LF Break Grabbing

[toolman.dustin]

LF Break Grabbing

A couple of months ago I replaced the 4400 lb axles (10" brakes) with 6000 lb axles and 12" brakes. The brakes felt very weak after the install, so I adjusted them but still felt very weak. I've pulled the trailer out for a trip from central KS to Brownsville TX. The LF brake grabs so hard the tire locks up on gravel roads and will skid on pavement. I've even lowered the brake controller to 2 and the LF brake still grabs.

These are brand new Dexter axles "https://www.theoempartsstore.com/60655E-ST-EZ-KIT.html"
12" x 2" Electric Brakes Nev-r-Adjust - EZ Lube spindle/bearings.

So, I pulled the drums off all 4 wheels. 3 of the 4 had grease that had escaped past the rear seal. 1 of those 3 had grease that had contacted the front edge of the brake and contaminated the brake surface.
However, the brake that is grabbing is the only drum assembly that didn't have grease that bypassed the rear seal.

I cleaned all for drums and brake surfaces and the LF brake still locks up. I checked the current draw and each brake is drawing 1.5-1.7 amps upon application of the brakes.

I've traveled 650 miles and I think I'm going to cut the wire to the LF brake so as not to destroy the LF tire and find the problem once I get to Brownsville.

I'm looking for suggestions that might explain why this electric brake is grabbing.

thanks, Dustin

[Russb]

I had similar issues with the brakes grabbing. Turned out the the brake wire inside the axle had been stripped of insulation when it was pulled through and was shorting out when the brakes were applied. I ran new wire along the outside of the axle. This happened on two different RV's.

[toolman.dustin]

Thanks for the idea. I've tried several things that didn't work, that might be it.

[Russb]

Originally Posted by toolman.dustin

Thanks for the idea. I've tried several things that didn't work, that might be it.

There was enough slack in the wires that I was able to pull some out of the axle and found the problem. The sharp edge of the hole sliced the insulation.

[Wingerdinger]

Originally Posted by toolman.dustin

Thanks for the idea. I've tried several things that didn't work, that might be it.

You probably already thought of it, but make real sure that the brakes are adjusted so that they don't make any contact. You should be able to spin the wheel, and hear no brake contact, no rubbing. If they rub at all, they will heat up and cause the lockup condition you mentioned.
I trust you replaced the bearing seals that were leaking. Easy-lube hubs are notorious for seal blowouts, because it's extremely easy to blow out the seal when trying to add grease. Many folks discourage using the easy-lube, and dismantle to repack the bearings.
The other thing that might very well be occurring is that because the other 3 wheels had grease on the brakes, and are not effectively working, the one clean brake is trying to do all the work. You should never use a brake pad that has had grease on it, you cannot clean them well enough for them to work properly. Once grease gets on them, they are junk.
Rather than try to troubleshoot the brake assembly, why not just replace it. They don't cost much.

[toolman.dustin]

Originally Posted by Wingerdinger

You probably already thought of it, but make real sure that the brakes are adjusted so that they don't make any contact. You should be able to spin the wheel, and hear no brake contact, no rubbing. If they rub at all, they will heat up and cause the lockup condition you mentioned.
I trust you replaced the bearing seals that were leaking.
Rather than try to troubleshoot the brake assembly, why not just replace it. They don't cost much.

Thanks for the reply. I've made contact with Dexter and requested replacement brake shoes and seals. These shoes are falling apart. I could replace the entire assembly at my expense, but these are NEW axles. After spending $1200 I'd rather not spend $108 each for new brake assemblies. I'll wait and see what Dexter says. I've got 6 more weeks here in Brownsville. I will replace the seals before I head back home. After this, I will never use the EZ-Lub feature. Wish I hadn't ordered that feature. I'll update as this progresses.
Dustin