Suspension not coming up to pressure

[jookul100431]

Quick update....was just onto my Mechanic....he says the car was flat this morning when he came in. I know the battery was completely disconnected on Saturday afternoon till this morning. So I'm thinking I still have a leak somewhere. He is still thinking pump

[ptjs1]

Charlie,

If the car was at normal height when the ignition is switched off, how does your mechanic think that a lowering car is anything to do with a failing pump? It's sensors or leaks that cause a car to drop when it's turned off. And, in theory, you've eliminated the potential for it to be a sensor.

Good luck

Paul

[jookul100431]

Hi Paul

Yep I'm with you on this one... I still think its a leak somewhere, though where I don't know. My mechanic metioned that he will have another look for leaks, so he may find something

I am hoping to get the car back this weekend and I am keen to do the soap tests if my mechanic does not find a leak. Lots of people talk about spraying the shocks but all I can see is the top of them. How do you spray the air bag itself.or other parts of the shock access is not great

Also on the US threads there is a lot of talk of of suspension fall when air temp goes below 0...its all over the place.... does anyone have any thoughts on this.... i'm only asking as it has been cold every night since last week and that is when I got the car back for a day or so.

[J44EAG]

Before I reconditioned my compressor, the car used to drop over night by about an inch each side at the front. With the compressor overhauled, I had no further issues. I can only assume the apparent pressure drop was due to some leakage back through the compressor piston ring.

Be aware that the car in a good suspension state is very sensitive to any slight ground surface irregularities. Its worth seeking out a piece of dead level ground. The system will try to adjust to keep the car level fore and aft and side to side. Note that the car will self level every twelve hours. Its worth doing the twelve hour test to see what happens. If you double locked the car at say 18.00hrs, then returned to it at 06.00hrs next day, you should see the car do a little dance as the adjustment takes place! Its quite intriguing to watch that occur.

A couple of years ago when attending my daughters wedding and reception at Canterbury Cricket Ground, parking was limited even for a Father of the Bride. The only place I could find to park was 90 degrees to and nose on to a six inch high curb and pavement. I just got the car onto this "plinth". I double locked the car and walked off to the reception with the nose of the car somewhat high in the air. When I returned a few hours later, the front suspension had fully deflated and the rear end had jacked itself right up. Wish I`d taken a picture of it. Opening the car and starting up without entering the car, I was relieved to see the front end come up and the rear end deflate. I gently removed the car from the plinth without bashing the underside of the front bumper on the curb.

In service following the compressor rebuild complete with replaced desiccant in the dryer, the suspension has proved faultless. The drive outside the house has a slight gradient for and aft and also an angle across it. Upon parking on that area, switching off and alighting the car, I`m now treated to watching the car rise and fall as I stand by it. This is usually accompanied with escaping air sound from the exhaust of the compressor. The car at that point is self leveling prior to the half hour or so shut down of the electrical system after double locking the car. Its also worth mentioning that if I`ve decelerated perhaps to stop fairly sharply at traffic lights, its not unusual to find the front of the car rising to a more level attitude after having weight thrown to the front during the stopping deceleration.

Just a few further pointers for you. As said, my car suspension did improve its air retention capabilities after compressor overhaul. Don`t discount that. In my opinion any compressor that has covered more than about 70K miles really could benefit from a new piston ring to avoid accelerated bore wear. Leaving the matter until issues occur frequently leads to the need for a new ring and cylinder head or complete compressor replacement. Wear in the cylinder is easily seen. If none is present, then a replacement ring is all that is needed. A classic case of a one stitch in time saves nine more later.

Mike K

[ptjs1]

Charlie,

I apologise if I've mislead you. I'm really interested in Mike's last post.

Mike,

I was intrigued by your description of the rear of your car levelling itself up. Would it be possible to show diagrammatically how the system works on the x350, either here or in the magazine? I know more about my Range Rover foibles than I do about the almost fautless system on my x350, but I'm guessing they are quite similar?

