Charge valve diagnostic help

Hello dear fellows,

Today I’ve tried to diagnose my hydraulics, early type 1989 (SLS removed), and would appreciate yout input.

I have pulsating hoses and the usual engine speed dependent clicking from the overpressure relief valve.
I have exchanged accumulator (it was finished), low pressure warning switch (it started to leak) and charge switch (on speculation).

So, today I took out the multimeter and started to measure.
Pressure warning switch open after 31 seconds of normal idle from unpressurised system, charge switch opens after 1m20s.
I therefore deem these OK.
So, I started suspecting the charge valve, measured up the electrics to it to be sure it had connection, indeed it has.
Took it out to diagnose it separately.

If I apply 12v across it, it sounds and feels dead, no solenoid action going on, it seems.
If I put my ear to it, I can perhaps hear something very faint, but I confuse it with the sound of the minute spark between the cable shoe and the battery I use as power source.
Does this sound like a dead valve to you?
It uses 0.4 amps when powered and has a resistance of 29.9 ohms.

I tried applying compressed air into the side hole and feeling over the wire screen for blowthrough.
Regardless of it being powered or not, the same amount of air gets through.

So, my conclusion is the charge valve is faulty.
Would you agree with this?
(not even whacking it with a brass hammer helped)

I’m a little confused as I would have expected no compressed air blowthrough in my overpressure situation, that an open passage means return to the oil tank, what’s your take on this?

I’d be very grateful for your expertise on this, before shelling out on a, rather expensive, new charge valve.
Thanks lads!

Fredrik …

Just a suggestion, perhaps it’s time to get rid of that entire complicated system and go with a vacuum brake booster like so many of us have. Very simple and reliable.

I’m just not beat yet.

1 Like

I have the 89 XJ6 have the old valve body that was swapped out with a better functioning one. The swapped out one has a solenoid on it and I cant blow through it… there are no numbers on it so I cant tell if it is the CHARGE solenoid. it has a easily audible click… the other one which has a metal protrusion beyond the wires and had number on side of 746 2326 45CX makes no noise though it draws same current as other solenoid… and it may be defective-jammed when I removed it.

May 7 2020

As I recall the longer solenoid on the old one used to make a slight sound, now sitting in a box awaiting my repair attention it is silent with 12v and yes draws normal current same as short solenoids
EBAY Ask if the longer solenoid clicks with 12V and or some info on car 65 is a fair price… otherwise source a new LONG solenoid… as yes any solenoid should make even some sound with 12-15 volts…
Hope it helps
Brad

I have a Jaguar’s service manual for this system, I can send it via email. Too large file to upload to the forum.

Thanks for your advise.
Indeed it is the long valve which is the charge valve.
I wish I’d found that ebay listing earlier, now awating a NOS one at around 250 USD shipped and imported.
I have the manual referenced, it’s the only way to understand the system.
I’ll let you know how I’m progressing, keep your fingers crossed :wink:

In my country new ones are available for about 34 $ :slightly_smiling_face:



Is that site to be trusted?

Why not? Because it’s in Poland?

Of course.
It’s a popular auction site.
tThe same as ebay, only in the Polish edition

I don’t know what stereotypes are.
But Poland is really a normal country, and even more normal than than other countries… :slightly_smiling_face:

1 Like

Thank you for the info, I’ll check it out from now on.
But why the quick jump to offense?
It’s not easy figuring out the legitimacy of a, to you, unknown site in another language.

it’s true :grinning:

I bought several parts from them.
They are selling inventory, you can negotiate the price.
If you have -> tel. +48 515 955 552, sklep@ipsparts.eu

Alright lads, troubleshooting continues!
I’ve fitted my new charge valve (which was as silent as the old one on applying 12v, hm…).
Anyway, I’ve got 0v over the solenoid when there is low pressure in the system and 12v when there is high pressure in the system.
To me, that seems like the wrong way around?
The manual says “when the solenoid is activated, it directs flow to the accumulator”, leading me to think that 12v applied means charging up the pressure.
I’m confused… like my charge switch has inverted operation.
Anyone know what’s supposed to happen on 0v and 12v respectively on the charge valve?

Hello Fredrik,
I stumbled upon your post because I am currently dealing with an XJ40 (1986) myself, with a continuously pulsating charge hose. However, after many hours of studying, I believe I found the cause, although I’m not 100% certain because the part I ordered hasn’t arrived yet. (fingers crossed).

I have 12 years of experience with hydraulic Citroëns and I am therefor very familiar with the ‘Green Fluid’ and high pressure systems, that are somewhat similar to the power brake system on XJ40. However on XJ40 it’s different in the sense that it works with electrical switches and valves.

First of all, thanks for your contribution. I was wondering: did you manage to fix your problem?

Also I do have the answer to your question:
First of all: the charge switch (attached to the accumulator body) can only transfer ground (-). It does so, when it closes and it closes when the pressure in the accumulator sphere drops below a certain value (when presure is demanded, i.e. when the brakes are applied or when you put heavy stuff in the boot for exaple).

So, the switch closes and ground (-) is being transferred to the charge valve via the yellow/black wire.
The valve gets its positive (+) current permanently from the fuse box via the white/grey wire, so there should always be 12 Volts on the white/grey wire, connected to the charge valve.

Now, when the charge valve receives both (+) from the fuse box and (-) from the switch, it closes and inside the valve block, pressure from the pump is then being directed to the accumulator sphere. Until the moment the pressure is sufficient again. Then the charge switch opens again, ground is shut off and the charge valve opens again, re-routing the green fluid from the pump directly to the return (to the container).

I hope this helps!

My XJ40 has a constanty pulsating pressure hose but I think I finally established that my charge switch is permanently open, sending (-) to the valve all the time. I was able to order a new switch and it should be in by next Thursday, so I really hope I fixed the problem by then.

NB: I already replaced the accumulator sphere for a brand new one because I didn’t trust it. It’s all 30+ years old and the membrane must have been shot. When I recieved the new sphere, I recognised it immediately: It’s exacly one like on the Citroëns (they painted it black, but the original green paint could be seen when I scratched the surface). They just fixed an adaptor to it, so the thread fits the XJ40 accumulator body. :slight_smile:

Lucky us! Finally new fresh spheres that we can install to our poor old Jags.

I hope this helped you and perhaps others. I for one am very grateful to this forum, it helped me a great deal sorting out how the system works, so much appreciated!!!

Greetings,
Leontien
The Netherlands