Okay, I was being lazy and opted to just buy a set of pre-formed brake lines from DC. The nut sizes on the lines don't match up correctly with what I pulled out of a 1967 F100 Ranger Camper Special with power brakes, all drum. On the old lines the one with the largest nut, 9/16" has the smallest nut, 3/8" on the other end. The ones from DC have the 9/16" nut paired with the 7/16" nut.


Am I right thinking that they all run to a manifold rather than a proportioning valve? So why have all the different nut sizes if it wouldn't make a difference which port the lines are connected to? Also, is the MC correct having two different size reservoirs in an all drum truck?

 

Standard flare nut size for 3/16" hard line is 3/8"-24. Ford also used special sized fittings in 7/16"-24, 1/2"-20, 9/16"-18 and 5/8"-18 on 3/16" diameter tubing.

MOST parts stores will not have the specialty sizes and this is where they point you to the adapters bin. Adapters don't look as professional as actual direct-connection fittings and every connection point in the brake system is just another point in the system for a potential leak to occur.

Classic Tube will have the direct-connection specialty size flare nut fittings for hooking up your brake lines.

If your truck is an F100, it would only have a pressure differential valve (no metering valve and no proportioning valve). The pressure differential valve will be located inside the left frame rail, right behind the steering gear box.

 

Ok, so that block on the left frame rail that the lines from the MC go to is a pressure differential valve rather than a simple manifold. I guess that means that I need to keep the lines from the MC going to the same port that they came off of.

Before I have to let DC know that the lines they are selling aren't made correctly, I need to verify that the rear line with the 9/16" nut should or should not go to the upper front port on the pressure differential valve with a small 3/8" nut. Do you or anyone else know if that is correct.

I want to have direct connections without adapters so I'll take a look at that Classic Tube site.

Thanks

 

I couldn't find any fittings on that Classic Tube website but the pre-bent stainless steel lines are pretty tempting...just pricey. $299 for all 6 lines in stainless or $259 for all 6 lines in steel.

 

This is the old pressure differential valve off my '69 F100. Like all '67-'72 F100s, my truck had drums all the way around (manual drums at that). F100s didn't get factory front discs until 1973.



This is the inner workings of the pressure differential valve.



In the diagram above, you may notice a stand-alone Metering Valve plumbed into the front brake circuit. '68 was the first year optional disc brakes were available on the F250s and F350s (front discs not a factory option on F100s). The '68-'72 F250/350s with factory front discs would have used the same pressure differential valve as the all-wheel drum F100s-F350s. The only difference was the stand-alone Metering (hold-off) valve for the front discs.

There are (3) ports on one end of the pressure differential valve and (2) ports on the other end. The end with (3) ports is for the front brake circuit. The end with the (2) ports is for the rear brake circuit. The (3) ports on the primary side of the valve are all for 3/8"-24 flare nut fittings. The (2) ports on the other end are for the secondary side and both are for 7/16"-24 flare nuts.

The primary port on the MC is the port closest to the firewall. It supplies pressure/fluid to the front brakes. The MC port closest to the radiator is for the secondary side --it supplies pressure/fluid to the rear brakes. The secondary port fitting will be larger than the primary port fitting, to keep the lines from getting swapped at the MC.

Typical Ford manual 4-wheel drum brake MC.



*Specialty size flare nuts for 3/16" brake tubing from Classic Tube.*

The 7/16"-24 fittings are color coded red. They are part number ST8006.
Search results for: 'st8006'


1/2"-20 flare nuts are color coded black. They are part number ST8007.
Search results for: 'st8007'


9/16"-18 flare nuts are color coded gold. They are part number ST8010.
Search results for: 'st8010'


You will probably be better off to fabricate your own lines rather than trying to install pre-fabbed lines. Look at all the engine pics people post on here and see how many have adapters on their MC (a LOT). For whatever reason, when you get a MC from the parts store that's supposed to be a direct replacement for your truck, RARILY will BOTH of your factory brake lines connect directly to both MC ports without adapters (or, without cutting a fitting off the tubing and installing a fitting that will directly connect to the MC port, without adapters).

The pretty pre-fabbed stainless lines will most likely have the same problem, when trying to connect them to the MC. The main difference though is that stainless steel is not so easy to reflare for the correct fitting and this means having to use an ugly adapter.

3/16" steel tubing is cheap and not hard to double flare or bend. I have something less than $20.00 in the lines and fittings I ran on my truck, when I converted the front to disc brakes.

 

Thanks for all the info!

I have nice flaring and bending tools, but I'm living and working about two hours away from most of my tools right now. That's why I went with the pre-bent lines. I'll see if DC will allow me to return them, pick up my tools and get the fittings from Classic tube.

Thanks again!

 

You're welcome.

It's been several years since I've bought any fittings and gravel guard (the spring looking stuff over the brake line tubing) from Classic Tube. I used to buy 25 to 100 ea. of the fittings and a 100' of the gravel guard at a time, when I ordered from them.

I will tell you that their shipping isn't like Summit, --who gets the products to you in 2 or 3 days.

I would advise that you order the fittings at least two weeks (maybe 3 to be safe) before you actually plan to fabricate your lines.

 

Ok, there isn't a rush on completing this work because I don't drive that hot rod truck in the winter. I think I might just keep the lines and replace a couple of the nuts to make them work. I'm still out on the road working and need to take another look at the lines to see if there is enough room to cut some off and put a new flare on.

