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Thread: rear shocks

  1. #11
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    Quote Originally Posted by SierraSkier View Post
    If I want to change over from standard to self leveling, do I need to change out the rear struts/springs as well? Thanks again.
    I think the self-leveling system involves a small air pump, tubing to each rear shock and a sensor that detects the ride-height of the tail end and turns the pump on and off. Not a simple upgrade, I would guess.
    '04 XC70 (petrol/auto), Nautic Blue / Graphite, Premium, Touring, Boosters, Xenia Wheels w/235x60 Nokian WR's (wife's kid-hauler)
    '89 Olds Regency (72,000 miles - my daily driver)
    '75 Chevy Caprice Convertible (253,000 miles - on blocks with raccoons living in trunk)

  2. #12
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    Do you have the non-self-leveling shocks now? If you have over 30000 miles on them, it is a safe bet they are in need of replacement. New Sachs struts will likely help your sagging rear end, even if they are not self leveling. Ride and handling will be dramatically improved. I have yet to read of a successful rear shock conversion on these cars, so I doubt it is very easy, and probably involves lots of $$$$$$$$$$$

  3. #13
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    Boston
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    The Nivomat self-leveling is entirely contained within the shock itself, that is why it is so expensive. There are no separate air pumps, hoses, etc. as in some other systems. Volvo couples the Nivomat's with much softer rear springs than come in the non-Nivomat versions. Therefore, if you want to get away from the Nivomat's, you have to change rear springs as well as the shocks. Apparently this can be done for about the same cost as buying Nivomats, but once done, the next change will be much cheaper (if you really hold the car a long time, this helps). Some people who have changed think that their Nivomats were a better ride and handling than teh nono-Nivo replacement route.

    Also, just for clarification, shocks and struts are two alternative things, and you only have one or the other. In Volvo's, there are struts up front and shocks in the rear
    Mike
    ----------------
    '09 XC70 T6
    '07 XC70
    '98 V70M
    '98 S70 T5M
    '95 855T
    '84 MB 380SL

  4. #14
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    Hi, my last car-855 1996- with 285000kms, have self-levelling
    rear shock. The same since 1996!! They just begins to die!
    Not so bad.
    Michel from France.

  5. #15
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    Jun 2006
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    Lightbulb

    Just so every one understands, the rear shocks on the P2 XC are a strut design. This is different than the previous generation vehicle, and probably explains why there are no aftermarket struts available for the rear. If you don't believe me, peak under your vehicle. You will see a shock inside a coil spring, just like the front suspension. This is Chapman-type strut, which is a McPherson strut modified for the rear suspension. And VADIS does refer to this set-up as a strut.

    The non-self-leveling struts are about $200 a set. Coil springs are usually relatively inexpensive, so if this is all you need to convert to non-Nivomat, it is probably a money saver even on the initial change over. But, it actually might not be so cost effective in the long run. The Nivo struts seem to be rather long lived - perhaps 100K miles by many testimonials. Try to find someone to claim that about the non-Nivo struts; many claim they are good for only about 30K miles. So you may be buying 3 sets of non-Nivos for every set of Nivos, plus the cost of labor (or time if your a DIY'er like me). Suddenly the non-self-leveling struts don't look so great. Another question that I have is whether you only need the spring and strut. If the Nivos use a different top strut mount or different lower control arm (I don't have the answer for this; I have not seen any posts from someone who does), the conversion could be quite complicated and expensive. In the end you have short lived struts that don't ride or handle as well as the originals. Don't think this would be a great mod myself.

  6. #16
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    Quote Originally Posted by mbsl98 View Post
    The Nivomat self-leveling is entirely contained within the shock itself, that is why it is so expensive.

    I wonder how that works, then? Anyone have any idea on what principal this works? Typically, a self-leveling system uses the shocks as auxiliary springs to augment the steel springs when the the rear sags. Normal shocks do nothing unless the suspension is in motion.

    I don't doubt that this system is self contained - just curious as to how it works.


    Edit, 5 minutes later - answered my own question - found this explaination somewhere - sounds like a real marvel - no wonder they cost:


    "Nivomat maintains a level suspension, front and rear, while trailering or at a fully loaded condition," says Uwe Grasse, product engineering manager.

