1962 - 1971 Wagoneer / J-Truck Brake Systems

[Harry Dawg]

Hello Folks.

Starting this thread for myself and others to document their experience with the above topic... Hopefully by adding this to the archives of the internet, it will help someone in the future.

I figured I would start off with factory options for these Kaiser era FSJ’s . As far as I know, the 2 choices were

1) 4 Wheel Drum Brakes / No Power Assist / Dual Port Master
2) 4 Wheel Drum Brakes / Vacuum Assist / Dual Port Master

Specific to the second option, there is a thread with some pretty good info here. viewtopic.php?p=214877&hilit=Brake+Boos ... er#p214877

The limiting factor on the second option is the parts (specifically the booster mounting bracket) are not available aftermarket to convert manual to power brakes. Unless you have a parts truck or are repairing your factory power brake system, you are basically SOL.

That being said, one will have to explore custom options, which leads us into the next portion of this thread.

Aftermarket Options

Starting with the actual brakes, there are kits available to convert the front closed knuckle axle as well as the rear Dana 44's to disk brakes. (This applies to other axles like Dana 25 & 27 as well)

You can use a Chevy Tracker Caliper / Disk assembly using an adapter from Brennan's Garage, or source parts from some Chevy pickups if you want a larger disk/ caliper piston.

I went with the former, as the latter requires grinding the axle down.
More info on disk brake conversions here

viewtopic.php?t=22381&hilit=Closed+Knuc ... 44+rebuild
and here
viewtopic.php?p=216176#p216176

Related to the Chevy pickup conversion, see here
https://www.motortrend.com/how-to/154-0 ... onversion/

One note on this - Either swap will require the use of a wheel spacer with longer studs or different wheels to clear the calipers.

So let's say you make it this far. If you are running factory size tires on 7" wheels, you may be fine without a booster.

However, if you plan on running larger tires you will 100% need a booster. I am running 35"x12.50" on a 15" steel wheel and it barley stops the truck with front disk / rear drum no booster.

At this point I think it will be good to throw in this free brake system calculator from Busted Knuckle Off-Road - https://bustedknuckleoffroad.com/collec ... calculator

Wish I knew about this prior to diving down the brake rabbit hole.

So what are the options? As far as I see it is either a Vacuum Booster or Hydro Boost.

-Disclaimer, this is where it starts to get into theoreticals for me

Vacuum Booster is probably the easiest option if you can obtain the booster mounting bracket and power brake pedal assembly.

According to user 44BZ, a 7” Dual Diaphragm booster with a Corvette Master Cylinder will work on these rigs with minor modifications, but you will need mounting brackets from a 67 j3000, the firewall spacer out of an early 70s Wagoneer and the brake pedal from the 67 because the pushrod on the booster won’t line up with the manual brake pedal. I would imagine any of the aforementioned parts could be sourced from a Kaiser rig with power brakes throughout the production years and is not limited to the years mentioned above.

Source - viewtopic.php?t=2377&start=40

So that is vacuum assist, but what about Hydroboost? Obviously ideal for those looking for max performance, but at what cost?

Bj’s sells a booster here, https://bjsoffroad.com/hydroboost-brake ... -shipping/ which could be an option, but you will still need the rest of the system. The price tag is pretty steep though for what looks to be a Chevy Astro part or something of that nature.

A couple concerns are that the Saginaw or Eaton pumps may not be able to product enough pressure to actuate both power steering and power brakes.

Secondarily, one will need to drill and tap a Saginaw box, which as far as I know there is no documentation of.

Lastly, one will need all of the lines and what not to create the system which would also be a bit of a wild goose chase depending on what threads your master cylinder, pump, box etc have.

So that is that. From here I pitch it to the rest of the FSJ community to get their feedback while I hunt for parts.

Leaning towards a vacuum assist setup, but if I can rationalize the Hydro Boost system it is worth considering.

[tgreese]

Just a comment - I would expect pre-1968-ish Jeeps to have a single port master cylinder. As I recall, the NHTSA mandated dual port for all cars around that time. The change could be a year or two earlier, prior to the mandate. The Wagoneers and lowest-GVWR J-trucks will all have the 11"x2" Bendix drum brakes all around. J-trucks with higher GVWR got the 12"x2" drum brakes (parts 100% unobtainium today) or the 12-1/8"x2" with 8-lug or 13"x2.5" with DRW.

[Yeller]

My vote would be hydroboost. It is simpler than most think. The bracket simple to modify and its height can be adjusted to match the manual pedal fulcrum point. I have considered redoing mine with a manual brake pedal to gain a lighter brake feel, in my opinion the power pedal has too high a ratio for really nice modern feeling brakes, still stops well but more would be nice.

As for the plumbing you need a pressure line from the pump to the booster and a pressure line from the booster to the steering box, plenty of ways to accomplish that. The return line from the booster needs a Y fitting in the return line from the steering box to the pump. No need to drill and tap anything.

Brake booster brackets for a Jeep YJ are a good place to start then you can add any booster you want to that. Having done both vacuum is a little easier but the brake power of the hydroboost is second to none

[sierrablue]

Just a comment - I would expect pre-1968-ish Jeeps to have a single port master cylinder. As I recall, the NHTSA mandated dual port for all cars around that time. The change could be a year or two earlier, prior to the mandate. The Wagoneers and lowest-GVWR J-trucks will all have the 11"x2" Bendix drum brakes all around. J-trucks with higher GVWR got the 12"x2" drum brakes (parts 100% unobtainium today) or the 12-1/8"x2" with 8-lug or 13"x2.5" with DRW.

