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Car Forum / BMW Cars / October 2007E39 Touring, hard rear suspension?
All, Re: 1997 E39 Touring Any ideas what might be causing the rear suspension to be VERY STIFF INDEED? I've been told to be worried coz of air suspension ... is this true? tia Dr D > All, > Re: 1997 E39 Touring > Any ideas what might be causing the rear suspension to be VERY STIFF > INDEED? > I've been told to be worried coz of air suspension ... is this true? No - it's actually pretty inexpensive to replace.  Signature*I was once a millionaire but my mom gave away my baseball cards Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound. >> All, > [quoted text clipped - 6 lines] > > No - it's actually pretty inexpensive to replace. is it a gas spring like the spheres on a citroen? cant seem to find anything on GSF ? On Sep 26, 11:40 pm, "Dave Plowman (News)" <d...@davenoise.co.uk> wrote: > In article <z%AKi.33$w2...@newsfe4-win.ntli.net>, > [quoted text clipped - 5 lines] > > No - it's actually pretty inexpensive to replace. ...with non-air parts. > On Sep 26, 11:40 pm, "Dave Plowman (News)" <d...@davenoise.co.uk> > wrote: [quoted text clipped - 9 lines] > > ...with non-air parts. now that sounds appealing ... pls do tell more ...? > On Sep 26, 11:40 pm, "Dave Plowman (News)" <d...@davenoise.co.uk> > wrote: [quoted text clipped - 8 lines] > > ....with non-air parts. Can you give us any references for that comment. I've never heard of non-air parts for the E39/Touring. Possible I guess - realOEM.com does show a standard spring for them - but doesn't give any part numbers. The air springs aren't particularly expensive, nor hard to replace. They list for $227/each, and can be gotten at a 20% discount from some on-line sources, so less than $200/each. Apparently they last for a bit over 100k miles. > > ....with non-air parts. > > Can you give us any references for that comment. I've never heard of > non-air parts for the E39/Touring. Possible I guess - realOEM.com does > show a standard spring for them - but doesn't give any part numbers. Oooh, no actually I can't. I was just assuming it can be done like with other models. >> On Sep 26, 11:40 pm, "Dave Plowman (News)" <d...@davenoise.co.uk> >> wrote: [quoted text clipped - 18 lines] > > Apparently they last for a bit over 100k miles. I can't imagine that the springs would be worn out, given the description of the problem. Worn springs would make the car sag, ride soft, wallow around in a turn, that sort of thing. given the description of a harsh ride, my bet is that the air shocks <whatever is operated by the air system> are <is> full of air causing the suspension to be stiff and harsh. It seems to me that BMW should have included some sort of suspension control inside the cockpit that would adjust the air system for the various loads that a Touring might have to carry. When th eload is light, the system is off (for all practical purposes), but when the load is heavy then the system can be set to level the load, which would make the ride harsh if there was no actual load for it to handle. I don't own a Touring, so I freely admit that I'm shooting from the hip here. But, I once owned a set of air shocks, and I had to fill and empty them at the gas station as the loads on the vehicle changed. I would be looking on my Touring for a button that did this function for me automatically. Barring an automatic system, the OP would have to bleed the air out with an unloaded car, and put air back in when the car was loaded. If there is an automatic system, then it is not working properly, and has remained in a state for a loaded vehicle when the vehicle is in fact unloaded. If the suspension was filled with air, and the car was unloaded, then he would have precisely the complaint he has described ... > I can't imagine that the springs would be worn out, given the > description of the problem. Worn springs would make the car sag, ride > soft, wallow around in a turn, that sort of thing. given the description > of a harsh ride, my bet is that the air shocks <whatever is operated by > the air system> are <is> full of air causing the suspension to be stiff > and harsh. If the air springs leak - the suspension drops to a set of rubber buffers, which will give a hard/harsh ride. That is the most common failure on this particular system. > It seems to me that BMW should have included some sort of suspension > control inside the cockpit that would adjust the air system for the > various loads that a Touring might have to carry. When th eload is > light, the system is off (for all practical purposes), but when the load > is heavy then the system can be set to level the load, which would make > the ride harsh if there was no actual load for it to handle. BMW's a bit smarter than that idea - it self-levels, using a control that attaches to the suspension, telling the suspension computer what the height of the rear is. It works quite well actually. > I don't own a Touring, so I freely admit that I'm shooting from the hip > here. But, I once owned a set of air shocks, and I had to fill and empty > them at the gas station as the loads on the vehicle changed. I would be > looking on my Touring for a button that did this function for me > automatically. No button is necessary. The miracle of modern computing power made it redundant. Barring an automatic system, the OP would have to bleed > the air out with an unloaded car, and put air back in when the car was > loaded. If there is an automatic system, then it is not working > properly, and has remained in a state for a loaded vehicle when the > vehicle is in fact unloaded. One doesn't have to do anything like that. The E39 is a MODERN luxury car. Self-leveling suspension has been around since the late 70's. This is one of the better systems - non-hydraulic and quite responsive. > If the suspension was filled with air, and the car was unloaded, then he > would have precisely the complaint he has described ... That isn't likely to be the case here. I think you're over thinking it without adequate knowledge of the topic at hand. <snip>> > If the air springs leak - the suspension drops to a set of rubber buffers, > which will give a hard/harsh ride. That is the most common failure on this > particular system. do you know what the ride height should be so that I might check it? It doesnt look *that* low at the back as to be resting on the stops but I guess it may be ... Does the std failure mode allow water to get into the air spring element which (being an incompressible fluid) might stiffen the action ? New units are £120 + VAT from my friendly local main dealer ... which is probably about right ... and I cant find them cheaper online anywhere so ... Any top tips out there on swapping them over? >><snip> > BMW's a bit smarter than that idea - it self-levels, using a control that > attaches to the suspension, telling the suspension computer what the > height of the rear is. It works quite well actually. are the level sensors generally robust? <snip> > I think you're over thinking it without adequate knowledge of the topic at > hand. 8-) TIA Dr D >> I can't imagine that the springs would be worn out, given the description >> of the problem. Worn springs would make the car sag, ride soft, wallow [quoted text clipped - 6 lines] > which will give a hard/harsh ride. That is the most common failure on this > particular system. I think you have hit on the trouble spot right here. I would have guessed bladders that were filled when the vheicle was empty, but if bladder failure cause the suspension to drop onto the bump stops, then this would easily cause the symptoms described. Let me ask a probing question; if the system is automatic, and it detects a load that does not exist, would it attempt to pressurize the shocks to level a load that is not there, and thereby make a harsh ride? I am asking this because I wonder if there is a troubleshooting opportunity that includes the level sensing device ... > Let me ask a probing question; if the system is automatic, and it > detects a load that does not exist, would it attempt to pressurize the > shocks to level a load that is not there, and thereby make a harsh ride? > > I am asking this because I wonder if there is a troubleshooting > opportunity that includes the level sensing device ... Dunno if it's a probing question - it's rather convoluted. Is there troubleshooting to test the level sensing device? Sure. Open the tailgate, engine running, and plop yer butt on the rear. See if it goes down then back up to the former level. If so - it's working. You can also exercise the self-leveling and read the level sensor using the GT1 BMW diagnostics computer - but the butt-plop test is equally as good. Hey Jeff, Jeff Strickland schreef: > I am asking this because I wonder if there is a troubleshooting > opportunity that includes the level sensing device ... The rear-left suspension of my E39 broke after 215.000km last year. The symptoms: hissing sound when I turn the engine off. Turned out to be a small crack in the rubber. When you press the gas pedal, it will pressurise it again, causing the car suspension to stabilize again. I noticed after my car became a kart.. :-) It's not common for both sides to break at the same time, I thought. A month ago, at 235.000km the rear-right side broke. Quite a lifespan. Kind regards, Pieter > On Sep 26, 11:40 pm, "Dave Plowman (News)" <d...@davenoise.co.uk> > wrote: [quoted text clipped - 7 lines] > > > > No - it's actually pretty inexpensive to replace. > ...with non-air parts. I don't think you can - the rear suspension is very different from the car to give a flat load area. IIRC, the air units are no more expensive than posh shock absorbers. Signature*Geeks shall inherit the earth * Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound. > > On Sep 26, 11:40 pm, "Dave Plowman (News)" <d...@davenoise.co.uk> > > wrote: [quoted text clipped - 13 lines] > to give a flat load area. IIRC, the air units are no more expensive than > posh shock absorbers. i read somewhere and sure it was someone in Germany said it could be on a e34 touring....and just recently mine has started sqeaking going over speed bumps > > > > No - it's actually pretty inexpensive to replace. > > [quoted text clipped - 3 lines] > > car to give a flat load area. IIRC, the air units are no more > > expensive than posh shock absorbers. > i read somewhere and sure it was someone in Germany said it could be on > a e34 touring....and just recently mine has started sqeaking going over > speed bumps I'm not sure why you'd want to replace a decent self levelling system with an ordinary one unless fixing it was horrendously expensive or it had a very short life? Of course if the vehicle is never loaded up it may not matter either way. Signature*Avoid clichés like the plague. (They're old hat.) * Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound. A description of the Self Leveling System begins on page 13 http://e38.org/selflevel.pdf > All, > [quoted text clipped - 8 lines] > > Dr D > A description of the Self Leveling System begins on page 13 > > http://e38.org/selflevel.pdf many thanks - most useful indeed I guess the pump should be audible as the load changes ... hmmm .... |
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