Hi, I have a 2004 CL 500 with only 40,000 miles. 2 years ago the front left suspension unit was going flat if the car was unused for a few days. This was replaced but the warranty only covered replacement of one unit leaving the car unbalanced when driving over bumps such as sleeping policemen. After a lot of discussion , Mercedes replaced the right unit. Immediately after that, the car developed a vibration in the suspension. The vibration is like out of balance wheels. It is relatively random - but the car is never free of the vibration.It occurs in a cyclical and oscillatory manner i.e the vibration can increase over about 1 mile and then reduce to the point that the car is smooth for a mile or so and then the vibration recurs. The vibration is not as bad on rough areas of motorway as the cycle seems to be broken. Mercedes have had the car back on numerous occassions over the last 18 months to no avail. the tyres have been replaced twice, alloys are new Mercedes alloys. any suggestions to eliminate the vibration?

I think there may be an air leak in the system but it has been checked,wheels balanced, alignment checked,one valve block replaced ( though a little doubtful on that as Mercedes do not like telling you everything they do ).

An additional thing that happened was that after the replacement of the right unit, the car developed a fine vibration felt throughout the body when under load at 1200 rpm. this equates to 50 mph and by load I mean even a gentle incline on a motorway.

thank you for your help.

 

The car has come back from the dealer with smoothness restored. But the cyclical vibration at constant speed remains. It happens at any speed above 60 mph and the oscillation gets worse for about 0.3 miles and gets better over about 0,3 miles. The car is smooth for about 0.1 to 0.2 miles and then the cycle starts again. Checked on the same 20 mile stretch of motorway and against other cars.
any ideas?New Mercedes Manager at local dealership very friendly and helpful - big surprise. The new man seems to be keen to help and resolve the problems. A complete and pleasant contrast to the last 18 months!
another question - the passenger door self closure does not work but did when the alarm was faulty for a time. where is the fuse box for the closure so I can try to reset it by pulling the fuse out.
Thank you and have to say the links to the hydraulic system diagrams were very interesting and useful in understanding the system.
JT.

 

Under the rear passenger side seat.....right side of the car. Pop off the floor lighting plastic cover at the floor and there will be fuses there for your pse pump. Should be a 20 amp fuse. This will restore your door operation.

 

Thank you. I will try that.
JT.

 

Hi, Seem to have lost a thread so if this is a repeat then I am sorry.
My car has been back to the dealer. They replaced the front right strut as all the problems started after replacement of the strut 18 months ago. The car has once again become very firm. But the cyclical vibration remains unchanged. It increases over 0.3 of a mile and then reduces. I note that at about 70 mph, the vibration is continuous and can start as low as 50 mph. The wheels have been balanced by Mercedes and an independant garage, the valve block has been replaced along with the front and rear suspension accumulators. I think the valve block and pulsation damper are the same thing.
Therefore I am still a little stuck.
The fine vibration at 1200 rpm which is not suspension related seems to have improved after replacing the rear gearbox mounts and the exhaust mounts.
Any help with the cyclical vibration?
Thanks. JT.