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1st Gen. Ram - All TopicsDiscussion for all Dodge Rams prior to 1994. This includes engine, drivetrain and non-drivetrain discussions. Anything prior to 1994 should go in here.
Took a look at this thread out of general interest and have a question. That valve looks quite substantial, but it looks like the pipe fittings are made for olives. As this will be used for high pressure hydraulic lines, should the fittings not be flared or even double flared? What is the pressure rating for olives on that size of pipe?
Another question. No idea how heavy this thing is, but I see no way to attach it to anything and take the weight off the lines. Is it OK to just leave t hanging on the pipes?
Got my new proportioning valve, anyone know if "increase" means more pressure to the rear brakes or more bypass?
I think it is just a needle valve like the air screws it a carburetor. They don't regulate just restrict the flow.The one I had on my jeep increased flow by screwing the valve out. won't say counterclockwise as mine had a left hand thread.
Got my new proportioning valve, anyone know if "increase" means more pressure to the rear brakes or more bypass
It gets confusing. I had to put on a label that suits me better for identifying what that **** is doing. Like a water faucet, closing it off will get you no rear brake pressure. Opening it up wide open will get you back to where you currently are.
But, don’t quote me, as I’ve learned some valves have the shut off attached to the **** inside and closes it off when you turn CW, and others have the closure in the bottom, spring loaded, and as you turn it CCW, it may close of the circuit. Best thing is to turn it one way all the way till it stops, then go the opposite way counting whole turns till it stops, then back the other way again at the midpoint. Then take it for a test drive at your local high school parking lot, and see the effects it has on turning it one way or another. Then label it.
i don’t know the make of that valve you have, but the first one I ordered looked exactly like that, and it ended up leaking right at that threaded connection where the **** housing threads into the body housing of that valve. I replaced it with a proven one from Summit(Summit’s own labeled valve, made by others)and although I liked your style better, I didn’t want to chance the leaks.
i have to ask, what are you going to do with your factory differential valve? The valve that is directly under the master cylinder(on a 1993 model, and mounted on the inside of the frame down low on other year trucks). It has the brake light switch attached to it. Others have called it a proportioning valve, a differential valve, and a combination valve. Mine is not liking my hydro boost set up. The metering valve inside is not liking the added pressures that comes with HB, and favoring the rear brakes ONLY, causing lockup situations.
I am getting ready to remove that factory differential valve altogether, and either replacing it with a new one, made for hydro boost, or not even having one and solely relying on the adjustable valve.
if you zoom in on that replacement Summit valve, you can see my mark I put on the valve so I understand what each turn does. For that valve, CCW means less rear braking pressure
Mextan, there are two 1/4" holes drilled through the valve body for mounting. Those fittings are double flare. no olives/compression sleeves.
The valve is a pressure regulator. "increase" means more max pressure, "decrease" is less max pressure. Although it does have a needle and seat type arrangement, it also has a pressure regulating spring to control output pressure. A needle and seat alone would only limit initial application flow. This valve will not only limit flow rate, but also limit and maintain output pressure. It needs to be mounted AFTER the combination valve for the system to work properly. The factory combination valve will shift, turning on the brake warning light, if the adjustable pressure valve is mounted upstream of the combo valve. The combo valve uses differential pressure between the front and rear brake circuits to shift internally. This shift effectively shuts off supply source to the lower pressure circuit so that in the event of a leak/failure, you still have a working brakes on one end of the vehicle. When pressure inside of the combo valve is equal, the valve is in a balanced state, and doesn't shift. When pressure inside the combo valve has different pressures, it will shift. This is why you really don't want to mount the valve upstream of the combo valve.
Mextan, there are two 1/4" holes drilled through the valve body for mounting. Those fittings are double flare. no olives/compression sleeves.
The valve is a pressure regulator. "increase" means more max pressure, "decrease" is less max pressure. Although it does have a needle and seat type arrangement, it also has a pressure regulating spring to control output pressure. A needle and seat alone would only limit initial application flow. This valve will not only limit flow rate, but also limit and maintain output pressure. It needs to be mounted AFTER the combination valve for the system to work properly. The factory combination valve will shift, turning on the brake warning light, if the adjustable pressure valve is mounted upstream of the combo valve. The combo valve uses differential pressure between the front and rear brake circuits to shift internally. This shift effectively shuts off supply source to the lower pressure circuit so that in the event of a leak/failure, you still have a working brakes on one end of the vehicle. When pressure inside of the combo valve is equal, the valve is in a balanced state, and doesn't shift. When pressure inside the combo valve has different pressures, it will shift. This is why you really don't want to mount the valve upstream of the combo valve.
Good info Trendz, thank you. My brake light has been coming on, and after many, many bleed sessions, I finally gave up. Light remains on, and when it comes on that’s when my brakes lock up, favoring the rear circuit. I want to add, and make clear, that I installed my adjustable valve AFTER the factory combination valve, just as you explained.
On a 93 model year, there is a junction block mounted on the frame, drivers side. That is where the brake lines for front and rear head to from underneath the combo valve. It was there where I made the transition to tie into an adjustable proportioning valve for the rear brakes only.
So, if the light comes on, then you know the combo valve is shifting. This means that there is a pressure differential in the combo valve.
Either you have air in the front system, a leak in the front system, or a bad master.
When you bleed brakes, you need to be sure that the combo valve doesn’t shift enough to turn on the light. If the light is on, you’ve shut off the hydraulic circuit and bleeding will have no effect. There are clips available that hold the combo valve from shifting during the bleeding process. Remove the wire on the combo valve, and install this clip. If you can have someone pump the pedal, you will see the pin move if the clip isn’t installed.
If air is not the issue, and you have no external leaks, then you have a failed master.
So, if the light comes on, then you know the combo valve is shifting. This means that there is a pressure differential in the combo valve.
Either you have air in the front system, a leak in the front system, or a bad master.
When you bleed brakes, you need to be sure that the combo valve doesn’t shift enough to turn on the light. If the light is on, you’ve shut off the hydraulic circuit and bleeding will have no effect. There are clips available that hold the combo valve from shifting during the bleeding process. Remove the wire on the combo valve, and install this clip. If you can have someone pump the pedal, you will see the pin move if the clip isn’t installed.
If air is not the issue, and you have no external leaks, then you have a failed master.
I looked at that clip and for the life of me I don't know how to put it on the combo valve on the earlier trucks with the valve inside the frame rail by the starter. I would have to be a small gumby person or a much more nimble mechanic than I am...Mark
Mextan, there are two 1/4" holes drilled through the valve body for mounting. Those fittings are double flare. no olives/compression sleeves.
The valve is a pressure regulator. "increase" means more max pressure, "decrease" is less max pressure. Although it does have a needle and seat type arrangement, it also has a pressure regulating spring to control output pressure. A needle and seat alone would only limit initial application flow. This valve will not only limit flow rate, but also limit and maintain output pressure. It needs to be mounted AFTER the combination valve for the system to work properly. The factory combination valve will shift, turning on the brake warning light, if the adjustable pressure valve is mounted upstream of the combo valve. The combo valve uses differential pressure between the front and rear brake circuits to shift internally. This shift effectively shuts off supply source to the lower pressure circuit so that in the event of a leak/failure, you still have a working brakes on one end of the vehicle. When pressure inside of the combo valve is equal, the valve is in a balanced state, and doesn't shift. When pressure inside the combo valve has different pressures, it will shift. This is why you really don't want to mount the valve upstream of the combo valve.
Initially I am going to place it after the factory metering block and see how that works. I just need to kill pressure to the back because I am shredding my brakes back there.
08-16-2018, 06:56 AM
