1992 Chevrolet P-30 Power Steering & Brakes Intermitant
Hello, I am in desperate need of some help... I am trying to leave on a trip with my family in our up to now dependable 1992 Fleetwood Bounder 34J mounted astride a Chevrolet P-30 chassis, but was surprised by the subject issue when I took the motorhome out of storage. My issue is that the power steering and power brakes only work intermittently. They work in park (kind of), but not in reverse and drive. I have replaced the hydraulic power steering pump, performed the bleeding operations according to the Chevrolet service manual with no improvement.
I considered replacing the hydro-boost assembly, but the service manual troubleshooting guide for the hydro-boost system does not describe my behavior. Out of ideas, I turned to the internet. Found numerous posts relating my intermittent power assist to the auto-apply parking brake system. My auto-park system uses the engine driven hydraulic assist pump pressure to disengage the auto-park brake function when gear selector is not in Park.
I learned from IRV2 posts that the auto-park release hydraulic actuator can over-travel if the park brake shoes are worn, and somehow this will allow air into the system and cause my condition. I am uncertain how the air gets in due to over-travel of the release actuator piston, unless it leads to the hydraulic fluid reservoir level becoming to low, allowing the pump to draw air into the system through the empty reservoir. I have some doubts, as I think my reservoir remains full enough to prevent this, but I could be wrong.
If worn brake shoes can cause the over-travel, I’m pretty sure my shoes are worn. My auto-park function satisfactorily parks the vehicle, but my manual parking brake pedal has a lot of travel. I have disassembled the forward parking brake cable and shortened it by adjusting the clevis were it meets the parking brake cable, and reassembled. I now have more pedal available for setting the brake manually in neutral, but otherwise no help. I have tried adjusting the cable at the auto-park release actuator both directions, tightening and loosening in an attemp to stop the over-travel, but no change. I even bled the actuator by running the engine in neutral (so that the actuator would be pressurized), and opened the bleeder valve. I heard a lot of hissing before fluid finally ran out in a stream, suggesting the presence of air in the auto-park actuator and supply line.
I am considering trying to adjust my parking brake shoes, but I am pretty sure I will need to remove the drive shaft to allow the adjuster window in the drum to match up with the adjuster mechanism on the brake shoe actuator. Because the forward drive shaft doesn’t have a slip joint, I am not sure I can remove the forward driveline without removing the rear shaft first, then the mid, and finally the forward shaft. But if I did, would it even help?
What am I doing wrong, and what should I be focusing on to repair the power assist brakes and steering? If it is auto-park release actuator over-travel causing the intermittent power assist, how do I fix it?
1993 Fleetwood Bounder M34J, Chevrolet P30, 454 with Banks Power