Yeah somewhere in there, there was a mandate on the master cylinders (for good reason). I know the '63 Panel has a single

[sierrablue]

I would probably vote hydroboost too. If you're running that power-sucking pump (yes, I realize it's not a ton, but it's quite a bit, and one more thing ALWAYS adding load to your system), you might as well make the most of it. And if you have a stock steering box, due to the valving in the box, it's way overboosted IMO anyway, so you don't really have to worry about losing a ton of power. It also has better/more mechanical like feel IMO, which I like.

Or just take up mountain biking (you know, 'cause everybody has a ton of free time right? ) and get some rock solid, beefy legs and use that for your power brakes lol

[Phils67]

My 2 cents, I run a vacuum booster and master from a XJ. Had to modify 2 holes on the firewall and it fit in there fairly easily. If you have a hydraulic clutch it may not work but in an auto or an older bellcrank style it shouldn't be an issue. Had this setup for years, it's compact, and back when I ran 35s on 4 wheel drums it stopped the truck no problem whatsoever. Now it stops basically 32s with 4 wheel disc on J20 axles, again, no problems. I even tow a 16' steel car hauler trailer with a load, with a trailer brake installed, again, no issues. Cheap to find, easy to install,doesn't take up much real estate and does the job. I also used the proportioning valve from the XJ. Just a thought but ANY boost is better than none.

[Harry Dawg]

Well, as luck would have it a guy down the road from me had a brake booster from a 99 XJ for $35.

@Phils67 Can you give a little more detail on which holes you drilled? I looked and there are a couple of possible holes to reuse for mounting the XJ booster.

Still haven't discounted Hydro boost, but I haven't installed the power steering system yet and I just need it to drive for right now.



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[Harry Dawg]

So I got the Cherokee booster and MC installed today. I purchased this universal mounting bracket and it bolted right up. Didn't even have to drill any holes.

The push rod fits perfectly and did not change the factory stroke at all. The only thing I had to do was drill out the hole where it mounts to the pedal.

Unfortunately I won't be able to use my adjustable proportioning valve because it sits too close to the wheel well for the lines to clear.

The Cherokee prop. valve fits, but doesn't have a brake light switch. I wonder if I could screw one into the end where this little bung thing is?

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[Yeller]

You won’t be able to just put a switch in the Cherokee prop valve, that’s actually the end of the shuttle that turns the warning light on. Having run plenty of those pressure switches for brakes I now refuse. I just mount a GM brake switch on a tab to the steering column pressing against the brake pedal. Way more dependable and it never springs a leak.

[Herk]

You're far better off relocating the switch to the pedal bracket like Jeep did in 73.

[Harry Dawg]

Ok. Thanks for the feedback y'all.

I prefer mechanical parts anyways.

Are y'all using something like this, or the spring type switch?

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[Yeller]

I’ve been using this one, there are others but function is the same. This one just happens to have dedicated contacts for TCC and Cruise control.

I’d have to go digging, I have pics somewhere of the install. Several of us here have posted about it. It’s super simple.

[Harry Dawg]

Good to know.
I have a 3 speed and no cruise, so I will probably go with the more simplified version of this.
If you have photos of mounting that would be great.
Having a hard time envisioning how this mounts to the column and where the contact point with the brake pedal is.

[Yeller]

Just so happens I’m 20’ away from my truck today

A piece of 1x1/8” flat bar with a 90 bent on the end and a couple of drill/tap screws securing it to the column.

Glad I poked my head under there the nuts were loose. So I was close to having brake lights all the time.

[Harry Dawg]

Perfect! Thanks for the photos.
It all makes sense with the addition of the flat bar mounting bracket.
Just got one ordered on Amazon. Should be here tommorow...

[Yeller]

Always glad to help when I can.

Sometimes its the small simple details that are the hardest to wrap your head around, just need a picture

Those small details often can also make or break a vehicle by making it more reliable, easier to use, ect so it gets used more.

[Harry Dawg]

Tested out the brakes yesterday.
They work like a charm! Almost too good LOL. Not used to such a sensitive pedal, which led to a few screeching halts.
Thanks @phils67 for sharing this idea.

[Yeller]

Nice when it works

[Harry Dawg]

Ok.

The last piece to the puzzle is the wiring.

After further reviewing my rear light circuit, I realize that my previous setup of brake light switch direct to light wont work, as the brake light and turn signals have to share a circuit, passing through something like this. https://www.amazon.com/American-Autowir ... B009T4TPRM

What part of the factory circuit acts as the connector point? The turn signal switch itself, or some box under the dash?

TSM shows that there was a hydraulic pressure switch from the factory, but this was missing when I got it, so I don't know what factory wire to tap into for the new brake lights.

[tgreese]

Turn signal switch. With a combined indicator and brake filament in the lights, the turn signal switch handles combining the two signals. I can look at the circuit later - off to a meeting now.

Does '73 have the early column? The wiring diagram on the Tom Collins site seems to suggest that. It has a table of what connects to what to switch the brakes and indicators. You could trace back to the brake light switch.