W123 300TD (1982) Air Conditioning rebuild advice - Page 5 - PeachParts Mercedes-Benz Forum

ROLLGUY · #61 08-06-2020, 02:51 PM

Quote:

Originally Posted by 300TD1982

I appreciate the tip!

The retrofit is coming along. I have the old compressor and bracket off. Had to remove the skid plate to get the compressor out. Installed the bracket for the oil lines, and the two brackets on the oil pan. Pulled the dryer. I just do a little each morning before it gets super hot and smokey.

Believe it or not, now is a good time to clean the underside around the engine and engine bay. You will enjoy installing the new parts on a clean engine more than you would on a greasy one!
Also, you can remove all the parts for the high side (discharge) hose assembly, as they are not needed. This makes the whole installation look cleaner......Rich

vwnate1 · #62 08-06-2020, 02:55 PM

Keeping the engine reasonably clean and oil free not only makes it easier to repair but cheaper and if you have another person do it, they'll do better works when not faced with a filthy, oily lump to work on .

Try the purple de-greaser from Sam's Club , it's amazing stuff and cheap to boot .

ROLLGUY · #63 08-06-2020, 03:17 PM

Quote:

Originally Posted by vwnate1

Keeping the engine reasonably clean and oil free not only makes it easier to repair but cheaper and if you have another person do it, they'll do better works when not faced with a filthy, oily lump to work on .

Try the purple de-greaser from Sam's Club , it's amazing stuff and cheap to boot .

I have found that the ZEP Purple Degreaser (yellow bottle) from Home Depot is the exact same stuff. Easier to get, as not everyone is a S.C. member.

300TD1982 · #64 08-10-2020, 04:29 PM

Making progress. I ran AC cleaner through the evap and through the single hose that I'm reusing (between the evap and the dryer). I removed the expansion valve and drilled it out and reinstalled it before blowing it out (thanks for the tip, Rollguy!).

Got the new compressor installed. It was a bit of a **** show. My oil dip tube was slightly in the way, so the plate pressed against it and I couldn't get the top bolt in. But then I was "clever" enough to tighten down the other bolts, which got the top bolt close enough to catch a few threads. So then I snugged that one down, and got the long bolt in half way, at which point it got stuck. The edge of the plate was also pressing into the dip tube in an alarming fashion! So I attempted to undo everything so I could rotate the dip tube a bit, but the long bolt was now wedged in and not removable. So I pulled the radiator (which I had to do eventually anyway to mount the condenser). Then I was able to tap the long bolt out from the front, remove everything, rotate the dip tube, and reinstall everything properly. Again, it was a **** show, and it sucked.

But now it's done.

Next I'll put the belt on (partway), install the condenser, reinstall the radiator, replace the coolant, bump the engine to get the belt on properly, snug down the adjusting bolts, double check the rest of the bolts, and call it good for the day. Should be smooth sailing from here.

JHZR2 · #65 08-10-2020, 07:21 PM

How did you drill out the expansion valve, and what size drill?

ROLLGUY · #66 08-10-2020, 07:59 PM

Quote:

Originally Posted by JHZR2

How did you drill out the expansion valve, and what size drill?

I used a 1/4" drill on mine, but it does not matter what size. It is just so the flushing solvent can circulate through unimpeded. This way, the hoses can exit the cabin, and contain the solvent/oil outside of the interior. After the flushing, a new TXV can be installed.

300TD1982 · #67 08-10-2020, 09:38 PM

Quote:

Originally Posted by JHZR2

How did you drill out the expansion valve, and what size drill?

One side of the disk had a little divot in the center so I used that as a guide to make a tiny pilot hole. And then I went up a few sizes until it was around 3/16" or 1/4". I think I could have just plunged a 1/4" bit through it though, as the metal is pretty thin. Then I blew cleaner through the high side hose that I disconnected from the dryer, and the low side hose to the compressor which I hacked in half.

