Ford 8340 Sle from Greece

[Giannis Patsalis]

Hello there and greetings from Greece..Iam writing here because I desperate need some help for my father ford 8340 SLE and disappointedly here in Greece nobody know professionally to reply or fix these one..The problem is with the ccl steering pump.suddenly we lost power steering and we send the hole pump for rebuild we found some o-rings broken and we replace them..after we put the pump in the tractor it worked ok and after 1-2 hours of ploughing we lost again the power steering. We detach for second time this pump and this time we find damaged seals and a broken aluminium plate on the steering pump. The repair shop manages to fix it again with new sales and machine the broken piece and fix it. We put again the pump on the tractor and tank also also some other parts because we want to find what causes the broken seals. We checked the steering motor relief valve. It was adjusted a little higher at 220bar we set it again on 190 as the manual says and put again on the tractor the pump. We thought that this was the problem the relief valve of the steering motor and this caused over pressure of the steering pump and broken seals and aluminium plate the second time.. now we put again the steering pump on the tractor and we measure the pressures on the return oil after the bypass cooler valve it is around seven bars on full throttle with cold tractor and end the pump on the front steering system is around 175 bar when you lock the steering completely left. The pressures seems right as the manual described.. now the problem is that when the tractor gets hot, they return pressure that also goes to the transmission lubrication and PTO lube falls to 5 bars. Sometimes they steering pressure light turn on and the steering is a little bit heavier on idle. I also checked the bypass cooler valve and the oil cooler my though is that the steering pump loses pressure due worn internals when the oil gets hot.. what’s your thoughts on this problem? What’s the correct pressure readings of the return line?is the 5 bars low?the front steering goes to 155bar with hot oil..is it low?
Thanks a lot, everyone I didn’t know where else to write this problem

 

[bobk]

@forblue @agrimax

 

[forblue]

Max steering pressure at ram 172b at 1000 rpm, l/p checked at switch on ccls pump 17-19bar, if ok when cold but not hot then yes pump is worn, when pump was dismantled housing should have been checked for wear. have you also done a flow and pressure check of main ccls pump.

 

[Giannis Patsalis]

Yeah in the ram with engine cold is 170-175 with hot drops around 150 steering ok but on the idle and when release the clutch the steering oil light comes on for a while..Iam afraid that the repair of the steering pump plate maybe looses some pressure when hot.you will notice the attached photos..we make a new bronze bushing on the plate to hold the seal because the aluminium broke.ccs pump seems good also the low pressure pump the one that goes to the pto valves is 18bar..the on I notice today was that the oil cooler return line was cold and the feed line extreme hot..so tomorrow I will check the cooler for blockage..when the pump was open the engineer said it has a normal wear for 10k hours.the other think that I notice it was that the first time I open the bottom bolt cap of the bypass cooler valve the spring and ball and the inside nut was loose and fall of immediately..after reassembly I screw it inside and and then put the cap bolt..maybe with blocked oil cooler (I will check tomorrow if it is)the blow relief valve 7 bar on the bypass valve didn’t work that’s why broke seals 2 times the steering pump..don’t know just making theories..one mechanic suggested thicker oil to rise the pressure of a worn pump but that’s old school stuff and I don’t like it..who knows..

 

[forblue]

It will make no difference if cooler blocked to pump seals as cooler only works after oil is hot, i have been out to a tractor on a de-stoner that the red light was on because the oil was way too hot but steering still worked ok seals can blow due to a pump being on max pressure all of the time or wear in pump, i have just done a main hyd pump on a 7710 that had blown both end seals never seen that before but it was on a straw chopper and max lift pressure all the time, if you could get a cheap used but good engine mounted hyd pump as fitted to dual power tractors this could be piped into the lube pipe to transm but that would not increase the steering pressure when hot or feed it to pipe that supply's the steering from ccls pump the pump is 3l less output but that not much different, return oil from original supply from steering pump to rear axle bar is higher but steering motor prv would be able to take care of that, pipework would have to be made up and if it worked ok fit another suction filter, oil pick-up taken from the round plate on left of rear axle, i did this many years ago on a 7740 which had l/p light on when feathering clutch pedal all done under warranty but it was still the same as this is slightly different in your problem it could work and be cheaper than new ccls pump but thats your choice.

 

[Giannis Patsalis]

Today I disassembly the cooler bypass valve and find that the thermostat didn’t work so the oil cooler wasn’t clogged but the bypass valve was Open all the time and didn’t use the oil cooler..until I search for a new thermostat I delete it and use the oil cooler all the time from cold till warm oil..after doing that the back pressure on the return line rised and I have 10-12 bars between oil cooler and steering motor return line..the oil goes directly to the cooler.i didn’t delete the spring ball high pressure relief valve on the bypass valve so if the cooler gets clogged it will bypass it but I delete the thermostat..

 

[forblue]

Should only be 7bar, the thermostat is there as you say to heat up oil, in very cold weather unless the tractor is being used hard the oil may not reach normal temperature.

 

[Giannis Patsalis]

Should only be 7bar, the thermostat is there as you say to heat up oil, in very cold weather unless the tractor is being used hard the oil may not reach normal temperature.

Yeah I will try to find thermostat or the whole bypass valve to ensure that it works okk