Update on 7020
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=114824
Printed Date: 21 May 2025 at 3:54pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Update on 7020
Posted By: joe
Subject: Update on 7020
Date Posted: 17 Nov 2015 at 11:08pm
| Went down and took a look at it. Tach is broken and farmer figures it to be around 4200hrs. Looks really good. Has a factory coolant filter. Runs nice. Shifts nice. 4-5 shifts feels a little soft, but 6-5 shift is good, so I'm not really sure what to think about that. IOS 4-5 normally a really smooth shift? My biggest concern is the clutch. When you press the clutch down, you get a grinding noise/hydraulic whine noise when the pedal is almost out of travel. If you press down all the way, the clutch works, but there is still a hydraulic whine there. When you press on the clutch all the way while driving around in the lot, it stops rather abruptly. Almost like it's a brake. it shift from H to L really nicely as well. One hydraulic lever feels pretty stiff, the other feels really nice. 3pth arms drop without standing on them. Quite different from a 200. Was actually pleasantly surprised at how quiet it was. Comparable to a Deere SGB. Does anyone have any ideas on price? Seems really high at $13,000. I don't feel like you could ever get that back out of it. Thoughts? Tires are maybe 30%, needs a cab kit, radio, tach. It's nice for the age, but by no means is it perfect. Was a PFC hydraulic system standard on these tractors? |
Replies:
Posted By: Orange Blood
Date Posted: 18 Nov 2015 at 5:59am
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It does sound a bit overpriced, based on tires, cab condition, tach not functional, etc. The power shift transmissions in the 70xx series tractors did have a habit of displaying different shift characteristics between different gears. Sames trans, different shift one would be a bit of a neck rock, while the next you wouldn't really feel at all. Nothing greatly exaggerated, but you could tell the difference. When you were pulling under load in the field with the throttle open, it wasn't as noticeable as driving empty around the lot. Now, what you mean by "Soft" could be what I described, or it could mean it slips into gear more than it should. As for the noises and the clutch performance, yes there is a clutch brake, you really shouldn't push the clutch all the way to the floor to stop the tractor in my opinion anyway. The clutch brake should be used to stop the trans from neutral, but the brakes should be used to stop the tractor, again personal preference, but it is far easier to service the brakes than the trans. It is very common to hear a pulsing line pressure, which is a high frequency line vibration when applying the clutch, sometimes they do that just sitting still, but very normal ------------- Still in use: HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060 Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7 |
Posted By: Tbone95
Date Posted: 18 Nov 2015 at 6:33am
| Any weights or duals? $13,000 is way too high I think. Maybe $9000. |
Posted By: Lonn
Date Posted: 18 Nov 2015 at 7:14am
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Around here $9000 would get you one with better tires and cab. Cab is a minor detail IMO and easily redone. I wouldn't worry too much about the hydraulic noise. Could be a line grounding somewhere and they all tend to make a bit of hydraulic noise. All 7000 series, except the 7000 itself, have PFC hydraulics and for it's time I think it was the best set up. The cab is quieter than a Deere SGB. Not by much but it was quieter. BTW When corn was $8 then $13,000 was more common. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: Dmpaul89
Date Posted: 18 Nov 2015 at 8:56am
| Too much. Thats tractor house pricing. Offer 7500 mailto:%20" rel="nofollow - |
Posted By: tornado8070
Date Posted: 18 Nov 2015 at 9:06am
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I agree with orange blood. Pretty much everything you describe seems fairly normal to me. Imo $8000-9500 should fetch it. As Lonn said corn isn't $8! ------------- 09’ DT205B, 08’ DT220A, 83' 8070 MFWD, 83’ 8070 85’ 8050 MFWD, 83' 8030, 82' 8010, 85’ 6080 MFWD, 84’ 6080, 79' 7020, 85' M3 RWD, 85' 920 diesel,AC C-50 forklift. |
Posted By: WC7610
Date Posted: 18 Nov 2015 at 5:31pm
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is your $13,000 CAD$ or USD$? quite a difference. $13k CAD should be around $9700 USD, so an offer around 8500 should be fair if thats the case. At worst, take the asking price and back off new tires and cab kit. ------------- Thanks Most Bad Government has grown out of Too Much Government- Thomas Jefferson |
Posted By: Joe(TX)
Date Posted: 18 Nov 2015 at 8:02pm
