so i purchased a 2013 xjl from a sketchy guy. he claimed to be a mechanic but no longer wanted to work on the vehicle so i got it for pretty low. a few months later now i have a problems with my air suspension. i noticed that when its driving it jumps up and down almost violently and when going over speedbumps or even up the driveway it makes an ungodly thump or scraping type of noise. the car sits low in the rear also. how would i know if i need to replace the air compressor, or air strut, or the lines themselves?

 

You could have debris or blockage in the lines, to be honest, no way to do it at face value. I'm guessing that the springs themselves leak, it would be weird to have something going on with your lines unless the previous owner told you he had it apart at one time and put it together improperly.

You need to run the compressor after engine start, soap test the air suspension springs in the rear themselves and see if you have a leak. At worst, you could replace the whole system. At best, just the springs themselves. Arnott offers a less expensive aftermarket version, and there are a few companies rebuilding the air suspension parts.

 

Based your first picture he have disconnected the air struts hoses from valve block and made blind plugs for the end of hoses. (metal parts on orange & green hoses should not be there. Hoses should be connected to the Valve block) Valve block are the part where black and red hoses are connected next to your hand in the pic. There are label of green and orange colours where these hoses should be connected. It seems like orange connector are broken? He have also tryed to fix an leak on green pipe by epoxy or some clue. That indicates he is not an mech, since these type of Quick pneumatic connectors can be fixed by multible times with ease by just cutting an small piece off from hose and rebuild it again for the fresh part.
The Repair and Service manual (available from Sticky section of this forum) have exelent pictures and diagrams of air suspension. By following that you can connect all hoses back. Most likely he have had an air leak on valve block orange connector, overtight it having an no clue how this type of connector works and losed the thread. If he haven´t then removed an fuse or connector from compressor, then compressor have worked overtime and burned itself. eBay have lot of 2nd hand x351 air suspension components, like valve block and compressor for reasonalble price. All x351 engine variants use same component.
I would just order 2nd hand valve block (and maybe compressor, if thre are no life on original) from eBay and remake all air hose connectors first and test if the system start to work. Original struts seems to be very reliable so most likely they are Ok. (check fuses too, they can be burned with compressor or just removed)

It would be usefull to have factory diagnostic computer (JLR SSD) on hand, because by that you can run compressor manually or deflate the system, but the system should also start levelling itself from empty phase after some time engine have been started. (normally the compressor are only runned when driwing. The resevoir are used for levelling in stationary for passenger comfort)
When working with the hoses be aware that the resevoir (or struts) can still have pressure in, so when opening connectors do it slowly and if you hear hissing, let it empty in time before continue.
Btw: You should not drive when suspension are in low position, because you have very limited movement of the suspension and practically no hydraulic "friction" from struts. This can be dangerous.

 

I agree with Vasara!!
You will need a working SDD setup. Do you have one? If not you can put one together.
The guy is a hack and you don't have air suspension problems? You have NO air suspension at this point!

Can you do the repairs? Perhaps find a car in a junk yard so you can take your time and remove ALL the parts that are screwed up?
Be prepared to find other such "fixes" too!
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i do not have an sdd set up but im in the process of buying all the necessary parts and rebuilding the suspension system myself with a close friend. so far in my cart i would need to get a new compressor, valve block, fuses, struts, diag computer, and possible air lines. i’m going to try the soap and water test as soon as i return home.

i’m so glad this thread is full of people who are very knowledgeable and looks out for others. i appreciate y’all

 

Again I strongly suggest getting a working SDD. I have fought with the air suspension a good bit and that's the only tool that will get you inside all the systems.
I would also gather as many documents you can about the air suspension and all the logic involved with how the car reacts to different situations.


Here are a few and I have a stack!
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This one is big. Not sure it will upload?
No it's too big. It's a factory dealer training guide and very useful.
Well I compressed it and it's not bad and still readable.
Please see attached file.
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Clubairth1: Note: All these documents are previous version of XJ, not x351. Different system.

 

Sorry I forgot what model XJ we were talking about!
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