Question about Jaguar XJ12

2 Answers

Hello expert, my recently bought XJ12 (XJ81) constr. 1994 fails to control the car´s height at all. Bleeding the hydraulic (HSMO) systen seems to be nearly impossible as very low (if any at all) pressure is built up when lifting the sensor link rod by 20-30 mm during engine run for several minutes. There is enough hydraulic fluid in the reservoir and the strut assy. shows no leak. Here in Austria I could not find good advise - the simple solutions like filling up the system dont really help. The few people faced with the similar problem either sold the car or changed to standard suspension parts. I would like to keep the beautiful car´s original condition - therefore... I would appreciate your help in this matter. Sincerely Heinz

Posted by on

  • 5 more comments 
  • tecinform Aug 30, 2010

    Hi, thank you for the reply.
    maybe (and it is very likely) the shocks have to be replaced - even if they are hard to find. But does this explain the lack of hydraulic pressure? I am afraid I will spend a lot of money and work in changing the shock absorbers and then...
    Please think about the pressure as well. I was unable to bleed the line because of this. There must be more...

  • tecinform Sep 01, 2010

    Rear Suspension ride levelling is deleted from VIN 682123? My XJ12 VIN 690108 got it. However, I still have the ride levelling system and the problem.

  • tecinform Sep 01, 2010

    My car is in original condition (no changes or "improvements" have been made), performs perfectly and all electronic and other features work as they should. So I want to keep the levelling system. Changing the dampers alone will not solve the poblem.

  • tecinform Sep 01, 2010

    you did not receive my reply?
    What I thought was: Most likely the shocks are defect This seems (and seemed always) to be clear. What bothers me is the fact that bleeding the hydraulik pressure line to the shocks shows low or no pressure. So when I install new shocks, they will be defective within a few miles of bad road.
    Without sufficient (about 100 bar) hydraulic pressure the shocks will sit on their diaphragm which will be destroyed in short time.
    So, this is the status.

  • tecinform Sep 01, 2010

    this is not an air powered system. It works as already mentioned with hydraulic high pressure.

  • tecinform Sep 01, 2010

    Somebody who is a real Jaguar expert?

  • tecinform Sep 01, 2010

    The only compressor in this car belongs to the air conditioning


2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Jaguar Master
  • 6,826 Answers

I have experience with a 1976 Cadillac Seville which has an air pump that is operated by vacuum and pump air into lines that way.

Also have experience with a 1999 Ford Expedition that uses and electric pump that pumps air into lines that way.

Also, have experience with a 1997 Cadillac Deville Limousine that uses an electric pump.

And, I have experience with a 1990 Cadillac Deville that has an electric pump.

I looked up the recalls on the XJ12 from 1994:

Rear Suspension ride levelling is deleted from VIN 682123.

Only the rear part of the pump remains which controls power steering.

Posted on Aug 31, 2010

  • Duane Wong
    Duane Wong Sep 01, 2010

    I think your low hydraulic pressure is the source of the problem, and not the shocks if they are not leaking. But, I'm thinking of it purely from the point of view of physics.

    If they deleted the rear suspension ride leveling from VIN 682123 on up, this tells me that they may have been having technical difficulty with it back in 1994 when the car was made.

    I don't really know why the pressure would be low, except maybe the pump doesn't seem to be designed or built well enough to do provide enough pressure.

    But, this is pure conjecture.

    Usually, the ride height control systems that I'm familiar with use air pressure and not hydraulic pressure.

    So, I'm a little bit out of my field on the Jaguar system of 1994 or so.


  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert whose answer got voted for 500 times.

  • Expert
  • 4,070 Answers

Hi! The real cure for this is to replace the hydraulic shocks. Yes the there is no leak but when the shocks is faulty it fails to give the desired ride height. Once the hydraulic is replaced you'll be good. Hope this helps and thank you for using FixYa!

Posted on Aug 30, 2010

  • 1 more comment 
  • dj_relly999
    dj_relly999 Sep 01, 2010

    Hi! How's it going?

  • dj_relly999
    dj_relly999 Sep 01, 2010

    Alright, please try to check the relay under the hood if it's blown. Usually the air compressor relay is #4 on the box. Please write back on the progress.

  • dj_relly999
    dj_relly999 Sep 01, 2010

    It's a wear and tear thing and things may go bad in any given time. If the relay is not bad then it's gotta be the compressor.


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Blower motor on drivers side quit working what could cause this I checked the motor outside of the car and it ran fine jaguar xj12 1994 4 door

Check for power to the switch and from the switch to the motor. You said you checked it outside, so if you put power to it and it works you have to back track the fault to where the power is lost.
It would be no power to switch or no power out of switch or wiring in between.

Jun 07, 2015 | 1994 Jaguar XJ12

1 Answer

Battery is charged but no power to 1994 jaguar xj12

try chanegen ignition then if not go online from there site.

Aug 12, 2012 | 1994 Jaguar XJ12

1 Answer

I have a 94 saturn sc2 that seem like the clutch is not fully disengaging. Is there any reason for this other than the clutch no good?

depending on whether the clutch is cable or hydraulic, the issue could be in the linkage (if cable), and you may have to adjust the cable so that when the pedal is on the floor the clutch is fully disengaged..if hydraulic, try bleeding the clutch cylinder. if that doesn't solve the problem, then you may have a leak in the line leading to the clutch

good luck with your fix!

Mar 03, 2011 | 1994 Saturn Sc

1 Answer

Fuel pump location for 1994 XJ12, Are there 2?

Hi, you should find your fuel pump in the fuel tank, and from memory there is only 1 main pump although on some there is a pre pump fitted which basically feeds the main pump, Cheers

Oct 05, 2010 | 1995 Jaguar XJ12

1 Answer

Are there new exterior door handles for 1994 xj12 jaguars

I recall seeing exterior door handles on Ebay the other night. I think that they were used, but I think that getting new ones are going to be expensive, and hard to find. I hope that this helps.

Jan 10, 2010 | 1994 Jaguar XJ12

1 Answer

Power steering fluid for jaguar xj-s 1996

Hydraulic System Mineral Oil...HSMO by Castrol....On ebay about 6-8 bucks a pint......

Oct 07, 2009 | 1988 Jaguar XJ6

1 Answer

Hydraulic fluid in the struts where nitrogen gas is supposed to b

you are being told the truth about the repair and its costs...i can guarantee that

Jan 24, 2009 | 2000 Lexus LX470

1 Answer

Daimler V12 6litre.

I recently purchased a 95 Jag XJ12, April 12.
I could not find the right manuals for self-repairs.
I have the OEM Jag DVD Manuals but they lack diagram details in some areas but are a good source of info.
Recently, bought website help at, $50 5 yrs,
It has more detail diagrams.
I would like to keep in touch to share info.

Jun 01, 2008 | 1995 Jaguar XJ12

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

233 people viewed this question

Ask a Question

Usually answered in minutes!

Top Jaguar Experts

Colin Stickland
Colin Stickland

Level 3 Expert

22133 Answers


Level 3 Expert

75807 Answers


Level 2 Expert

489 Answers

Are you a Jaguar Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides