1995 E320 A/C manifold replacement.

Never, ever use teflon tape on A/C system, but DO replace the o-rings made for R134a refrigerant. Teflon tape belongs underneath the kitchen sink, not on a car.

Always replace the receiver/dryer along with the pressure switches, without exception whenever the A/C system is opened. It is located in plain sight behind the driver side headlight.

Highly recommend you also replace the expansion valve.

And if you are not familiar with A/C systems, do not do this job yourself.

320forME said:

I replaced the receiver drier and the manifold and replaced the o-rings but I did not replace the pressure switches, why is it important for those as well?


I am having a shop vacuum and refill the system.

Click to expand...

Because that is the best time to get at them when there is no pressure in the system, besides the fact that the original switches are pushing a 1/4 century.

If a switch goes bad in a few months, you are looking at another receiver dryer, vacuum down, replace, test, refill, etc.

The dryer removes and absorbs any moisture and contaminants from the A/C circuit to prevent corrossion, oxidation, etc.

Even just 1 hour is enough to render the dryer almost ineffective.

Yes, the pressure switches are located on top of the dryer.

Do it once, and do it right. Replace the switches before refilling. Ditto on the expansion valve.