ABC suspension - Driving with a broken pulsation damper

[khkc]

My car (C216 CL500) developed a loud drone/ humming noise (engine speed correlated) over the weekend, Mercedes Mobilo came out and the technician said it's highly likely to be the pulsation damper by the ABC pump or a pipe that is touching the bodywork hence making the noise/vibration. He'd wanted to take it to a dealer which I declined as I would like to take it to a trusted independent specialist.

The suspension otherwise performs flawlessly, the ride is as absorbent, corning is as flat and it doesn't sink.

I have a 200 mile journey planned for the Easter holiday and the specialist is about 100 miles away from me, my question to the boffins here is would driving with an expired pulsation damper (with the extra vibration) cause damage to the ABC pump or pipeworks?

Also, for those with ABC, the helpful technician taught me how to check the fluid level properly, on the dipstick there are two sides, one for engine on (motor an) the other engine off (motor aus). The fluid should be within the indentation on the dipstick depending on the state of the engine, and not between the two indentations as some posts suggest.

I had to top mine up with 200ml (system has a 10 litre plus capacity), is it considered normal for a car with 28000 miles on the clock? hopefully that wasn't the reason for the premature pulsation damper failure.

Anyway, should I drive the car?

Any advice/thoughts appreciated. Thank you.

 

[Alex Crow]

Yes, although it needs fixing, it will do no harm in the short term.
When the pulsation damper fails it takes on more fluid, through the split diaphragm, so we expect the level to drop 200ml or so.

The level check is indeed possible with engine running or not running (as per marks on dip stick), but if checking with engine OFF, allow a good time for the level to rise before checking/topping up.

 

[brandwooddixon]

Also remember to check with the suspension set to the normal ride height.

I believe that pulsation dampeners are a DIY fit, just make sure that everything is clean, as the system is self bleeding.

 

[khkc]

thank you both for your advice.

Alex, if oil is now inside the damper, would fragments of the split diaphragm/ rubber be circulating through the ABC system if I continue to drive? Probably a good idea to replace the fluids and filter too?

I had hoped that the system in the 216 would be more reliable but it would seem the pulsation damper/dampener is an issue judging from the posts on the American sites.

Enjoy the glorious weather.

 

[Alex Crow]

thank you both for your advice.

Alex, if oil is now inside the damper, would fragments of the split diaphragm/ rubber be circulating through the ABC system if I continue to drive? Probably a good idea to replace the fluids and filter too?

I had hoped that the system in the 216 would be more reliable but it would seem the pulsation damper/dampener is an issue judging from the posts on the American sites.

Enjoy the glorious weather.

Yes, you might get rubber fragments circulating, as you may from many of the other ABC components. There is a filter in the system to deal with this, but yes, ideally you will change it and flush the system too.