The RR system uses a compressor, reservoir tank and valves in each spring. I think that the reservoir must hold air at a pressure in excess of that in the springs as one can raise the car without the compressor initially cutting in. That also seems to be the only way the system could theoretically level up a RR (or x350) if the ignition was off? Eventually, if there was a leak on one corner, the car would presumably only level up until it ran out of pressurised air in the reservoir, at which point, it would then have to start levelling down. If there was a failing sensor, it might level down only. When I had the dodgy sensor on my RR, the car only ever levelled down, it never tried to level up.

With the lines between compressor, reservoir and springs, one would expect a variety of non-return valves, so I'm intrigued that a weak compressor seal might enable reservoir, and even spring air to leak all the way back to the compressor.

Is there something in the online version of the workshop manual that describes the system, which could be published here? I'd really like to understand it better.

Cheers

Paul

[jookul100431]

Hi Mike and Paul thanks for the support on this and it's great to know its.not just me making up my own theory...
So me mechanic is still going with pump though I know he won't say and doesn't want to upset me. O think I just need a bit more evidence beofee I spend the 400 quid and I can only find a wabco pump at that price from Germany...I thought I would find in the UK bit not yet... I digress....so on the pump first some facts.... The car had done 110k miles before recondition the was some marks on the lining.. the air dryer spring was rusted to prices and broke and the air dryer material itself was very wet....we reconned all that and that is when the trouble started.

Sine then alternator went last week and got one from Berkshire Jag and that has been replaced... When fitted I ask d my mechanic to lock the car and leave overnight so it did and yesterday Morning he noted the car was down again bit when he started he noted 2 things...the car started a lot better then it ever had before and the car pupmed itself up faster than the previous week. I had also talked to Andy Fulton and he explained that the exhaust value does not control any height adjustments it just let air out. He explained that it is the solined block in the Booth that controls the 4 corners. So he said for air to leak out through vthe pump or valve it must come from the solinoide block first...makes sens I think. He was confused as why the car was going down equally he said he would expect the front or back to drop first and the opposite would follow. He strongly believs it's a leak. He also confirmed filling the battery will remove all the electronics out of the equation...

My mechanic did looks for more leaks and couldn't find any.

So what next week last night I drove home and parked in my garage where the ground is level though that being said the rear of the garage is about 1cm higher in the rear than then front....

So I parked up liked the car 1 press first and then 2 a few minutes late to fold mirrors. I took some measurements with my tape that are attached the bottom four rows the car dropped about 1.5 to 2 inches overnight. Does that loss when car it soaked on almost perfect ground sound too much over a 18 he period. I then started her this morning and car pumped up into about 1 min or a bit less

I'm not too sure where to go. I think I'm going to take it for a small drive and pull the battery and look for leaks and monitor for height loss...I think at this stage I am thinking brand new pump or air block.

Mike I am intereguedthat you car settled after recon of pump maybe the are more place the pump can learn than we think while from a height perspective my started after. Though I do the the palusability error that I was try to repair has gone...

[ptjs1]

Charlie,

As the car drops every time you park it on level ground, why don't you just try and take the pump out of the equation.

Park the car up as you have done, then carefully disconnect the output pipe from the compressor (don't know if there' a return pipe also?) and securely plug it. Be careful, as I'm not sure if there'll be any pressure in that pipe. If the car goes down that night again, then it's not the pump, as far as I can see? (I'm still not sure that a faulty pump can cause it to drop overnight, without there also being another fault elsewhere?)

So that would make it, valves, valve block, sensors or leaks.

If it does it again with the battery disconnected, then that takes the sensors out of the equation.

Just a matter of elimination, one logical step after the other.

Good luck

Paul

[jookul100431]

Hi Paul

I think the pump may have been taken out of the equation some time ago....when we pulled the pump off the car. We discovef that I needed to get a new spring for the air dryer. So my mechanic drove the car off the 4 poster ramp and the car did not drop in any way and my mechanic park it up. Now when he came back 2 days later to the car it had fallen flat. I explained this to Andy Fulton and he said that with the proved the pump doesn't affect the ride height as the car didn't fall quickly..

