1989 244DL brake problem: do I need new Brake proportioning valves?

[JMarkK]

Girling front calipers, ATE rear. Replaced Master Cylinder and all hoses. Bench bled master, though air may have been introduced as we were doing the initial bleed (conventional two person operation) that revealed ruptured hose. Left rear caliper not getting fluid. Fluid present at intake of rear brake valve, but not after. Bled using an air compressor at low pressure (18PSI) and with an oil/water filter fitted to brake reservoir. Incidentally right rear caliper seems to be leaking, rebuild kits ordered, doing both at the same time for good measure. Does not seem to hold a bleed, last night I thought I had good enough pressure to drive it, but not this morning.

Question 1: Is my diagnosis that I need a new rear brake proportioning valve correct? Or would there be another reason fluid is not getting past it?

Question 2: Should these also be replaced in pairs? Wow they are pricey......

Question 3: Could it also be the pressure sensor?

 

[cosbySweater]

get rid of those rear valves and put a manual one in, it will save you alot of headache. Or just get rid of them and put a m10x1.5 bubble flare union in there. Ive struggled with those rear prop valves on my 240s recently so ive just been deleting them and the brakes feel infinitely better

 

[JMarkK]

How should I adjust the aftermarket ones to be balanced since there are two? Wondering if it may cause problems....

Also would you agree with my diagnosis?

 

[cosbySweater]

those proportioning valves trap air all the time and feel like youve lost a good bleed. i would personally plug off one line at the brake octopus and run a single line back to a manual valve and run a union on the axle for the hardlines.

 

[JMarkK]

Got it. That makes sense. In the end I decided to order a pair of new ones though. I should get them tomorrow.