2000 gmc 6.0L power steering pump quits

[chute450]

i've put 3 pumps on my truck they work fine without a hitch but as soon as my truck hits the rev limiter the pumps goes and i cant steer and i have no brakes?

[Doug_Scott]

Are you re-using the pump pulley, or does new pump come with new pulley? I would imagine a quick cheap fix(other than not running up to rev limiter) is to stick a larger pulley on it to slow the pump down.

 

I have no idea what pulley to use, maybe someone else has some idea as to what pulley to try. After the pump fails, does it fail completely, and require replacement, or does it start to work again after the air gets settled out?

[chute450]

after it fails my brakes immediatly go to the the floor and its arm strong steering from then on out.. the pump dosent wine or make any different noises it stays quiet and even if i rev it. it makes no difference

[Doug_Scott]

The hydraboost should not cause the loss of brakes if it is not getting any hydraulic pressure from the power steering pump. The brake pedal should just be very hard to press. If you are getting the brake pedal going to the floor with no braking happening, you need to look elsewhere for the issue, it will not be the power steering pump.

 

Have you checked the fluid level in the power steering reservoir after the pump fails to work? Are you seeing any signs of a leak in the power steering system?

[chute450]

when the pump goes the fluid stays full but my brake fluid goes down? lol its mind boggaling

[Doug_Scott]

Good luck with that. There is no connection between the two hydraulic systems, beyond the mechanical connection of the push rod between the booster and the master cylinder, and the mounting hardware.