Allis-Chalmers 7020 Tractor Air Conditioning Overhaul "Disaster", Part 1

[@bakonfreek]

"Do I hear something leaking? I think maybe I do!" "No, you can't, you're not allowed to!" I enjoy these little bits of serious commentary veiled as humor.. or is it humor veiled as a serious comment? Perhaps both, I personally do the same thing at work when I'm 7 hours into a 45 minute job 😂 (there's a story behind that from today, but I will need to embellish it because the real series of events was somewhat embarrassing). Your dad's a real character and I mean that as a comment of endearment.

[@uxwbill]

"Seven hours into a 45 minute job" has absolutely made my day. It didn't get captured on video, but we also got a lot of humorous mileage out of vacuuming up all the mouse garbage.

[@uxwbill]

In this same vein, I would also like to point out one of my all-time favorite video moments. kzbin.info/www/bejne/nJi7p6OgnLuWfZI , ~18 minutes.

[@uxwbill]

An additional point or two, as if there weren't enough already...I hold both the EPA 608 Universal and 609 MVAC cards. As for the original factory-installed expansion valve, I noticed odd behavior from it when I was running nitrogen through the system. The nitrogen would start out flowing very freely as it moved through the valve, and then it would slow to a stop. After a few moments, it would start flowing freely again. I'm of the impression the valve was possibly opening and closing, though without refrigerant or a temperature change, I don't think it should have been doing so.

[@RaidifyLifts]

It’s awesome that ur starting to upload more than u used to. Currently u uploaded almost more than you did all of last year and in at most half the time. Probably less

[@ENB2002]

What the dealer was doing is absolutely unbelievable. I hope the powers that be threw the book at them. I will say that one takeaway I got from this video that I combined with my own experience is not to chalk up issues to old age and just leave it. Usually, it is something that can be fixed. It is also possible that this could turn into the Ship of Theseus (or in this case, tractor), at which point you’ll want to replace it anyway. In the end, I agree with you on not taking shortcuts. I have certainly learned that lesson myself before.

[@joeyf504327]

looking forward to part 2!! Wild story buried there in the description!

[@compactc9]

That's a WILD story!! I'm glad you included it in some way! People ran all kinds of wild scams back in the day.

[@uxwbill]

Upon looking into it further, I found an explanation of the "purge" fan speed setting: forums.yesterdaystractors.com/threads/purge-setting.1319576/ This would tend to suggest that the cab blower fan switch is wired incorrectly on this tractor. Believe me, that is not a surprise.

[@Edvinas_channel]

Hopefully everything will be resolved without the need of third or fourth part!

[@retro_88yota]

TXVs are actually super common in automotive ac systems. ford and GM used fixed metering devices from the 70s into the mid 2000s, other than that TXVs with a liquid line drier are basically the norm for automotive air conditioning.

[@uxwbill]

Makes sense, since almost everything I've ever worked on was domestically produced in that time frame. (The very few Japanese cars I've worked on also had fixed metering devices. Another commenter reported that the Volvo 240 had a TXV, though I never examined the A/C on it.)

[@retro_88yota]

@@uxwbill what Japanese car have you seen with a fixed metering device? All Toyotas going back to the 70s, along with Honda's use TXVs in their factory ac systems.

[@uxwbill]

@@retro_88yota I want to say the 1990 Prelude we had long ago was equipped with a static metering device, as was the 2005 Accord. (However, I'm no longer sure about the former. We did have the A/C system on the Accord taken pretty far apart and I don't remember seeing a TXV.)

[@JamesLee-oe7mt]

My 85 Dodge pickup has a txv !

[@retro_88yota]

@@uxwbill typically the TXV is inside of the evap box directly connected to the evaporator, unless you pull the evaporator you are pretty unlikely to see it. For the most part cars newer than 2000ish have TXVs that are the "block" style valve. They bolt into the evap core using Allen bolts, they are typically buried in the firewall right where the lines pass through.

