tkacki

Hi,

I have just installed my PS system (rack, rods, pump, lines, etc.). I have bleeded the system and started to use it. I have a strange effect: PS works only when car is not used for few hours. I feel the power on steering wheel only for 5 min. after car is started, then the power decreases slowly to zero. If car is stoped it requires huge force to turn the wheel. Stop / start of the engine does not help. And again....this morning it worked well for few min. I have checked the belt tension - OK. System has zero leaks. I have loosen the nut on high preassure line to see if pump pumps. It does - nice high preasure spary of ATF. ATF remains unchanged - I did 200 km with new rack.

WTF ?

Travis - sflraver

You have one of the following:

Leak in the pickup line from the reservoir to the pump. Not leaking ATF out, but air in. This will cause a foam to build up through the system that should be evident by removing the cap to the reservoir.

One or both of the high pressure relief valves are sticking in the open position inside the rack. This will let all of the fluid pressure bypass the rack and go directly back to the tank.
It is not usual to see one stick but what does happen, in racks that have been run low on fluid for long periods of time, is the internal springs will brake. This is caused by the cavitation of air in the ATF as it moves through the small pressure relief valve opening and onto the spring. That nasty "I need more fluid" grown is really your pressure relief valve springs screaming at you for help.

tkacki

Thaks for Your answer.

No foam in the tank. Oil clear, like new.
So.....the rack is gone ? Not a good news .

Travis - sflraver

I wouldn't say the rack is gone.... it can be fixed if you are willing to pull it apart. Thats up to you though. It could also be a few of the band seals in the racks gear unit giving way and letting fluid bypass. Based on what you posted, beyond those two, there is not much else that can be wrong.

austin944

You might check for a collapsed or pinched/crushed hose from the PS reservoir to the pump. Not sure this would really cause the behavior you're seeing but it's a simple check. Had this happen on another car where the steering effort would seemingly change at random.

shortyboy

i got a good used power steering rack if needed.

tkacki

Hi,

I have found the cause of problem (hope it's the cause not a side effect). The pump ! Pump's rod internal circlip snaped and pump's pulley with rod moved forward which resulted in dis-engage the internal rotor. I need to dismanltle the pump and replace the circlip with new one.

Will let You know abot the results.