Propotional brake valve piping ?

[350ep70gr]

Yesterday i got around to fit again on the car my willwoods. Then starting to flush the back calipers and due to a problem came up i start searching all the circuit of the brake system and i notice that my propotional valve was conected wrong way for ages.
I havent notine any braking problem at the past or a side efect or whatever...tho..
What i need to know is now i have conect it the right way would have any positive effect at all?

The difference was that my two front brakes was conected to the T and both of the lines of the master cylinder went to the propotional valve.

Chris

 

[weeJohn]

Is that not right? The master cylinder has 2 circuits, diagonally plumbed up, 1 front one rear. The proportional valve regulates between the front and rear so it does away with the diagonal circuit and the front tees and the rear tees.

Never fitted one mind you but looked at it before.

 

[350ep70gr]

I think it isnt too correct the way it was with mine. The master cylinder has to ports. The front port goes to a T with the one of the front calipers and other side of the T goes to the one input of the proportional valve.
The other port of the master cylinder at the midle goes directly to the second input of the proportional valve.
Then the two pipes from the valve goes to the back (but each one is fed by a different pipe of the master cylinder) and the last pipe of the valve directly to the other front caliper. The above is the right way...mine was a bit diferent than this...and now i moved back as it should be!
Do you know how i can check the proportional valve if working on the bench? I start searching because i went to bleed the back brakes and one of the back calipers was getting no fluid at all.
Thanks for the input!

Chris

 

[Texx]

Is this of any use to you Chris?

The sure way to check the valve is operating correctly would be to attach a pressure gauge to both bleed nipples of opposite front and rear calipers, bring the fluid pressure up by pressing the brake pedal, bleed the air from the gauge lines and then check the difference in pressure between the front and rear brakes.

I'm not sure if the pressure readings for a Starlet would be much different, but good pressure readings for a Tercel would be:

Front: 2,452 kPa (25 kgf/cm², 356 psi)
Rear: 2,452 kPa (25 kgf/cm², 356 psi)

Front: 7,845 kPa (80 kgf/cm², 1,138 psi)
Rear: 3,805 kPa (38.8 kgf/cm², 552 psi)


If you can come up with a way of connecting a couple of pressure gauges to the P valve, capping the remaining ports and then pressurising the valve with fluid, it could be possible to test it on the bench. However if you have any doubts, it would probably be less hassle to just replace the valve for a known good one.

 

[350ep70gr]

Thanks for the input Terry! I have found this drawing before and thats why i made the search. Mine was a bit diferent with two T involved.
So far i have tryed compressed air at 6 bar to all of the port and i have no air passing to the ports for the back calipers.(but at least one had fluid when on car)
Maybe need more pressure to open the valve since you said 300+ psi. But i am quite sure if you open the bleed nipple on the back calipers, fluid should come out by gravity. Also when you aplly pressure at the brakes, ok the valve is controling and adjust the pressure on the back but should not fluid return back by its own when you leave the brake petal or even when you try to open the pads of the caliper against each other? I am asking this cause even when i put compressed air on the back ports i have nothing return to the inlet of the valve..
New one should be something like 200 euros going by toyodiy.
If my valve is fucked i may buy an adjustable one and adjust it the way i want it!

Chris

 

[thefalls]

And if it works well then you may have opened a new way to get better braking power on our starlets!

 

[weeJohn]

I dont think compressed air would operate a hydraulic system the way oil would. A hydraulic power pack (from a jacking system) or a spare clutch master cylinder would do the trick.

 

[Texx]

So far i have tryed compressed air at 6 bar to all of the port and i have no air passing to the ports for the back calipers.(but at least one had fluid when on car)
Maybe need more pressure to open the valve since you said 300+ psi.

The valve should close as the fluid pressure between the P valve and rear brake rises, that's how it reduces the fluid pressure to the rear brakes under heavy braking. When the fluid has no pressure the valve should be open, so you should expect the air your blowing in to the valve to pass straight out the other side.

Something doesn't seem right with the P valve your using Chris, maybe there's been a previous build up of shit in the fluid and it's blocked the P valve up preventing the valves or valve seats from floating. Could you not use a valve from an EP82 or EP91? I'm sure someone with a breaker would send one out to you.