khutchinson22

I just purchased my 2004 CL55 and the front struts need replaced. I knew going into this purchase that I would have to do some repairs to the ABC. I didn't think it would be within the first week of ownership but such is life. Front struts are a fairly easy job but with the added element of the ABC system I want to see if this is still a job I can do and what I should be looking out for or performing at the same time. I'd like to save the $1800 and perform the job myself. I searched to see if anyone has done this but it seems that everyone just takes it to the shop.

Any help appreciated. Thanks!

khutchinson22

Mostly what I need to know is how to best bleed the ABC system. I've seen a couple threads that people have bled them by raising and lowering the vehicle multiple times but I want to make sure there isn't something else that needs to be done once the struts are replaced as well as if there is anything else I need to be cautious of.

Welwynnick

Sure, lots of people have replaced their own, including me. You just undo the old ones and refit the new ones. Ultimately they're just nuts and bolts.

Of course its a bit more complicated than that, as you have hydraulics, electrics and level sensors as well.

The electrical connector is removed from the top using pliers.

The level sensor is unbolted from the top wishbone, but its awkward. The nut will likely be seized, and the L-bracket at the end of the link is rather fragile.

There is just one hydraulic connection, and its a quick-release connector. The release collar is often seized, and may need to be freed with heavy and patient use of strong pliers. It can be a real pain.

The lower connection to the wishbone is the real problem. There are two hex grub screws, and they usually rust and seize. Many pro's say you have to undo them with an oxy-acetylene torch. Terrible design and a big problem.

Bleeding is no big deal. The best way is to run a rodeo using STAR, but most folks are happy to raise and lower lots of times, and keep the reservoir at the right level (ie: at the lower dipstick mark when the engine is running).

Nick

khutchinson22

Awesome! Thank you so much for that. That's a huge help.

tusabes

Also change both the abc filter and power steering filter in the reservoir and fill with fresh pentosin

khutchinson22

Thank you! Much appreciated!

SL55_Forever

Since you'll be tearing apart the front struts, it's a good time to check your accumulators/dampeners are not worn.

With the car turned off, push down hard on the front of the car, if there is any movement then you need to look at replacing accumulators/dampeners.

Welwynnick

I gotta say there that the accumulators do not provide the primary springing for the suspension. They do have some influence in dynamic conditions, but not in the static.

When the car is stationary and the engine is off, each hydraulic strut is isolated from the rest of the ABC system by an isolator valve in each valve assembly. That means oil cannot go in and out of the strut, except if there's a gross leak in the valve.

Therefore when you bounce the car up and down, you're only bouncing it on its coil springs.

Faulty accumulators aren't so easy to diagnose. The best way is probably to check the CHANGE in the oil level in the ABC reservoir. When the accumulators are OK, the oil should be at the upper dipstick mark when the engine HASN'T been running for around an hour. When the engine HAS been running for around a minute, the oil level should be at the lower dipstick mark (because the accumulators have been charged up with pressurized oil, which has to come from the reservoir).

If the oil level doesn't behave like that, you almost certainly have an accumulator failure. But you can only find out which one by trial and error, unfortunately.

Nick