Aluminum. Worked on removing the old backing plate from one wheel tonight. Not easy. It is all rusted on. I am having to use a grinder to grind the integrated mounting bolts from the mounting plate. Miserable job.... My neighbor came by and was asking me about why I didn't go with electric brakes for the rebuild, so I was doing some research on them. It looks to me like I can only get electric brakes that are drum brakes. With all the salt and snow, I'd rather go with disk brakes, so I think I'm going to stick with this plan. Doing a bit more reading on trailer brakes tonight, I see that you can buy an "electric over hydraulic" actuator, which uses an electric brake controller to control a hydraulic pump mounted on the trailer (in lieu of an actuator coupling) to control the hydraulic brakes. This gives the advantages of hydraulic brakes (not the least of which is the ability to go with the Kodiak disk brakes that are superior to any of the drum brakes), while having the ability to control breaking with a controller in the vehicle. The downside? Well, first, you have the prolem with break-away control (how do you activate the brakes if the trailer breaks away from the tow vehicle when you are relying on an electric hydraulic pump?). Second, the pump units appear to start at about $500. Ouch... But, for the sake of covering the ENTIRE trailer brake issue, I thought I'd mention it. Many of the boating websites talk about it, because electric brakes are not ideal for boat trailers, which are submerged in the water. The wiring and magnets do not like water - particularly salt water. Indeed, drum brakes generally do not like water. Thus, some poeple are going with the disk brake systems, but using an "electric over hydraulic" pump to run the hydraulic disk brakes. This provdes control over the braking offer by electric brakes, with the benefits of hydraulic disk brakes. I have read that the electric brakes do not provide as much braking power as hydraulic (including surge) brakes. I do not know if this is true or not. I think I'll stick with the surge brake actuator coupling and disk brakes. I can't see putting a $500 electric over hydraulic pump on this trailer just so I can control the amount of braking, unless I find that the braking is obiously too much or too little. I read that, in very hilly areas of the country, some people like to put the electric over hydraulic system on their hydraulic brake trailers to avoid having brakes being partially applied during long downgrades. Interesting... I took some pics tonight but won't get them posted until later....
Mark, I think that after you get the disc brake system up and running, you might think: What was all the fuss about? Or even as the Peggy Lee song said, "Is that all there is?" An automotive brake proportioning valve might work in the system. On some of those Dico hitches there is already a pretty small orifice on the output side of the master cylinder to slow the onset of brakes. Check it out, it might be only on the drum brake hitches though. Jim
More pictures of the trailer brake project. Hope this helps someone, at some point, with a boat trailer brake project. You can see that the right side brake assembly is now installed. Working on bearings/seals on the non-braking wheels, and the left side brake is in progress. Note the close-up that shows how the brake mounting flange on the trailer, and the torsion axle member, have to be modified with the grinder to accept the disk brake assembly. Otherwise, it won't fit. Newer axles should come with the proper shape to accept this type of brakes. This has been an interesting learning experience - a bit more involved than I had thought it would be....
