Timeking wrote:
These are Dexter self-adjust that I have dragged 15,500 miles. At zero miles (i.e., new) the pads are 0.18 inch (9/32) and after 15,500 they are 0.08 inch (1/8). So I am figuring that the pads are losing 0.01 inch every 1550 miles. If you are supposed to replace the brakes at 0.04 inch (1/16), I only have 6200 more miles until worn.
I figure (My brain hurts!!) that if we are planning to go from Florida east coast to California and up to Canada, I need to go ahead and do this thankless job. I've done this before on previous trailer.
All that said, I wanted to see if I am figuring this right or not.
In advance
Thanks
Hi,
As was pointed out, you mixed up the math but you are past that now. I'm picking up on the 15,500 miles comment. I'm just passing this info along to try and help you, plus gets some more learning in. One never stops learning.
What is the size of your brakes? 12" x 2" or 10" x 2 1/4"? And what year was the set new?
Three other questions, what is the weight of the camper?
Tell us some about the 15,500 miles. Long cross-country trips, weekend warrior 2 to 3 days trips 100 to 200 miles from home, just lots of them?
How many years did it take to accumulate the 15,500 miles? This sort of ties into the type of camping you had over that 15.5K mile period.
I was one of the first here on RV. net to report on the Dexter self-adjusting brakes. It is shown here in this post from 2009. I was still working then, and now retired but our trips were more weekend warrior short trips still, but a lot to them, until 2016 when I retired. I still have and use that camper.
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/23458294/srt/pa/pging/1/page/1.cfmMy camper weighs just under 10,000# loaded. It has 12 x 2" brakes and I did the brake wiring upgrade to # 10 AWG wire to each coil and got rid of the wire in the axle tube. Both hot wire and ground are direct to the 7-wire cord. No rusty frame ground in the middle of the brake wiring or corrosion in the connections. The wiring makes the power transmission more dependable and the best you are going to get from an electric brakes setup.
I replaced my first set of the self-adjusters in August of 2020, about 11 years of use. I would have to go back and add up the exact mileage, but it was in the 20,000-mile range. It could be a 1K- 2K +/- from that. I replaced them as my stopping power was slowly starting to fade. I could tell by the dusting on the truck wheels, the truck was doing more stopping than it use to. With the Ford integrated brake controller that works so smoothly, it was hard to tell the trailer was not stopping like it use to, the truck was compensating.
I was not yet worn to the 0.060" (1/16") target, but I was getting closer on one wheel that had an issue early on with an out-of-round brake drum. And since stopping was fading away, I just changed them out assuming I would get back to the braking I once had. And we were going to head out on a long trip.
Well, nope, the braking/stopping did not change. Now what? I was on all-new self-adjusting brakes that I had burnished in the pads, and it still is not stopping as it should. After about 1,000 miles of this, I pulled everything apart to see what was globally affecting the braking. I checked the current to each brake coil, and the magnet ohms. That all checked out. Hmmm, OK now what?
Well, to make a long troubleshooting search short, the problem was too deep and wide of grooving on the brake drum magnet surface. When the grooving approaches too deep or wide, the magnet does not have enough surface to grip on, the brake coil is not strong enough to power through the air gap, and the issue ends up with the brake power slowly dropping.
The end result learning was, it was not the brake shoes, they were not yet at 1/16", the problem was the magnet surface wore into a grooving pattern first. After I found this, all new brake drums and the new 1,000-mile new brakes worked well again like they always have. It was a global shift as soon as I came out of the shop, it all worked again. If I would have known the groove depth/width that is too much, I could have still used my prior self-adjusters longer. Seeing a level of small scratches on the magnet surface is normal, but when the grooves get too deep and too wide, that is a problem.
Point: Check the magnet surface on the drum.
I have pictures and depth data on this just did not want to make this any longer than it is already. If anyone wants to know about the drum grooving, let me know and I will see if I can dig it up.
Hope this helps,
John
