The purpose of this thread is to recognize that some forum members may be experiencing slow leaks with one of their air shocks but not able to determine which shock may be at issue vs the rest of the air suspension system.

For the USA forum member who is willing and able to tackle testing their air shock issue and willing to report back to all on this forum, I would like to loan out this air shock testor to you.

The design of this particular gauge set up (see picture attached) using “push to connect” fittings (similar to Xag member) is to allow the cars air compressor to pump up the shock and with the air valve, one can turn off the air going to the shock and at the same time closing the captured pressure from the air shock to the guage making it a closed system with the air shock. Then by letting the car sit one can watch the gauge to see if the shock is leaking (of course one would have to realize that differences in outside temperature through out the day and night can move the pressure a little naturally). One could hook them up to both front shock or both rear shocks at a time or one front and one rear.

Note that this set up uses “push to connect” fittings, such fitting are only rated to handle pressure up to 150 PSI or 10.3 Bar (the black hose has a pressure/tearing rating of up to 1,565 PSI or 107.9 Bar). So this type of air shock setup is only good to pressure test each air shock at the air shock connector only. The normal pressure range for the air springs is 101.5 - 130.5 psi / 7 - 9 bar. Thus this set up is not designed to be hooked up to the Reservoir or the Solenoid Valve Block which are located in the trunk as these hold pressures up to 218 PSI or 15 bar.

I will PM you with additional information regaring the air suspension system.

 

Good initiative!

Guus

 

Superb, very helpful and very generous

 

That's great! I almost wish I had a problem so I could borrow it. ;-)

 

This is indeed a generous and useful idea, and could help a lot of folks who suspect leaks, but have no testing parameters or equipment. I have been chasing an intermittent ASF, but some smarter people than me, including BagPipingAndy think a leak is unlikely. Things have been quiet on my issue, but its great to know you have this tool available for diagnosis.

I am curious. I assume you designed and built the tool to resolve a suspected leak of your own. If you were able to use it, what is a typical atmospheric or temperature effected loss of pressure? I ask because I quickly observed how much lower temps seem to bring out all the faults in marginal systems.

Its in the back of my mind to add a gauge to the reservoir, that can be viewed without pulling the spare wheel out. I think it would provide a lot of useful data, but I don't have a clear idea of how to implement it. Would you agree it could be useful for a system-wide pressure monitor, and if leaking was suspected, then a shock level tool such as yours would be the next course of action? I realize that there's a junction block there as well, that all the lines pass through, so perhaps a gauge on the reservoir is too simplistic, when you don't know what state the junction is, or what is open or closed. I just think we need more data when things fail. Do you agree?

 

Hi Blairware,

One member, did exactly that, put a pressure guage on the air tank. See the link below. Issue here is that if you have a leak you will not know for sure where it is coming from, thus the need to investigate possible leaks at the air shocks as the typical next step.

https://www.jaguarforums.com/forum/x...too-low-66911/

My goal is to further the knowledge of the air suspension system so we can all benefit. I personally have not had any issue with my air shock system...knock on wood.

 

So far a couple forum members have used and benefited from these guages and I have it back now ready to be used by another USA forum member. Just let me know.

 

I really could use this test rig but I'd like to go ahead and build one for myself... I have one question about your setup though. I see at one end you have a brass fitting that looks like it would thread into the fitting in the top of the check valve on the strut but how do you deal with the threaded male fitting remaining on the factory air line? The locking ferule looks like it permanently bedded into the plastic tube on mine. Is there a way to take that apart and put it back together?

 

A picture is worth a thousand words so here is a picture of the fitting. Since it is a push on fitting you just push down on the blue flange and pull out the air line, than you can screw the fitting on and simply push the air line back into the fitting.

 

Looks good but where can I find that fitting? Is it BSPP or NPT or other and does McMaster Carr sell it?

 

I wouldn't mind building one for my own tool collection. Where can these fittings and air line be procured from?

 

I've pulled the check valve out of the shock and I have it with me right now. I'm going to figure out what the thread is and post the info for everyone. It's one crucial piece of information that I just can't find anywhere in these posts. It's not a factory tapered thread... not to say a tapered thread won't work but ideally an adapter would be used to transition from the straight thread of the fitting to a tapered piped thread. Sometimes you can get away with ramming a tapered thread into a straight thread and still get a good seal with loads of teflon tape. I'd like to be more formal about it.

