Power steering belt comes off under high acceleration load.

[Cotuit Boy]

I'm scratching my head on this.  My R1 with power steering, having just been completely rebuilt, operates perfectly but if I punch the engine hard, I lose power steering and find the belt off once I get back to the garage.  Not broken, just off.  The pump is still tight and in its original tensioned position.  If I put the belt back on, all works the way it should.  I have found the belt inside out which leads me to believe that the engine has overpowered the pump and driven the belt off the pump pulley. Did I miss something on the pump rebuild?

[Gunslinger]

Your belt could be glazed and not able to have enough friction to stay in the pulley.

While this may have no bearing on your problem, I had a different experience with a '69 Corvette I owned.  I installed new belts on it and when driving the alternator belt twisted and turned upside down in the pulley.  It turned out that belt manufacturers have consolidated parts numbers for obsolete applications...basically if a belt was a certain length that applied to different cars, they changed their guides to one number fit those applications.  That didn't account for the V-angle or the depth of the belt.  The belt that NAPA said fit my Corvette did fit, but only filled the pulley only about half its depth so there was less belt area on the pulley.

I ordered a reproduction belt made correctly for the car and had no more problem.  

[Cotuit Boy]

Thanks Gunslinger for your reply.  I'll take a look at the condition of the belt although it was relatively new.  Alignment of the drive and driven pulleys is also good so mis-alignment is not the problem here either. Still scratchin' my head.

[Kennie B.]

Make sure the sheet metal brace the goes from exhaust manifold to pump isn't missing.

My car had horrible alignment of pulleys.  Verify that the pulleys are square and parallel.  This takes 2 straight edges.

[Cotuit Boy]

Kennie,

Thanks for your reply.  The lower  support bracket is in place.  I have checked the alignment of the p/s pump and the pulley on the crankshaft that drives it in the past.  Since the engine was just rebuilt, it would be wise for me to check it again.

 

[Cotuit Boy]

Well,

Kennie sent me off to recheck my pulley alignment, which was a little off.  I made a shim adjustment and rechecked.  It was terrible.  Too terrible to have been from the minor shim I had just installed.  Upon further inspection, I discovered that the pulley was bent.  Most likely the belt climbing off strained it enough to bend it.  It has quite a wobble.  New one on order and I'll take it from there.

Thanks Kennie for making me stick my head back in the engine.