 3-inch-wide trailer tongue. You'll need a brake line kit like # 24TA-BLKIT.

For hub/drums you can use the linked page to select your wheel bolt pattern, axle rating and your bearings. New hub/drums must use the same inner and outer bearing as your current hubs. For example, if you need 5-on-4-1/2 hubs with inner bearing 68149 and outer bearing 44649 then you can use Dexter hub/drum # 84546UC3.

Please feel free to let me know the details noted above and I'll be glad to help you select the items you need.

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expert reply by:
Adam R

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