Adding Brakes To The Second Axle

[Trailer Guy]

I’ve noticed a lot of people asking about adding brakes to the second axle of their trailer. This might seem intimidating to some, but this is actually much easier than just about any modification that you would ever do to your 4x4. Over the next few post I’ll try and explain what to do and provide a picture that will help. I did not take pictures of repacking the wheel bearings and changing of races in the old hub/drums because most of us know how to do that, and it should really be covered in another thread. So instead, this is more about adding the brakes themselves.

The trailer we are working with is pretty common for most of the wheelers out there. This is a 16’ flat deck car hauler with tandem 3,500 lbs. axles. As with most that are out there, this one came stock with brakes on just one axle. This trailer has been on the road for about 4 years now, so the brakes that are on it have seen better days. The owner of the trailer helps me out a lot with the buggy, so I’ve decided to change out his old brakes and add brakes to the other axle for him as a surprise.

In the first picture you’ll notice that the front hub (non-braking) has gotten hot. No paint left, just rust, which tells me that the bearings might be getting ready to go. The rear hub/drum also doesn’t have paint, but it is braking, so if the owner has gotten the brakes super hot, this will happen.

The owner also complained that recently the trailer started to sway side to side when towing at highway speeds. If you notice in the picture, the rear shackle is flipped the wrong direction. That will do it for sure. After talking to the owner for a little bit, we figured out what had happened. This can happen from hitting large bumps in the road and jumping the trailer. It can also happen when someone lifts the entire trailer off the ground to change the tires, which is what happened in this case. Just something to look at and check when you pick your trailer up from the tire shop.

[Trailer Guy]

Rather than screw around with the old bearings on the braking axle, I’ve decided to just go ahead and replace the bearings and races in the old hub/drums. I knew ahead of time that this trailer has seen lots of miles with loads that are at the limit, and the brakes didn’t work that well anymore, so it’ll also get complete new loaded backing plates for the old braking axle. Of course, new loaded backing plates for the front axle, and new hub/drums. There are also the new bearings, races, and seals that are needed to complete this task. The new hub/drums come with the races already pressed into place. You might notice that the hub/drums are one unit. These are not separate units like you’ll find on most automobiles. I get asked a lot if you can buy just the drums and slip them over the hubs, as you can see, the answer is no.

[Trailer Guy]

The first thing I did was removed the hubs, and hub/drums from each side. (I’ll get into how this is done on the next tech thread, “Repack Your Bearings”) Since I was going to ditch the old backing plates completely from the rear axle I un-bolted those as well. On the 3,500 lbs. axle, the backing plates are held on by (4) 7/16” fine thread studs. On the 5,200 lbs. (and 6k and 7k) axles, the backing plates are held on by (5) 3/8” bolts. They could be either fine or course thread, they don’t always come with the new backing plates. Some older 5,200 lbs. axles at just (4) bolts that retained the backing plate. After un-bolting the backing plate, I simply cut the two wires going to the magnet and toss the old plate.

[Trailer Guy]

With the new loaded backing plates it makes the job very easy. Simply bolt up the new backing plates and connect the wires. I’m often asked if it matters which wire goes to ground and which goes to power. It does not matter at all. An electric magnet is a simple short really, so it makes no difference. To hook up the electrical to the front axle I simply ran the wiring from the rear brake to the front brake on each side. Covered it with some loon and used a clamp and self-tapping screw to retain it out of harms way. Some axles come with wiring running through the tubes. This front axle did not however. If it did, I would have just tagged into the brake wiring at the frame and ran it down to one side. Then grabbed the wiring coming out of the other side of the tube and wired it into the backing plate. This sounds confusing, so if someone wanted to see a picture of that set-up, let me know and I’d be happy to get one for you.

Also notice that the arms the magnets are attached to both go in the same direction. Backing plates are directional. They are usually stamped to tell you, but if not, you want the arms going towards the front of the trailer. In this picture, the front of the trailer is to the right, so this is the pass. side.

