When I installed rear discs on my car I tossed the combo/prop valve and installed an adjustable prop valve.
proportioning valve or combination valve or both ...???
- Thread starter Malibu 361
- Start date
dwkohout said:
How has that worked so far and how long have you had it like that?Is it a DD??Thanks
Works great. Did the swap 3-4 yrs ago. DD? Daily Driver? Used to be and could be but Im too cheap to keep regular licence and ins on it. #-o
If you do away w/the OEM combo valve, you lose the brake warning light. The other function is handled by the adjustable proportioning valve.
I believe some prop/combo valves also divide the brakes to diagonal or front to read, depending.
Otherwise, the brakes will function normally.
I believe some prop/combo valves also divide the brakes to diagonal or front to read, depending.
Otherwise, the brakes will function normally.
cobalt327 said:
With no combo valve & an adjustable proportioning valve you only get front/rear proprtioning. You lose metering. Without the metering valve you can have heavy nose dive under braking, early/excessive front tire lockup & increased front pad wear.
Tommy
cobalt327 said:
Well, it's more of an issue with disc/drum setups. The disc/disc masters are usually biased at 65% front/35% rear , but the master itself can't provide the perfect balance for every application. You can still have too much initial front brake bias. If you just rely on the adjustable valve, there's no metering so the front brakes can actuate a little too fast on initial pedal application. That's why they make disc/disc combo valves.
Like I've siad, you can absolutely run safely & effectively without a combo valve on factory style systems, they just work better with one.
Tommy
I stand behind my earlier assertion that the combo valve is not needed in a correctly designed 4-wheel disc brake system. There are sound reasons for this statement and I'm willing to go into it in depth if need be. But in that I'm here on this thread to try to help the OP, I will leave it at that.
If the OP wants to retain his combo valve, AT LEAST do the following modification. It will disable the proportioning function but leave the other functions (brake warning light, the oh-so-coveted metering section :lol: ) operational. If you do not do at least this mod, you will in essence be adding a proportioning valve to a proportioning valve- meaning that you would never be able to go below the OEM combo valve's pre-set, non-adjustable proportioning setting, when using the aftermarket prop valve. Make sense?
Remove the (usually rear-pointing) proportioning valve that is screwed into the end of the combo valve. Up inside the now-open port, there will be a small rubber piston/seal-looking part. Remove it.
Replace the (now disabled) prop valve back into the combo valve body, and tighten securely.
Now when you plumb the aftermarket adjustable prop valve, it will actually work as it was designed, and you get to keep the remaining functions of the combo valve- if that's what you want.
Some prop valves are different than the type described. If the OP's is different, get back and I'll try to sort it out for you.
Good luck.
If the OP wants to retain his combo valve, AT LEAST do the following modification. It will disable the proportioning function but leave the other functions (brake warning light, the oh-so-coveted metering section :lol: ) operational. If you do not do at least this mod, you will in essence be adding a proportioning valve to a proportioning valve- meaning that you would never be able to go below the OEM combo valve's pre-set, non-adjustable proportioning setting, when using the aftermarket prop valve. Make sense?
Remove the (usually rear-pointing) proportioning valve that is screwed into the end of the combo valve. Up inside the now-open port, there will be a small rubber piston/seal-looking part. Remove it.
Replace the (now disabled) prop valve back into the combo valve body, and tighten securely.
Now when you plumb the aftermarket adjustable prop valve, it will actually work as it was designed, and you get to keep the remaining functions of the combo valve- if that's what you want.
Some prop valves are different than the type described. If the OP's is different, get back and I'll try to sort it out for you.
Good luck.
I'm just gonna loose the original combination valve and go with the proportioning valve ...Thanks guys ..
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