 

Hi
I think I have narrowed down a significant air leak to one of my front struts. The leak must be pretty significant, as once pressurized, it cycles between the pump running for 10 seconds, then the system holding firm for 25 seconds, then the pump restarting for 10, etc. So, enough to lose pressure consistently in 25 seconds. Have sprayed soapy water on all visible fittings - how do I inspect the struts for leaks without removing them? They seem pretty well encapsulated - I can't really even spray them with soapy water.

Is there any way to inspect them without just removing them?

 

PM'ed
Griff

 

This is a copy and paste of an older message I posted perhaps a year ago but it should all still work.


An enterprising forum member who is suffering from the air suspension woes that plague many of us tracked down an old post from a couple of years back where I had fabricated a pressure testing rig for the front shocks out of readily available pipe fittings, adaptors, gauges, etc. He asked if I had ever put together one for the rear shocks as they have a different size airline and fitting. If I did it has long since found its way into a dark corner in one of my 3 storage sheds and I couldn’t find it.

Since I had subsequently given up the fight and swapped the air suspension for a set of coil-overs I had laying around the 4 shocks I had removed (I’m a packrat so sue me) so I took the factory fitting out of the one blown rear shocks to see what I could figure out. Now we’re dealing here with an alien species of metric fitting and some variation on British thread pitches etc., it’s not very likely you’ll find what you’ll need in the shrink wrap stand at your local Walmart.

I looked on line at a couple of British websites with no real luck as the descriptions weren’t good enough to convince me what they had would work. I checked several local supply houses to see what might be available but that didn’t pan out either as the fitting from the rear shocks is a very small piece with an 8mm 1.0 thread pitch/size that is for a slip through pressure line sealed by a small press fit brass collar from the inside.

On a hunch I went to the local NAPA store as they also custom make high pressure HVAC and hydraulic hoses thinking perhaps they could fabricate something or lead me in a good direction. There tech, who matriculated through the 60’s and later car wars that I did, took what I had and disappeared into his cave for about ten minutes and returned with two small parts. When attached to the tester I built last year and then attached to the fitting from the rear shock I salvaged I had a working tester that could be used (with a couple of parts swaps) on both the front and rear shocks to test them for leaks.

Here’s the link to my older post from 7/2013 describing what I made withpictures and parts #’s if you want to make your own and below are the two newparts which are both Gates pieces with the following descriptions and NAPA part#’s.

Link for 2013 post:https://www.jaguarforums.com/forum/general-tech-help-7/diy-air-suspension-pressure-tester-98790/#post772872

New parts required for rear shocks: G31100-25023/8” pipe coupling & G60631-0202 slip-fit adaptor

With those and a short piece of the appropriate sized and type of 1/8” pressurehose as well as the fitting from the top of a blown shock you can make a testerof your own.
OR
You can message forummember John Tuberville and he’ll send the one I’m sending him to the nextmember in line for a nominal fee to cover his investment just as I have donewith him.

 

Great post.

What is the appropriate pressure to test front shocks? Rear shocks?

Thanks
-mag

 

Which coil overs do U go with? How do U like them?

 

110-120 psi should be sufficient as the shocks have an operating pressure of between about 100-130psi.

 

Vmaxie, I went with Strutmasters and have been very pleased with the overall results. My only complaint is a small one. Since we live in a rural area the last 1/3 mile or so to our house is over a hard packed dirt road and the rains create ripples/ridges that cause the suspension to give off some mechanical noise as it tries to react to the rapid surface changes.

On anything resembling a real road the car is sure footed to any speed it can get to and I regularly cruise on the 4 lane highways in our area at 85-90 without any handling problems whatsoever. I'd rate it among the top 3-4 of any car I've owned over the last 50 years.

I know there are some posters who make a point of excommunicating anyone that dares switch to coil overs but my response is that if they're so superior why is that that even Jaguar, with all their engineering prowess, felt it necessary to quite using them why shouldn't we do the same.

 

To lcmjaguar.

May I ask you to inform about the brand of quick-connect fittings which you have used to build the pressure test equipment. If available, also the part numbers and in particular for the M10x1 brass fitting towards the air spring. I have in vain tried to find a M10x1 fitting with internal thread which can be connected to the fitting on the tube for the air spring. The fitting on the tube can be disassembled but in order to avoid future leakages, I consider it better not to separate.