I've noticed recently (but it may have always been there) that on raising my height from access to extended, or back, that there's a point where the suspension seems to stick momentarily then give a little jump rather than moving smoothly. The point at which it happens is never quite the same. <br>
Everything looks normal underneath, no chafing or dull spots on bags, no grease nipples to grease. Even sprayed bags and rubber bushes with rubber lube (oooer missus). Still the sticking is there. <br>
Anyone else have this, is it just paranoia because I've noticed it and am now looking for it?!
Suggestions welcome...
Sounds familiar, I cant test mine yet but I'm pretty sure it would rise to standard level then adjust itself before continuing to high level but I'm not sure I would call it a jump.
Mine too. When rising it first rises rear, then front followed by a final correction, first rear again, then front. Lowering to access is the other way around.
Also have corrections when standing still, it lowers an inch and corrects itself. Maybe a dead spot in the height sensors
Will always do the rise in steps, rear first so that if headlights are on it doesn't blind anyone, all the p38s I've had do the same,, mine at the mo is having a heart transplant, spent a bit of time on this job, everything cleaned and resprayed if needed, will post some pics when finished ( hopefully today 😀)
I noticed that earlier with mine, it'll rise and fall as it adjusts itself sometimes with a bit of a "clunk". It's nothing to do with the ECU driving it, it's a much quicker "jerk" as something pops free.
Yep, that's the one Gordon. Exactly like something popping free. <br>
Not running Koni's on yours by any chance are you?
Orangebean wrote:
Yep, that's the one Gordon. Exactly like something popping free. <br>
Not running Koni's on yours by any chance are you?
Nope, although that's one question I do have - how do you "bounce test" air suspension to see if you've got a knackered shock? My gut feeling is that the air suspension would be somewhat damped already compared to a spring (lower "Q" as it were) so it wouldn't bounce as much.
Going over speed humps the driver's side rear seems to come down with a hell of a whack.
Bounce testing a 2 tonne car on bags would be a challenge for sure! <br>
Looking at the way the suspension is put together, I'd put it into extended, put a ratchet strap round the axle/ chassis somewhere handy to stop it over extending and pop off the bottom nut on the shock. <br>
This should give enough room to work the shock through its range of movement to check the damping. <br>
That's my theory anyway! <br>
The reason I asked about the Konis was that the P.O. fitted Konis to mine. As part of the design they have heavier rebound damping than the Boges and I was wondering whether the stiction could be a side effect of that.
When raising up, system is designed to lift in stages. First the back lifts up approx 70%, then the front lifts up to match it, then the back final 100% followed again by the front. The reason as mentioned is to prevent headlight dazzling.
As the solenoid valves switch in and out it may appear to be a bit jerky and not very smooth.
No, this is definitely a mechanical jerk and nothing to do with the valve action. It even does it with the EAS ECU disconnected, driving the solenoids externally.
I wonder if it's just a slight 'pop' as the fold of the rubber on the air spring rolls over itself to go into the higher settings?
I was thinking similar- hence slapping loads of rubber lube onto the bags. Aside from the weird sensual pleasure I got from doing it, nothing was achieved. Thunk still there!
Other than lubing your bags for pleasure, I don't think it would do much as I think it's more a case of as it articulates it just gets to that 'point' where it rolls over and pops... take that how you like....
I get it sometimes on mine and it looks like it's just as the suspension geometry changes as it goes up. I get it some times if it's lowered on it's own when I go away, as the air spring then re-pressurise on start up too.
I don't think it's anything to really worry about at the moment, as frustrating as it could be...
Found the same problem - but that it is worse when the ground is not level; When on a slope as it raises you can also get a 'kick' through the steering wheel as the bag 'pops'; Not sure but I have assumed that on a slope the body is not actually 'horizontal' and so rises asymmetrically - and then it slowly corrects/levels itself out as the bags (more) fully inflate and so there is also some lateral/sideways motion involved (?); Changing all the bags (for the other usual reasons) did not remove this effect either !
I found this was happening with my truck and after some investigation I greased the sliding part of the drive-shafts and it stopped.
When you say drive-shafts Ray, do you mean prop-shafts?
I suspect he means the propshaft sliding joints which would make sense if they were a bit sticky. My front prop had a bit of slop in the sliding joint which meant I got a bit of vibration which was worse when in normal height than at motorway height as it was extended more.
Ah well, that's one off the possibilities list then! <br>
Cleaned and re-greased both ends when I replaced all of the UJ's recently. No slop on the splines either. <br>
The hunt for the stiction continues...
Yeah I did mean propshafts Doh!