W123 suction hose routing - PeachParts Mercedes-Benz Forum

Demothen · #1 09-11-2016, 11:48 AM

Can someone please share a quick picture of how the suction hose routes around the coolant tank on a 300d turbo? I need to make a new hose and I am not quite sure how to route it.

Thanks!

Charlie Foxtrot · #2 09-11-2016, 12:22 PM

white strip of wire laid on top of suction hose for contrast ('85 300D W123)

Demothen · #3 09-11-2016, 03:14 PM

Perfect. Thanks!

funola · #4 09-12-2016, 10:00 AM

How did it go? I researched making custom AC hoses when I was told I should replace my non barrier hoses with barrier hose and found this video with some exc tips https://www.youtube.com/watch?v=IPT3sEiR1uc

Turns out from pressure testing, my non barrier hoses are fine and I did not replace them.

Demothen · #5 09-12-2016, 10:17 AM

I ran into a problem, then out of patience.

I replaced the grommet where the two hoses pass through the firewall to the evaporator with a new one, since mine was torn and I could see light through it. That part is very much not fun to replace, it's a real tight fit and took a good 30 minutes before I got it in place. Then I tried to pass the new hose through it to measure for length, and the grommet popped back out. I decided to just measure the hose without the grommet and add an inch or so to make room to recenter the hose, cut the new hose, then realized that in my efforts wrestling the hose around, it had gotten gouged on the sheetmetal of the firewall. I cut the gouged portion out of the hose, but it's too short to use for that location again. Fortunately I bought way more hose than needed, so I'll be able to try again this week.

I did figure out that the best way to pass the hose through the grommet seems to be to heat it up with a hair drier, and add a bit of lubricant to the end of the hose. I'm undecided on using silicone grease (shouldn't hurt the grommet) vs pag oil (wont contaminate the hose). Any thoughts?

funola · #6 09-12-2016, 10:24 AM

Quote:

Originally Posted by Demothen

..... Any thoughts?

Use boiling hot water and let it soak for a few minutes, not a heat gun, on the hose or the grommet if you want to soften it to make it easier to work.

When in doubt what to use as lube on the hoses, google rubber chemical compatibility and look it up. How about plain old soap? That won't hurt it.

Demothen · #7 09-12-2016, 02:39 PM

Sorry, one more question - roughly how much clearance between the stock R4 compressor manifold suction side and the driver's side frame rail is there? The Sanden system I'm using has a metal replacement for that hose, but it can be clocked into any position and I'd like to be sure there's plenty of clearance between the manifold and the frame rail. I wish I had thought to get more pictures.

On a side note, I was thinking about starting a gallery somewhere with all of the "technical" pictures I've taken of the car since I've owned it to aid in reassembly. I have several hundred, but they never seem to be of what I need. I would think that something like this for various years/models would be really beneficial, but it would be pretty high upkeep.

funola · #8 09-12-2016, 06:12 PM

It's about 2.5 to 3 inches.

Demothen · #9 09-12-2016, 09:43 PM

Thanks, Funola.
Does that mean it runs in between the two oil cooler lines? Or does it run outside of those lines but inside of the frame rail? My oil cooler lines are now supported by a new bracket but I think they are pretty close to their original locations. If I run the suction line outboard of those I can probably get one inch of clearance max.

funola · #10 09-12-2016, 10:46 PM

Rereading your post, I don't think I gave your the correct info. If the R4 compressor and manifold is being deleted, why do you care about the R4 suction hose clearance?

Demothen · #11 09-12-2016, 11:14 PM

I just want to make sure my sanden compressor's manifold has similar clearane to the r4, since that should mean I have enough clearance to deal with engine movement.

BillGrissom · #12 09-13-2016, 03:53 PM

Pretty sure my suction tube runs vertically up outside the 2 oil cooler tubes, but my photos are at home. This is on both my 1984 w/ R4 compressor, and my 1985 w/ Sanden on Rollguy's bracket. I bolted the factory tube manifold to my Sanden, using a certain rear head w/ "GM Pad" ports. Search for posts, if interested, which should answer your question too.

I later changed both the suction and pressure hoses w/ new barrier hose. I have a Master-Cool ferrule crimper (shown on a recent Wheeler Dealers episode for a 60's Volvo) which makes it look factory, but you could use Oeticker stepless ear clamps or Breeze smooth screw clamps.

Demothen · #13 09-13-2016, 04:08 PM

Thanks,
I checked with the kit manufacturer and they also told me that it should run outboard of the two oil lines, and that it's fine as long as it doesn't touch either the oil lines or the frame rail. I'll double check mine and probably err on the side of caution and keep it closer to the oil lines than the framerail.

I've also got that ferrule crimper - I haven't used it yet, I ended up buying it then realizing that I only needed to make one hose (suction side from evap to metal pipe above engine). Hopefully this weekend I'll finally get to try it out.

Charlie Foxtrot · #14 09-13-2016, 05:55 PM

I gotta ask - why fight with a tight hose/grommet fit? Just drill out the hole and use a larger grommet.

Demothen · #15 09-13-2016, 06:15 PM

Its not really a standard grommet. I dont have a picture, but its oval shaped, about 5 inches long, and has three ports. I could open up one of the ports to make it easier, but I am afraid it will leak or fail prematurely. You cant really change the grommet without draining the AC, or possibly cutting slots into it.