300TD1982 · #68 08-10-2020, 09:45 PM

Got the condenser installed. It's an inch longer than the one that Rollguy's kit is made for, so I had to fuss with the brackets. I ended up just positioning both of them at an angle. I was hoping to put the extra inch entirely on the driver's side but it just wasn't working. So now I have a 1/2" less on the passenger side which is where the hoses are, but it looks like everything is still going to fit.

Pulled the fan and removed the steering belt to put the compressor belt on, reinstalled the steering belt.

Did a dry fit of the aux fan and the condenser hoses and I think it all fits?

Dropped the radiator back in but didn't hook it up. I'm done for the day. It's hot as hell here and it sure makes everything go s-l-o-w. But I feel like I'm in the home stretch now.

300TD1982 · #69 08-11-2020, 05:32 PM

Getting closer! Reattached the fan, shroud and radiator. Refilled the radiator. Bumped the starter to get the compressor belt on. Tightened the belt and tightened all the adjustment bolts. Feels like the hard stuff is done. When the sun is off the car I'll double check all the fasteners and take the car off the ramps and for a spin.

Left to do:
Install aux fan and Rollguy's aux fan relay kit
Install the expansion valve which is still in the mail (grumble grumble).
Install the dryer and the remaining hoses.
Add some oil to the dryer.
Pressure test.
Vacuum.
R134a fill.

ROLLGUY · #70 08-11-2020, 08:15 PM

Quote:

Originally Posted by 300TD1982

Getting closer! Reattached the fan, shroud and radiator. Refilled the radiator. Bumped the starter to get the compressor belt on. Tightened the belt and tightened all the adjustment bolts. Feels like the hard stuff is done. When the sun is off the car I'll double check all the fasteners and take the car off the ramps and for a spin.

Left to do:
Install aux fan and Rollguy's aux fan relay kit
Install the expansion valve which is still in the mail (grumble grumble).
Install the dryer and the remaining hoses.
Add some oil to the dryer.
Pressure test.
Vacuum.
R134a fill.

You forgot the last item on your list: Take and post photos

resago2000 · #71 08-13-2020, 02:33 PM

pictures please

what angle fittings did you use on the condenser, I'm installing the same size you used.

Thanks!

ROLLGUY · #72 08-13-2020, 03:43 PM

Quote:

Originally Posted by resago2000

pictures please

what angle fittings did you use on the condenser, I'm installing the same size you used.

Thanks!

#6 90* for the lower (other end connects to the drier)
#8 90* upper (other end to the compressor discharge)

resago2000 · #73 08-13-2020, 07:55 PM

Thanks!

300TD1982 · #74 08-17-2020, 02:48 AM

I forgot to order the expansion valve until last week, so I haven't done anything with the AC for a few days. Today. I installed the new valve. I used PAG100 on the o-rings and Nylog Blue on the threads. I understand that the Nylog shouldn't be necessary, but I figure "why not." Getting the new hoses through the firewall was a bit of an adventure, what with pulling the battery and air filter and wrestling the hoses through the firewall. The rubber gasket popped out of the firewall and I was pretty sure it wasn't going back in, but judicious use of three flathead screwdrivers coerced it back home. The expansion valve and the two hoses that hook to it are all I did today, and boy did it take awhile. It's super hot here so I can only work in bursts.

I still have to hook up the cross engine pipe, so next I'll do that and attach all the hoses except to the dryer. Then I'll hook up the aux fan relay mod from Rollguy. And then I think I'll be ready to add some oil to the dryer along with the pressure sensor, and then hook it up and then do a pressure test. Assuming the pressure test passes, I can vacuum it and fill with R134a and maybe I'll be done!

Except for pictures! I will take some pix, I promise.

300TD1982 · #75 08-17-2020, 09:22 PM

Today I finished installing all the hoses and making all the connections with the exception of the two on the dryer. I used PAG100 on all the o-rings and Nylog Blue on all the threads. I also installed Rollguy's fan mod that makes the fan come on whenever the compressor is on.

Tomorrow I'll install the new pressure switch into the new dryer, add oil to the dryer, install the dryer and do a pressure test. Depending on how long that takes and how it goes, I might pull the vacuum too. After that I'll just need to attach the wire to the compressor and charge with R134a!