    Nivomat is a semi-supporting system working in combination with a mechanical spring. The Nivomat shocks are only mounted on the rear where most of the additional weight is located.

    Nivomat looks like a standard shock absorber with a piston rod with damping valves at the end, an outer tube and a cylinder tube. Several components are added to provide the leveling function. Two reservoirs are contained in the outer tube, an oil reservoir (or low pressure reservoir) and a high pressure chamber. Inside the piston rod is the pump chamber (with inlet and outlet valve) and the pump rod, which serves as a height sensor or regulator and a release bore which releases the pressure after the vehicle has reached level.

    A load initially causes static compression of the vehicle's suspension. Once the vehicle begins to move, the pump is activated by the relative movement of the body. Extension of the piston rod causes oil to be drawn through the inlet valve into the pump. Compression then pushes the oil through the outlet valve into the high pressure chamber. The pressure in the oil reservoir decreases as the pressure in the high pressure chamber increases. The increasing pressure acts on the piston rod and raises the vehicle at a continuous rate.

    Once the vehicle has reached optimum height, oil is no longer drawn in. The height regulator opens a bypass between the high pressure chamber and the pump chamber preventing oil from flowing out of the oil reservoir.

    When the vehicle is unloaded the vehicle begins to rise. The height regulator opens the release bore. Oil flows out of the high pressure chamber into the oil reservoir, the pressure drops in the high pressure chamber and the vehicle lowers to the initial height.

    Since Nivomat is mechanical, the vehicle needs to be moving before the pump starts to work and it takes about a mile to a mile-and-a-half of travel before the vehicle reaches its optimal level point.

    "It takes very little input to actuate the pump," says Hunt, "about plus or minus a millimeter is all it needs, so even on smooth roads the Nivomat pumps up quite quickly."

    ZF Sachs is currently developing a Nivomat with a small electric pump attached to the tube. Once the vehicle is started the electric pump will level it and the mechanical pump will take over once the vehicle is moving.
    Last edited by skibo; 11-30-2006 at 11:52 AM.
    '04 XC70 (petrol/auto), Nautic Blue / Graphite, Premium, Touring, Boosters, Xenia Wheels w/235x60 Nokian WR's (wife's kid-hauler)
    '89 Olds Regency (72,000 miles - my daily driver)
    '75 Chevy Caprice Convertible (253,000 miles - on blocks with raccoons living in trunk)

  7. #17
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    I have found (and I sell a LOT of Volvos) that regular rear shocks are good, (for the average driver) for about 60-80K miles, some have actually still worked fairly well at 90K.
    Fronts are good (again, for the average owner, not an enthusiast) for 90 to 110K miles.
    NIVOMATS are usually good for around 100K, plus or minus. At that time they start to make small noises which become bigger noises soon thereafter.
    Naturally all cars are different, if you live in the south with smooth roads they can last for much longer. If you live here in PA or in Mich, they crap out much sooner!
    JRL

  8. #18
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    Quote Originally Posted by SierraSkier View Post
    Thanks for the response Volvoshad. That makes sense. If I want to change over from standard to self leveling, do I need to change out the rear struts/springs as well? Thanks again.
    In short yes. The rear springs are lower rate when S/L is fitted. Faced with 360 ukp (which is 700 usd at the current exchange rate) for one shock absorber I considered binning the S/L set-up but this proved too hard.

    After many many calls the best I could find (in the UK) was from http://www.nordiccar.com/ who offer discounts for Volvo club members as well. Price for one shock came down to 236ukp delivered to my door after they spent ages looking at the ID details on my car to work out what unit was required.

    C

  9. #19
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    Question

    Xc70-uk, it sounds like you investigated this pretty thoroughly. I have never seen a post from someone who actually made the conversion, or could authoritatively describe the details. Do you know, if someone were to make the conversion from Nivomat to non-Nivo, are parts other than the strut and spring needed?

  10. #20
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    Quote Originally Posted by volvoshad View Post
    Xc70-uk, it sounds like you investigated this pretty thoroughly. I have never seen a post from someone who actually made the conversion, or could authoritatively describe the details. Do you know, if someone were to make the conversion from Nivomat to non-Nivo, are parts other than the strut and spring needed?
    Not sure - ring the guys as Nordiccar (url above)

    I seem to recall the top mounts are different as well but not totally sure

    C

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