engine and drivetrain Notes on modern receiver drier and hose mounting

[thehackmechanic]

I am slowly getting back to putting the tii back together after ripping the a/c, heater box, and injection manifold out for reasons that, well, made sense at the time.

I thought I’d capture what I learned about available options for replacing the a/c’s receiver drier.

On the one hand, replacing the drier is the most trivial part of a/c repair, but when it’s part of refurbishment and improvement of the a/c system, it gets more involved because the mounting and connections are no longer the same. The original drier that’s part of a dealer-installed Behr system is shown below.

In this post:

http://www.bmw2002faq.com/component/option,com_forum/Itemid,0/page,viewtopic/t,376354/view,previous/sid,155df6b4846c376695fd4d0d510e51c0/

I went into gross and gory detail about what the original fittings are on a Behr system and how you’d probably update them if you went to modern components with o-ring fittings. I’m a practical guy, so I thought that if I could find an exact replacement for the original drier, I’d use it, but if I couldn’t, I’d go with o-rings.

The Behr systems I’ve seen have the drier installed in the nose. It’s a bit of a tight fit in there, but it’s out of the way, and the drier’s fittings are oriented perfectly for the intake from the bottom of the condenser and the outflow to the evaporator. The drier has a pair of 10mm studs attached to a mounting bracket that’s welded to the side of the drier. These go through two holes that have been drilled in the nose as part of the dealer installation, and in this position it allows the outflow side of the drier to line up perfectly with large lower hole in the nose for the hose.

The problem is, I have yet to find an exact replacement for this part. I thought I did – Four Seasons part 33394 that replaces Mercedes part 107 830 00 83 seemed a dead ringer, but when it arrived, I found that the bracket and the posts are at a 90 degree angle relative to the original.

If you absolutely had to use this drier, I suppose you could somehow turn the bracket around, or bend it, or chop the original one off the old drier and weld it on the new one, but I went for Plan B.

I ordered a conventional #6 o-ring fitting drier and clamp 41-0322 from Old Air Products. I tried to mount it inside the nose, drilling an extra hole in the bracket so that I could use the two existing holes in the nose, but I couldn’t fabricate a hose that would make the connection to the bottom of the condenser; the crimp-on hose fittings themselves are too long, creating rigid length where you need a flexible piece of hose. I thought I’d simply mount the drier inside the engine compartment against the right fender wall, but the thought of drilling holes in that sensitive area gave me the heebie-jeebies.

After a good deal of searching, I found #6 o-ring 90 degree “short drop” fittings at http://autoacfittings.com/6-Female-O-Ring-90-Steel-Standard-Short-Drop-SB-1321-SD.htm that are short enough to allow a hose to be fabricated to make the connection to the bottom of the condenser. The standard length fittings and “short drop” fittings are compared below. You can see that the “short drop” fittings are shorter enough that they accommodate the needed piece of hose.

Using these, I was able to crimp up a hose that made the connection perfectly.

If I keep this up, a little every night, I just might have this thing together in time to drive to The Vintage on Memorial Day.

Coming attraction: My next post will go through the five different fans I used, trying to find a good mate to the Porsche fan motor for the heater box.

[TobyB]

Those original fittings look like AN fittings...

t

[JLENHAM]

I am so glad you are doing this ahead of me. I am also plotting some way to get my whole set up together so you can crimp everything for me over some Vintage weekend. Not this year though, currently cutting out rust in the floor and patching in hopes to have new carpet and seats in place!

[Retrogroucher]

Cool stuff, Rob. Your problem solving and fabricating skills are getting a little too advanced for guys like me. Be careful you don't lose your title of "The Hack Mechanic," and get relegated to "The Mechanic Formerly Known as The Hack Mechanic" or simply, "The Mechanic." You know you've befuddled all of us when you become a symbol that we misinterpret as stylized rear trailing arms: ¥.

I've dropped some strong hints to my wife that your book makes a perfect Dyngus Day present: http://www.dyngusdaybuffalo.com. Us Buffalo people take spring very seriously, indeed.

