proportioning valve?

[claybill]

i have a proportioning valve on one of my cars....

i know it has a brake line to the front brakes and to the rear brakes..from each of the brake fluid resovoirs in the m./c.

what does it do? is there an adjustment?

i think my front brakes are not doing their job...very slow stopping.

ideas? explanations?

bill

[martybose]

i have a proportioning valve on one of my cars....

i know it has a brake line to the front brakes and to the rear brakes..from each of the brake fluid resovoirs in the m./c.

what does it do? is there an adjustment?

i think my front brakes are not doing their job...very slow stopping.

ideas? explanations?

bill

Generally a proportioning valve is used on a car with front disk/rear drum brakes. Since disk brakes typically require higher line pressure than drum brakes, a proportioning valve is there to limit the pressure to the drum brakes, since otherwise the drums would lock up long before the disk brakes start working effectively. Most OEM proportioning valves have no adjustment, as they were set by the factory. Aftermarket valves have an adjustment, since there is no way of knowing what the correct ratio should be.

My first thought is a simple one; is there any chance that it is plumbed backwards? If it was you would have virtually no pressure to the front disk brakes, and would be stopping on the rear drums only. Boy, would that be slow stopping!

Marty

[martybose]

Do you have a combo valve or a standalone proportioning valve? A combo valve would have two lines from the master cylinder (generally to a pair of center fittings) and another pair of lines to the front and rear brakes. A standalone proportioning valve would be in the rear brake line only, so it would have a single line in and a single line out.

Marty

[claybill]

marty...thanks for your help. i do have a combo valve.

i have more pressure to the rear brakes..sometimes they squeal.

the fronts dont seem to do much stopping.

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i have had a problem with stopping with these new disc/power brakes for a month. the mechanic tried everything he knew... the mfg sent new parts in case others didnt work...i am in a fix. my old drum brakes performed much better than the new power disc unit.

how do you know if it is plumbed backwards by looking at it.? it seems a logical installation.

if you can help on this please email me separate from the forum..

claybill@galenalink.com