Installing trailer brakes

MCNPathfinder

Petty Officer 2nd Class
Joined
Jul 24, 2010
Messages
118
Hey guys. Question. I failed pretty miserably on my trailer brake setup. I bought a 10" kit thinking everything would work fine, but apparently the hubs were too large for my axle. I had existing surge brakes on there, and I'm wanting to convert them over to electric. The old surge brakes are there (no "plumbing" there anymore though). They seem to bolt on just like the electric ones would. What I'm wondering is if I can just replace the hydraulic ones with the electric ones and use the same hubs?
Also I'm wondering if the sizing on these are pretty standard? From what I'm gathering online there seem to be a 7", 10", and 12" option. You don't think my trailer would be something goofy like an 8" setup do you? I haven't gotten to measure because I can only work on it about 5 minutes per day before it starts down-pouring/hailing like it has been for the past 10 days. Based on just visual inspection, the hydraulic backings that are on there only seem to be a little bit smaller than the 10", which is why I'm concerned they would have put some weird size on there.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,524
Re: Installing trailer brakes

Hey guys. Question. I failed pretty miserably on my trailer brake setup. I bought a 10" kit thinking everything would work fine, but apparently the hubs were too large for my axle. I had existing surge brakes on there, and I'm wanting to convert them over to electric. The old surge brakes are there (no "plumbing" there anymore though). They seem to bolt on just like the electric ones would. What I'm wondering is if I can just replace the hydraulic ones with the electric ones and use the same hubs?
Also I'm wondering if the sizing on these are pretty standard? From what I'm gathering online there seem to be a 7", 10", and 12" option. You don't think my trailer would be something goofy like an 8" setup do you? I haven't gotten to measure because I can only work on it about 5 minutes per day before it starts down-pouring/hailing like it has been for the past 10 days. Based on just visual inspection, the hydraulic backings that are on there only seem to be a little bit smaller than the 10", which is why I'm concerned they would have put some weird size on there.

Ayuh,.... Measure the diameter of the brake drum, 'n you'll know...

personally, I'd never put Electric brakes on a wagon I'm dunkin' in the water, Regularly....
 

Chip Chester

Petty Officer 2nd Class
Joined
Apr 17, 2012
Messages
109
Re: Installing trailer brakes

Just to clarify, are you going all-electric, like a travel trailer? Or electric over hydraulic? (Electric actuation/control of hydraulic system.)

Chip
 

Josh P

Petty Officer 1st Class
Joined
Aug 26, 2009
Messages
328
Re: Installing trailer brakes

drum size depends on alxe and wheel size, do you have a typical 3500# axle with 5 lugs and 13'' or larger rims? than 10'' is you size. The 12's are for 5000-7000# axles and 7'' are usually for the 2000# axles.
 

H20Rat

Vice Admiral
Joined
Mar 8, 2009
Messages
5,201
Re: Installing trailer brakes

What not? You dunk your lights every time.

And how many boat trailers do you see with lights that don't work 100% of the time... Manual surge brakes on a boat trailer are the ultimate in simplicity. No user intervention, no electronics, and nothing but pure physics to operate them.
 

MCNPathfinder

Petty Officer 2nd Class
Joined
Jul 24, 2010
Messages
118
Re: Installing trailer brakes

I'm going full electric, like a travel trailer. I plan on unplugging the boat trailer from the car before dunking it, this is what I typically do just in case water gets into the lights. It had surge brakes on there and I noticed one of the axle has the drums for the surge brakes, this is why I was wondering if I could just swap out the backings and use the existing hubs/drums. My axle has 5 lugs, but those smaller brakes... Weird. I think my rims are somewhere around 13", maybe larger? Not smaller though.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,837
Re: Installing trailer brakes

You have to measure the drums as noted. And, some brake drums can be use with either hydraulic or electric brakes, but some can be used only with hydraulic, it depends on how the inner surface of the drum that is around the hub it self (not the part that the brake shoes contact) is machined.
Keep in mind if you go electric you need to have the correct wiring on the truck end (7 way connector) and a brake controller in the truck. Personally I'd just keep it a surge system, cost wise it may be about the same, except if you had to replace brake lines it's more work than running wires. If you are in a salt or brackish water area I would not use electric, only surge.
 

Jlawsen

Master Chief Petty Officer
Joined
Apr 22, 2012
Messages
810
Re: Installing trailer brakes

And how many boat trailers do you see with lights that don't work 100% of the time... Manual surge brakes on a boat trailer are the ultimate in simplicity. No user intervention, no electronics, and nothing but pure physics to operate them.

LOL. Really... Seriously... You don't know you're supposed to unplug them before dunkin them? Lights and trailer brakes are for driving not launching. Don't you disable surge brakes before you back up? If you have a problem holding your boat on the ramp without the trailer brakes then you're towing with the wrong vehicle.
 

Josh P

Petty Officer 1st Class
Joined
Aug 26, 2009
Messages
328
Re: Installing trailer brakes

electric brake drums must look like this inside.

images.jpg


you probably have 10'' just measure the drum you dont even have to take it off just measure the od.
 

MCNPathfinder

Petty Officer 2nd Class
Joined
Jul 24, 2010
Messages
118
Re: Installing trailer brakes

I had purchased 10" brake drums, and they looked way bigger than what was on there. I suppose I'll just pull the hubs off and see what's up. I already took care of the brake controller and everything on the car side. I like to unplug my lights before dunking the trailer. I would do the same with the brakes. My truck keeps the trailer on the ramp just fine, and pulls it out just "fine", I don't need the trailer brakes for that part of it. The kit I bought had a way wider diameter for the bearings that were in there than the trailer had. I guess I would prefer to go with 10" or larger, but I also don't want to replace the axle to get to the right spindle size.
 

HalfFish5087

Petty Officer 1st Class
Joined
May 30, 2012
Messages
278
Re: Installing trailer brakes

I recently switched over from surge to full electric. The existing drum brakes were 10" dia and 2-1/4" deep and were machined on the inside for good magnet contact. I used dexter ner-r-adjust brakes which are working great and had the typical 3.5k axle 4 bolt pattern. The brakes are wired with 10 gauge (positive and negative) with an emergency break away battery and switch. After much research, I decided to go with the Prodigy P2 controller which I must say has worked well. So far they have been dunked about 20 times this year with no problems and I have accidentally forgotten to unplug them for at least 6 dunks. Most important part of the install was the wiring connections. I prefer soldering all connections, covering with liquid electric tape, heat shrink and thick electric tape. Good luck!
 
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