I have done some soap tests this morning but not all....I check the solenoid block and the top of the two front shots and air connectors and could find anything obvious... The only very very small this I found was the tinyest of air bubbles that did even have enough pressure to burst it...I bounced that shock up and down and that problem stopped so I don't think that is a problem....

So for now I have pulled the battery and am retaking height measurements over today to see what happens. I am doing this under Andy Fulton's advice to see if one side is dropping father than the other. Not sure what evidence that will throw up

[jookul100431]

So here are the results of the battery disconnected test... Very poor I'm afraid.....I have attached the results below. Bit not certain what results I can clearly other than I have a leak which affects all four corners. From the results over the first 10 hrs. The brop is consistent but I takes about 4 hrs to really start dropping. So I noted the following
The real drop start after 4 hrs
The drop across all 4 corners is consistent
The back does seems to loose a bit more air than the front. If u look at the 10 he results u can see that.


So what next I do need to find the leak though I don't want to start pulling stuff apart. But looks like I will have to.
So what are my suspects....
The rear left shock is still original the other three are less then 9 months old
Solenoid block I believe they can corroded interally and not show any extrnal signs of leaks. The pump. No that I know better how the system works that is still a suspect. Looking at the air flow diagram you can see that the only way four shocks can fall is a fault solenoid block and a faulty exhaust value. You must near in mind my battery was disconnected so now self levelling going.

For now I won't have much time to do more hunting till after Christmas so for now I'll keeping driving around.. but if I was taking a stab at it I would go for the connector block first then the pump

I have attached an other tech doc I found online which give a good high level description of the system operation and a tech bulliten on leak detection...these maybe on the forum already so sorry if I'm repating...looks like o can't attached the 2pdfzs so if anyone wants them ping me on a message and I can email......one of the big things in the doc was it says that car is lowered via the exhaust valve on the pump. It also says that with every process the valves on the solenoid body operate simulatiously to let air in or out.... these are the two sentences which makes me think I have to faulty items

Manged to add to images of relevant pages

[J44EAG]

Fortunately, good, used valve blocks are easy and fairly cheap to obtain. I`d give Eurojag a call and discuss. Their service is excellent and next day delivery is the norm. At this point, I think it worth you getting a block to hand and installing it. It might save a lot of messing about. Valve block failure is not unknown.

Mike

[jookul100431]

Thanks Mike

Yeah I ended up making that decision yesterday too. I was thinking of getting a used one but felt that it's hard to determine long term usage with them though I may go that way yet
Bit I have ordered a new aftermarket parts from messiler automotive from Germany theu are air suspension specialist as much as I would have preferred not to go after market I am hoping the product is good quality

It's good to know I am not alone in my thinking

I suspect it will take a good week to get to me
I will keep this post updated on how things are going

[jookul100431]

While waiting for my balance block to arrive I decided to do a bit of leak testing on my pump. I didn't find anything of any major significance but what I did find was a tiny leak where the in/out air house connects to the air filter...it was that small that I am not sure if it really significant bit based on what I know to date I would expect not to see any... anyway I am holding on to this as possible evidence that the valve block is indeed leaking and also possibly that I have a leaky exhaust valve on the pump....valve block first and we will see what happens

[ptjs1]

Charlie,

I wish I'd starting taking bets on the outcome of this one! I'm quite happy to be proven wrong, but I'm still struggling to see how a fault in the pump or exhaust valve can cause the car to drop unless there's also a fault elsewhere. And you also confirmed that with the pump (and exhaust valve) removed, the car still dropped.

Looking forward to the next update!

Paul

[jookul100431]

Hi Paul/Mike

So I am back with another update. But first Paul I do agree with your thinking. I don't believe the pump on its own can cause the suspension to drop. All I was trying to to confirm was to see if I could confirm if the valve block was leaking and If I saw air at the outlet of the pump then the only place this could come from (by my reckoning) was a faulty valve block. But i would suspect that exhaust valve on the pump is faulty in that air is escaping past that.

