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Hi all... I'm in the middle of BRAKE HELL. But answering this question will help immensely. Google didn't help.
Is the larger reservoir for the front or the rear? I was of the opinion that the one closest to the firewall was the front. But these fittings won't allow for that... unless someone before me switched them and re-flared them. And the previous owner is guilty of all kinds of tom-foolery on this truck. When I got it the front brakes wouldn't work at all, which is what would happen if the lines were switched. Also, I made sure to ask the NAPA guy to get me the one for DRUM/DRUM. In the attached picture the line with the blue tape is definitely to the front brakes.
Any help is MUCH appreciated!
Oh yeah, this is on a 1969 F250 Camper Special, 2WD, HD brakes.
The drum master cylinder has a residual pressure valve that is not used for disc brakes. What this does is keep a little bit of pressure on the drum brake side at all times to keep the wheel cylinder cups tight against their bores so that they don't seep fluid. Disc brakes would be applied all the time if they were used with the residual pressure valve in the circuit.
So, the correct drum/drum MC will have different threaded ports on it that will fit the correct fittings?
I guess I will go back to NAPA and try to find one from Raybestos or Centric... jeez...
I would match yours up online
Then get the part number
Then go shopping at NAPA or anywhere else
** The old 4 wheel drum master cylinders often had different size reservoirs too (because of the different size wheel cylinders) front to rear
You look under the cap of one of the flat top master cylinders (with the small bumps for air) and you'll see a front reservoir that is bigger
So, just to try to nail this down... where exactly is this "residual pressure valve" on a drum/drum MC? Can it be seen and identified so there is NO QUESTION as to which MC I have? I think I have one of each on my bench right now and I'd like to be SURE of what is what, other than just which hose goes where. Unless that is the only way to tell? Two of you identified the picture as disk/drum... How do you KNOW? Is it because of the ports?
It's on the rear brake port coming out of the master cylinder
That is a BIG port (bigger port threads than the 1/8-3/16 inch brake line fitting on the front)
Here they are side-by-side. The old one has the LARGE port toward the firewall (front brakes?), and the new one has the LARGE port toward the radiator (rear brakes?) The fitting that fits the LARGE port will only thread onto the FRONT brake line. The two fittings are identical from new to old, but they are different from each other. As far as seeing what is inside the ports, I can't tell on the old one, but the new one is brass on the male flare inside the port. One thing is for sure, if I install the old one back in, I will be able to hook up the FRONT brake line to the larger reservoir which, if I am getting this right, IS INDEED for the front brakes.
In the morning I will bench-bleed and install the OLD ONE back in and see if I can bleed the whole system.
One more question: Do I even need the fittings? It looks like a male flare inside the ports... won't it mate up with the flare on the brake line?
Last edited by SteveCasas; Mar 29, 2026 at 08:48 PM.
The large reservoir in the master cylinder will always be the front brakes
Port size coming out can differ
Sometimes the rear brake port is 3/16 when both fronts are 1/8 or have a tee
Same with the rears, there will be a tee at the rear axle and a bigger line running down the frame for the rear brakes
I went to the MPC and it calls out C9TZ 2140-H which I found NOS on EvilBay. Same configuration just though it was described/boxed wrong.
I have heard of this but they were CHI-COM.
First time I have seen it on a FORD and I am old.
Now for the RPV's. (Residual Pressure Valve) Being drum/drum, both ports should have one. FORD did away with RPV's around 1972 and went to wheel cylinder cup expanders
in the wheel cylinders to accomplish the same thing.
If it is off-shore, only GOD knows what it is. Does the take-off have any ID MARKINGS, FORD or BENDIX?
EDIT - If the take-off is OEM and not a HU FLUNG POO copy.
Now it will have to be verified if the MC has or has not.
If not, you will have to use external in-line valves or rebuild the wheel cylinders with the newer style kits.
Okay folks I have to step in ask a question I have done a Disc/Drum conversion and my MC is a Disc/Drum MC. should I have these on both or just the rear drum brakes?? The rear drum are the original brakes nothing has been changed. I just bleed the brakes after setting for almost 20 years in the shop and I’m still not really happy with the brakes they’re kinda spongy and to me the pedal is going way further than I want it to plus I added a power brake booster when it was a NON power brake truck.
