Power Steering issue
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=204764
Printed Date: 01 Feb 2025 at 11:34pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Power Steering issue
Posted By: jpi72
Subject: Power Steering issue
Date Posted: 31 Dec 2024 at 6:21am
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I own an Allis Chalmer forklift (621?). We are having issue with the power steering when we start in the morning, especially when it is cold. The steering does not work for a while. After a few minutes it does work. This forklift has a lot of d15 parts. My son thinks it is a relief valve issue. Do you have any suggestions? The hydraulic lift works fine when the power steering does not work. Joel
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Replies:
Posted By: DrAllis
Date Posted: 31 Dec 2024 at 9:48am
| NOT a relief valve issue. The hydraulic/power steering pump is losing its prime when sitting for extended periods of time. Cold weather makes it worse. Do the other hydraulic functions work when the steering doesn't ??? I would bet they are dead too. Is the hydraulic tank FULL ?? Is there a suction filter in the hydraulic tank ?? I still think you have a "worn out pump" scenario. |
Posted By: ekjdm14
Date Posted: 31 Dec 2024 at 11:23am
I'd agree it's not going to be a relief valve, but assuming the other hydraulics are working when steering is dead then it's surely less likely to be an issue with losing prime?
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DrAllis wrote:Posted By: DrAllis
Date Posted: 31 Dec 2024 at 12:26pm
| I know nothing about its system. There could be a pump just dedicated for steering and another for implement function. Either way, it sounds like it loses prime. I see an internet picture of the right side of the engine and there isn't a typical power steering pump that is gear driven on the engine. If your lift works fine, I still think it's a loss of prime to a pump dedicated to the power steering, which might be belt driven ?? |
Posted By: Coke-in-MN
Date Posted: 28 Jan 2025 at 10:59pm
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Is the steering fully hydraulic , or is there a mechanical link from wheel to tires ? If fully hyd then suspect the unit attached to steering wheel valve body as part of problem . On my TLB it's fully hydraulic with only a slave cylinder attached to the tie-rod under tractor , ------------- Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something. "Challenges are what make life interesting; overcoming them is what makes life meaningful." |
Posted By: jpi72
Date Posted: 29 Jan 2025 at 6:10am
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The steering is fully hydraulic. As of now we do not suscept the pump. The forklift has one pump, and it feeds two systems. One system is the mast, and the other is the steering. What is a TLB? We blew a head gasket and expect the head back this week. Hopefully soon it will be fixed. Joel
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Posted By: DiyDave
Date Posted: 29 Jan 2025 at 3:08pm
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tractor loader backhoe... ------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |
Posted By: orangeman
Date Posted: 29 Jan 2025 at 7:49pm
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jpi72 - can you post a picture of the 621 that you are working on? AC released and revised the 21' lift on a reversed D15 Farm Tractor, they also released and revised over time their 21' lift offering including an I- 60 with a 21' lift, and I-600 with a 21' lift and a later model referred to as a 621. AC Form TPL-554 is the Parts List for the Industrial 60, and Industrial 600 Fork lifts. It would be helpful to have that as a reference. The steering cylinder attached to the axle used on the I-621 forklift has a supply and return line connected to an orbital motor or as AC refers to it a (power steering control valve) located at the bottom of the steering shaft. Without being able to see the unit I would guess that the return and supply lines could be leaking enough and possibly have leaked enough so that you have no remaining pressure to move the steering cylinder. What does fresh cardboard show when you leave it overnight underneath the steering shaft and the steering cylinder - any leakage? What are the ambient temperatures where the unit is stored or parked? Is it freezing - I would guess also if the system has not been drained and refreshed that there is moisture in the system and perhaps has frozen and has turned to ice. If hydraulic supply is low you might not be making the necessary pressure to move the cylinder to allow "power steering" to work at all or even partially. Also, if you have access, to the supply line you could plumb a T into the supply line and hook a pressure gauge into it to see what pressure you are carrying. Will check my AC library to see if I can find a pressure criteria for the 621 steering cylinder. HTH's ~ Orangeman
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Posted By: jpi72
Date Posted: 30 Jan 2025 at 8:51am
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Last summer I drained the hydraulic system and added new oil. The oil is not milky, so I doubt it is a moisture problem. I will put a cardboard under it when we get it running. You make a good suggestion that we have a leak in one of the lines. The problem seems to be worse in the wintertime. It usually happens the first start of the day and rarely after that during usage. I will try to reply when we get it running again. Waiting for the head to return from the machine shop. I will try to post a photo. It is a 160 cu. inch engine. Joel
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Posted By: orangeman
Date Posted: 30 Jan 2025 at 6:36pm
On some of the I - 621 forklifts there is a rectangular piece of sheet metal cowling that covers up the hydraulic supply lines that lead to the dash mounted hydraulic controls. That said, I have personally experienced a situation where it appeared that a lot of grass and pine needles were coming out of that same rectangular box. Yes, I had the unit outside, it was late fall and going into an Indian Summer. Upon inspection I found a red squirrels nest tucked up inside as they were preparing for the long winter. That said I was fortunate enough to catch their progress in time that none of the hydraulic two wire hoses had suffered any rodent damage. I sprayed the compartment down with cosmoline and white lithium grease and so far no rodents have chosen to use that compartment as a home. If memory serves the orbital motor at the bottom of the steering shaft lies in the same compartment and would allow inspection of the hoses leading from it to the axle steering cylinder. In looking back on this I got very lucky that no damage had occurred, and as Yosemite Sam would say "From those Pesky Varmints"! 
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Posted By: jpi72
Date Posted: 30 Jan 2025 at 7:22pm
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Thanks for the life lesson learned by experience. I will check it out. Joel
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Posted By: Gary
Date Posted: 30 Jan 2025 at 8:21pm
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Link to a picture for reference only: Built 1970 to 75, 160 Gas Engine https://www.mecum.com/lots/301717/1973-allis-chalmers-621-forklift/" rel="nofollow - https://www.mecum.com/lots/301717/1973-allis-chalmers-621-forklift/ |
Posted By: jpi72
Date Posted: 30 Jan 2025 at 8:37pm
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That looks like mine. Joel
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Posted By: jpi72
Date Posted: 30 Jan 2025 at 8:38pm
| What price did it sell for? |