Power Steering Pump Replacement

While the rust on this 2000 Corolla was being processed it was still drivable, and the owner reported a sudden rattling noise and then the steering became very heavy, followed by the accessory belt coming off. The cause was the power steering pump pulley stripping its splines. On-line research showed that this is a not uncommon problem for this model.

If the pulley is undamaged, all that is required to remove it is to secure the pulley and remove the M10 nut that secures the it on to the pump shaft splines. This allows easy access to the two M10 nuts on the bolts that secure the pump to the engine.

With the pulley splines stripped, normal removal is of the pump is not possible. In addition, the holes in the pulley do not permit aligned access to the M10 mounting bolt nuts. Perhaps the original design used a larger diameter pulley. The only recourse is to use a small air-powered cutting wheel to remove the pulley in pieces. See the image below.

Getting access to the pump pulley requires that the removal of the

The power steering pressure sensor wiring harness has a removable connector. Look carefully and press the connector release detent lever.

On this car, the pump M10 mounting bolt nuts were exceptionally tight, perhaps double what is needed as a long extension bar was required to loosen them.

The above image shows the competely stripped pulley splines, and the expected ground down splines on the pump shaft. Both the pulley and pump have to be replaced. The pulley is made of cast iron and once cut across the belt grooves is easily broken into sections, as shown. The nut on the pump shaft had both sides cut off with an angle grinder, then struck off the thread.

In addition, the M10 pump mounting bolts are perhaps 4mm too long, as getting a wrench or socket on them behind the pulley is a problem. The pump has to be installed before the pulley is attatched, because the M10 nuts cannot be gripped.

The fluid hoses and sensor are attached with a a multi-part assembly that has to be separated once the pump is free of the engine. This assembly was also excessively tight.

Because of the damaged pulley, getting the pump off the engine took 4 1/2 hours of labour.

 

Complete reassembly with the new pump and installation of a new serpentine belt took 1.5 h. Note the difference in the splines compared to the damaged unit.


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