The combination valve consists of three functions, balance, metering and
warning switch. The metering function ensures that pressure is not applied
to any brake at less than 130psi. the balance function limits the pressure
to the rear at some % of the front pressure to ensure that the rear brakes
do not lock up before the fronts.
>I'm not sure how "proportioning" valves work. The ones that
>I see in catalogs have adjustment knobs on them(I guess they must
>since they're not specific to one installation). The combination
>valve on our GMCs does not allow any pressure on the rear until the
>front brakes are up to a preset pressure(90psi). If you think
>about it, having the front brakes apply before the rear on the GMC
>(especially on a wet road) could be a very nasty experience.
>
>Patrick
>
>> Thanks Paul!
>>
>> It probably is called a combination valve however I think
>> some parts stores
>> like napa call them proportioning valves. It is the valve
>> that causes a
>> differential in hydraulic pressure exerted on the rear brakes
>> so as not to
>> have our front brakes grab first. Something like that? Right?
>>
>> Scott Adohen
>>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
warning switch. The metering function ensures that pressure is not applied
to any brake at less than 130psi. the balance function limits the pressure
to the rear at some % of the front pressure to ensure that the rear brakes
do not lock up before the fronts.
>I'm not sure how "proportioning" valves work. The ones that
>I see in catalogs have adjustment knobs on them(I guess they must
>since they're not specific to one installation). The combination
>valve on our GMCs does not allow any pressure on the rear until the
>front brakes are up to a preset pressure(90psi). If you think
>about it, having the front brakes apply before the rear on the GMC
>(especially on a wet road) could be a very nasty experience.
>
>Patrick
>
>> Thanks Paul!
>>
>> It probably is called a combination valve however I think
>> some parts stores
>> like napa call them proportioning valves. It is the valve
>> that causes a
>> differential in hydraulic pressure exerted on the rear brakes
>> so as not to
>> have our front brakes grab first. Something like that? Right?
>>
>> Scott Adohen
>>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
