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990 Power assisted steering

Posted: Fri Mar 18, 2016 6:37 pm
by huliesm1
Hi all, new to group and have 990 with non-working PAS. No oil leaks in lines or on steering ram. So can this pump be rebuilt? I've read they cannot. Where can I get new parts or kits if available? Any help appreciated. Will try to post pictures of system but i'm not real savy at this. :?:
Sorry, wont allow attachment. Says file to big. Any ideas?

RE: 990 Power assisted steering

Posted: Fri Mar 18, 2016 7:09 pm
by ollek
Leaking hydraulic pumps can be repaired by changing seals. Worn pumps can not be repaired, they have to be changed for new ones. Are you sure it is a PAS and not a hydrostatic (Orbitrol) steering. The following link shows the cylinder in a 990 Implematic tractor with PAS http://partstore.caseih.com/us/parts-se ... 82ar990477 The following link shows a steering ram for a Hydrostatic steering http://partstore.caseih.com/us/parts-se ... 3ar1298840

PAS

Posted: Sat Mar 19, 2016 12:58 pm
by huliesm1
Thanks Ollek; the link 990477 has the same ram but a different pump. My pump has 3 lines from it and the tank is part of the pump. It is gear driven. Is there any way to test pump? the year of my tractor is 1974.

thanks again

RE: PAS

Posted: Sat Mar 19, 2016 2:20 pm
by ollek
I have never heard of a PAS steering with a pump with integrated oil tank. This is the link to that pump http://partstore.caseih.com/us/parts-se ... 6ar1299233 This pump version have never been used in Europe in combination with the PAS cylinder (link 990477) but only with the hydrostatic steering. To my knowledge no tractors have been supplied to Europe with PAS steering after 1970. But there is a possibility that US had their own specifications that was for US only. The combined pump/reservoir has 2 hoses from the pump, the upper one with a 90 degree connector is the pressure line from the pump to the steering valve (Orbitrol) and the bottom one is the return hose. The valve is turned by the steering wheel and the other hose is the return hose. The steering valve is mounted on top of the clutch housing, just under the fuel tank. From the upper part of the oil container you have a smaller diameter plastic pipe and this is the breather for the pump reservoir. The pressure relief valve is a part of the pump rear cover (ref, 9 and 10 in the link). You can disconnect the pressure line from the pump and connect a pressure gauge to the pump. Be careful not to run the engine for longer then it takes to get a pressure reading, as the pump will work against the main relief valve.

PAS

Posted: Sat Mar 19, 2016 3:03 pm
by huliesm1
Thanks, that pump looks like the one on my 995 with hydrostatic steering. It is larger body pump and close configuration to my 990. There is no valve under the steering column. the 2 hard lines appear to go from pump to steering ram. The third line looks like garden hose an i'm unsure where it goes to, possibly to reserve tank, will find out later, tractor is 100 miles away. Sure wish I could get pics to upload, that would be a great help. Will keep trying
THANKS AGAIN

RE: PAS

Posted: Sat Mar 19, 2016 4:47 pm
by ollek
The following is a link to the PAS for Implematic 990 tractors from 1961 to 1965. http://partstore.caseih.com/us/parts-se ... 82ar990477 If this is the pump/reservoir you have, then I think someone has fitted an PAS steering from an old Implematic 990 to your Selectamatic 990 tractor. I also think that this pump is a vane pump made by Houburn/Eaton.

RE: PAS

Posted: Sat Mar 19, 2016 5:45 pm
by huliesm1
Thanks Ollek but that is not the pump I have. I will do more research on what I do have. You may be right n saying it may be a US only fitted pump. How can I find out how to post photos?

RE: PAS

Posted: Sat Mar 19, 2016 9:30 pm
by wheelbarrow
To resize your photos open them in a program called Paint, it's on most Windows computers. Then resize till you find a size the site will accept.
Hope it helps

Posted: Tue Mar 29, 2016 3:09 pm
by huliesm1
Thanks for your help Ollek. Took grill off and found tank for fluid up high and out of sight, put in about 1 quart or so and started tractor up and all works as it should.I assume the PO did not know it was there either. Again, thank you.