Adding a parking brake (Split from previous thread)

WilliamA

I've split this thread out so I can focus on the parking brake upgrade I am doing on my T@G.

Here is the new (left side) backing plate with the parking brake pawl sticking up on the back.

Here's a rudimentary demonstration of how the parking brake works. By pulling the parking brake lever forward, it moves the brake arm toward the rear engaging the front shoe into the drum. As the brake adjuster (bottom of the shoes) simply floats within the drum, moving the front shoe out moves the rear shoe out from the bottom of its pivot.

You can see at the bottom of the photo how far the brake magnet has moved rearward as I push the parking brake lever forward.

Here is a photo of the backside of the backing plate so you can see how long the parking brake pawl is from pivot to pivot.

I've done a few drawings of the entire cable run in order to get a well-defined idea of the details yet to be worked out. My main concern with the cable routing is how much off-angle there will be between the line of thrust of the parking lever and the line of pull of the cable. I've not measured anything exactly as yet, but so far, the off-angle looks to be fine and well within the tolerance of the parking lever without binding. Keep in mind here that these drawing are not to scale and the off-angle I've drawn indicated by the red line is much more dramatic on the drawing than it will be on the trailer. Just by looking at the trailer, I'd say the angle will be within 10 degrees or so. Fine for what I'm doing.

A side angle of how the cable should go from rear to front. In the front, the cable will go up into the space between the frame rails and most of the mechanism will be hidden, or at least, up out of the line of debris spraying off the Jeep.

After spending waaaaayyy too much time foraging the net for different kinds of parking brake handles, I've decided I have too much stuff on the tongue. It's way too tight up there for me to have a comfortable place to put a handle on top of the tongue. I'm not at all disappointed as I feel that all of the things there are purposeful. Having said that, I need to find an alternative to where I can place the parking brake handle. I think I've found a good spot where it's easy to get at, but out of the way when traveling. It's also a good spot to put it so I don't have to make yet another turn in the cable pull. I want the cable run to be as straight as possible so there's no problem with the cable retracting when releasing the brakes. Too many tight turns is just asking for a spot to bind and partially hold the brake on. I don't want that. In addition, having only one cable makes for a much less complex arrangement when rigging the cable. The spool where the cable rides on the handle will rotate freely, meaning the parking brake pressure will equalize for both sides. It also means that I will only need a single adjuster on the entire cable assembly. I'll (probably) put a steel turnbuckle at one end or the other where it attaches to the parking brake pawls at the backing plate. Adjusting one side will automatically adjust both. Less fiddling will be the result of it.

Here's the detail of the parking brake handle, sans dimensions. I needed to get a shape on paper so I can start to do the detail math necessary to get the mechanical advantage and total throw correct. For the distance between the parking brake lever anchor and fulcrum, I'll wait until I have all the pieces in and mounted, then measure the cable throw at the parking brake lever and see how much travel it takes to tighten the brakes sufficiently to hold. Then I can see how far I want the handle to move in order to apply that number to the fulcrum. From there it's a simple matter of drilling a hole (then welding in a bung on the handle) to mount the spool.

You might have noticed there are details (in addition to the dimensions) still missing. The main one is that some sort of detent will be necessary to hold the parking brake lever in place when locked. I have about 5 different designs for various methods to do that but at this stage, it's not necessary to get too far along with that. Much of the detail for a lock mechanism will depend upon the exact angle between the handle and right frame rail and a few other critical factors. Measure twice, build once. I'll get to that.

For now, the "bones" of plan "A" are on paper and I will proceed to get things in order enough to make some parts.

I'll keep you in the loop....

WilliamA

rfuss928

What an elegantly simple solution. Very nice design.

Just a brainstorming thought (sorry no drawings):
If it would help, you could make your handle dogleg shape with the spool at the knee and move the pivot near the centerline of the trailer. Then you can create geometry that will hold itself engaged by passing over center of the pull at the end of the stroke. It might be a handy feature.

I look forward to seeing the final results.
Have fun,
Bob

WilliamA

Hmmmm.....An interesting idea Bob. I hadn't considered that. I think I will add it to my drawings list.....Hmmmm...

Thanks!

WilliamA

WilliamA

Working on an idea from Bob....