 

You hit on the real answer in the last line of your first post. An all drum truck will have equal sized reservoirs. You have a disc MC installed on your truck (small/large reservoir). If they sent you the lines for drum/drum they will fit if you have a drum/drum MC.

 

Parts store replacement MCs will come with unequal reservoirs whether your truck (F250/F350 w/factory front discs) or whether your truck has drums all the way around (F100-F350).

Their port sizes will be 9/16"-18 and 1/2"-20 with a 1.00" bore (manual or power brakes) on an F100.

Parts store 1.00" bore replacement MC for manual all-wheel drums. --notice reservoirs are unequal in size.



Some F250/F350s had 1.00" bore MCs (for either manual or power brakes). Some had 1-1/4" bore MCs (for power brakes only). 1-1/4" bore MC has a 9/16"-18 port and a 3/8"-24 port.

Parts store 1-1/4" bore replacement MC for an F250/F350 with power front discs/rear drums.

 

Equal sized reservoir units are still available from parts houses that are not reducing inventory requirements (and therefore floor space) through reassignment. The correct MC is equal sized. A lot can happen in 48 years including kludging incorrect parts for the sake of operability. Also, I am not trusting of 'also fits' applications as they are generally 'close enough' with some caveats like the need for an adapter or two. I can't tell you how many professionally rebuilt carbs I've opened up that had the wrong booster(s) and mismatched jets. Just sayin.

 

I understand what you're saying. In most cases, parts store replacement MCs, for all-wheel drum applications, will be of unequal reservoir size, regardless of how the OEM MC may have been.

As far as an all-wheel drum brake system goes though, it doesn't really matter if the primary (front brake) reservoir is larger than the secondary reservoir. All wheel drum brake systems don't require as much fluid volume to actuate the wheel cylinders as a disc brake caliper piston(s) would need. A larger primary reservoir on an all-wheel drum brake system would just have more fluid reserve for the front wheel cylinders.

The bore size is the bore size of a MC and it's going to generate a given amount of pressure output, dependent on how much force the driver is applying to the brake pedal, for whatever ratio the pedal has in relation to the MC, regardless of the type of brakes on the vehicle.

Going the other way though, it's not a good idea to use a drum/drum MC, of equal reservoir sizes, on a disc/drum application. A drum/drum MC of equal reservoir sizes does not have enough reserve fluid capacity in the primary reservoir to support a disc brake caliper, once the pads and rotor friction surfaces have worn down --which will cause a drop of fluid level in the MC, as the pistons move outward, and is why a typical 'disc/drum MC' has a larger primary reservoir with the extra fluid reserve capacity built into it.

It's (generally) best to use a MC that's designed for the type of brakes you have --drum/drum, disc/drum or discs/discs. However, if you have an understanding of the various brake system components, hydraulic principles and how the components will react, when changing parts up, you can have a brake system that actually operates better than what was originally installed.

If a person is not comfortable or knowledgeable about these things, it would probably be better to stick with the same components as what came on the vehicle originally, for the sake of their own safety.

 

I agree. Although a D/D MC will work in a Disc system when the pads are new, it will not last long as the pads wear and as more fluid stays in the caliper the reserve level in the MC will get to unsustainable levels. And there's no low fluid warning switches on this variety. I see it all too often that people just start throwing parts of different origin at their braking system and the first thing I think is this *is* the most important system on your vehicle and it was originally *engineered*. Guessing and cobbling has no place here. Either buy an engineered system or learn about it and do some calculations. I've studied the Mustang systems, specifically 67-70, to determine the differences between drum and disc, and there are many including the differential pressure switch port sizes. While mixing these up will not prevent the system from working it will slow down their action (drum unit in a disc setup) because the port size is smaller restricting flow. My first rule of Old Cars is "It must stop before it can go." I always go completely through the brakes and get new tires (brand new looking 10YO tires are an accident waiting to happen) despite what the PO says. Going to die of something. It doesn't have to be stupidity.

 

@Rasputin53. We have VERY Similar philosophies, when it comes to the importance of the brake system. I've posted essentially the same thing about the brakes and suspension of an old car/truck should be addressed BEFORE hopping up the engine. 'Go' is no good if you don't have (controllable) 'whoa' to stop it.

Pumping up the horse power in a vehicle that has a shoddy suspension and brakes is asking for a bad outcome.

I do have brake components from various Ford vehicles on my truck but, I do have a fair knowledge of brake systems/brake system components and an understanding of how the components would work, BEFORE I installed them. My brakes were not so good before my most recent changes but, they work really well now.

 

Yessir! A vehicle is a system and it all must work to not end up in your demise. I always laugh to myself when someone's first post is 'how do I make it go faster?' Is that *really* what you want to do with your collapsed suspension and 35 degrees of play in the steering? And the 4x4 guys that install a 4 inch lift with 35 inch tires and wonder why their stopping distance just doubled or worse. I'm swapping my wife's 67 Mustang to the factory disc setup. My convertible is a different story. Adapting an IRS rear using the guts from a SVT, but custom frame, half shafts and control arms. Also using the Explorer rear cover for the two ears to add stability and increase mounting options. That's requiring significant study of suspension systems and there will be a test. That whole brake system will be custom and will start with possibly the ABS from an Explorer. Still working that out. ABS has saved me and also nearly killed me so I'm on the fence about that one. Fortunately I now know rumble strips fool the ABS and to be extra careful any time I encounter them. They stopped using them here in NC thankfully.