Does anyone have the MB procedure # for changing out the Expansion Valve. No luck looking through the paper manuals. The hoses going to the compressor should be easy to disconnect but it appears that the disconnection at the evap needs to be done inside.
O.

all can be done feom outside, once you remove the manifold hoses you will see 2 4mm allen bolts, remove the allens and the valve will come off, be sure to coat the new o-rings with a/c iol prior to installing. i have instructions if you want i can email them to you. mercedessd@cox.net

Thanks Ray. Getting the old exp. valve out of the 87 300d was not too bad once I was able to get my hand in there to disconnect the bolt holding the hoses to the valve. I used a 1/4in ratchet with a swivel and 10mm socket. The new valve (with the same P/N) uses a threaded stud instead of a tapped hole. This may actually be easier to install once I find a nut.

In order to flush the evap., I was thinking of slipping a hose over the evap stub outs to direct the flow. Has anyone tried this? My first try will be to just blow compressed air thru it. If any particles come out, then use a standard a/c flush.

__________________
Dan
1981 240D
1987 300D Turbo
1973 220
Das Beste Oder Nichts

With the expansion valve out you can indeed easily flush the evaporator. Blowing compressed air through with no flushing agent will prove nothing.

You can use the hose to get as much flush out and into a container as possible, but after thoroughly flushing, you will want to remove the hose so you can blow it out better. In most cases leaving ANY flushing agent at all inside the component is as bad or worse than not flushing.

Are you flushing the entire system? If not, there is no need to flush the evap.

Good luck with it,

Larry, I was planning on flushing the evap and condenser. Unless there is a whole lot of debris in the evap, I agree that air will prove useless. I have a rebuilt compressor, rebuilt manifold hose, new exp. valve and a new drier/receiver. The old compressor did not seize up- It was leaking at the front seal and at the exp. valve. The UV dye appeared to be localized to the seals so I'm hoping that the evap is okay. Will retain R-12 as it gets a little warm here in AZ. Also added new viscous fluid (6000 CST from Toyota) to the fan to keep it all cool.

__________________
Dan
1981 240D
1987 300D Turbo
1973 220
Das Beste Oder Nichts

oilyrag,

It sounds like you are working with a very good plan. Under those circumstances there is no serious need to flush, however, since you will have everything so thoroughly apart, flushing all components not replaced would remove all oil and start with the correct amount. If you don't know the history of the car this may be a very worthwhile step. When recharging a system that has leaked, it is simply guesswork as to how much oil to add back in. By cleaning out the system and putting in the correct amount of oil, you will know that you have the correct amount.

Having too much oil can destroy a compressor and having too little will wear it out prematurely.

Put in and hook up a new receiver dryer as the last step. Put the correct amount of oil in several system components. A few ounces in the compressor, a few ounces in the evap, a few in the condensor and a few in the r/d. Do some research and find the exact amount to use.

Good luck,