WilliamA

WilliamA

Having been inspired by rfuss928, I took his idea about a more simple lock and pivot mechanism and put it to use. I went in today and picked up a couple of bags of hardware and will be putting the main parts of the handle and mechanism tomorrow. I'm excited to get it put together. With the current Greek God like weather we're having, I think the installation of the new backing plates will have to wait for warmer weather but I can put most of the ideas to work.

Stay tuned...

WilliamA

WilliamA

I got some time this afternoon to flesh out a few general drawings of how I want the linkage to work now that I have the material to work with. The local sourcing of material requires me to work within the box of what's available. It's half: "fit the material to the design" and half "design to fit the material". In any case, I have a good enough handle (no pun intended) on the design that I can cut some material and see how things work.

Here are a few basic drawings to give you an idea of where I'm headed:

Here's the basic layout of what's there and how to best use the space. I wanted to know exactly how much travel the lever would have at any point along its length. It's not as simple as "half the distance, half the throw" because there is angularity in both the lever and the cable as it comes up.

Here is a bit of detail of the linkage assembly. The red bar is 1x1" steel at 11 gauge wall pre-drilled square tubing. Easy stuff. Not elegant, but easy....The light green bar is 3/4x3/4" tubing (non-perforated) that just slides inside the 1" tubing. The dark green bar is the same material as the red lever. I'll relieve the tubing with a cut up the side so the 3/4" tubing will rest inside the 1" tubing. At full extension, the two pieces should go past vertical and lock in place.

Here's the parking brake in the "ON" position. The sheave will attach approximately in the center of the lever which should yield about 2" of travel, give or take. The lever on the brake backing plates is 2 1/8" eye to eye and I have guessed that it's about 1/2-3/4" of throw from relaxed to locked. If I have 2" of throw, that leaves me with an inch of cable slack in the unlocked position. None of that can be known until I start stringing cable to see how much slack I will actually need. I have plenty of throw so it will only be a matter of getting the adjustment right.

So far, so good. I have all the lengths so it's time to get to cutting and make some sparks.....

WilliamA

WilliamA

I spent some time yesterday grinding up a bit of metal. I have most of the fitting work done and am on the detail side of filing and then a bit of finish to keep the rust off. I'll fit the lever assembly into the trailer first just to make sure everything fits in where I want it.

Here's the new lever assembly with all the hardware I'll need to hook it up.

The lever laid on my 100% scale drawing. Shown in the "parking brake applied" position.

Here, the lever is shown in the "parking brake off" position.

My full size drawing for fitting reference to the pieces.

Now I need to either wait for the temperature to get above 0 or just get brave and go out to see how the lever assembly fits. I also need to make one more small bracket to attach the handle to the lever assembly so it will sit below the bottom edge of the frame rail. I'll also need to bend the lever out at 45 degrees so the ball is exposed in both positions. I'll do the lever attachment this morning and see how the weather looks later today.

WilliamA

WilliamA

I got my lever bracket made up and installed, then went out and stuck the whole thing in to see how it works. As it turns out, it works and fits fine. When I pull it all out to paint, I will open up the holes for the mounting pivots just a bit as it's a wee bit tight, but otherwise, it seems to work as designed. I even got the lever angle bent exactly right on the first try. Measure twice and all that...

Here's the install. I had to move the wiring harness a bit to use the hole, but I have picked up some new wire harness clamps and will reattach it underneath from there forward.

The spring is just to keep it in the rearward travel position. Cable tension should hold it fine in the applied position.

In the "Parking Brake Applied" position:

Parking brake in the travel position

Detail photo of the small drop bracket I made to get the handle under the frame.

Curbside shot of the lever in the travel position

Parking Brake in the "Park" position. That lever is all you'll see...

Now it's wait for a hole in the snow to get out and put the backing plates on, then hook up the cables and adjust everything....

WilliamA

WilliamA

The temperature snuck up to 8 degrees today so I geared up and went out to get some work done. I got the backing plates on and am now ready to route the cable and try some adjustment to see how it works. It should take an hour or two in order to get the cable sheaves on and then put the swages on the cable ends. Hopefully, tomorrow I should have the bulk of the big stuff done.

Once the cables are on and adjusted, I'll need to crimp on some wire connectors for the brake wiring and then reroute the side marker light wires to get them out of the way of the cables. Not hard work but too putzy to do until the temp is up above 20 or so.

