Bostig AC mod

[Tommy Turtle]

Just wanted to thank all who helped this happen for me.

My first foray into A/C, and I couldn’t have done it without the many Samba members. Because of all the knowledgeable help…

My system held a vacuum of -30” for SEVEN DAYS.

It blew 57 degree air on a humid 92 degree day…a 35 degree differential, which I’m quite pleased with.

The cleaned grounds, feed wires, and relays in the D pillar never got hot enough to cause worry. Even on fan speed 3 & 4.

Thanks again!

Tom

[Pchill2]

These are pictures of my trinary switch flying leads. Since you are using a binary switch just ignore the blue wires.

You will need to connect the black wires (or whatever color are on your binary switch leads) to Red/Blue and Red/White in your d-pillar and then run your wire to your alternator and you should be good to go.
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87 Syncro Westy
Honda K24 swap

[Tommy Turtle]

Pchill2,

I went with the binary for two reasons.

One was to mimic the factory (dealer installed I suppose) setup to keep it simple. The binary switch implementation is well documented various places…minus the wiring peculiarities due to dead photo links.

Secondly, it was again to keep it simple, for now. I don’t have the time in this block of days off-11 days, or the rest of summer most likely, to do the wiring for the radiator fan and associated under the dash work etc. to my ridiculous OCD standards.
A trinary is in the future, since I have the manifold gauges, vacuum pump & a six pack of RedTek standing by.
Kind of bass akwards, I know…just a finite amount of time.

FYI the increased idle is handled by using the kit’s included SCT engine scanner/programmer to bump up the idle to 1200, I think, for summertime.

John, thanks for the info! Mine is an ‘87 as well. While we’re on the subject of binaries & trinaries, any words of wisdom, since you’ve been there/done that.

Thanks guys!

Tom

[Pchill2]

The large red wire goes to the alternator.

Why are you going with a binary switch rather than a trinary? Both will work, I'm just curious.

If you are putting the switch on the receiver/drier, you will need to run wires back up into the d-pillar and connect to the factory pressure cutout switch wiring. It does not matter what wire connect to what. They just need to be connected to the two wires that plug into the factory pressure switch connector

I'm not super familiar with the Zetec engine computers but I assume there would be an A/C switch signal required by the ECU to bump the idle so the engine does not bog down when the A/C compressor cycles on. Maybe a Zetec expert can chime in on this.
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87 Syncro Westy
Honda K24 swap

[Tommy Turtle]

Thank you gentlemen for replying.
With all the dead links of pictures at the Bostig site, I wanted to clarify the wiring solutions.

I’ve suffered a bit of mission creep, and have purchased everything new, except for the quite pristine evaporator. Motorcraft compressor, EZ Clip hose & fittings etc. You get the idea.
The cleaned and flushed evap, and new exp valve went in today. Condenser & R/D yesterday. Cabinet & serviced fans, and the hose/fittings tomorrow and Tuesday.

I don’t have to be back to work until Saturday, and would love at very least to have a sealed system & be able to draw a vacuum, to see where I stand…possibly even charge it.

From gleaning everything I could online previously, and now with a focus on electrical…

First, does the long red main power wire coming down from the closet go to the alternator post? I’m planning on using a length of 6 gauge I have for this. There’s surprisingly no evidence of prior overheating or melting in the D pillar.

Secondly, the wires from the high & low pressure switches that were in the D pillar originally, will be moved to the Nostalgic Air binary switch located in the new receiver drier. This is following djkeev’s great post on his ‘86 weekender.
I’m unsure how this is ultimately accomplished.
It sounds like I can combine the existing wiring directly to the new two wire binary switch…but I’m unsure which ones and where. Originally it’s Red/blue & red/white on one switch and brown/black & brown/white on the other. Any guidance here would be greatly appreciated.

Lastly the compressor clutch. I bought the Dorman two wire pigtail plug for the FS10 recommend by Jim, it’s getting delivered tomorrow.
Does this merely splice in to the Vanagon’s wiring for clutch engagement?
If I remember correctly, polarity isn’t important.

I’m praying that the switches & wiring up front is ok, but I have the Bentley & a multimeter ready for that last step.

Thanks guys!

Tom

[jimf909]

This is the plug for the compressor that I bought and used. Ignore the 'kit' part of the title. As I recall it was a plug with two wires that I mated to the VW harness.

https://www.amazon.com/dp/B000IYHEP2/?coliid=IGY4V..._lig_dp_it
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- Jim

[John Sullivan]

The only wire change is the compressor clutch. The ford compressor similar to the Vanagon compressor has a 2 wire coil for engagement. My 87 Vanagon had a Red/blue wire at the connector (actually 2 wires) and the brown ground wire. The ford compressor on Bostig is on the opposite side to the VW compressor and required an add of about 3 ft of shielded tw/pair with crimped fastons to mate to existing Vanagon connector. I picked up a ford compressor plug with wire off of a 2000-04 ford focus, yellow/green and black wires with connector. I connected the yellow/green to the red/blue (hot) and the black to the brown VW ground via the added 3 ft of cable extension.
Maintain wire size, gauge.

That's the only wire change for the whole job. Should work no problem.

[Tommy Turtle]

Vanagon squad,

Any luck with your Bostig A/C wiring?
I’m about to wire mine, and as you know, concise information is hard to come by.

Tom

[vanagoonsquad]

Resurrecting this thread for a relevant wiring question. I'm sure the photos posted here would have helped answer this, but the links are all dead. I've checked out all of the relevant threads here and on the Zendesk site, but I'm still not sure.