[Trailer Guy]

Now that the loaded backing plates are on both axles and wired up, you can pack the bearings with grease and install the hub/drums. Once again, the Wheel Bearing Pack can be covered in another thread if needed. But most of us know how this is done. Once the hub/drums are on, it’s time to adjust the brakes. Now there are ways of doing this with measuring devices that make it easy, but lets face it folks, not everyone has that stuff, and Dexter doesn’t even suggest it in their owners manual. Below I’ll type out how Dexter Axle Company put it.

1: Jack up trailer and secure on adequate capacity jack stands. Follow trailer manufacturer’s recommendations for lifting and supporting the unit. Make sure the wheel and drum rotates free.

2: Remove the adjusting hole cover from the adjusting slot on the bottom of the brake backing plate.

3: With a screwdriver or standard adjusting tool, rotate the starwheel of the adjuster assembly to expand the brake shoes. Adjust the brake shoes out until the pressure of the linings against the drum makes the wheel very difficult to turn.
Note: For drop spindle axles, a modified adjusting tool may be necessary.

4: Then rotate the starwheel in the opposite direction until the wheel turns freely with a slight lining drag.

5: Replace the adjusting hole cover and lower the wheel to the ground.

6: Repeat the above procedure on all brakes. For best results, the brakes should all be set at the same clearance.


So, I hope this helps to show people how easy it is to add brakes to the second axle of their trailer. Having two axles with brakes in not just easier on the trailers brakes, it is easier on the trucks brakes, not to mention the safety factor. This is not an all day project either. This could be a quick morning project on a weekend before it gets hot. Heck, I did this in the morning before the shop opened for work. With adding the brakes, and doing the wheel bearing pack, taking a few pictures, and helping two customers that came in early this morning, it still only took me just less than two hours.

To get the most out of your trailer, I suggest adjusting the brakes every 3,000 miles and doing a wheel bearing pack with fresh grease and new seals at least once a year or 12,000 miles (which ever comes first). This will also give you a chance to inspect the brake lining and magnets. And don’t forget, while you’re down there; also inspect the suspension parts to make sure the thin plastic bushing aren’t worn out. Once they wear out, everything else goes quickly.

If you guys would like to see more tech stuff about suspension, wheel bearing packs, break-a-way kit installs, etc. just post up and as I get a chance I’ll take some pictures and post a thread. If anyone has questions, please ask. You maybe asking the same question that 100 others are too scared to ask.

Happy Towing,
Aaron

Oh, and thanks goes out to TacomaJoe95 for the use of his trailer, even if he didn't know about it.:flipoff2:

[KWTMECH]

Nice write up---by the way, when are you going to flip that shackle?:)

[Trailer Guy]

Nice write up---by the way, when are you going to flip that shackle?:)
:laughing: I was waiting to see if anyone noticed that. I did flip the shackle when going pack together. Actually, right before I put the tires on.

[ibrocun]

Great write-up. Thanks Aaron!

[Mud Slayer 2.0]

Awsom tech ! This cleared it all up for me.. Thanks again !
on a 2nd note. how about a write up on spindle replacement ?? ive been told when bearings get overheated it ussally junks the spindle ?

[Trailer Guy]

Awsom tech ! This cleared it all up for me.. Thanks again !
on a 2nd note. how about a write up on spindle replacement ?? ive been told when bearings get overheated it ussally junks the spindle ?
This would be a great tech write-up because unless the spindle actually hits the road, I'd say 90% of the time, we're able to save them. I'll see what I have for examples in the back and see about doing a write-up like that.

[4x4not]

For me I think I'm going to just order a whole new axle for mine. The non-brake axle has seen better says (the tube anyway) and it isn't THAT much cheaper to do just the brakes. Overall a good writeup though :D

[yager]

Great write up...

Also i had a trailer/axle that didn't have the small 4 hole plate welded on. (where the brake backing plate bolts to) I had many shops, axle sellers, etc. tell me i needed a new axle. After some trecking and calling even gettting the wrong size plates, I ended up finding the plates at Tractor Supply for ~$5 and welded them on myself. (the axle stub was steped for the plate, just never had them added)

[Trailer Guy]

For me I think I'm going to just order a whole new axle for mine. The non-brake axle has seen better says (the tube anyway) and it isn't THAT much cheaper to do just the brakes. Overall a good writeup though :D
The tubes on this trailer had nothing wrong with them, so there was no need to pull the u-bolts and replace. By replacing the whole axle it does give you a spare beam in case you ever had one bend really bad.