Good luck with the AC :/)

[thehackmechanic]

Mike:

1) I like the idea of my personal being reduced to an unpronounceable symbol, but I think it would need to be something round and hexagonal, connoting a guibo.

2) An M2 build, and you're telling me my mechanical capabilities are outstripping yours? Yeah, right.

3) This is the part of the book about you, in the chapter about the Techno Violet M3:

"But my absolute favorite comment was the following unsolicited e-mail from CCA member Mike Roach. Keep in mind that Mike and I have never met. “I was getting ready to board a plane, send out an email to everyone I know in Boston, call the state mental hospital, basically do anything to keep you from getting it. This is the car that would have been your undoing. It would have crushed your spirit. It's tragic to see a car guy tormented to the point of hobby desertion. You would have shuffled around, staring at the floor for years. The return of Bertha's tender love would have been our only hope, and lord knows where she is. Your family, CCA friends, band, etc would have still loved you, but missed the Old Rob.” Note that, while I’ve written in detail in these pages that Bertha is the 2002 that I sold to my friend Alex nearly 20 years agoin 1988, I hadn’t written about Bertha in the Roundel in many, many years when I received Mike’s email. I told Mike that anyone who throws around the phrase “only the return of Bertha’s tender love” knows me better than I feel, uh, comfortable with."

[thehackmechanic]

Oh, Mike -- I followed your link to http://www.dyngusdaybuffalo.com. You had me at "flirt with pussy."

[Retrogroucher]

LOL. I'm not worthy, Rob! I like to think I may have a small part of keeping you intact: that Techno VIOLENT was a very rough car from an even rougher part of town. An intervention was in order. Your FAQ and CCA brothers & sisters were ready to protect you from yourself. Marshall's car is on the other end of the spectrum (not the ROY G BIV kind), and he would have driven up in his well- maintained Techno M3/4 to show you that these cars don't have plastic louvered hoods and front fenders, yellow painted brake calipers, light blue racing seats from Autzone, belch smoke when hot/cold/under load/not under load, idle with a coolant temp needle in the red zone despite the fans working, etc.

You're too generous-- my mechanical skills are rusty & non existent. Making PB&J sandwiches for my kids nearly requires a factory manual.

Dyngus Day is a family event. Take Maire Anne for the weekend. Bring your ax and sit in a couple sets :/)

Best,

M

[Mike Self]

when you replace a receiver-drier, make sure that little pressure switch is installed and functioning. Its job is to prevent the compressor from engaging (wired in series with the electric compressor clutch) if refrigerant pressure drops in the system due to a leak. Since the compressor's lubrication is contained in the refrigerant, its loss will mean catastrophic failure in the compressor...

I found this out the hard way--my system, as originally installed, had a plug there--no switch. Not having owned an air conditioned car before, I didn't know any better until my system lost pressure--on a 90 degree day on I-65 in Alabama--and my compressor literally exploded. An autopsy revealed nothing much larger than my thumb inside the York compressor--pistons, rods and crankshaft!

After I got all the compressor fragments out of the entire system I installed a pressure switch! The shop that did it at my insistance was happy I insisted, as they failed to properly pressurize the system and the switch shut down the new compressor before it could fail...

cheers

mike

[thehackmechanic]

Thanks Mike. It's not fully installed and wired up yet. Those wires hanging to the left ARE for the cut-off switch.

[02fanatic]

Speaking of receiver-driers my '76 has the original Frigiking rec-drier in there still, and talk about an outdated piece of equipment!!!....I've been wanting to replace it for years, but haven't found anything like it to use. The Behr is totally different.

Anyone have a good source for vintage recriver-driers?

Thanks,

John

P.S. and yes the entire Frigiking system is in tact, complete with the huge York compressor! The A/C actually still worked when I bought the car in the last 90's!

[Robert Kyle]

Pictures are dead.

 

Can anyone recommend a replacement drier?  I think the OEM has a binary switch.  Thinking maybe have one with a trinary switch to power the aux fan as well instead of splicing like the original wiring.

 

[Robert Kyle]

Maybe this?

 

https://www.amazon.com/Vintage-Air-07323-VUC-Trinary-Switch/dp/B002VVXDGE