ch33sehead

AC Compressor is rattling, does not work (no pressure at all).

ABC makes a noise that sounds like an air leak (yes I'm aware it's a hydraulic system, it just sounds like an air leak). Every time I turn the steering wheel, the air leak noise goes away then comes back again almost instantaneously, so I'm sure it's related to the ABC/Steering. When I shut the car off the leaking noise continues for a couple minutes (varies depending on how long the car was running).

Edit: Should also mention the noise is coming from the front left (driver side) of the car. I can't exactly pinpoint it. It's like a "shi..........shi" hissing noise that is constantly being made until I turn the steering wheel.

callchuck

Sounds like your tandem pump is gone. Did you run it low on fluid suck air into it. How much fluid is in your tank. This pump runs your power steering and ABC.

ch33sehead

I got the car early this year. I added a little to the ABC & P/S reservoirs to get them up to the correct levels, and it still does the same thing. It's always been making this noise since I got it. Power steering occasionally feels a bit weak. I did a rodeo and the ABC averaged 170 bar at first. It dropped gradually to about 155 bar. Is it supposed to decline during the rodeo?)

callchuck

Your main line is suppose to run at 200 b. It sounds like you might have just a valve clogged. You need to bleed your lines get all the air out. I am not sure if your pressure is suppose to drop when you rodeo the system. Make sure you keep adding the fluid to the correct level. Pressure your system with 1 b from the resevoir and turn the car on. Press the lift button on your ABC several times until the light goes out. Make sure your car is on the ground with all 4 wheels touching compressing your suspension. Press the lift button again turning the light button on and off 3 times make sure the light is out when finished. Turn the car off and check your fliud.

ch33sehead

The first time I did the rodeo, it got stuck in one position and the pressure kept rising. I shut it off at around 192 bar, got out of the menu, got back in, and redid the rodeo. Then it got to a max of about 172 bar, and dropped to 156 bar. I think you're right about a clog.

"Pressure your system with 1 b from the reservoir" <-- not sure what you mean by this?

callchuck

If your pump was bad you would not get the pressure. You diffenantly have something stuck in your line. I would flush the entire system with new fluid. Any kind of dirt or air will cause this.

callchuck

The 1 bar is the pressure you need to apply to the reservoir tank to fill a new pump with fluid so it will not suck air.

ch33sehead

Thanks for the replies. So, if I read you correctly is this the proper procedure for bleeding out air:

1. turn on engine while wheels on level ground
2. press "up" , "up" , "down" , "down" about 3 times

?

Ifari

Have you added fluid to the smaller power steering reservoir?
Vent the cap of the ABC fluid reservoir when bleeding air from the system the way Chuck described.
After the 3x 'up - down', when you turn the engine off you should hear an audible 'whoosh' sound as air is being bled off.
Re-install cap securely and then test drive.

super_monkey

I have the same symptom on my SL. Did you ever get to the bottom of the problem and would you mind sharing the solution?

ch33sehead

leaking/hissing noise appears to be air in the ABC system. System needs to be bled and/or fluid/filter needs to be changed if it's dirty. A/C compressor rattling suggests compressor bad if it's not compressing. Definitely take it to an expert.

super_monkey

I had a bad AC compressor and had it replaced a couple of months ago but the hissing as you described it matches exactly what I am hearing. I am taking the car in to have ABC flushed today actually.

I was looking for a cracking noise while turning wheels thread to see if I can get some information on that while I came across this post.

ch33sehead

How much did it cost to replace the compressor?

super_monkey

I paid $1000 for the part and $700 labor that included an A service. However, I can get parts at wholesale price and a friend of mine owns a mercedes shop so the labor is probably less than what I would expect to pay if I took it some place else.