School Bus Power Steering Pump Front Seal

This is a Haldex 2 stage Power Steering Pump removed from one of our 1998 Pusher School Buses. The problem found was the power steering level was rising on it's own. No, it's not magic but a front seal allowing engine oil to enter the pump suction side.

The power steering pump is bolted in tandem to the rear of the air compressor which has an open crankcase with lots of engine oil being splashed about. Since the suction side of the pump is facing in this direction, if the seal is faulty engine oil will enter the pump and end up in the power steering reservoir.

One quick check to confirm this is the engine oil is black as usual from hydrocarbons while P.S. oil is standard 10w30 engine oil so there is a noticeable difference from the normal appearance.
To change the seal the pump must be removed and the front housing taken off. Always mark the pump stages before dis-assembly for easy reassembly.

With the end housing taken off the seal snap ring can be removed then the front seal can be easily replaced. This pump operates not only the power steering but the hydraulic fan motor as well. There are 2 output ports on the pump which supply pressure oil to run the 2 systems. This pump is mainly found on the 3116 cat Engines in our fleet & work very well in normal day to day operations.

Replacing Power Steering Hoses on a pusher school bus

Replacing power steering hoses on a pusher school bus involves bypassing the original steel power steering lines. This school bus is almost 12 years old, the pipes deteriorate over time from rust and vibration. They are clamped to the underside and usually start to leak in that area.

To make the job quicker we replace the pressure and return lines with high pressure double wire braided hoses. The ends are pipe thread and can be easily adapted to fit properly. The factory piping needs to be flushed out after and plugged since it will drip oil for days after and appear to look like the power steering is still leaking.

The hoist makes this job much easier running the new lines and securing them to the body. Once the lines are installed, the filters in the reservoir should be changed and 10w30 engine oil added. We found on occasion that 15w40 is too heavy an oil and creates a backup in the reservoir causing seepage.

The hoses are approximately 40 feet long and can be made up at a hose shop. They have all the tools that a mechanic shop could not justify to have since this is not a regular failure. This mechanic fix isn't hard to diagnose since oil leaks are pretty obvious to the naked eye.