Dear Members,

Greetings. I know this is probably an often asked and often answered question, but any assistance would be appreciated.
Car: Daimler Double Six 1993 Insignia, V12, 5.9L.

Nine years ago I purchased the self-levelling conversion kit and my mechanic replaced the faulty self-levelling system with regular rear shocks. To the best of my knowledge, he followed the instructions and disabled the self-levelling unit.

My question is this: Do I need to keep filling up the green fluid now?

When I picked the car up nine year ago, I was surprised to see the self-levelling reservoir still in the car. When I asked why, my mechanic told me that it serves a tandem pump that operates both the steering and the self- levelling fluids. So he didn't take the reservoir off. He obviously therefore didn't drain the green fluid out.

The self-levelling fluid hose or unit itself has now started leaking and the fluid has drained from the reservoir. Is this a problem for the tandem pump?

Will the tandem pump continue to work for the steering (red ATF fluid reservoir is fine and full) if there is no green self-levelling fluid in the reservoir going to the pump? My mechanic didn't know if the pump would stop working without the green fluid. He also mentioned that it supports the brakes, but I didn’t quite understand the explanation.

If the unit is leaking, do I need to replace the unit? The hoses for the self-levelling fluid are virtually impossible to find now.

Many thanks,
Charles

 

Hi Charles,

For some reason I thought I had seen this same post from you a day or two ago and had already replied, but maybe the Covid is affecting my mind! (I'm actually over Covid as of Sunday).

The manual at the link below gives a thorough explanation of the power hydraulic system. On the 1990-1992 cars, the Hydraulic System Mineral Oil reservoir serves the SLS and power steering systems. However, for the 1993 models, a new steering rack and pump were used and the power steering system used its own supply of fluid, which was Dexron IIE ATF (later superseded by Dexron III).

These manuals should help you determine whether HSMO is still required by any active system in your car. If your car has a separate power steering fluid reservoir for red ATF, then a lack of HSMO should have no affect on your power steering pump.

Jaguar XJ40 Power Hydraulic System Manual

Jaguar XJ12 Technical Introduction 1994

Cheers,

Don

 

Dear Don,
Thank you for your post. Extremely helpful and reassuring! I was worried I would have to track down some second hand hoses for the SLS or the actual tandem unit itself. This is a relief.
You are correct, I believe I submitted an earlier version of this post but I couldn't find it anywhere.
Many thanks and best wishes,
Charles

 

Thanks for posting this. I have been wondering about the same thing. The cap to my SLS tank has been drilled at some point but still contained the oil.
I also had the issue with leaking around the pump which I hope is just lose connectors.
I made the assumption that although no longer needed, as the SLS pump is on the same drive as the power steering pump it would need to retain fluid to prevent over heating and both pumps then seizing.
I will have to read through the documents.
As the car is off the road at the moment I haven't got round to refilling or checking for continual leaking.

 

Greetings and update,
I have been driving my 1993 Daimler Double Six virtually every day for the past two weeks with no fluid in the self-levelling reservoir (green cap). I can report no problems with power steering or brakes. The SLF fluid has drained away completely and subsequently my car has stopped leaking the green mineral oil.

I can across the following website that explains the brake/self-levelling separation from MY1990 onward.

https://rensswart.nl/daimler/power-h...-system-en.php

The author concludes that the brake boost cylinder and the self levelling system were completely separated from one another from MY1990 onward.

As Don pointed out above, from MY 1993 onward, the power steering and self levelling system were completely separated with two reservoirs utilized.

So, the conclusion I have drawn is that there is one less set of hoses I need to worry about!!

Charles

 

I still have my worry as on the v12 the power steering and SLS pump share the same drive shaft how much of the pump lubrication and cooling is provided by the fluid being pumped. If the SLS pump is run with no fluid will it have any chance of overheating or seizing?

 

So, this discussion raises an interesting question. Jaguar built two pumps (NAB3731AA - tandem PS & SLS) and (NAB3731CA - only power steering). If someone with a disabled SLS system needed to replace the tandem pump, could they simply get the reconditioned single pump version (NAB3731CA) and then get rid of all the SLS hoses and reservoir?

Anyone with experience?

Charles

 

From the parts diagram, it seems the mounting is the same for both versions.

 

I have one on a '96 XJ12 parts car. It would be the CA non-leveling type.
I don't know if it's good though, as the car is dead.
I'd be willing to send it for you to try, although you may only want a known to be working one, considering the work involved, and the distance/cost of shipping.
Good luck,
Rob

 

Here's the pump I have. No Jag part # on it.
I had trouble sending you this picture through the private messages.




Rob

 

Any news on this topic?

@CharlesHK: Is your pump still operating without the green fluid, no damage or malfunction?

As mentioned in another thread, my tandem pump is probably leaking, if I can stop it from leaking green fluid by just draining it without taking the risk of damaging the pump, I will try it before attempting to get the pump exchanged or overhauled.

 

Greetings. I was able to get a second hand dual pump in very good condition. It hasn't leaked at all, so the green fluid just sits there waiting in the reservoir to leak another day!

 

Hi Charles,

Ok, so you never made a long-term test without the green fluid.

Actually I also don't want to take the risk of destroying the pump, that stuff is too expensive nowadays to play trial and error. I have been thinking about using a thicker fluid, that will not pass through where ever the green fluid found its way out, but what could that be? Maybe a very thick engine oil like 20W50?

Oliver

BTW: Nice Xj81 you have there, I think that's a unique color.