450 steering problem

756puller · Dec 18, 2010

i have had two 450s in the last two days blow the gasket out of the behlens steering unit. the way i have the system set up in i took and cut the high pressure tube and plumed in a prince flow contol valve i have the controled flow posr plumbed in to go to the behlens and the excess flow port plumed in to go to the the high pressure line and back to the actual tractor hydrolics, which i would assume that since i am not using the remotes or the safty regulator valve anymore the oil is just dumping back into the sump. i have ran this setup on all of 450s that i have and two have blown up and the other two seem to be working flawlessly for about 3 years now. i did install new hydralic pumps on three of the tractors what could be going on here?
i also have the fitting caped that use to feed the behlens from the tractor hydralics

Wardner · Dec 18, 2010

Some priority valves are adjustable with an adjusting lever but most are fixed. Those that are fixed come in different priority flows. I think the Behlen wants around 3 GPM.

You can check Surplus Center to see all the various priority valves.
Surplus Center hydraulic page.

IH fan · Dec 18, 2010

I'm not familiar with the Behlen unit, but is there a chance you have something [u:6aca1a072a]restricting the return flow[/u:6aca1a072a] from the Behlen unit? From looking at the outside design of the Behlen, I would assume it is a "gear motor" with valving on the "in" shaft from the steering wheel, the "out" shaft being driven by the gear motor to the steering. If it's like most, the return needs to be pretty much free of back pressure to the reservoir.

Owen Aaland · Dec 18, 2010

By cutting into the pressure line from the pump without using the 450 power steering valve you no longer have any pressure relief valve in the steering system. When the pressure builds up under load the weakest point will fail. It sounds like you found the weakest point.

pete 23 · Dec 18, 2010

I see that some of the Prince flow divider valves have a relief valve in them which would divert into the excess flow back to regulator valve at reservoir. Don't know what you have of course. The original flow divider on those tractors have a seperate relief valve for power steering. Don't know if you have original flow divider on yours or not but you indicated that you capped original outlet to power steering. If so, you need to alter that flow divider also other wise you are dead heading flowdiver flow not that it would cause the problem you are having but would strain system. Flow from your flow divider does not go directly to dump it goes through the reglator circuit also. At any rate, pressure to steering has got to be too high and like pointed out, finding weakest link.

450 steering problem

756puller

Member

Wardner

Well-known Member

IH fan

Well-known Member

Owen Aaland

Well-known Member

pete 23

Well-known Member

Similar threads