proportioning valve or combination valve or both ...???

[Malibu 361]

Ok,I am going with a manual brake system Wilwood disc front and back...My question is, do I get rid of the combination valve all together and just run the Wilwood proportioning valve in its place or run them in conjunction with each other ?And where to mount the Willwood proportioning valve ??I figure anywhere that's easy as long as I can get to it ?Thanks

 

[Killerdave8813]

Re: Adjustable prop valve and combo valve question

Hey There,
Well for what it's worth the only reason I've ever found for the combination valve is that it has your low pressure warning light switch in case of a blown line or wheel cylinder/caliper,basically an anti-idiot device as anyone with any sense should know if your brake pedal suddenly drops you have a problem,there are those that call them proportioning valves as well and although I've never tried to disassemble one I just can't see it as they're small enough that the pressure warning device appears to take up the whole thing,since I found out that a line lock for the front brakes is supposed to be after the combination/(prop) valve I'm going to delete mine anyway and I'll also have a wilwood prop valve in the rear line,I figure I'll need it since I have big drums(9" rear) & tires on the back,as long as you're not worried about a low pressure warning light it shouldn't be an issue,you probably don't want to wait for me to try it though as I get side tracked a lot but will get mine done some day! Later,KillerDave

 

[LS6 Tommy]

A combo valve handles proportioning & metering. If the Wilwood prop valve is adjustable it's not meant to be used with a stock style master without a combo valve.

Tommy

 

[Killerdave8813]

Well I stand corrected,after all the years I've fooled around with cars I googled up brake combination valve and How Stuff Works has a quite informative article on how a dual circut master cylinder and combination valve work as Tommy said it meters and proportions both and also has the warning light,seems to me I got the idea of eliminating
the combo valve from some of the guys on here for drag racing anyway,
I could be mistaken but it also seems that I remember scarfing a brake system off of a 67 or 68 Chev PU that was dual circut and didn't have a combo valve and put it on a 65 PU to replace the single "fruit jar" system,of course we're talking four wheel drums as well so that might be different as well,I guess I'll have to re-think plumbing my line lock as I have it before the combo valve and the NHRA rule book says it's supposed to be after,anyway If anyone needs to know how something works check out How Stuff Works,I was impressed,KillerDave

 

[Malibu 361]

oo yeah an im running a Wilwood master ...

 

[LS6 Tommy]

oo yeah an im running a Wilwood master ...

Is it a dual master, or are you running separate front/rear masters with a bias bar system? if It's a dual master I would still use the combo valve.

Tommy

 

[78elcamino]

i dont want to hijack but didnt want to start a new thread either. im in the same boat, running wilwood disks on back and stock fronts for now, did the manuel brake swap, and have a adjustable prop valve and a strange master cyl(the one that comes in the tnt kit) so do i junk the stock one or what??

 

[Malibu 361]

See now, the place that I bought both setups include the adjustable prop valve and said junk the combo valve all together and just use the adjustable prop valve ... :-k

 

[LS6 Tommy]

See now, the place that I bought both setups include the adjustable prop valve and said junk the combo valve all together and just use the adjustable prop valve ... :-k

It's done that way quite often on race cars. I believe the attitude is that the combo valve's unnecessary on a race car. Racer's also like the fact that there's nothing "interfering" with the braking so they can get better "feel" for the modulation. Adjustable prop valves are for fine tuning. Can you get your brakes to work without a combo valve? Sure. In the real world they'll just work better with one.

Tommy

 

[malijuice]

wilwood just came out with a combo valve jegs has it part #260-11179 wilwood combo proportioning valve