Electric brakes: Theory, Troubleshooting & Maintenance

WilliamA

I was asked by MichiganMike if I'd pen up a bit of information on electric brakes so I thought I'd better get on the stick.
I pulled a hub this morning to get some photos and got a few other surprises. We'll start with what I found first:
I had previously put in a Dexter axle spacer kit (http://teardrop-trailers.vanillacommunity.com/discussion/230/off-road-ready-upgrades-and-mods/p1) and found the tires to be rubbing the inside of the fenderwells. I carefully centered the axle and thought I'd be "okay for now". Turns out....no... Both clearance light wires on both sides are worn through to the copper. I thought about simply rerouting the wires but as you can see from the fenderwell, the tires have been rubbing pretty much the whole side of the trailer so moving the wires isn't going to fix much. I hadn't wanted to use wheel spacers and REALLY don't want to buy a new set of offset wheels, but will step up and get some spacers. For that, I'll need to take everything apart (again) and press out the wheel studs so I can install longer ones. Rather than wasting two new sets of grease seals, I'll park it, order the wheel spacers and longer studs, press out and in the new studs, then pack and reassemble the hubs. Grrrrrrr....

To be fair, I do a bit (more than a bit) of offroading with my trailer and get into some off-camber situations. I'm sure the axle has more give than the tiny 1/4" clearance my trailer has. I'll need to do the wire repairs (both sides) and get some wheel spacers before I do anything else. I'll get to it.

If anyone needs coaxing on why trailers need to have the grease changed at least annually, have a look at the following two photos.
This grease looks okay at a glance, but it's runny and not very stiff.

Much closer inspection (I use a jewelers loupe) shows severe contamination with all sorts of stuff. If the grease looks like metalflake in this closeup, that's because it is exactly that. Before you get too worried, I'd say that this stuff looks about normal to me. It's not milky or water contaminated, just weak and dirty. Out with the old, in with the new. Grease and seals, that is...

And if I needed any more prompting, when I spooned the grease out of the hub, there were bits of this inside. Hmmm. This isn't normal. I suspect it's a bit of metal shaving left inside the hub from the machining process. It's the right size and diameter to be a sliver of debris from a tap, but there's nothing inside the hub that has threads. I'll clean it out, pretend I didn't see it and move on.

In any case, I'll be putting pen to paper over the next day or so and should have a primer of sorts out soon on e-brakes. As to the maintenance, well, now first I need parts.... Wheel seals, spacers, wheel studs (grrrrrrr), wire connectors and elbow grease.

WilliamA

TomD

I’m having PTSD just reading your post.

WilliamA

Thanks Tom. No worries. I'll get it done. I have a bass stalking trip planned for next weekend and it'll need to be shipshape by then. Last night I tiptoed into the ethereal realm (www) and located some atomic, 6061 aluminum offset wheel spacers with 1 1/2" thickness from "Extreme Terrain.com" and traded plastic for metal. They should be here by Wednesday. Now I need to find or make a special wrench to install them. In the meantime, I'll do my maintenance chores inside the hubs and get everything else ready. As to the clearance light. Wiring, I'm rerouting the wires so they won't be an issue again. Fool me once...
Oh yeah...I also have three utility trailers sitting in the yard to completely rewire by Tuesday...no problem..
WilliamA

WilliamA

I'm a pot of coffee into the day and just checked shipping status of my wheel spacers. According to UPS, they are in Baldwin, Wi. and are "out for delivery" today. That probably means I should get into my work clothes and do my bearing maintenance in prep for installation of the spacers. I also need to fashion some sort of wrench to tighten the spacers onto the hubs. There are still a lot of things that can go wrong (wheel stud length, lug nut diameter, stud diameter and thread pitch to name a few) but I'll get to the spacer hi-jinks after my bearing maintenance. I try to take my problems and beatings one at a time. Maintenance first... All of this ruminating on wheel tightening has me thinking about lug nut torque. I'll talk about that too...
Photos to come...
WilliamA

WilliamA

Well, wheel spacers arrived. They need a bit of machine work to go over the stock hubs. The spacers I got are hub-centric and the hubs on the T@G are not, so I need to open up the inside diameter of the spacers from 2 3/8" to 2 9/16". I know a guy who has a lathe so I'm blasting over there tomorrow and get it done. Here's the (not) progress to date:
This is as far as they will go on without machining. No problem. I'll deal with it tomorrow.

These are nice pieces. Plenty heavy and bulletproof.

On the upside, I did get my wheel bearing maintenance and brake maintenance finished. I didn't find any more surprises and got that job all sewed up. Now just the wheel spacers reside between me and the trail. Should have things all done by the weekend.
WilliamA

WilliamA

This week is proving to be like working at the cop-shop. Crazy busy. We split 2 cords of wood, worked on the fine detail of the go kart and then I took off to a friends house to use his lathe. I got my spacers machined out from 2 3/8" to 2 5/8" (2.620 on the lathe). I blasted back and put one on in the pouring rain to see if they would work. They do.
Here are the finished pieces. If you compare photos, the thick hub-centric ring is now all but gone, leaving only about 3/32". I thought about just machining it off flush but decided it's not interfering with anything and it's plenty thick enough not to break off and cause problems so I just left them on. It's been awhile since I did any meaningful machine work so I too my time and took off about .0012 per pass. Also, I was using a long inside cutter to clear the wheel studs so I had to go pokey to avoid chatter.

I got home and put one on to see how they fit. Fantastic. I bolted the wheel on and it's just out past the edge of the fender. Nice. No more interference.

Tomorrow, I'll bolt the other one on and take it for a 10 or 15 mile jaunt, come back and retighten the spacers. I've put thread locker on the inside (drum) studs so once I've checked them post test-drive, they should be okay until fall maintenance.
Back in business. Woo-Hoo!
I'll get some better photos tomorrow.
WilliamA

WilliamA

A few more photos, now that the rain has stopped...


The spacers put the wheels out just a tad past the fender. I'll live with it.

Back up and ready for more adventure. I did a few miles with all the bits in place and when I got back they were still all there. I'll be taking a day trip this coming week just for fun.

WilliamA

LuckyJ

@WilliamA good job. You finally did your before I did mine!

WilliamA

"Patience is a bitter virtue that only the strong can drink."
I haven't forgotten about this thread either. I'm about 40 or so threads behind on my posts across all the forums I write to but am slogging forward as they come to the top.

Short version for the nearterm is this incredibly handy and comprehensive PDF from Dexter on electric brake theory, maintenance and troubleshooting. Truth is, I doubt I could pen up a more comprehensive document than this one anyway. I'll keep looking but for now....:
https://www.dexteraxle.com/docs/default-source/default-document-library/light-duty-electric-brakesc67a839d2ba463c18d7aff64007a4014.pdf?sfvrsn=0

WilliamA