expansion valve 85 300sd - PeachParts Mercedes-Benz Forum

al b · #1 06-14-2009, 03:12 PM

I am trying to replace ac compressor and I am having a hard time getting to the expansion valve . I have a 1985 300SD and wonder if someone can tell me where its at and how to get to it ? Thanks

JimmyL · #2 06-14-2009, 03:25 PM

It is up under the steering wheel area kick panel, and you can't get there without Sherpas.

Some folks will remove their front seat and steering wheel to gain better angles at the thing.
My approach? I haven't purchased an SD.......

leathermang · #3 06-14-2009, 04:01 PM

Take out all the seats, the steering wheel, the dash and the engine.... it will be easy to access then...
OR switch to a 123 model which has it in back of the glove compartment...

Hit Man X · #4 06-14-2009, 04:52 PM

One thing I can't figure is why MB put it in that AWFUL place in the W126s.

Anyway, remove carpeting, knee bolster thing, and follow the accelerator pedal up to an alu block with four lines... there it is...

My advice for doing it in this heat, drink a beer once you find it, then get out three to four, 16" box fans, you'll need them. Turn on some music as this isn't a five minute job and get the airflow on you.

Remove the lower right line first (liquid line), then the low pressure line on bottom left. Then the top two you can loosen easily.

TRY NOT TO BEND ANY OF THE TOP FITTINGS.

You will need a tool called a Crows Foot to get the top to come out easy. Best way to flush that evap is using the old expansion valve with a 3/8" or so hole.

This is why you see so many 126s without working A/C

dannym · #5 06-15-2009, 08:04 AM

You can use the seat to your advantage. Then it won't be nearly as difficult as everyone's making it out to be. Move it back and lay across it, you'll be able to easily reach the valve.
No need to remove the steering wheel either.

I disagree with using crow's feet wrenches. Flare wrenches work much better.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=99993

Quote:

Remove the lower right line first (liquid line), then the low pressure line on bottom left. Then the top two you can loosen easily.

This is why people don't like doing this. It's made out to be a lot harder than it is. How do you get to the lower right without removing the lower left?
it's lower left, lower right, upper left, upper right.
Installation is reverse of removal.

Danny

BHutch · #6 06-15-2009, 10:57 AM

I did this very recently and it wasn't as bad as it was made out to be. I only had to remove the drivers side panel under the steering wheel. If you are going to flush the evap. you should take all the floor coverings off as it's very hard to do without making a mess. I had read some web postings about later model W126's and was expecting to take half the dash apart. If you're not doing it on a lift I recommend knee pads. You can also make your own crow's foot wrenches from some short box-end wrenches. 22m, 19mm, and 17mm if I remember correctly.

leathermang · #7 06-15-2009, 11:22 AM

BHutch, I believe you meant that one could make ' flare' or ' line ' wrenches from box end wrenches....
A crow's foot has flat sides and is meant to attach to an extension at a 90 degree angle.
I am just mentioning this in case someone goes to the parts store asking for something and the store guy brings something unfamiliar looking...

Hit Man X · #8 06-15-2009, 03:02 PM

Quote:

Originally Posted by dannym

You can use the seat to your advantage. Then it won't be nearly as difficult as everyone's making it out to be. Move it back and lay across it, you'll be able to easily reach the valve.
No need to remove the steering wheel either.

I disagree with using crow's feet wrenches. Flare wrenches work much better.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=99993

This is why people don't like doing this. It's made out to be a lot harder than it is. How do you get to the lower right without removing the lower left?
it's lower left, lower right, upper left, upper right.
Installation is reverse of removal.

Danny

The lower right is the easier one to get to, it's smaller... I just finished up the SD. PO had the upper two lines tweaked so getting the bottom left (suction to compressor) to line up was a chore. That's the way it worked easiest for me and on other 126s.

Oh I guess I'm using line wrench that attach to a socket with a long extension. Looks like a Crows foot.

al b · #9 06-16-2009, 01:52 PM

It wasn't as hard as i thought , but i am a jockey by trade . Being small does have its advantages . I got it out easiy enough but when i went put the new one back in I didn't have a washer that fit the low pressure end right . I had to go to work (racetrack) and thought I would go to the auto parts store the next day and get one that fit it better . I thought !!! I went down in a bad spill and broke my collar bone . Now I have plenty of time to do it ,but only have one arm to do it with. Thanks for all the help hopefully I can get it it finnished in a couple weeks when i get to feeling better.