Got a used 05 burban recently noticed occasional hard brake pedal and a little whine in the power steering pump... topped off PS fluid and it got better. Recently took a steep windy dirt road down out of the mountains... lots of steering on switchbacks and heavy braking. Towards the bottom I noticed brakes were harder than normal and steering whined and brakes caused power steering pump to whine quite a lot... checked fluid when I got home and still full. Next day no noise under normal driving conditions. Did I overheat my PS fluid? Pump failing under high demand? Thanks
Hydroboost brake and steering problems on a 2005 suburban on 2005 Chevrolet Suburban 1500
Sounds like you hydrobooster is leaking. It is assisted by the power steering pump. See if the ps fluid is low. The hydrobooster usually leaks right where it bolts on to the master cylinder.
No leaks to speak of thus far... replaced pump good so far
1 more answer
get a pressure test on pump and hydra boost. poss either one could be going out