How, or can you adjust the power steering PSI on a tractor?
Submitted: Saturday, Jun 19, 2010 at 19:13
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Member - G N (VIC)
Hi All
WE have a 45-66 fiat which is bending the drag link which connects the two front wheels for steering as there is only a ram on one side.
I think that the PSI getting to the ram is too high, as the ram would normaly have some travel left when the wheels hit the stoppers as they are adjustable.
The other reason i suspect too high pressure is that this tractor labours much more than others of the same make / model when the steering is on full lock.
My question is, HOW can i adjust the PSI?, the only component that has any possibility of adjustment, i think, is the unit that sits under the steering wheel, but doe they have adjustment or is it a factory settting?
I think this unit may of been replaced by after market part at some point, Hmmmmmmmm
I amsure there is a machanic or two on here.
Bit off topic i guess, but there was a tractor run accross the country a couple of years ago, so bit relivant!
Regards
GN
Reply By: burnsy - Sunday, Jun 20, 2010 at 17:37
Sunday, Jun 20, 2010 at 17:37
I'm not familiar with Fiat power steer systems. Having said that I think you will have a external gear pump with what is called a priority head bolted to the end of it There should be one or two plugs in this head. If you have two one will be the relief valve and the other will be the flow control which as said earlier has a orifice which through that and a spool ensures that the steering receives the same amount of oil at idle as it does at full idle.
If you have only one than both flow and pressure is incorporated into the same spool.
Either way you probably have to remove shims which will be under a stiff spring and not a weak spring which may
well be in there too The pressure should be somewhere between 1200 and 1500psi. Usually people complain about too little pressure.
If your tractor has non of this than please forgive me and go looking in the steering box instead.
Regards Mike.
AnswerID:
421564
Follow Up By: Member - G N (VIC) - Monday, Jun 21, 2010 at 09:55
Monday, Jun 21, 2010 at 09:55
Hi Mike
Thanks for info.
I agree with what you are saying and on a larger tractor the pump does have an added section which i assume houses a relief etc.
However i found a danfoss orbital unit diagram on the net which showed it had an adjustable relief valve built in. Then i looked on the orbitalunit on the tractor with issues, NO relief! Then i looked at another tractor same model as one with issues and YES it has a releif on the orbital unit.
I know the tractor with issues has an after market orbital unit fitted, which i belief is the wrong unit for a tractor that does not have the reliefs set up at the pump and this is where all the problem is originating.
I was going to pressure
test the lines yesterday but they are some metric type thread, but think i will find in town, just want to prove the PSI is too high before i go any further.
Does what i recon make sense?
Regards
GN
FollowupID:
692019
Follow Up By: burnsy - Monday, Jun 21, 2010 at 19:27
Monday, Jun 21, 2010 at 19:27
Hi GN
Sounds good .
In case you don't already know when you
test for pressure you Tee the gauge into the line.
It is HIGHLY unusual not to have any sort of relief in a hydraulic system as when the pump is in good condition it will continue to pump oil until something gives. At best a fitting or hose or at worst the pump ect.
Remember a pump pumps oil not pressure, Pressure only is present when there is a resistance to flow
You may be lucky enough for the pump to be somewhat worn in which case it will bypass internally.
If you still can't find some sort of relief take a trip to your local hydraulics
shop and I'm sure they will sort it out.
Regards
Mike
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