How to bleed hydraulics
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=199070
Printed Date: 13 Nov 2024 at 4:03pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: How to bleed hydraulics
Posted By: MadCow
Subject: How to bleed hydraulics
Date Posted: 05 Jan 2024 at 9:56pm
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Just did some hydraulic work. I had tried lifting a bale on a spear dangling off the loader this fall, and it wouldn't budge. A heaping load of snow would bog the loader. So I got a gauge, and after doing my work, tested it. Was about 1000psi going up, hit 2000-2100 at peak. Then quickly dropped to 1000. Think there might be air in the lines after doing my work. Does anybody know how to bleed air out of these? If it'll help with my issue? Read somewhere else it might be stuck pump? Any idea how to unstick it? Anything I can do without pulling and rebuilding the pump I want to try first. Not sure how long the tractor sat before I started using it. But I've put it through the paces since July, so it should be worked well. |
Replies:
Posted By: AC WD45
Date Posted: 05 Jan 2024 at 10:22pm
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Not sure what tractor you are working with, but a lot of these systems will bleed off on their own when you cycle them a few times. Extend all cylinders as far as they'll go, top off your fluid and then cycle it several times over. Check fluid with rams extended and fluid warm. You'll probably need to add. ------------- German Shepherd dad 1957 Allis Chalmers WD45 #WD234847 1951 Allis Chalmers WD #WD88193 |
Posted By: steve(ill)
Date Posted: 05 Jan 2024 at 10:31pm
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Was about 1000psi going up, hit 2000-2100 at peak. Then quickly dropped to 1000. I think this is the D15 tractor.... You should have around 3200 psi i think. That is what the B -C- WD pumps put out.. HIGH PRESSURE, LOW FLOW... I "THINK" the D15 is similar.....Your guage should be working right.. but you could take the hose off to the cylinder and put the gauge ON the valve and dead head it... Should hit the PEAK PSI as it goes over relief. ------------- Like them all, but love the "B"s. |
Posted By: steve(ill)
Date Posted: 05 Jan 2024 at 10:34pm
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might check LINKAGE ??? ... read here https://www.allischalmers.com/forum/d15-series-2-hydraulics_topic156475.html" rel="nofollow - https://www.allischalmers.com/forum/d15-series-2-hydraulics_topic156475.html ------------- Like them all, but love the "B"s. |
Posted By: steve(ill)
Date Posted: 05 Jan 2024 at 10:37pm
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I know this is not exactly your problem... but some things to CHECK prior to pump work... mostly linkage movement.. https://www.allischalmers.com/forum/d15-hydraulic-problem_topic124740.html" rel="nofollow - https://www.allischalmers.com/forum/d15-hydraulic-problem_topic124740.html ------------- Like them all, but love the "B"s. |
Posted By: Tbone95
Date Posted: 06 Jan 2024 at 6:57am
Dang, that blue text is next to impossible to read on a phone! Gotta hit quote just to make it easier! 
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steve(ill) wrote:Posted By: Jim.ME
Date Posted: 06 Jan 2024 at 6:59am
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It helps to have all the info. The answer to my questions may be here, but I don't see them, and I think the answers could lead to different responses. You are dealing with a loader issue, not the rockshaft hydraulics, is that correct? What loader? Single or double acting cylinders? Loader control valve? Do the hydraulics for this loader come from the tractor's internal (high pressure, low flow) hydraulic system or a separate pump driven from the crankshaft (lower pressure, higher flow)? 2000 -2100 psi sounds about right for the hydraulic system using a crank driven pump. Edit: I have since seen your previous posts. It appears you are using the internal hydraulics, so the 2000 -2100 psi is low. Does the loader have single acting lift cylinders, controlled by the tractor's hydraulic lever (not feeding a separate loader valve) and trip dump?
