[GeeAea]

Help me out with this here............

Why would a proportioning valve inhibit brake bleeding?......other than a load compensating one (you know one of those that attaches to the axle and has a lever that senses the riding height of the rear - hence the load). With those you must "simulate" load by detaching the spring or lever to allow the fluid to reach the rear brakes. What I mean is .......you put your foot on the brake to stop and it reaches the threshold of the proportioning/metering valve ......why should bleeding be any different?
Just curious ......this is a first for me.

GeeAea

 

[GeeAea]

I'm well versed on metering valves and proportioning valves......they've been in most cars since dual master cylinders were put in production cars.........the only time that I've EVER had to do anything "special" with them is either when it was a "load compensating" valve ...........or if one of the fluid circuits had a failure and the light came on in the dash..........I seem to remember.....I think it was AMC....that when one system failed.....a plunger inside the valve biased itself to turn on the light on the dash.......after it happened .....the thing was servicable only by replacement.......there was no way to "re-seat" the plunger.
I'll buy the stuff about the pin thing......but the caliper doesn't know if I'm going 95mph or at a stand still.......if I'm put X amount of pressure on the pedal..........there is X amount of pressure on the caliper.........so if I'm standing on the brake pedal (beyond a certain pressure) the proportioning valve shouldn't even come into the picture to inhibit the flow to the rear brakes. Maybe it's a "workers comp" feature so that petite 100lb. female (or male for that matter) mechanics don't develop vericous veins by straining to put enough pressure on the brake pedals.
GeeAea