It’s a fact that Corvettes are meant to be driven to extract the ultimate experience of ownership. The fact is that Corvettes are built to showcase their razor sharp handling as well as blistering performance both on the streets and at the track, should you choose to up the ante and bring your car to a sanctioned event. One of the most important parts of keeping your Corvette in top performance condition is to be attentive to its regular maintenance as it starts to age and the miles pile up. At some point you might notice a dark red puddle under your car when you move it after it has been parked overnight or there might be a slight whining-type noise coming from under the hood. Either of these can annoyances can point to a potentially suspect, failing power steering pump. You might also notice potential failure at a track event where the pump might start to overheat. In any case, it’s time to correct the matter.
On a recent trip to Saginaw, Michigan, we stopped by Turn One Steering Systems to check out how they revive tired C4 Corvette power steering pumps by incorporating their extensive years of experience into its rejuvenation. Turn One’s rebuilding service includes a full teardown of the pump, an inspection of every individual component and the replacement of all the seals. Once the rebuild is complete, the unit is dyno tested to ensure the pump is operating at its optimum performance level. Looking at the history of Turn One, it was started by Jeff Roethlisberger whose extensive background includes 14-years spent working at Saginaw Steering Gear, GM’s steering division as a ride and handling engineer till starting the company in 1997. The talented team at Turn One has a combined experience of over 60 years in rebuilding services. By following the images in the story you can see just what it takes to bring life back to your tired C4 Corvette power steering pump.
The company offers a number of comprehensive rebuilding services, including ones for your power steering pump and power steering box as well as the rack-and-pinion. If your needs are for a perfectly restored part back to factory specifications or one specifically built for high-performance applications the team has you covered. In addition, Turn One offers their own custom line of performance parts including power steering boxes and pumps, billet aluminum pulleys, fittings and accessories. It’s as easy as giving them a call to talk with the experts and outline the specific needs for your application to get the job done. Vette
1. Here you can see the well-worn C4 Corvette power steering pump ready for a full rebuild by the talented team at Turn One to return it to better than new condition.
2. With the pump secured in a bench vise, a small punch is used to push through a hole in the housing to remove the rear snap ring.
3. Air pressure was then used though the oil intake tube, causing the back cover to lift from the housing so it can be removed.
4. With the back cover removed you can see the ring rotor and vane assembly housed inside the pump.
5. The O-ring was then removed from the pump housing.
6. Next, carefully remove the set pins for the ring rotor and vane assembly and secure them in a safe place so they don’t get lost.
7. With the set pins removed you can now disassemble the components from the inner housing. Pictured here are (from left to right) the housing, spring, lower pressure plate, vane assembly and ring. All of these parts will be thoroughly inspected prior to reassembly.
8. The pump was then reversed in the bench vise to have the snap ring removed from the front of the pump housing.
9. A slide hammer was then threaded onto the driveshaft to remove it and the bearing from the housing.
10. A special tool was then used to remove the inner driveshaft seal located deep in the housing.
11. Next, carefully remove the pressure regulator from the pump housing. Be sure to note the sequence the parts were removed in, including the fluid pressure valve and spring.
12. Finally, to complete the disassembly, remove the O-ring from the bottom of the pump.
13. The housing and all the related parts were thoroughly cleaned and inspected for normal wear to determine if any of the internal parts would need replacement during the rebuild process.
14. The pump driveshaft was inspected and then polished on the lathe using 400-grit emery cloth.
15. Here you can see the driveshaft fresh from being closely inspected and polished, ready for reinstallation.
16. A fresh O-ring was then installed into the base of the pump housing.
17. A new bearing assembly was then press-fit onto the driveshaft.
18. Next, using a press, a new driveshaft seal was installed into the housing.
19. With the housing in a bench vise, the driveshaft and new bearing assembly were pushed into position.
20. The bearing assembly was then gently tapped into place using a hammer to secure it in the housing.
21. Finally, the snap ring was reinstalled to hold the assembly in place.
22. The fluid pressure valve, spring and new O-rings were then set in place within the housing.
23. This was followed by the installation of the flow restrictor fitting to the housing, which was screwed into place.
24. The unit was then torqued to factory specifications to complete the installation.
25. Here you can see the rear of the pump with the (left to right) spring, new O-ring and lower pressure plate ready.
26. With the spring already installed into the housing, the lower pressure plate with new O-ring was set in place.
27. The two set pins for the ring rotor and vane assembly were then aligned and set in place on the ring. Take note just how nice and clean the inside of the pump is.
28. The rotor and vanes were then set in place, making sure it perfectly aligned with the splines of the driveshaft.
29. Next, a fresh O-ring was installed.
30. Making sure to line up with the set pins, the back cover was set in place.
31. The cover was then press-fit into place using an arbor press. The snap ring was then installed, completing the rebuild.
32. The rebuilt pump was then hooked up to Turn One’s exclusive power steering pump analysis system to check its performance under load. Here, the pump gets put through its paces to test the pump’s seals, flow of 2 1/2 gallons per minute and pressure relief of 1,500 psi.
33. Here’s the completed power steering pump ready to be reinstalled in your C4. Clients have the choice of requesting the housing be left natural or polished, painted or powdercoated to suit their application.
Photos by Chuck Vranas