Power Steering Shuddering Resolved (1 Viewer)

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Joined
May 21, 2019
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Location
Salt Lake City, UT
So wanted to share a resolution to my power steering issue on my 1996 LX450. I'd seen limited info on the forums and none had the solution listed. Try this simple fix before replacing all the power steering system if you have pulsing/shuddering/intermittent in power steering.

Noticeable problem: Intermittent shuddering, sometimes no power steering, sometime power steering works perfectly normal. Return line to the PS pump would pulsate significantly sometimes.
Secondary less noticeable problem: Oil pressure fluctuated quite a bit, even barely hitting the bottom mark while running. Increasing RPM wouldn't move the oil pressure indicator.
Tertiary issue: Excessive squealing of the belts.

Attempted solution: Replaced PS pump, cleaned reservoir filter, checked that all fluids (oil & PS fluid) at proper levels, blead PS fluid multiple times per FSM.

Actual solution: Tighten crankshaft main bolt. The gear on the crankshaft that drives both the oil pump and power steering pump is only pressure fit onto crank and is "squeezed" by force from the main crankshaft bolt against a shoulder on the crankshaft. Since the bolt was loose, the gear could slip and wouldn't rotate - hence not driving either the PS pump or the Oil pump. The shuddering would happen when the gear would intermittently "catch" on the crankshaft and turn. After tightening the crankshaft bolt all three above issues resolved. PS pump being constantly driven so PS works perfect. Oil pressure normal. No squealing on belts anymore. Probably didn't need to even replace the PS pump since it wasn't leaking but at least i have a new OEM PS pump.

Many thanks to George (IYKYK) for solving the issue that four different shops didn't find.
 
The gear on the crankshaft that drives both the oil pump and power steering pump is only pressure fit onto crank and is "squeezed" by force from the main crankshaft bolt against a shoulder on the crankshaft. Since the bolt was loose, the gear could slip and wouldn't rotate - hence not driving either the PS pump or the Oil pump.

Have seen this stated several times. Both gears have a keyway, and are keyed to the crank.
There should be no way for them to slip if the key is in place.
If the crank bolt isn't tightened down, i could see gears possibly vibrating, but not slipping.
 
Respectfully disagree per FSM for my 96. I'm referring to the Pump Drive Shaft Gear in FSM which has no key. The timing gear and pulley are keyed however.
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