[@misterrocks3035]

Around 30 years ago, a Massey-Ferguson tractor, with an airconditioned cab, was purchased for the family farm after years and years of advocacy on my Dad's behalf (who bore the brunt of bee and wasp stings, as well as bites from spiders, and other nasties, not to mention chronic hayfever during hay cutting & baling seasons), as it was obvious the older pair of MF tractors operating were grossly underpowered for the work expected of them, which was not helped by poor placement of the radiator after the hydraulic oil cooler, with a nasty void between the two that naturally filled up with all manner of detritus, causing endless trouble with overheating. For what it's worth, one of those tractors stayed in service for another 20 years, although it was absolutely knackered when it was finally replaced, boiled more water than it burned diesel and somehow kept on going - but I digress. Anyway, the A/C on that "new" MF was unceasingly problematic, and needed regassing every season from new. A leak was never identified, and the tractor was really only brought into service for the hay season as time went on. Based on what I recall reading on "Bimmerforums", back when I was driving a 1990s 3-series BMW, those cars were equipped with a TX Valve for their A/C systems. As far as I knew, the system on my car had never been serviced, and it blew cool air (the compressor cycled around 8ºC, vs around freezing in both the Toyotas we had at the time), in traffic, on the highway, regardless of whether it was 20ºC or 45ºC outside, even using the fresh air option, as is right and proper. Whether that can be attributed to the presence of a TX Valve, I don't know. The car's VIN did, however, turn up results for a "Tropical Cooling Kit", which, among other things, included a different A/C compressor, different fan pulley and viscous clutch, maybe even different fan blades, that may have improved the A/C performance. All that, and I'm only 11 minutes into the video.

[@The_Magic_of_Zelda]

The only tractor I ever driven was a 1941 Farmall that one of my friends had. Good machine but not so much fun to operate during the summer due to lack of AC. He did install a fan later on but it only made a little difference in the summer.

[@uxwbill]

I've done plenty of time on 1940s and 50s tractors, working under the summer sun. The most amusing of these was a Ford 8N with a tendency to overheat when pulling steep hills and running a belly mower. The throttle lever was also broken, so one had to hold their knee against it in order to keep the throttle open. Another noteworthy tractor was a Deere 420 with a wide front end. That one was used mainly to haul hay bales around, and it's impressive just how far apart those famous two cylinder engine pops can get under heavy load without the engine stalling. I can only imagine what a revelation even early tractors were compared to farming with animal power.

[@AricVogel]

I'm sure TXVs have some kind of efficiency/performance advantage, but I think I prefer the simplicity of a fixed metering type system. It's unfortunate to hear from other comments that apparently every manufacturer is switching to TXVs now, but I'm sure it's all in the name of meeting EPA fuel economy requirements (or something silly like that). Also, while it obviously didn't turn out in this case, I don't think it was a bad idea for you to give it go (especially after seeing it hold positive pressure). Cutting corners can definitely burn you, but agonizing over things that may not even be an issue can as well (and I'm guilty of both for sure). One final thing, for whatever it's worth, as a non-HVAC guy, I really do enjoy your HVAC videos. I'm not looking for a how-to, I just enjoy the troubleshooting process (even if things don't always go to plan).

[@uxwbill]

Indeed they do. I too appreciate the simplicity of a fixed metering device. As of this writing, there are still some split systems (and even heat pumps) being sold in the US equipped with fixed metering devices. Some can even be used with either type of metering device. Unless things turn political, as they did with 80% efficient furnaces, I suspect the days of fixed orifice metering devices are numbered outside of repair applications.

[@johnmay4803]

in england we dont seem 2 have as much of a problem with mice as you guys have over there! i remember a couple of years ago i went 2 look at a server that a person ad put in there shed and the mice had eaten every bit of insolation off the wires inside it and left there mess! the funny thing was the guy that was selling it still thought it was worth money! the mice mess begs to differ!

[@zachb9011]

very good video uxwbill i see you eventual swaping out the tube and fin for a parallel flow condenser

[@uxwbill]

I don't think anyone makes a better condenser coil for this tractor. Even as much as I like my cold air, I would have my doubts that I'm anything like dedicated enough to find one and "make it work".

[@ihartmacz]

Love it! Thank you

[@KrissBartlett]

looks like big job there Bill

[@Bluethunderboom]

Speaking of the AM radio, does the AM radio work, does your father like using the AM radio while operating the tractor, or does he really need to install FM/AM radio to the tractor?

[@jamesdye4603]

Did fleet work and we had McCormick and Case IH tractors. The whole roof had to come up to do anything with the evaporator core or the fan and fan speed resistor. Total pain in the A. I hate climbing ladders and would rather have to split the tractor and do a clutch than work 12 feet in the air.

[@uxwbill]

This one's no different. It also doesn't help that a conventional ladder can't be placed very close to the cab roof internals with this tractor.

[@erp65]

Guarantee if you turn that AM radio on Paul Harvey's voice will come out.

[@twocvbloke]

Given the ol' meeces did a number with making nests in places you don't want them, it's very likely they've chomped wires going to things like the starter solenoid from the dash, that or made another nest somewhere and, given they pee constantly on everything, left the wiring so corroded it's just a stinky green mess of ex-copper... :S

[@uxwbill]

All the wiring so far has been thankfully un-chewed-upon. The tractor could be started in the proper way until one day when it couldn't. It's believed that there are two starter safety interlock switches, though the schematic we have shows only one for the clutch pedal. That one is good. The other one -- I think it's associated with the PTO engagement control -- cannot be easily seen. Of course, with all the cobbling together of disparate things to make one tractor, a schematic doesn't help too much. It doesn't help that there are various unitized connectors in extremely tight quarters under the dashboard and on the firewall. Some of these have been bypassed, and others are definitely showing their age. I'm not sure why my father decided to invest in such an old tractor. While it runs well and has been put to use in the field, who knows how much longer it will last. Though this part of the world isn't Allis-Chalmers country, these 7000 series tractors just aren't seen here any more.

[@thelazyfishkeeper2730]

hey bill, i am np expert. but i did stay a holiday inn express once.the txv was for a r22 system? i can't recall if it is compatable with the r134a refigerant. will look for any and all updates on this project. . stay well

[@uxwbill]

R-12.

[@JohnSmith-xq1pz]

Imagine the fun you would be having ifmthis tractor was from a brand that doesn't belive in right torepair

[@uxwbill]

I don't know if any recently or currently produced tractor from any manufacturer is any different in that regard. I do know that John Deere is absolutely *terrible* in this regard (also true beyond their tractors and farm implements -- everything's a secret). I think a lot of the reason Deere gets away with it has to do with the name recognition they have compared to every other make.

[@HDXFH]

Thai made compressor, good units

[@uxwbill]

Sanden also has a manufacturing facility here in the US, and this compressor was domestically produced.

[@joyinjection]

If you’ve never seen a TXV in a vehicle go find a Volvo 240.

[@uxwbill]

kzbin.info/www/bejne/rpzTn4pmnrl2j5o ...we never attempted to troubleshoot the A/C system...

[@jcc3279]

Why are you such a jerk bill i mean c'mon now lol i'm kidding hopefully you can get the A/C blowing ice cold in that tractor. That AM radio looks like a older Delco. I wonder how hard it would be to swap it out with another shaft style AM/FM radio.

[@HDXFH]

Most cars use TXVs

[@uxwbill]

Our domestic makes seem to have been notable exceptions for the most part.

[@joeyf504327]

@@uxwbill that changed with r-1234. You'd be hard pressed to find a fixed orifice now. Also, all cars with rear a/c have a TXV for the rear system as the fan can be turned off while the front still runs and demands a/c with no solenoid to stop the refrigerant to the rear a/c. Think Suburbans. They've been that way since the 80s

[@uxwbill]

@@joeyf504327 I've yet to work on an R-1234yf system, and so far I have only been around one. I'd hope that at this time, the majority of them have not yet broken down. My experience with vehicles having rear A/C is also limited to the lone example of the long departed Black Plague Van.