Thanks Richard. Slight problem is that with the Rangie running a bit rich - see other thread - the cost of fuel to go and collect them (nearest LR dealer is 20 miles away so 40 mile round trip) will probably dwarf postage cost!
During a regular test of the HEVAC system and running the blowers/distribution/blend motors through their paces I just felt a barely perceptible dampness down by the lower blower output an the drivers side and, yes, it's hardly anything but definitely the start of the O ring problem! Been replaced once before in 2009. I'm not going to do the 'replace the matrix job' but what are the best replacement O rings to get (and what to avoid), what size and where from? I'd like to get some that will last another nearly 13 years like the last ones (which I can't find the detail of!).
Vehicle seems to be running absolutely fine with no warning lights or messages but I noticed the exhaust getting a bit black of late and thought it might be running a bit too rich. Plugging in the Nanocom reveals that it is throwing codes P0135 and P0155 which seems to indicate that the upstream O2 sensor heating circuits have both probably gone AWOL (one may have gone AWOL before the other without me really noticing). They seem to be on separate circuits form a common fuse - fuse is OK but one of the sensors appears to be fixed at 4V and the other one is dancing around somewhat. Before I go and order a couple of new O2 sensors can anyone:
a) Confirm my diagnosis or is there something else that could be causing the problem?
b) Recommend makes of sensor to go for (and ones to avoid)?
If the ride was firmer and, therefore, more ‘controlled’ at Standard height there would be no need for the lower ‘Motorway’ height at higher speeds!
Forget pressure for the moment and look at the dynamics of the bag itself. The spring rate just isn’t dependent on the pressure it is also dependent on the flexure of the rubber bag walls. When at High the bag has a lot of opportunity to flex outward. As the bag deflates/lowers and certainly at Motorway level where the bag is doubling over around the ‘piston’ the ability to flex becomes less and less and so the structure becomes stiffer and the effective spring rate increases.
When towing it will feel more stable in Motorway than in Standard. In Motorway the trailer will not be level but tipped forward slightly with resulting increased weight on the tow hitch and, therefore, increased weight on the rear suspension. The pressure inside the air springs will be increased to maintain the same height with the increased weight and the air within them less compressible giving a firmer and more stable, but less ‘compliant’ ride. There may, however, be resulting effects on the trailer but these should be pretty minimal.
For best results and a chance of removing them in future then No14 (6.3mm) hex head stainless self drilling screws and No14 zinc plated (or anodised) U clip captive nuts. For the fronts the lower fixings also require plastic captive nuts but these generally come with the mud flap. If not then CZA4705L is the part number. Upper fixings need a 1” or 1.5” long screw and lower fixings may need a longer 2” or so screw. The captive U clip captive nuts are fixed around the holes previously occupied by the plastic fixings for the wheel arch liner which will need to be removed.
If you want to look OEM then the screws need to be black cross head self tappers but beware that because of where they are and the environment they experience they are traditionally nigh on impossible to remove after a few years!
Do not over tighten the fixing screws as this will cause the rear edges of the mud flaps to come away from their snug fit on the bodywork with an unsightly gap appearing.
By doing the solenoids one at a time I meant number them, then remove them all from the block and then complete the refurbishment of each solenoid one at a time. As they are numbered it should be possible (with a simple diagram) to get them back in the right position after the valve block has been cleaned. I number the solenoids with a white marker pen all on the same side when looking at the assembled valve block and the take a photo of it. That way even a simple diagram isn’t required - just refer to the photo when rebuilding; it also ensures the orientation and wiring routes are maintained.
A few further tips:
Mobile phone is your friend for taking photos at each stage as you disassemble - they are invaluable for referring to when reassembling. Particularly which way the non-return valves and diaphragm go.
Use a marker pen to number the solenoids as they are removed with a simple diagram of which number goes where.
I find it less confusing to disassemble and immediately reassemble each solenoid in turn.
When refitting the pressure switch don’t forget to ‘unwind’ the wires to it a few revolutions before screwing it back into the block.
First time then 3-4 hours from start to finish is reasonable. The secret is to be patient, methodical/systematic and employ extreme cleanliness.
Having refurbished the EAS valve block a few times now I can probably do it in half that time. However, I treat the valve block as a preventative maintenance item so have a spare that I refurbish ready to swap in. When I refurbish the valve block I also thoroughly clean the block itself when completely stripped down which involves a couple of hours in the dishwasher and overnight drying in the nice warm airing cupboard.
When reinstalling always, always make sure the ends of the air pipes are clean and smooth to avoid damaging the newly installed o rings.
Refurbishing the compressor takes 15 minutes or so once it’s out and on the bench. Again, I have a spare that I refurbish as a ready use spare. Inserting the piston and new seal into the cylinder is one of those techniques that once acquired takes seconds but learning the technique can take some time! It is important to make sure the grub screw engages correctly and firmly on the machined flat face on rebuilding. Cleanliness is essential - I once allowed some FOD ingress during one refurbishment and the compressor was toast within a week or so requiring another complete refurbishment.
Drain holes: I thought about putting drain holes in the tubes. However, the front one is right in the firing line for all the muck in creation coming off the front wheels. This is what rotted out the original front tube. I concluded that drain holes would let as much in as they drained out and, unless quite large, would get clogged up pretty quickly anyway. I went for the thicker walled tube, paint, waxoyl, stone chip and seal approach instead.