So where am i know. Well the valve block from germy arrived on Monday and i went about replacing this on Tuesday....want i thought would be an hour or two was a 7 he job when i was done and dusted.. but i am slow at these things. The valve i purchased was a aftermarket part two of the push fit valve did not work correctly one of them would not hold the pipe and the other leaked. I did contact the company and they are sending me replacements. But to try and keep me going i used two of the old connector with the new olives that came with the connectors on the new valve block. I check the block for leaks after this and i couldn't see anything obvious though I will say that the one that had the leak was the feed from the compressor. I believe the compressor was running when it was leaking... It was not a big leak but as mentioned about I did replace the connector. Now when I tried to leak test this there was no leak but I think this will always be a hard one to prove as I think the pump will have to be ruining to fully test and since I have no easy was of training the compressor on I can only assume I do t have a leak. I did give the car a good run today so that I know the pump would switch in and out and that there would be some pressure on that line and I check again. For a leak and found nothing obvious. So for now I will go with that...so back to the operation after replacement of the valve block. So I drove the car for about 20 mins and parked it in my garage.. when I got out of the car I saw the rear drop down a small bit so I s**t off the car a took some measurements the rear was 38 cm drivers side and 37 cm passenger side. For the full test time of about 36 to 40 hrs these measurements did not change. The front was a Little different. After I drove into the garage the fronts were at 41cm drivers side and 41.5 passenger. After about 30 to 40 mins of shutting the car off o noticed that the car tried to settle and the front end dropped a bit. I have owned that for 5 months and never seen this happen. So I took measurements again drive 40cm and passenger just over 40cm I took this as that base line. So after about 8 hrs the front had dropped to 39.5cm both sides. The following morning the front had dropped to 39cm both sides... I left that car in place for another 22 hrs and the fronts had not moved anymore they were both still at 39cm so it would the front dropped 1cm over a period of about 40 hrs. The only thing to note was that I had to open the driver door after about 19 hrs but I dont think this effected anything. So I don't want to speak too soon but I do think it of fixed and the real problem was the valve block..... Now some obervations and notes of my own
1 I think the valve block should have some isolating rubber bushes for noise reduction but it seems that the one I took out did not have these fitted. I must see if I can get them from Jag from looking at the internet it seems some do and some don't have them so I'll see what I'll do .
2 I still think the in/out valve on my pump is faulty and so I will need a new pump in time. So I will look at getting a new pump for that reason in time. I am in no immediate rush for this. I she other things to repair...including my mini Cooper s 2005 which has been neglected while the Jag has been taking all my money over the last 5 months
3 My theory on what was wrong...one ingesting thing I saw on you tube was some guys reconning a pump and one of those suggestions was that thier air dryer media was so wet that it was completely clogged no air could get past it. And the pp was running trying to push air. Well my media in my pump was soaking too and I was I possibly struggling with a similar problem. My pump was struggling to push air past it and exhaust air was also struggling to get past it. With that in mind I am wondering was it possible that my block air dryer was managing to hold back the leak from the valve block and that the low pressure leak could not get past the air dryer. So when we reconned the pump and put new media in the pump which was fresh and dry the low pressure air was able to go through it and least out through the exhaust valve... Just a theory
4 work with the after market valve block. I got it from Germany and it definitely wasn't the same quality at the denso one.... I had two faulty push fit connector. No replacem rubber bushes for noise reduction though I am not certain if my model had them orginally... O am not a fine of the push fit would much prefer the normal ones. I must say though that the company in Germany have been very good on sending replacement though if it's all working I may not change them.

I don't want to say it if fixed yet as there are many stories of stuff being fixed for a few days and then.... So I will monitor over the next couple of weeks.

If I feel all is good then I may split open the old Val e block to see what they look like inside and will post here if I do.

The the thing to note is that car has not felt better on the road. So I suspect my valve was faulty for some time

[cornershop]

Interesting - i was planning on replacing the valve block with a Meissler item as a preventative measure.

was it this one you ordered? their so called 'upgraded' item? http://www.air-suspension-shop.com/Jagu ... n-C2C35166