Chrysler Repair: Voyager Brakes, brake hydraulics, brake pipes

Question
QUESTION: Hi Roland, I am sorry but I seem to have lost the link to reply.

If I pump up the brakes with the engine off and then start the engine the pedal drops, as expected, but it does not just go a small way.  It goes virtually to the floor and the warning light comes on. From this it would appear that the servo is working OK but is not getting enough resistance from the brake hydraulics so I don't think that there is any need to send the relevant pages by post but thank you for the offer.

I do have manuals back in France, but not here - perhaps I should get another one!  How are the brakes connected?  I am assuming that, with the dual circuit, there is one proportioning valve for each circuit and I would expect that one feeds LH Front and RH Rear and the other RH Front and LH Rear. I am not losing significant amounts of fluid since the brake pipes have been replaced but I may be losing some (no obvious puddles on the driveway).

I keep coming back to the Master Cylinder.  If it was bypassing, possibly more on 1 circuit than the other, would it do this?

Another thing you may be able to clarify from the manual; The mechanic at the garage said that the proportioning valve is load dependant, feeding more pressure to the back wheels when the vehicle is loaded.  That would explain the price I am being charged for the part.  Is this the case, or is this some development on later vehicles?  It seems rather advanced for 1993 but there are quite a lot of surprisingly advanced things on these vehicles.
Regards,
Roger

ANSWER: Hi Roger,
I would hold off buying the proportioning valve until this is sorted out.
Try this:
with engine running, apply the brake pedal very slowly. Gradually increase the pedal effort while watching for red warning light (I assume you don't have anti-lock brakes so yellow light is not relevant). Then see if warning light comes on with moderate pressure and stays on when pedal is released OR
warning light comes on with moderate pressure but goes out when pedal is released OR
if no warning light with moderate pressure then increase the pressure until very high effort with both feet and hold for 30 seconds and then release pedal slowly and then note whether pedal moves slowly down under heavy pressure OR if light doesn't come on.
Tell me which of these scenarios happens.
Roland
PS Thanks for the nominations, which you can continue to do up to 5 times at which point that is the 'limit' for the month.

---------- FOLLOW-UP ----------

QUESTION: It is getting dark here now, and I am away tomorrow, so I will continue with your recommendations on Friday.  Thanks for all your efforts.
I have found and ordered a second hand Haynes manual on eBay. Hopefully that will arrive quickly.
I tried to put a hold on the part which I had asked my local supplier to get.  It was too late.  He had already ordered from USA and it was in progress. If it turns out to be wrong, I will have to see if I can return it and how much they will charge.  Otherwise I will have to try to sell it on eBaY!
regards,
Roger

ANSWER: I will await your results. And perhaps there is a leak at the proportioning valve? On the leakage situation, if you are having to add any fluid then there is a leak somewhere. Check the sidewalls (insides of tires) as that is where the drip often lands, rather than on the ground. Thanks for the nominations.

---------- FOLLOW-UP ----------

QUESTION: I have been and tried your suggestion.  With the engine running, applying brakes slowly the light comes on.  Releasing and the light goes off.

Something seems a bit odd because I am sure that at some point the other day the light was staying on when the pedal was released, but it is not now.

Since the pipes were replaced, I have not noticed any significant drop in fluid.  I have checked the wheels but do not see any sign of fluid.  There is some sign of leakage around the proportioning valve, which I have now located but this seems to be from the new pipe connections rather than the valve.  The proportioning valve does, indeed, have a connection to the suspension which would operate the control lever according to load.

Answer
Hi Roger,
The sign of leaking at the proportioning valve needs to be addressed by the person who installed the tubing.
If the light comes on with moderate pressure on the pedal and then goes out when releasing the pedal, then it is possibly air in the system which needs to be bled out (that air could be getting in via the wetness area at the proportioning valve). If the light comes on with moderate to heavy pressure and the pedal continues to slowly sink then that is a fluid leak (again the wetness area).
Thanks for the rating and nomination.
Roland