I did exactly the same. I used 30mm square box tube but with 3mm thick steel so it will last the lifetime of the vehicle if not my own lifetime. I also used the plastic end caps after spraying the internal box tube with black hammerite foolowed by a good dose of waxoyl. The plastic end caps were sealed on with silicon sealant.
I, too, used aluminium strengtheners on the end caps but used angle section for added strength and alignment.
The bare metal side steps were cleaned, sanded and degreased and given a couple of coats of smooth hammerite and the underside and box tubes were then given a good coating of stone chip. I also sanded back the mounting plates on the chassis, coat of black smooth hammerite followed by a good coating of black stone chip once the steps were bolted in place.
I also mounted the steps tighter into the bodywork for a better ‘look’.
The only issue I found was that the rubber ‘covers’ had shrunk during storage (I had the steps off the vehicle and deconstructed for over a year) and are now about an inch too short in length with a slight gap in places to the end caps!
It’s a right old malarkey trying to piece together the algorithms that swim about inside that EAS ECU! Back to the first question - so why does my compressor run so often for such short periods of time when there is no evidence of any leaks?
Mrs Garvin has short legs - so it is always parked in access mode! It rises to normal height within a few seconds of driving off.
I agree that I would expect some delay in the ECU to stop the system correcting when it’s not strictly necessary but to cater for a ‘flying carpet’ ride without excessive dive/squat under braking/acceleration the delay might be quite short. I also think the pressure switch may also be a bit too ‘keen’ in its operation, kicking in with very (too) little loss of pressure in the reservoir tank.
From another thread I have gleaned that the compressor is rated for a 15% duty cycle which equates to 9 mins total running time per hour.
I am told that the pump only runs when ‘on the move’ the pressure switch detects a drop in pressure i.e. when there is a change of height requested or when there is a leak on the reservoir’s side of things. Now I know this can’t be the case because when previously I had a minor but definite leak on the air tube to the NSF air bag the system would try and keep that air bag inflated whilst travelling 100’s of miles on motorways without the speed dropping significantly. The only way it could do this was if the height sensor told the system that that corner was drooping slightly.
Now when my compressor was incorrectly mounted (my fault) it was very obvious when it ran due to the vibrations and noise. The obvious vibrations were only very noticeable during last few seconds of ‘top up’ when back pressure was high. I noticed that the compressor would run for a few seconds only and mostly (but not always) when I applied the brakes. I now believe this was due to the front suspension compressing, the height sensor providing the reduced height reading and the system operating to counteract the movement. Hard cornering would have the same effect. Once rebounded the system would be too high and air allowed out to bring the suspension back within limits. This continual operation would result in the reservoir pressure inexorably dropping over time and the compressor running to replenish the reservoir tank.
It was also noticeable that on a motorway/A road drive the compressor would seldom run giving further credence to this continual compensation when on the move. Does anyone know definitely how the system works on the move and if my assumption is wide of the mark?
Furthermore, there are no leaks when the vehicle is parked up for days as the ride height is rock steady with no sagging and when moving off the suspension goes quickly up to normal height. I do not have a pressure gauge fitted so cannot swear to absolutely no leak on the reservoir side but I would think after a week stood standing with even a small leak it might struggle a little bit to get up to normal ride height.
Does anyone know how long an in spec compressor should take/run (mine is in rude health) between the two operating limits of the pressure switch? From my rough estimation the compressor would run in town driving (frequent braking) for a total time of much less that 9 mins an hour. Now I have corrected the compressor mounting I can’t really detect when it’s running when on the move so can’t measure its overall running time.
However, having said all that I have the feeling that the on/off limits on my pressure switch may be a bit too close together resulting in the compressor switching on too often (albeit for short durations) and without fitting a pressure gauge the only other way to do a rough test is by timing it’s running period.
If you still have all the skin in place on all your knuckles as well then you can consider it a great result ;-)
Where did the 15% duty cycle figure come from?
Yes, that’s the sort of stuff. Mine is narrower than that and white . . . . . . . but I’m hoping nobody will notice on the inside of the ducts ;-)
Controlled aggression is the key . . . . . and a bit of patience. The ducting is made of ‘tough stuff’ so can take a fair bit of ‘abuse’. I find it’s not so much the ducting that can be damaged, more the surrounding cable looms, switches and connectors so some ‘care’ is also required.
PS: I note RAVE says some ‘helpful’ things like ‘remove ducting’ and ‘replace ducting’ or words to that effect, as though it is just a straightforward simple task!!!
PPS: I also have a reel of ‘bog standard’ window/door self adhesive seal that I use instead of trying to track down pukka replacement seals. It’s pretty narrow so three layers side by side usually fits in the female part of the ducting - make sure the ducting surface is stringently clean before application and it sticks pretty good.
New seals, gash thin foam rubber strips, hot air gun, BF&I and duct tape.
Fit seals. Fit ducting nicely in place on one end. Heat the ducting up and it becomes more pliable. Apply brute force and ignorance to get the other two ends of the ducting just butted against each other. Apply more BF&I to pull both ducts the same way to get the male end just starting inside the female end and then wiggle whilst pushing the ducts in line ‘folding’ the male into the female. Push gash foam strip into gap with small screwdriver or similar. Wide duct tape around joint. Jobs a good ‘un . . . . . or as good as it’s going to get!
Just Heat and BF&I to remove.