I'm getting ready to buy a new Rear Hydropneumatic Shock Absorber. I'm going to have a mechanic do the work. Any idea how many hours labor this job will take. I'm only replacing the one shock. Every time I drive over a bump or dip in the road there is a thumping coming from the rear end driver side. Any help at would be appreciated.

Thanks

Manny

Lets make sure your replacing the correct item. If the actuator ( the item that replaces a normal shock absorber) is leaking then it needs replacing. If is not leaking then it is OK. What will give you the knocking sound as a bad accumulator.

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1B81CZ6JA&year=1984&make=MB&model=300-TDT-001&category=L&part=Accumulator

These are the units that absorb the shock of the road. I would suggest replacing them in pairs. Not 100% required. But if he has the car up on a jack and has opened the system you might as well do it.
Also have the fuild filter and fluid flushed. The filter is in the reserviour and should be replaced.

Also check the mounts on the actuator. It could be loose. Check the trailing arm stops located at the trailiing arm subframe mounts.

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Thanks for your help and quick reply. All leaks have been looked after.... I pretty sure that the accumaltor is not leaking but not 100% sure. I've gone ahead and ordered one of those too. I can always send something back if it is not needed. I know mechanics and parts people like to sell things in pairs but when the shocks are like $300 ea plus labor..... ouch. I can understand doing them in pairs if they were regular struts but I just want to fix the problem and move on to other problems before I run out of money.
Is there an online repair or diagram pics etc in pdf or something of the suspension on this vehicle? I have located an online repair manual for the 123 chassis at http://skinnerbox.steaky.org/123_DISK2/program/123-cd-index.html It is good but nothing there for wagon suspension.

Regards

Manny

Ok if nothing is leaking then your wasting money on the strut.
Your accumulators are a sphere that has a diaphram in it. One side has a gas charge of nitrogen and the other is the hydraulic fluid that is routed from the strut. The nitrogen can leak out over time and that is what provides the shock absorbtion for the system. No liquid, just nitrogen. So it sounds like your accumulator is the problem, NOT the strut.

Hydraulic Suspension Questions


The Mysterious Insides of an Accumulator Exposed!

Replaced my air cells / accumulators! (long)

Your system

http://skinnerbox.steaky.org/123_DISK2/program/Maintenance/My81/3251.pdf

At skinner box look at job numbers
32-520 thru 671


Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car