Porsche Repair: pulley system 1987 924s, automatic transmission fluid, crank pulley


Question
how is the power steering pulley attached to the crank pulley mine has broken off and the pulley was just lying in my driveway

Answer
The pulley on the power steering pump is secured to the pump's hub using three 6mm bolts.  For a pulley to simply fall off of a 924s is not common, however here are two situations which will cause it:

A) The pulley was removed at sometime and the three bolts did not receive a fresh coat of Loctite 270 and were not properly torqued.

B) The power steering system had a leak (fluid is Dexron type II or III, non synthetic, any brand as long as it meets the spec.).  The pump, which requires fluid to keep its rotor/vane assembly lubricated, as well as the shaft/bearing, did not receive enough lubrication and the pump "locked-up"; as the drive belt attempts to drive the pulley the pump refused to turn so the bolts sheared off.

With the engine off, inspect the front of the pump.  Its hub is a hexagon with three holes. If you can't see through the three holes then the bolts sheared.  If you can see through the threaded holes then the bolts fell off.

Review the vehicles repair history if available and look for work involving the power steering system (pump, rack, hoses, adding ATF, etc.)   If there is a history then you have an idea as to the possibility as to how the failure occurred.   

If you have had to add fluid to system tank then you have a leak somewhere.  You can check the hoses, PS tank (the short hose from the tank to the pump is common for leaks), clamps, pump and rack for signs of leaks.  Pull back the boots on the PS rack to check for fluid in the boot (sign of a leaky rack).  If you find a suspect repair it. Do NOT attempt to use any fluids that state they will seal the system or "revitalize" it.  They don't work.  Only use Dexron type (which is also an automatic transmission fluid, aka ATF).

Let us know how you make out.