Which Grease to Use for RV Trailer Hubs and How Many Amps Should Be at Trailer Brake Magnets

Question:

I have the 3500 lb 10 drum-brake axles from AL-KO on my RV trailer. 1 What is the max amps for each magnet? My controller reads 10 amps at max output 2.5 amps per wheel. 2 What is the best grease to use? The grease I have tried so far turns to gray pea soup after 3000 miles. I plan to try Lubrimatic L11402 marine grade. 3 What causes the magnets and the inside of drums to wear uneven?? My next brake job will require full replacement. Shoes and drums are wearing even.

asked by: Lynn F

Expert Reply:

Since the brake shoes and drums are wearing evenly, the angled magnet wear is not a problem. They do not have to wear even. As the magnet is charged it swings the arm out and may put an angle in the wear. Even with all brand new parts this can happen. If the surface inside the drum that the magnet attaches to is worn unevenly, the magnet will too.

The grease is degrading for probably one or both of a couple reasons. Certain base compounds for grease are incompatible. Mixing these greases can cause them to react and degrade. If your bearings, hubs, or races need to be replaced, they would be wearing and burning the grease. We use the Lubrimatic LMX Industrial Strength Grease, part # L11390, when we replace hubs and bearings and seals. If it is a boat trailer then we use the Marine Grease. I have included a link to an FAQ article on grease that covers compatibility.

When you do your next brake job and replace everything, check the spindles on the axles. Make sure they are smooth and the edge of your fingernail does not catch on anything. Check for discolored or cracked areas. It may be beneficial to replace spindles, drums, bearings, seals, everything. Start from scratch. Just make sure you clean the old grease thoroughly on any parts you re-use so you do not have an incompatible greases mixing.

To further test your magnets, first make sure the trailer is not connected when performing this test. If the trailer is connected, you run the risk of shorting out a brake controller or various other electrical components. Follow the testing procedures in the FAQ article I have included on testing brake magnets.

expert reply by: Patrick B