1971 300SEL 3.5: AC - does anyone know if this drier fits?

[werminghausen]

I am starting to renovate my AC.
I think I need to redo all my hoses, put a new compressor and new drier in.

first question is about the drier:
The new drier I bought a while ago has the ports closed (which is good to keep vacuum for the desiccant) but I can't see the fitting threads.
New drier has part numbers 108 335 06 71 and 525 424

Drier should fit relatively but the intake port direction is slightly off.
(see the attached picture showing the old and new drier)
Can someone confirm if this is the correct drier?

If the drier is correct how would you make the lower intake port work?....try and bend the drier port or the condenser ? However the condenser is copper and I am hesitant bending something there.
What should I do?

[Pooka]

The dryer will work just fine, but you might have to use some other fittings to adapt your fittings to work with it.

[thorsen]

May I make a suggestion here? If you are replacing the compressor and drier, I suggest you spend another $100 and replace the condenser. I'm thinking something like ones of these that will fit:
Unpainted Aluminum

For driers, I would pick one of these, probably the first one:
Receiver Driers

That will give you the ability to use common o-ring fittings which are inexpensive and (in my opinion) seal better than the flare fittings your car probably has.

[Tomguy]

I have to agree with thorsen simply because if you do use R134a which is most likely your only choice in Oman I'd imagine (Unlike some areas of the US that have insane stockpiles of R12 still), you will need the upgraded cooling capacity of a parallel flow condenser. Ideally the evap should be switched out too, but that will be a bear. From thorsen's link, the dryer PN: 4-1006 is the one that looks a lot like the one on my 108 4.5 if memory serves and is likely more correct for your car.

[suginami]

My 4.5 has been converted to r134a, and the entire system was replaced: compressor, receiver/dryer, condensor, hoses, etc.

I don't know if it is a parallel flow condensor, but it is significantly larger than the stock size.

I think because of the over-sized condensor, the a/c is incredibly efficient. It will freeze your ears off it is so cold.

[werminghausen]

Good for you!

I am not a specialist and you need to know the entire AC equation in order to get an optimized system like you seem to have. One parameter is for sure the efficiency of condenser, evaporator and compressor but I have no clue in dimensioning these.
Only chance right now FOR ME is to go with stock components even if this is not the most efficient system. I am trying to use the existing condenser and evaporator/expansion valve, reman hoses, new drier and R12....hope I 'll get R12 in this country.
Martin

[werminghausen]

other question on drier:
In the picture you see the 52 degree switch connected to the drier...
The stock system has a temperature switch as a cut- out safety for the compressor....how does this work?
If the drier gets over 52 C the compressor is cut out?

This is strange...because this temperature can easily occur in Oman. An ambient temperature of 52 C can be measured during day in summer.
Bad if compressor gets cut out in this situation?
Martin

[68_280SE]

The 52 degree temp switch only controls the aux fan. When the temp of the refrigerant leaving the condenser is higher than 52 degrees celsius , the switch activates the aux fan to aid in cooling. To the best of my knowledge, these cars did not have any high or low pressure safety switches.

John

[werminghausen]

Originally Posted by 68_280SE

The 52 degree temp switch only controls the aux fan. When the temp of the refrigerant leaving the condenser is higher than 52 degrees celsius , the switch activates the aux fan to aid in cooling. To the best of my knowledge, these cars did not have any high or low pressure safety switches.

John

Okay...thanks. This makes all the sense. There is no low pressure or high pressure cut out!
Does this make sense? I mean the system gets quite simple. If the system runs into problems the compressor is toast at a point.
Do you suggest some alternative cut out safety?
Martin

[68_280SE]

There is a port on the top side of the new dryer that you can put a hi/low pressure switch in. The port is probably closed with a screw plug. The later W116, W107, W123, W126, W201, and W124 chassis cars have a hi/low pressure switch in this location and you can use a hi/low pressure switch from one of these cars. You would have to wire the switch into the compressor clutch circuit.

John

[werminghausen]

Originally Posted by 68_280SE

There is a port on the top side of the new dryer that you can put a hi/low pressure switch in. The port is probably closed with a screw plug. The later W116, W107, W123, W126, W201, and W124 chassis cars have a hi/low pressure switch in this location and you can use a hi/low pressure switch from one of these cars. You would have to wire the switch into the compressor clutch circuit.

John

Thanks John,
You are right the new drier has a port which is closed.
Would you use such a safety switch?
If yes I'd need to do this right away because the port is open to the freon.

I think with 'wire into the clutch circuit' you mean a relay that cuts out the power to the clutch?

Martin

[68_280SE]

When I rebuilt the AC in my car I did not put in a pressure safety switch, but it would not be a bad idea to add one. The safety switch is a pretty common part and the part number for it is 1248208310. You can easily find them by searching on the internet.

John

[werminghausen]

Hi John,
thanks.
Just to understand the system:
With the stock equipped temperature switch only at at the drier(which turns on the Aux fan if temps are over 52degrees Celsius...not sure if Aux fan turns on only if the AC is on or in any case if temperature is over 52 degrees C?)
the compressor clutch is engaging even if there is no freon in the system and thus at some point killing the compressor... I guess.

So if I turn the AC fan on in the car and turn the temperature switch(next to the AC fan switch) to low then the compressor clutch sees 12V and is engaging no matter what? Or is there any other safety switch installed?

[werminghausen]

Back to my initial question: does the new drier fit with the somehow different angle for the 'in' port?
I was removing the condenser today for cleaning purposes and I find the copper tubing pretty easy to bend.
Do you think I can just bend the port into place?
Martin