I'm trying to wire up my compressor. Here is a photo of the wires that have been tucked away after the WBX removal.

The wire at the top with a ring terminal is brown. Beside it is a red/blue wire that forks (via some sort of quick disconnect) into a single male pin connector and a female spade connector. The largest wire is red and I've gathered this needs to be connected either to the post in the distribution box or the post on the alternator (does it matter?)

Is the fork on the Red/Blue wire redundant? It seems the fork once led to the idle stabilizer unit? My intuition is to snip the fork and connect the Red/Blue wire and the brown wire to the compressor, but I learned early in this process not to trust my intuition...

Thanks.

[shizzon]

Thanks. I don't have a sanden compressor (it's a ford one).

Unfortunately I pulled the compressor in a friends driveway on a road trip and didn't measure how much oil came out.

I think I'm going to assume that there is still a few oz in there and just put 4.5 in the compressor and 0.5 in the drier.
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1989 Bostig Syncro Westy

[Farf]

Follow steps for compressor replacement on Page 22 (I think). You may not have a Sanden compressor but the process is the same. Add an additional .7 oz for the new R/D, you can add this right into the compressor too.


www.sanden.com/productlibrary/manuals/SD_Service_Guide_Rev_2.pdf

[shizzon]

Thanks!

Quick history - I replaced almost everything last year (all new hoses, new parallel flow condensor, drier, expansion valve, cleaned out evaporator with air line cleaner), but stupidly used a compressor that was used and had been sitting for a while.

Not long after getting the system fully functional, the compressor started to go (clutch was staying engaged even when system was off).

So now I'm just replacing the compressor and drier. I'm trying to figure out if I should just add 4 oz to compressor and 1/2 oz to drier, or try and put in a complete 7 oz into the system. I assume a fair bit of oil remains in the evaporator, condensor, and lines.

Any advice on how much to put in, or does it not matter that much?
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1989 Bostig Syncro Westy

[LemonCove]

I used 7. From my notes in 2013: I added 4 oz of oil to the compressor through the ports (new Ford compressor shipped dry). I also added 2 oz to the evaporator, and appx 1/2 oz to the receiver/drier, and the same to the hoses where they connect to the condenser at the front of the car.
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'88 Bostig Westy

[shizzon]

So is 7 oz total or 9 oz total correct? It sounds like 5 or 7 oz goes to compressor, and then the other 2 goes elsewhere in the system
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1989 Bostig Syncro Westy

[JudoJeff]

7 plus 2, I don't think you overdid it. And it's cooling!
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________________________________________
1989 Vanagon GL Westfalia Camper, Burned up on 7/31/16.
1987 Vanagon GL Westfalia Camper, Bostig & Rebuilt, sold
1986 Vanagon GL Westfalia Camper, Bostig Sold May 10, 2021
1999 Ford GTRV Westfalia camper (30% bigger Westy layout)

[sanfordphoto]

Does anyone know of the correct amount of oil to place in a Bostig converted A/c system? I originally followed the Bently recommendations (about 5 oz in the suction line to compressor and about 2 oz into the evaporator etc). Now I'm realizing that my new compressor already had oil and when I'm filling 2nd/third can of redtex, I bit of oil comes out when removing the manifold lines, also see liquid referent/oil in the sight glass above the air dryer?

But it is cooling....

Thanks for any thoughts or ideas.
Sanford

PS I love my Bostig conversion.

[LemonCove]

Reviving the thread to add another example of a Bostig A/C conversion using the Focus FS10 compressor connected to the stock Vanagon system.

New Compressor, Expansion Valve, Receiver/Drier, o-rings, "jumper hoses," completely cleaned/flushed system, refilled with Envirosafe (RedTek type hydrocarbon refrigerant) and Double end capped PAG46.

I owe a lot to the Samba, especially John Sullivan, http://www.weidefamily.net/vanagon/, and of course the "DIY Red Tek Conversion" thread and Terry Kay.
http://www.thesamba.com/vw/forum/viewtopic.php?t=292488&highlight=redtek+diy

I took a ton of pictures to document my process, thinking I may be able to make things easier for the next guy who wants to get his A/C working.

One unique Bostig related problem is that after removing the old VW wiring in the engine bay, the wire that provides power to the 50A fuse block in the closet is no longer "live." I had to make up a new wire to provide power to this panel for the system to work. Here are my photos:

https://picasaweb.google.com/13VelosdeRemi/BostigACConversionAug2013#

I still have to put my plenum back in, and maybe try to fine tune the system pressure, but it was nice driving in 98 heat today and feeiing the blast of cool air. Too bad I missed most of the summer.

Jed
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'88 Bostig Westy

[Destructo]

Some pictures of your project would be greatly appreciated Brungeman...
I'm planning on doing this in the next couple of weeks and would like all the visual stimuli possible, so I can formulate my route of attack.
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1985 Wolfsburg Edition Westfalia Camper Bostig conversion

Dude, where's your van?

[Brungeman]

[John Sullivan]

Yes that is the fitting that needs to be cut down some. It will then exactly match a male insert fitting. I did have a 90 there as you can see in the gallery pictures of the link. You will need some more length besides a 90. Also I used an R12 fitting from Ray Everett. You could use an R134 fitting. That would work fine. I have a guage set that works with R12.
The other hose is exactly the part I had cut off and spliced onto. Then run both hoses in front of the Bostig interface plate as described. Keeping away from the exhaust and cat as far as possible. I put sleeving on both hoses. See gallery.
My AC works great. Used it all summer, no leaks.