Engine compartment rear AC line routing

[BadDog]

I know this information is out there, but searching here and on Google proved fruitless.

I'm getting ready to run the turbo downpipe, and I just don't like anything about running it through between AC box and head. Just no room, too close to things that don't need to get hot, and a future maintenance nightmare. So I'm looking at routing the 3" downpipe under the AC box just outside the frame rail until about 1/2 way under the AC box and then back to the inside of the frame rail to meet up with the rear pipe. Bends aren't that much more than running it down the inside, and it looks like only a minor modification of the inner fender will be needed for this.

But then I realized, the rear AC lines are roughly in that area, so I needed to mock them up along with the inner fender to see what was feasible. It seems obvious that they go up just outside the firewall rib where the inner 3/8" body bolt secures the inside of the inner fender to the firewall. But when I get on top of the inner fender, it seems like the pieces don't fit they way they should. Some of it's likely due to accidental bending while in storage, but I'm also missing dryer, condenser, and radiator shroud, so there is a lot of pieces just not locked down in final location, and no practical way to mock it up further.

So, I would really like to see what a fully buttoned up set of AC lines with rear AC should look like when complete. Where do they attach, and how the high/low lines fit alongside each other from the AC box to the core support. I also have similar "where can I put it" issues with the waste gate actuator, which if mounted stock, would put the diaphragm head on the wrong side of the inner fender, and I don't want to relocate it only to find out it interferes with the AC lines.

If anyone knows of a thread where this is shown, I would much appreciate it. Or good search terms ("rear ac" combined with various relative terms didn't pop anything useful). Otherwise, if you could take and/or post some pics, it would be much appreciated.

 

[Wes Harden]

Here are some photos from my 77, think the rear was dealer install def not factory.

 

[imiceman44]

I know this information is out there, but searching here and on Google proved fruitless.

I'm getting ready to run the turbo downpipe, and I just don't like anything about running it through between AC box and head. Just no room, too close to things that don't need to get hot, and a future maintenance nightmare. So I'm looking at routing the 3" downpipe under the AC box just outside the frame rail until about 1/2 way under the AC box and then back to the inside of the frame rail to meet up with the rear pipe. Bends aren't that much more than running it down the inside, and it looks like only a minor modification of the inner fender will be needed for this.

But then I realized, the rear AC lines are roughly in that area, so I needed to mock them up along with the inner fender to see what was feasible. It seems obvious that they go up just outside the firewall rib where the inner 3/8" body bolt secures the inside of the inner fender to the firewall. But when I get on top of the inner fender, it seems like the pieces don't fit they way they should. Some of it's likely due to accidental bending while in storage, but I'm also missing dryer, condenser, and radiator shroud, so there is a lot of pieces just not locked down in final location, and no practical way to mock it up further.

So, I would really like to see what a fully buttoned up set of AC lines with rear AC should look like when complete. Where do they attach, and how the high/low lines fit alongside each other from the AC box to the core support. I also have similar "where can I put it" issues with the waste gate actuator, which if mounted stock, would put the diaphragm head on the wrong side of the inner fender, and I don't want to relocate it only to find out it interferes with the AC lines.

If anyone knows of a thread where this is shown, I would much appreciate it. Or good search terms ("rear ac" combined with various relative terms didn't pop anything useful). Otherwise, if you could take and/or post some pics, it would be much appreciated.

I have a factory rear a/c I will try to take pictures tomorrow

 

[Big Ray]

I have rear ac parts in the garage. My current 2 rigs don't have rear air. Hell, I still need back glass for my tailgate. If I stumble on some pics I'll post them up!

 

[BadDog]

Thanks guys.

I've got the routing sorted out underneath to the back. It's the engine compartment passenger fender well that's giving me some trouble. Once I get more of the pieces final installed, it may become more clear, but right now the high and low pressure lines seem to want to go right through each other. The only thing I can figure out is that sometime between when we harvested them off the donor and when I tried to piece them together, one or both got tweaked a bit. And the lines I've got appear quite different than the engine compartment shown above, so not sure how to resolve that (yet).

The main reason I was asking this question instead of waiting to sort it when more is assembled was to also consider these lines when building my turbo downpipe. But I came to the conclusion that there was only one logical way to route a 3" turbot downpipe without requiring denting or downsizing to 2.5" (or smaller). So I routed that where it needed to be, and I suspect I'm going to be fabricating a tunnel into the inner fender to make room for these hoses just outboard of the inside "big washer" bolt flange.

 

[white90burb]

Pretty certain factory rear air lines are mostly hard line. At least on my old 90 burb they were. Also thats what lmc shows.

 

[BadDog]

They are. It's the routing of the 2 sets of triple lines that connect there that I'm interested in.

I've now got more of it together, and still not sure exactly which side the low and high pressure lines go as they sort of weave together right in front of the AC box. Clearly my lines (salvaged from the 90' Sub where I salvaged the interior) got a little tweaked at some point after removal and before install as they had to be tweaked a bit just to make up. But that lower section seems like everything wants to be in the same place and cross through each other.

 

[Big Ray]

Here's a link of the liquid line. Notice the connection for the rear unit.
https://www.rockauto.com/en/catalog...+&+air+conditioning,a/c+refrigerant+hose,6900

And the compressor hose with the rear connection.
https://www.rockauto.com/en/catalog...+&+air+conditioning,a/c+refrigerant+hose,6900

The hoses run under the evap box and down the inside of the frame. Wish I had better pics.

Bottom 2 pics.

 

[BadDog]

Thanks.

I've got the rear lines routed along the bottom of the passenger cabin, and up below the AC box, I'm clear on that part. The problem is that when the normal front lines are connected per-normal mode, the 2 lines that go to the rear cause the whole tangled lot to bind up. I can get them all to make up in 2 rough woven combinations, but neither seems to set naturally together, or be able to secure to the inner fender by an adel clamp that is on the lower high pressure line.

Once I get the radiator shroud in to support the upper cross over lines (currently just propped in vague approximation), maybe it will become more clear. But the high and low between the AC box and the core support clearly got bent/twisted during the acquisition/storage/install such that they don't play well together. Doesn't help that I recently realized that the upper low pressure tube coming out of the AC box had gotten bent (sort of pushed back accordion style with 2 mild crimps at the 2 bends) so that the dryer doesn't sit/clock just right, so now I've got to remove the evaporator to swap in the evap from my K5. It would probably be ok just straightening the tube, but it's kinked a bit which may reduce efficiency (can't sacrifice ANY hear in Phoenix), plus being aluminum it could crack in use. I should have looked closer at it sooner, but apparently had "too much to do" blindness (related to clutter blindness that afflicts my wife).

We were quite careful taking pictures while disassembling all the rear air stuff because I was retrofitting a non-rear AC Sub and had to add various bits. But I guess it never occurred to me that the forward lines would be so problematic. Never much paid attention to them in the past because it was just remove, replace, and the routing was "obvious".

 

[Big Ray]

You can cut the ferrules (CAREFULLY) and install new barrier hose and custom route the lines. Once you get them the way you like you can take them to a garage or hydraulic shop to be crimped.

That's the plan with mine, I scavenged the rear ac to add to my rig. Didn't have enough sense to save the fittings for the long hoses, as I saw them on rockauto at the time.