What is this brake line junction thing?

[Jim Bathgate]

What is this thing doing in my 1968 Ford F350 brake line between the front and rear axles? The truck is a Camper Special with factory front disk brakes. I know it's not the pressure differential valve or the metering valve (just rebuilt both of them with kits from Muscle Car Research). I don't see it it anywhere in the 1968 Ford Truck Shop Manual, but it seems like it might be an original Ford part. Any insight would be appreciated.

IMG_3116.jpeg

[cep62]

That might be a line lock to hold pressure electricaly while you work the gas and clutch , on a hill.

Do you have a manual trans or automatic.?

[Jim Bathgate]

It's a four speed manual transmission (NP 435 with Dana 70 rear end), but there's no electrical connection to this junction. Just a brake line going in, and one coming out. I was thinking maybe a check valve but that doesn't make sense either since the brakes wouldn't then release. Perhaps a replaceable filter canister or water separator? Or maybe even some kind of buffer reservoir to soften the brake application, like a water hammer reservoir in a household system. I suppose I could take it apart but without a description or replacement parts, I wouldn't know what to do with it.

[DuckRyder]

That isn’t a switch in the top of it?

Where was it mounted?

Is there any possibility that it somehow adjust the brake bias depending on load?

[Busboy]

I'd say it's definitely a line lock.

[Jim Bathgate]

It is mounted inside the frame about halfway between the front and rear axles. It is rearward of the pressure differential and metering valves. The thing that looks like a switch is a cap with cotter pins holding the pins on top. Today I will see if I can move those pins up and down. Since this truck is a camper special it came with some extra equipment on it including a second battery, a larger radiator and alternator, and an electrical harness that would feed a camper. Would a line lock be something to use when the camper is parked at a campground to lock the rear brakes on so the camper wouldn't roll away if somebody bumped the emergency brake by accident? If those two posts on top are some kind of on/off switch for the rear brakes, then it would require two people to engage - one to hold down the brake pedal in the cab, and another to press the line lock. Is this how it's supposed to work? Again, no electrical connection to this junction at all.

[Busboy]

No, it's definitely aftermarket.

[Ranchero50]

Going with some flavor of line lock based on the larger inline coil.

For references sake attached is a pic of the neutral safety switch on my '58 MF50. It uses bullet connectors and the bent spring wires hold them in place.

DSC03866.JPG

[Jim Bathgate]

Thanks for the information. I didn't get a chance to do any more investigation today since I spent most of the day working on getting the rear bearings regreased and axle back in, then adjusted the new rear brake shoes. Maybe I can take a closer look at this thing in the next day or so. I suppose I could just remove this and plumb a short brake line in to replace it. From what I just read, it doesn't sound like a line lock is something I really want or need. Any opinions on the value of a line lock?

[DuckRyder]

I believe there is a factory union in that area anyway.

I did some google image searches for “old line lock” and found a reference to a "mico-loc (truck stuff)” but unfortunately “mico-loc” and “micro-loc” seem to mean something else now...

I don’t really see what use a line lock would be on a truck save perhaps loading on steep hill or something.

[Ranchero50]

We use a line lock on my buddy's tow truck for an E brake.

[Jim Bathgate]

I took the unit off the truck today and can confirm that it is (was) a line lock from Fasco industries in Rochester, NY. In fact, hidden behind the unit was a cut-off electrical wire that must have activated the unit from the cab at some time in the past. I guess I will just fab a jumper brake line to tie the line back together without the line lock. Hopefully, after rebuilding the rear brakes over the last week, the emergency brake will work a little better than before. And I alway carry wheel chocks with me anyway.

Thanks so much for helping solve this mystery. FYI, I got the engine running again today after rebuilding the carburetor (Autolite 2V original). Just a few more items to check off and the truck should be ready for my 7000 mile tour across the U.S. and back. I'm taking our youngest son's "pile of stuff" he left behind in California over to him in Boston via route 80, then down to Baltimore to visit the family, then back over route 40/66 to do some sight seeing on the way back.

[Busboy]

I searched your posts and didn't see any pics of your rig. I have a 72 F-350 with a 159 inch wheel base also so I'd sure like to see your truck.

[Jim Bathgate]

Here's my baby. 1968 F350 Camper Special Custom Cab. 22K original miles, 360 engine, 4 speed NP 435, Dana 70 rear (3.73). I'll build a plywood box to keep the load protected on the trip, but then disassemble it when I get home to San Jose. This truck was owned for its first 40 years by a guy in Gilroy who had a 1000 acre ranch. I bought the truck about 10 years ago after the guy became too old to run the farm. He died a year or so ago at age 98. He must have kept the truck in a barn most of its life because it still has the original paint and seat upholstery. I recently had the burlap under the seats redone since it was disintegrating. My first car (bought in 1970) was a 1967 Dodge Dart. Also had a 1967 Chevelle along the way, so this vintage vehicle is something I can relate to. I'm retired now so have some time to put into fixing up the truck and traveling around in it.

[DuckRyder]

That thing is nice!



You should give us a road trip thread on your cross country...