Foretravel Owners' Forum

Does anyone have a part number for the correct TXV valve for the dash A\C? I do not think I have the right one.

Why do you think that you have the wrong TXV?

I changed my drier and expansion valve last year.  We probably have the same system.  I bought mine online from NAPA.  I believe it is the exact replacement.  Works good so far.  https://www.napaonline.com/en/p/TEM207376

Jerry

I replaced it with Amazon.com: URO Parts 1394712 Expansion Valve : Automotive (https://a.co/d/fNzSCtg) a while back and it worked ok for a bit, but would only really cool if we were moving. I've since replaced the compressor and condenser trying to improve the performance and it still isn't working well. The low side sits at 50 psi with that TXV, so i'm thinking either something is stuck in it, or it's bad, or the wrong one.

I replaced the dryer and TXV valve and it worked well for one trip, then I found some leaks and fixed them, recharged and it just barely kept up with cooling.
I have now replaced the compressor and condenser and dryer,  flushed all the lines and the evaporator and replaced all the o-rings. It's still not keeping up. TXV is my next try. The low side just sits a 50, and it fluctuates a little when the fans kick on, high side would creep up, fans come on, low side drops a few psi and high side comes back down to about 200.

That valve that coastprt linked crosses to the same one I used. so looks like I got the right one, it just might be bad or have gotten something stuck in it.  Thanks!

Are you aware that the original system was R-12 and conversions lose some of the cooling capabilities? Lower the pressures a little and see what happens to the dash outlet temps.

Yeah, I'm aware of the loss from r12 to r134. I charged it slowly. I added some and waited and watched.  The low side would stay at 50, even with the high at ~150.

So a couple things to ponder about. The expansion valve is the smallest restriction in your system. Having 50/200 doesn't sound good. Does the low side drop at above idle? I came to the conclusion that at the current cost of Freon one must own an evacuation machine on these larger systems. Did you replace your condenser with the original round tube or did you upgrade to a flat tube (highly recommend) If your operating R134 your low pressure is critical as soon as you go above its happy pressure it no longer works well. 50 is way to hi. So with 200 hi pressure I'm assuming your condenser fan is working well. I too would be looking to change the expansion valve again. Unknown what your correct part number is but sounds like it doesn't produce the required resistance to get the low side lower or compressor isn't up to the task.

Check out Universal Condenser Parallel Flow 18 x 30 O-ring #6 And #8 AC A/C on eBay!
Universal Condenser Parallel Flow 18 x 30 O-ring #6 And #8 AC A/C | eBay (https://www.ebay.com/itm/181701142189?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=UrocE-yFSEa&sssrc=4429486&ssuid=kPJXfftpQVa&var=&widget_ver=artemis&media=EMAIL)

Check out New OEM Sanden A/C Compressor fits 2001 Mack RD / 2000 Kenworth W900 on eBay!
New OEM Sanden A/C Compressor fits 2001 Mack RD / 2000 Kenworth W900 | eBay (https://www.ebay.com/itm/254566740921?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=4miu-OdoTty&sssrc=4429486&ssuid=kPJXfftpQVa&var=&widget_ver=artemis&media=EMAIL)

So that's the compressor and Condenser I put in. It doesn't drop at idle.

I picked up 7 recovery machines and boxes of parts and got one working, so I can pull it all out and replace the valve. It's got to have something stuck in it.

Might consider adding a condenser fan pack to increase the low speed airflow .

Are you working on the U300? I'm assuming you are. Does the condenser use an engine driven fan or electric? Being your Hi pressure is so low and low so high I keep thinking your compressor isn't keeping up. I normally have to increase idle operation to get usable numbers. Higher highs lower lows?. I like the condenser you've reverenced. Looks very simulate to what I put into bronco. Planning the same for my 2001 U320

https://www.sanden.com/objects/AC_compressor_guide_USA_20210730.pdf

Looks like there are different sizing and in link they go into detail about fake copies.

Looks just like this. SD7H15 is the model.  Replaced the sd508 that was in it. I was hoping the larger compressor and condenser would make up for the r12 to r134 change.

Looking at a 134a pressure chart for a 95 F ambient temp.

50 to 55 psi low side and 275 to 300 psi high side.