WilliamA

WilliamA

I got my brakes hooked up and working this morning, then put everything back together so "Chuck" (wagon) is back on his wheels again. The installation of the cable and sheaves went off without a hitch. Here are a few photos of the finished job:

The passenger side cable run has an adjuster on it. The adjuster is 3/8" NC L&RH thread for those interested. Cable is 1/8" galvanized steel 7X19 strand. I still need to source a left-hand thread NC nut for the lock on it. They should have it at ACE Hardware.

This is shown in the "brake applied" position.

Here, the brake is in the "unlocked" travel position. Plenty of slack. I might add a small (20 lb metal stainless) fishing leader to the front just to keep it from hanging on the cable, although I don't know why it needs one.

Drivers' side in the "Brake applied" position. I used two swage clamps per side on the cable as well as a cable-end clamp just to keep things tidy. I borrowed the cable swage tool from my brother. He'll want it back before fencing season starts, although right now the top of his fences are about 2 feet down under the snow.....

It looks in the photo like the cable is very close to the fender light wire, but it actually sits about 2 inches away from it. No worries about contact.

Here's the front lever mechanism with the cable running through it. The cable is a single piece and goes all the way around, terminating at either backing plate.

Here is one of the cable sheaves I used to route the cable to change its direction. I simply used the holes in the frame and just bolted them on. Took about 2 minutes per side. The sheaves are 3/4" radius with 1/4" bolts. There's no bearing, but there is a steel bushing inside the sheave and bolt.

I had the trailer on jackstands for the installation and had the wheels off. Once I got things all assembled and adjusted the brake, I hooked up the new electric connectors for the brake and put the wheels back on, then set it down. Once it was sitting on the ground again, the rotation of the torsion suspension loosened up the adjustment a tad. I re-adjusted it and it was fine. I am surprised (delightfully so) about how hard the parking brakes hold with just a little pull on the cable. I had expected it would need more force to lock the wheels, but not so. I had the trailer on the jackstands while I put the wheels on and when I torqued the wheels by setting the parking brake with the tires still off the ground. It will easily hold the trailer in any sketchy situation I want to put it. No more messing around with chocks. I don't plan to leave the parking brake on while at home to keep the shoes from sticking into the drums over a long period of time. I'll still use the wheel chocks for storage.

Now a few details yet to do. I had to move the emergency pull switch from inside the trailer frame to put in the lever assembly, so I need to make a small bracket that moves it forward a couple of inches, then put it back on. I also need to re-attach the wiring harness into its clamps and a couple of other things like adding a few zip-ties to keep the wiring harness tight up there. Perhaps tomorrow I'll hook on and run down the road with it to see how well the new brakes (electrical) work. I also need to take the ball off the parking brake handle and put a dab of epoxy on the threads to keep it from either falling off or getting stolen. Dang kids.....

This was a big job. Perhaps one of the most involved and technically challenging I've done yet and I'm glad that it worked very well right out of the chute. Planning and all that....I'm really pleased with it.

WilliamA

LuckyJ

Really nice! Can't wait to get on mine! But since it also involves suspension work, I could take a little longer. And we still have all that snow on the ground.

But vacation time begin next monday, so I should have time to mesure, cit and burn metal!

Again, nice job!

Somemedic

It begs the question...

How much is the kit? You did the hard work, sourced the parts, have the instructions practically written. Packaging and marketing is all that's left.

Sharks, who's in?

LuckyJ

@Somemedic said:
It begs the question...

How much is the kit? You did the hard work, sourced the parts, have the instructions practically written. Packaging and marketing is all that's left.

Sharks, who's in?

In my case, I already have 99% of my components, they are all differents. So I would not be part of the customers base.

WilliamA

Hmmmmm.... It seems that my quoter won't quote anymore, but the copy and paste seems to be operational for now.....

Anyway,

Somemedic said:

"It begs the question...

How much is the kit? You did the hard work, sourced the parts, have the instructions practically written. Packaging and marketing is all that's left."

I said:

"Whoa there.... No wanna. I'd make a parts list for anyone interested, but I've no interest in getting into a retail operation. As it is, I have to hold a gun on myself just to get me to buy my own parts!"

The backing plates I sourced from Etrailer.com, the remaining hardware came from "various sources."