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What do you mean when you say PFC hydraulic system? The hydraulics are closed center load sensing. ------------- 1970 190XT, 1973 200, 1962 D-19 Diesel, 1979 7010, 1957 WD45, 1950 WD, 1961 D17, Speed Patrol, D14, All crop 66 big bin, 180 diesel, 1970 170 diesel, FP80 forklift. Gleaner A |
Posted By: skateboarder68
Date Posted: 18 Nov 2015 at 8:12pm
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Pressure & flow compensating ------------- Orange & Silver still earnin their keep on the farm: R62, Series IV D17 nf, 185, 6080, 6080 fwa, 220, 1968 D21, 7045, DT240. |
Posted By: Lonn
Date Posted: 19 Nov 2015 at 6:36am
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PFC is more than just closed center. PFC senses pressure and flow while closed center just senses flow and open senses pressure. PFC is the best of both worlds and the 7030/7050 were the first tractors to implement it as far as I know. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: DrAllis
Date Posted: 19 Nov 2015 at 11:01am
| Correct !!! Allis-Chalmers pioneered "pressure and flow compensated" hydraulics in the 7030-7050. It took John Deere until their 7000 series about 20 years later to offer it on their tractor line. |
Posted By: Joe(TX)
Date Posted: 19 Nov 2015 at 9:51pm
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Not Correct. To an engineer like myself, PFC is meaningless and a misunderstanding of how the system operates. There is no such thing. The pumps have a pressure compensator that senses the pressure and adjusts the flow to maintain that pressure. There is not a flow compensator. Closed Center Hydraulics are always pressure compensated. The 7000 series pumps go one step further in that they have load sensing to allow them to be at low pressure when flow is not needed. ------------- 1970 190XT, 1973 200, 1962 D-19 Diesel, 1979 7010, 1957 WD45, 1950 WD, 1961 D17, Speed Patrol, D14, All crop 66 big bin, 180 diesel, 1970 170 diesel, FP80 forklift. Gleaner A |
Posted By: joe
Date Posted: 19 Nov 2015 at 10:10pm
| So just wondering if pressing the clutch down all the way is supposed to bring the tractor to a quick stop. It vary much acts as a brake. That is my biggest concern with this tractor at this point. Thank you for all the replies and expertise. |
Posted By: Orange Blood
Date Posted: 20 Nov 2015 at 6:15am
Yes, that is the clutch brake I was referring to. There is a hydraulically actuated transmission brake that is triggered by the last small bit of travel of the clutch control valve spool. If the transmission is in any gear, and the two speed range transmission is in either high or low, the tractor should stop moving very quickly, as if you had your right foot on the brake pedals. ------------- Still in use: HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060 Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7 |
joe wrote:Posted By: Lonn
Date Posted: 20 Nov 2015 at 6:26am
------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: Tbone95
Date Posted: 20 Nov 2015 at 7:02am
Wow. No response yet? 
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Posted By: joe
Date Posted: 20 Nov 2015 at 8:16am
| No disrespect intended, but it's been known as PFC for the last 40 years. It is pressure AND flow compensated. It doesn't say how it achieves it, and for the sake of argument, it doesn't really matter. It makes only the pressure necessary, and only flows what is necessary. |
Posted By: Lonn
Date Posted: 20 Nov 2015 at 9:22am
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Now we're splitting hairs ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: DrAllis
Date Posted: 20 Nov 2015 at 9:51am
| It was an important milestone in Farm Tractor hydraulic engineering, and Allis-Chalmers pioneered it in 1973. I believe Case was next, then maybe IH and on down the line with Deere 20 yrs later. I believe Caterpillar was the first to use it before A-C did. |
Posted By: joe
Date Posted: 21 Nov 2015 at 2:15pm
| I was talking to the former owner of this trator, and he said he was told he could adjsut the aggressiveness of the transmission brake. How would this be done and to what extent does it help. Could you eliminate the transmission brake, or lessen it enough that it would still allow H and L to shift. |
Posted By: Lonn
Date Posted: 21 Nov 2015 at 4:37pm
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Just don't push the clutch pedal all the way to the floor. Push far enough to stop the tractor as a normal clutch would do. The last inch or so of pedal travel activates the transmission brake for shifting. The operator's manual will explain how the tractor should be operated. Eliminating it or lessening it would probably make it very hard to shift. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: joe
Date Posted: 21 Nov 2015 at 6:17pm