Additionally, a valve designed for 134a would be helpful, 134a appears to need a higher flow volume.

R134a vs. R12 – Griffiths (https://griffiths.com/ac-system-help-introduction/r134a-vs-r12/)

Tim

You are on the right track, Back when they outlawed r12 I converted a lot of systems to r134. I learned that r134 is thicker viscosity than r12. I cannot recall witch expansion valve I would use but I did allot more systems with expansion tubes and I would use a Ford expansion tube, larger orifice and that would allow the r134 to flow better. Also the condensers would need more surface area to accommodate the slower thicker r134. You will see the first r134 factory systems had a larger condenser. Jim.

Tim good article. They also mentioned something important and often overlooked. a High pressure switch need to be installed in series with the low pressure switch. R134 does need more condenser area for the conversion to work and will overpressure the hi side easily if condenser fan is interrupted. Came across this last week on a friends Bronco prerunner. His conversion didn't have the switch and he thought get could run back home without continuous fans operation and vented Freon out the overpressure valve. Thought be blew a line. He had changed his expansion valve out for the 134R and I was real impressed, actually envious of how well it was working. 110 degrees outside and with both doors open was producing 40 degree air. I really need to finish my Bronco system and get it serviced . Next month maybe??

So this morning I evacuated the system and replaced the TXV valve. Charged it back up and had the same issue. Just not enough cooling. Took a minute of checking things before I realized the compressor was spinning backward. The original SD-508 compressor is an SD5 series and can spin clockwise or counterclockwise. The new one I put in in an attempt to upgrade is an SD7 series and only spins clockwise.

My engine spins the compressor counterclockwise...

So I pulled all the refrigerant out again and swapped the original compressor back in and recharged.

Pressures at "simulated cruise" I had the wife hold it at 1500 rpm and put a box fan in front of the grill


Duct out temperature, max fan, recirculate

Intake temperature in the cabin. 78°F to 65°F is not too bad considering the ambient

Ambient temp taken just behind the headlight

Temperature behind the condenser

Temperature in front of the condenser

I also attached pictures of the two condensers next to each other. Not a huge increase in size, but some.

Universal Condenser Parallel Flow 18 x 30 O-ring #6 And #8 AC A/C | eBay (https://www.ebay.com/itm/181701142189)

Looking forward to how it does on the next trip. Thanks for all the help and suggestions.

Had a good chance to really test the a/c on this trip. Running west from little rock Arkansas to Murfreesboro, into the sun with 90f ambient, the dash a/c kept us comfortable.  Yesterday saw higher ambient and about 96 was the limit where the a/c was just keeping up.

In case anyone is wondering what these old systems can do. They will cool if you get things working right and I think the bigger condenser helps.  I could feel the difference with engine speed too. When she would downshift, the cooling increased a little.

This is the 91 gv if anyone is wondering.

I have an old thread where I replaced TXV and found desiccant balls in it from the filter dryer.  I got all the correct parts somewhere on the internet, but they were the original parts from the vendor that made the A/C system. When it is working correctly, your engine driven A/C will give more btu/hr than your roof.

Anything in these? :

Dash A/C question (https://www.foreforums.com/index.php?topic=31179.msg273605#msg273605)

Need Help With Dash A/C Problem ..... (https://www.foreforums.com/index.php?topic=21661.msg162482#msg162482)

YES!  Those two above posts have most (if not all) of the useful information.  Looks like the Victory Climate systems is still in business, but the links are dead. Might have to contact the company to get service and parts info...or use the wayback machine.

Looks like here be some parts for sale: Victory Climate Systems (SCS/VCS) Climate Control Products - (https://comfortairgr.com/product-category/scs-victory-climate-systems/)

Specification sheets with part numbers here: Spec Sheets - Replacement Parts List - Victory Climate Systems (https://comfortairgr.com/product-category/scs-victory-climate-systems/spec-sheets-victory-scs-vcs-parts/)

The Air-conditioning system is a Acme Air Bubble Unit. Here is a link. I bought a tx valve from him for mine.
ACMEAIRPARTS.COM https://share.google/2566MOQh5ViqTTNAS

Evaporator Assembly 4100778 - ACME Evaporator Assembly 4100778 - ACME (https://share.google/mSLpPcgXhLUC13rHi)