[Trailer Guy]

Great write up...

Also i had a trailer/axle that didn't have the small 4 hole plate welded on. (where the brake backing plate bolts to) I had many shops, axle sellers, etc. tell me i needed a new axle. After some trecking and calling even gettting the wrong size plates, I ended up finding the plates at Tractor Supply for ~$5 and welded them on myself. (the axle stub was steped for the plate, just never had them added)
Good call. Yes, you can get just the plates to weld on. I sell them here at the shop. You're right though, a lot of dealers will tell the customers that hoping to sell them a new axle (more profit). It is too bad that some dealers feel they need to act like that, it really gives the honest ones a bad name. I get people in all the time that act surprised that we aren't trying to screw them over, and that really ticks me off. I would much rather people come into my shop with an open mind, but I don't really blame them for feeling that way. After getting screwed with by a couple shops, you come to feel like everyone in that industry acts that way. It really is too bad.

Thanks for the compliments on the write-up. I do plan on doing more of these, so hopefully I'll get better at them. And if there is something you would like to see, just say something, I need ideas on what to do.

[rockyota83]

If you guys would like to see more tech stuff about suspension, wheel bearing packs, break-a-way kit installs, etc. just post up and as I get a chance I’ll take some pictures and post a thread. If anyone has questions, please ask. You maybe asking the same question that 100 others are too scared to ask.





i would love to see any and all information you are willing to share and have time for, awesome thread the more tech i read the more confident i get in working on trailer axles. id really like to see a wheel bearing replace/repack write up..

thanks a bunch

future customer :D

[TacomaJoe95]

:) Nice write up. Big thanks for the hook up on the new brakes.:) You didnt have to do that. I enjoy working on your buggy. We got a big build up coming up soon on my Tacoma to get ready for. I cant say thanks enough man. Your a good friend! This is a good guy right here people. You should buy lots of stuff from him. Thanks again Aaron

[rockyota83]

This is a good guy right here people. You should buy lots of stuff from him. Thanks again Aaron


thats for sure, i havnt boughten anything from him but when ever i need somthing or ANYONE i know needs somthing trailer related they will all be sent to him. i wish more people would run thier business's with an attitude and respect like Aaron , im glad i live in norcal.

Aaron do you stock trailers or just order them?? you should make a thread in the vendors forum you keep updated with what you have to offer trailer wise

[Roc Doc]

Thanks for the writeup...perfect timing for me. I've got a trip to Big Bear coming up, and I want to have enough brakes.

In future writeups, maybe you can point out some common damage to be on the lookout for. Things rusted in place and how to get them out, or inspecting/testing wiring, that sort of thing.

Doc

Edit; Pimpin for Trailer Guy. I just ordered four new backing plate/shoe/magnet setups and two hub/drums, and even with shipping he is substantially cheaper that what I was seeing on Ebay. Once again, support the PBB vendors!

[jmhinescj]

Funny that you just did this Iv'e been checking around for prices on carhaulers, around here hardly any seem to come with brakes...a couple of trailer vendors were telling me it would be $400 per axle to add brakes to a trailer. I was looking in Northern where I can get a loaded drum for $99. I was thinking that surely I was missing something.
I guess I could add brakes to one axle on a trailer about as easy as i could add them to the second axle. I'll for sure pm you for the parts when I decide to do that. Is their any more to it than just mounting them up, running 2 wires up front, and changing from a 4 wire flat to a 6 wire connector?

[Mechanos]

Funny that you just did this Iv'e been checking around for prices on carhaulers, around here hardly any seem to come with brakes...a couple of trailer vendors were telling me it would be $400 per axle to add brakes to a trailer. I was looking in Northern where I can get a loaded drum for $99. I was thinking that surely I was missing something.
I guess I could add brakes to one axle on a trailer about as easy as i could add them to the second axle. I'll for sure pm you for the parts when I decide to do that. Is their any more to it than just mounting them up, running 2 wires up front, and changing from a 4 wire flat to a 6 wire connector?
I would also add a break-away battery/charger & switch. It's required in many states and just simply a damn good idea.