I think I paid a couple hundred bucks for both backing plates with shipping. I've probably (possibly? maybe? Actually, I have no idea come to think of it) got around a hundred bucks or so in the rest of the do-dads.

WilliamA

Somemedic

That's too bad. I was in

WilliamA

@Somemedic said:
That's too bad. I was in

Just to be clear, I would be happy to help anyone who is working toward what I'm doing but I don't want to get into mass-market fabrication. There are a couple of reasons for that. First, I don't feel comfortable making and selling something that I haven't tested. I don't have any doubts whatsoever about my parking brake mods but that said, I haven't tested it either in the world. Until I get a couple of trips in, it's all speculative. Until then, I can't even say that "it works". Second, My tools and equipment here are pretty rudimentary and space is a serious consideration. I live here through the kindness of my ex, so I need to keep my debris field in order and keep things "fluid" if you know what I mean. Workspace is always at a premium.

If anyone is interested in projects I'm doing on the order of the parking brake etc, I'd be glad to work up some components, but most of the stuff is available off-the-shelf so it's not really a tall order.

WilliamA

WilliamA

I went out yesterday for a scavenger hunt to pick up some miscellaneous bits and find my left-hand thread locknut. Picked one up at Ace Hardware for less than a buck.
Boom....Done......Boom.....
WilliamA

WilliamA

Using my new Rube Goldberg design parking brake has been great and I'm lovin it, but daily use has exposed a flaw in my design. It works fine, but one (me) needs to remember to release it before travel. My clever design of the handle

has it tucked up out of the way where it's also easy to overlook. Hmmmmm.....
I contemplated a few options such as moving the brake handle up on top of the hitch, making a mechanical "flag" that deploys over the hitch to tell when the parking brake is applied (that would have worked) or putting a warning light circuit on it to help my rememberer. After much rumination, I decided to go with a warning light.

I picked up an LED marker light and made a bracket for it on the tongue where it's hard to miss. I made another bracket for a sealed starter switch button and put it down where the parking brake linkage presses it in when the brake is applied. A devilishly simple design....sort of...

here's the problem:
When the parking brake is applied, the light comes on and stays on....forever.
Not what I wanted. I wanted the light to come on ONLY when the trailer plug was attached to the Jeep. It could sit for a hundred years with the light off and brake applied, but illuminate as soon as I plugged in the trailer umbilical. The Doctor to the rescue. I knew I would have to isolate the circuit from the trailer battery in some fashion. I could use a rectifier or relay, but would need some discrete voltage-sensing circuitry to tell the relay when the Jeep was hooked up. I was trolling (in the fishing sense, not the internet tense) my local Fleet Farm and stumbled into such a device sitting on the shelf.......on sale! It's a battery isolator. As opposed to the standard, rectifier-style, this one is actually a 100A relay with voltage sensing to control it. Perfect! I admit to being a bit too laissez-fair (LuckyJ...did I spell that right?) about hooking and unhooking my rig to keep my volts separate, so a battery isolator wouldn't be a bad idea in any case. To be honest, when I'm out camping, other than an occasional glance at my voltmeter, I pay no attention to my battery condition at all....I rarely disconnect from my Jeep if I'm moving the next day. The last thing I worry about is battery voltage.

So having a battery isolator might just protect me from myself.
I opened up the junction box and pulled the tow vehicle charging line off the lug and ran it to the "main" lug on my battery isolator. I ran the "aux" off the battery isolator back to the junction box and put it on the common hot lug. Now, when I disconnect the umbilical or when voltage drops below 12.8V, the isolater relay opens. I tied the 12V circuit for my parking brake warning light onto the "main" lug of the battery isolator so if the umbilical is disconnected or the isolator senses loss of charging from the Jeep, the relay opens and the light goes off. As soon as I plug in the umbilical with the parking brake applied, the light comes on until I release the parking brake, opening the switch and turning off the light.
Simple.....

WilliamA

LuckyJ

Well, if thoses are the words you wanted to use, You got just a little spelling mistake (but who I'm I to comment on this. ) It would be "laissez faire". But I think that the exact expression is "laissez allez". As in letting go or bing a little laizy. It that what you ment?

As for the light indicator, that is a lot of work, but nicely done. But I might just be going with the little type of flag like the "remove before flight". Thing, that would move from the brake handle when on the move to the hitch when parked.

But, nive work!