B Hydraulics question
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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=47445
Printed Date: 28 Aug 2025 at 3:06pm
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Topic: B Hydraulics question
Posted By: Charlie175
Subject: B Hydraulics question
Date Posted: 17 Mar 2012 at 2:47pm
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I was out plowing and everything has worked as normal, got to the end of the row and went to raise the plow and it does nothing. I pulled the transmission plug and I have fluid to the rim. I removed the RAM from one of the supports and was able to extend and contract the RAM but with the plow weight on it, it acts like it doesn't have enough fluid to push it out. Any thing you can think of that happened? (And yes I had the PTO in gear!) ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Replies:
Posted By: wfmurray
Date Posted: 17 Mar 2012 at 3:23pm
| Sleeve that holds bypass ball down may have slid up. Plug on top of valve body you can take out and loosen set screw on side and you can drive it down to increase presure. Drive it to much and it will not lower and you have to take pump apart to be able to drive back up. |
Posted By: Charlie175
Date Posted: 17 Mar 2012 at 4:12pm
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Interesting, I'll check it out Thanks! ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: BrettPhillips
Date Posted: 17 Mar 2012 at 11:10pm
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Also a good chance that a piece of dirt got into the relief/lower valve. Also, were you on a hill, pointed downhill? If the original PTO housing gasket has been removed, the oil will run to the front and leave the hydraulic pump with nothing to pump. My C is that way due to my own dumbness, but some day I will replace the gasket with the right one that has the paper dam built in. Brett |
Posted By: Charlie175
Date Posted: 18 Mar 2012 at 8:20am
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Nah, it was flat land.
------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: Charlie175
Date Posted: 18 Mar 2012 at 9:14am
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No joy. Removed the plug and the ball is already at the bottom of the set screw port, I assumed it would be higher for restricted flow? ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: BrettPhillips
Date Posted: 18 Mar 2012 at 9:21am
| Do you get any flow at all with the hose disconnected? If not, you may very well have a stuck plunger(s) or broken springs. From my experience, rust/dirt, springs, and bad check balls are the primary causes of trouble with these pumps. |
Posted By: Charlie175
Date Posted: 18 Mar 2012 at 5:07pm
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Took the unit off, plungers work fine (working them squirted oil out the port), I removed the top Inflow port, spring and ball bearings and they were in good shape. Removed the bottom outflow plugs but didn't take out the bearing or seat. Hosed it out with brake cleaner and mounted it back up. It has more power than before (I can't hold it back) but not enough to lift the plow.
------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: DennisK (/WA)
Date Posted: 18 Mar 2012 at 7:45pm
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Hi Charlie, My suggestion would be to install a pressure gauge at the port the hose is currently hooked to at the pump to see what the pump/valve is actually putting out. It should be around 3200psi. If the pressures are up then you will know your problem is the hose, cylinder or maybe the plow is binding for some reason to where the pump can not over come it. If pressures are down then look for the problem at the pump or blockage of the pickup tube. good luck, my two cents Dennis
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Posted By: Bill Long
Date Posted: 18 Mar 2012 at 9:18pm
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Listen closely to what is said above. All are excellent suggestions. The results to date indicate your pump is working. Check the pressure with a Hyd. Gage. The B pump is very a very simple mechanism and reports show that many are still working well and that some have even been brought back from rusty conditions. Be sure they are cleaned thoroughly since it only takes a little to cause problems. Can't have my favorite not operating well. Good Luck! Bill Long ps: Let us know how it goes. |
Posted By: BrettPhillips
Date Posted: 19 Mar 2012 at 7:33am
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Charlie: After sleeping on this one, I believe WFMURRAY (above) may have it right. On the top of the pump are three ports arranged in a triangle. Two of them are in a line parallel to the centerline of the tractor, these are the pump exhaust valves. The third port is either plugged or used as the outlet to a cylinder or selector valve. Beneath the plug or line connection is the relief valve seat. I would recommend removing the plug or hose/line from the pump and measuring from the top of the pump housing to the top of the relief valve seat. This measurement should be between 9/16" and 5/8". If the seat has slipped as WFMURRAY suggested, this measurement will be off. The location of the seat determines the pump output pressure, and it is held by a press fit in the housing. A hammer and punch are used to drive the seat down into the pump a few thousandths at a time until the outlet pressure reaches 3200 psi. The manual warns not to drive the seat any deeper than 5/8", otherwise the valve may not lower properly and complete disassembly will be required in order to drive the seat back out of the housing. I've never run into a slipped relief seat before, but then I haven't worked on a bunch of these tractors either. Two pumps certainly hasn't made me an expert! Let us know how it works out. |
Posted By: CTuckerNWIL
Date Posted: 19 Mar 2012 at 9:34am
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If I were doing this and found the seat was too high, I would get a piece of round stock that was too big to fit in the hole, turn the end down small enough to drive the seat but only make that diameter 9/16 inch long. You might want to relace the ball and re-seat it while you 're in there.
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: Charlie175
Date Posted: 19 Mar 2012 at 11:15am
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OK, I will measure it and see what I find. I know it is barely above the bottom of the set screw hole. I am still looking for a pressure valve locally. ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: CTuckerNWIL
Date Posted: 19 Mar 2012 at 5:08pm
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20 bucks will by a 5000 psi gauge from Northern. http://www.northerntool.com/shop/tools/product_200322889_200322889" rel="nofollow - http://www.northerntool.com/shop/tools/product_200322889_200322889 When I was working on the Build a B pump, I hooked it up to the porta power at work so I could see what pressure it let off at. ------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: Charlie175
Date Posted: 24 Mar 2012 at 2:51pm
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Issue Resolved! Thanks to all that chipped in to help. I disassembled the pump, removing everything that I could. When I removed the second inflow port with a 5/16x24 bolt a hair ball the size of my thumb nail came out. I continued to take it apart and under the relief valve was another chunk of goo. I cleaned it all out and put it back together. Works real smooth now! ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: CTuckerNWIL
Date Posted: 24 Mar 2012 at 5:56pm
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: BrettPhillips
Date Posted: 24 Mar 2012 at 7:18pm
| Well done Charlie! Now to get that plow to pull easier... |
Posted By: DennisK (/WA)
Date Posted: 24 Mar 2012 at 7:19pm
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Glad you got it going. Thanks for reporting back Dennis
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