| According to him, and my test drive, it will not stop fully if you don't push it(the clutch) down all the way. If I bought it, I'd like it to be able to stop without the transmission brake being activated. I can certainly see a use for it, but it's so aggressive right now. Is there a way to adjust it, (the clutch) so the clutch would stop the tractor by letting it coast to a stop(like most clutches), but maintain the aggressiveness of the transmission brake when the clutch is pressed fully. |
Posted By: Orange Blood
Date Posted: 21 Nov 2015 at 8:16pm
I don't mean to be disrespectful, but if the clutch is adjusted properly, which it sounds like it is, then no there is no adjustment to make it only partially come on, unless you mess with the cable to make it "Out of adjustment" The proper way to not have the brake come on is just as Lonn said, simply don't depress the clutch that last inch of travel, and you are golden. Now if for some reason, your brake is coming on PRIOR to the last inch of travel or so, then yes there may be a problem with the cable being too tight, and that can be adjusted. ------------- Still in use: HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060 Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7 |
Posted By: joe
Date Posted: 21 Nov 2015 at 9:14pm
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I don't think I explained it well enough. The brake only comes on in the last inch oftravel(give or take a bit), BUT, that tractor WILL keep moving if you don't press the clutch down all the way. IE. If you pressed the clutch in all but that final inch, it will continue to move under it's own power(it would go uphill). Don't know what would happen if there was a load on it) The only way to get the tractor to stop moving is to press it in all the way, which turns the brake on. What I'm wondering is: is there a way to have that clutch set up that the tractor would coast to a stop with the clutch pressed in all but that final inch, and once pressed in that final inch, the brake would come on? I really do understand that that brake function is perfectly normal, I just don't like that to stop the tractor, you HAVE to use the brake function, or it won't stop. I really don't want to start ticking anyone off. I genuinely want to understand this. The way it is, it just bugs me that I'm wearing out very expensive(if not obsolete) PS friction discs. I absolutely see the value in it, I just don't want to be jamming it in 2 gears in order to slow down from 7mph.
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Posted By: critter
Date Posted: 22 Nov 2015 at 6:41am
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Was the tractor good and warm when you test drove it? It sounds like the tractor wants to creep it will be worse when cold but should be less noticeable when warmed up. You say the clutch brake was the only way to stop the tractor did you try the regular brakes? They should have no problem stopping you. |
Posted By: DrAllis
Date Posted: 22 Nov 2015 at 7:06am
| Cold transmission oil (under 120 degrees F)and higher engine speeds are all that's going on here. You depress the "inching pedal" (it's not a clutch pedal) just down to the brake zone and use the wheel brakes to stop the forward motion of the tractor. If you have the engine revved up with cold oil, it takes more time to release and more wheel brakes for the oil to release. Going down farther into the brake zone applies the reverse clutch pack and a forward clutch to stop everything, which you want to avoid. That's why the pedal is set-up like that.....down to the beginning of the brake zone to stop and down even more ( higher spring pressure) gets you into the transmission brake zone. It is adjustable for when you just get to it....that is all. Next time you drive it, shift the range lever into LOW range and have the Power Shift in neutral. Leave your inching pedal up. Run the engine wide open throttle and see how the tractor wants to pull itself around....this is the cold lube oil flinging out between all the clutch discs/plates wanting to drag the tractor along. When the oil is really at operating temps, this pretty much goes away. |
Posted By: wekracer
Date Posted: 22 Nov 2015 at 8:30am
| As doc said. If you work the clutch pedal with the engine off you will notice a heavier spring in the last little bit of pedal travel. This is the brake zone. It's a two stage clutch pedal of sorts. And it should coast to a stop like a normal clutch without getting into the trans brake with warm oil. |
Posted By: tbran
Date Posted: 22 Nov 2015 at 3:16pm
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there is a pesky little snap ring on the spool for the trans brake in the inching spool. 70923837. Unfortunate that pops off, but it does or breaks off. When missing , the trans brake will not apply - PS units here. Also if one orders a valve to put a loader on these units as well as other brands, the valve is called a Pressure Compensated Valve.. ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |