Expansion Valve Removal - W126
 

Here's a well-done, blow-by-blow description of how to change the expansion valve on a W126 chassis.

Expansion Valve Removal

That's a great writeup.

More work that I would have thought.

Thanks for the link.

Good deal. Now what do I need to do so I can flush the evap core... :confused:

In the end, it was all for naught (I had to replace the evap anyway) but I pulled the old TXV, drilled it out so that fluid could flow through it, reinstalled the drilled TXV in the car and blew the flush though the evap from the engine compartment using the liquid and suction lines from the cabin.

TXV? Is there a DIY on how to do this?

w126 expansion valve
 

Since this is a very old thread the link works, but the info doesn't seem to exist any longer. Is there any way to get access to this invaluable blow-by-blow description?

These links may help.

https://www.peachparts.com/shopforum/diesel-discussion/130072-replacing-expansion-valve-300sd.html

https://www.dieselgiant.com/repairyourac.htm

Expansion valve
 

Thank you for the links. Helpful in locating unit as well as disassembly and assembly. However, is there any magic to loosening the bolts? I can only guess that this unit has never been replaced before thereby being in place for 36 years. Perhaps I'm simply not strong enough to loosen. Can I use some extra leverage? I read where extreme caution must be taken to preserve the connection tubing to the valve. I get it, but I'm wondering how to remove safely.

Try heating it.

Long handled wrenches will give you better mechanical advantage.

Remove the small compression fitting first.
Large open end wrench (looks like 24 mm or greater) on the flats of the body (parallel to the flats on the small compression nut).
Long handled open end wrench (looks to be about 17 mm) on the flats of the small compression nut (with its handle closer to the engine bay than the handle of the larger wrench).
Have an angle of about 5 to10 degrees between the wrench handles.
Then pull the smaller wrench towards the larger wrench in the direction of the trunk (turns the compression nut ccw to loosen it) to crack the torque on the compression nut.

Next remove the large compression fitting in the same fashion (looks like it takes a 19 mm wrench).

I finally loosened the two bottom bolts. Working on the uppers now. Used the crows feet wrenches of course with the help of PB Blaster to help loosen 36 years of being in place along with some leverage. Regarding further removal, I see the upper left connection - I'm working on that now. But I do not see the smaller right side connection. It's hidden by two wires in the way. Any advise as to how to get to that right side? Do I need to remove any other component to accomplish?

I once twisted one of the copper lines and was told striking blows would have been better than just torque. Firm hits on the wrench with a hammer, together with heat, can be a winning formula.

I've actually used large crescent wrench to hold exp valve while turning line connection.