[ScottFJ40]

Thanks for the great write up.

[ScottFJ40]

Thanks for the great write up.

[reson46]

Great write up! I've been considering the same thing.

I've been browsing the tow rigs forum the last few weeks and have really enjoyed your posts. You always provide a lot of great information and explain things in a way that is easy to understand. I've learned a lot through your posts. :D

Willy

[Trailer Guy]

rockyota83
Aaron do you stock trailers or just order them?? you should make a thread in the vendors forum you keep updated with what you have to offer trailer wise

That is a good idea. It would work for the guys/gals that need a trailer that's in the Nor Cal area. Or for someone passing through. I'll check into doing something like that.

Roc Doc
I just ordered four new backing plate/shoe/magnet setups and two hub/drums, and even with shipping he is substantially cheaper that what I was seeing on Ebay. Once again, support the PBB vendors!

Thanks for the order. We apprecciate the business.

jmhinescj
Is their any more to it than just mounting them up, running 2 wires up front, and changing from a 4 wire flat to a 6 wire connector?

Not really any more to it than that. But yes I agree with Mechanos, you do need a break-a-way system if the trailer doesn't already have one. Heck, here is California, if the trailers gross is over 3,000 lbs., then it has to have brakes. And if a trailer has brakes (whether it needs then or not) then it has to have a working break-a-way system. Legally, a dealer can't sell a trailer that isn't legal for the road, at least not in CA.

reson46
You always provide a lot of great information and explain things in a way that is easy to understand.

That's only because my vocabulary won't allow me to explain things in any other way. I mean really, I'm just poor trailer trash.

[rock-rod]

This thread should be stickied!

thanks for the info. I plan on doing this soon and will order the parts from Trailer Guy when the time comes!

:)

[Isley]

...If you guys would like to see more tech stuff about suspension, wheel bearing packs, break-a-way kit installs, etc. just post up and as I get a chance I’ll take some pictures and post a thread. If anyone has questions, please ask. ...

Good info, thanks for the write up.

I'd like to see a writeup/pics of a break-a-way kit install (as mine came without one) when time allows.

[rocksteadyrobk]

Trailer Guy,

Great write up.. Whats the easyway to fix the shackles from inverting.

thanks,

RK

[Trailer Guy]

Trailer Guy,

Great write up.. Whats the easyway to fix the shackles from inverting.

thanks,

RK
To fix the inverted shackles you can do one of two things:

One: Use a long pry bar and stick it between the two shackle plates and rotate it. This will put leverage on the spring and flip it over to the correct side of the equalizer. This can be a tough way to do it, and if both sides are flipped, it may take two people, one on each side.

Two: Jack up the trailer so that both axles can come off the ground and put the frame on jack stands. Now using a floor jack, jack the axle that is correct all the way up as far as it will go. Then use the pry bar method. Once the shackles have flipped to the correct position, slowly return everything back to the ground. This method is easier, but takes a little time. Even though it take time, I prefer using jacks and stands. What's the saying: "Work smarter, not harder"

[rocksteadyrobk]

worked like a charm.thx rk

[thump93yj]

If you guys would like to see more tech stuff about suspension, wheel bearing packs, break-a-way kit installs, etc. just post up and as I get a chance I’ll take some pictures and post a thread. If anyone has questions, please ask. You maybe asking the same question that 100 others are too scared to ask.

Happy Towing,
Aaron


I ain't skeered :D

I've since figured out what I needed to when getting my trailer fixed up... But, back when I was trying to figure it all out... finding a decent diagram of trailer wiring was unusually difficult. Typical 4wire setups I found a bunch... but I needed 7wire info including the break-away switch&battery integration and if and how to hook up the power wire from the tow-rig to recharge said battery.

[jays68yak]

What would it cost to do this on a trailer? Parts wise? Can you pm me a price for both axles?