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Posted By: MadCow
Date Posted: 06 Jan 2024 at 9:45am
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Apologies for not putting all the info in. It is a D15 Series 1. I am using the internal pump. Trip bucket loader taking fluid from the line going into the remote block on top of the lift arms under the seat. Tested the pressure using a gauge plugged into the remote. The low lift power on the loader is what keyed me into the issue. The tractor hydraulics to to a selector valve, out of the valve into the remote. The loader is hooked to the selector valve. I'm about 99% sure the lift/lower is adjusted right in the center. However, using the detents is slow up or slow down. In order up get full speed I need to go passed the detents. This seems to jive with how the manual says it should be. But I would feel more confident if the "swing" between the two was shorter. I didn't think about adjusting the lever to check pressure. But in my mind that would only effect speed/flow, not pressure. |
Posted By: Ted J
Date Posted: 07 Jan 2024 at 12:57am
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Sounds like you have some hold valve problems. You are probably getting leak-by around the balls in the pump. Keep the thread going as there are a LOT of guys smarter than me who will chime in. It is a constant problem with these old pumps. ------------- "Allis-Express" 19?? WC / 1941 C / 1952 CA / 1956 WD45 / 1957 WD45 / 1958 D-17 |
Posted By: DrAllis
Date Posted: 07 Jan 2024 at 7:25am
| On the older D-series, the "HOLD" range is quite wide. There isn't a "detent" like a WD/WD45. If you release the lever anywhere in the middle of the range, it is automatically in HOLD. To lower (depending on how you adjusted the lowering screw) you have to go below horizontal in the lower window. Fully RAISE should be when locked in the upper window. |
Posted By: MadCow
Date Posted: 07 Jan 2024 at 6:07pm
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Adjusted the lever all the way the one direction so the arms started raising before even hitting the top detent. Still only about 1000 going up, and 2000 at peak. I was able to "pump" it, like relaxing the lever, pushing up, relaxing, pushing up, and could get up about 2200-2400. Is there another adjustment I'm missing? Also, about three weeks ago, I did drain and refill the hydraulics with new fluid, about a quart or two of water came out... So it's highly likely there's some rust somewhere in there, dunno if that means somethings rusted closed, though. |
Posted By: DrAllis
Date Posted: 07 Jan 2024 at 6:10pm
| Sounds like a tired pump as the max pressure should hit over 3,000 psi like 3400-3700 psi top spec. Nothing can be done externally and if it lifts what you want it to lift, keep using it as-is. |
Posted By: MadCow
Date Posted: 07 Jan 2024 at 8:11pm
Dang. Was hoping you wouldn't say that. I might have some cylinders I can replace on my loader so I can actually pick up bales. But it's jjuuusssttt fast enough I don't complain. Don't really want to make it slower. Don't need to split the tractor to do anything on the pump do you? |
Posted By: Codger
Date Posted: 07 Jan 2024 at 8:26pm
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Are the hydraulics quiet when you see maximum pressure or is the system squealing loudly? Seen many a relief valve spring break from fatigue and the pump be fine after this is replaced and system calibrated properly. Got an Acura MDX in the shop now brought in after the dealer said pump was bad. Gauges prove otherwise and the steering rack is defective. Water coming out is not good any way it's looked at and you probably have a worn out pump but still worth checking over.
------------- A career built on repairing and improving engineering design deficiencies, shortcomings, and failures over 50 years now. |
Posted By: DiyDave
Date Posted: 07 Jan 2024 at 8:34pm
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You can drop the pump without splitting, but that brings up another situation. I'd drop the pan, and look in the bottom, to see if you have any parts down there. This is a cam driven 4? piston pump, has rollers that follow a short cam shaft. If any of the rollers lock up, or have damage, they will, in turn damage the cam, and to replace that, then you have to do a split, IIRR. Like the doc says, leave it alone, if you can live with the speed and pressure you have... ------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |
Posted By: MadCow
Date Posted: 08 Jan 2024 at 6:19pm
It doesn't squeal when up. It rattles like a maraca on the way up. But once it's up it goes mostly quiet.
Anywhere we can get parts for this? The pump rebuild kits I see are >$250, and it looks like seals and gaskets, no pistons or cylinders sleeves (if there are sleeves). Same - if the cam is bad.
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Posted By: steve(ill)
Date Posted: 08 Jan 2024 at 6:22pm
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normally you can disassemble, clean and adjust the pressure... Might need a couple o-rings, but surely not $250. kit.. "B" tractor is about half that size (pump), but same design.. I have done several of them over the past 20 years with zero parts. ------------- Like them all, but love the "B"s. |
Posted By: Codger
Date Posted: 08 Jan 2024 at 6:59pm
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That "rattling" is cavitation of the fluid. Change this first before any effective troubleshooting can take place.
------------- A career built on repairing and improving engineering design deficiencies, shortcomings, and failures over 50 years now. |
Posted By: DrAllis
Date Posted: 08 Jan 2024 at 8:08pm
| Those tractors were a piston pump and they did have a rattling sound of their own. With warm hyd oil and engine throttled up the lift arms (unloaded) should fully raise in less than 3 seconds bottom to top. Just because the 3 second speed may be there, doesn't mean the unloader valve is at its lifting pressure spec. |
Posted By: MadCow
Date Posted: 17 Jan 2024 at 8:47pm
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Forgot to thank you, Doc. It'll last me this winter. But if she gets a break this summer I'll take it apart and put it back together and see if that helps. Thanks for sharing your knowledge! |
Posted By: WF owner
Date Posted: 18 Jan 2024 at 6:55am
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I don't know how similar the D-15 is to a D-17. I had a similar problem with one of my D-17 (Series 1) that I bought at an estate auction. on the snap coupler lift arms. It would take close to a minute to fully lift the hydraulic arms. I dropped the hydraulic pump (very easily) and made a list of the parts I thought needed to be replaced, only to find that several parts are no longer available. I ended up buying a used (salvaged) pump from a D-14, which is the same. I learned a lot of new words getting that pump in place. I have a 9000 lb. four post car lift and had the tractor up in the air. I can't imagine how to get the pump in laying on your back. If you find something wrong with your pump, make sure you can get all the parts before you order anything! Good luck!
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Posted By: DrAllis
Date Posted: 18 Jan 2024 at 7:23am
| Generally, springs and balls and Orings and a couple of gaskets are all that is needed and they ARE available from AGCO. |