10.3 - Power Steering Pump Repair / Replacement ( John Ping,
The power steering pump arrangement on the XJ40s is quite unique with regards to the setups on more conventional vehicles. The XJ40 has the power steering pump driven by a jack shaft from the engine. It is NOT belt-driven. The power takeoff from the engine is via a small jack shaft located slightly behind and to the rear of the ignition distributor. The entire power steering pump assembly is tucked up neatly in front of front section of the exhaust manifold. The engine jack shaft and the power steering pump shaft are joined via a small conventional coupling arrangement where each shaft has a hub installed and a plastic disc coupling element links the two hubs. This article is written based on the 90 XJ6, but should be applicable to all XJ40 models.
Replacement and/or repair of this power steering pump assembly is of medium difficulty. Expect about 2 hours for removal and 1 hour for re-installation. This does not include any extra time for pump coupling hub removal and re-installation or pump shaft seal work, if needed. If you perform this work yourself, you will save a considerable sum of money ($600 - $800 US). An owner does not need any specialty tools for removal from the vehicle as simple hand tools are all that is required. However, removing the pump shaft hub (press-fit onto the shaft) requires specialized equipment. Likewise, the re-installation of the hub onto the pump shaft following pump exchange or seal work requires a specialized tool. The good news is that any well equipped machine shop can handle this work in short order for a minimal price. You do NOT have to visit the local Jaguar dealer service department to ensure this task is performed correctly.
Tools Required for Power Steering Pump Assembly Removal and/or Replacement:
2 vehicle jack stands, floor jack
13 mm & 16 mm combination wrenches
3/8" drive ratchet with 6", 2" extensions, (wobble head socket adapter is great)
13 mm & 10 mm 3/8" drive sockets
flat tip small stubby screwdriver (for removing pump suction hose clamps)
oil drain / collector pan
cool touch drop light,
6" slide caliper with depth measurement capability
Other tools are required for coupling hub and/or shaft seal removal purposes and are discussed in the appropriate sections.
Removal of the Power Steering Pump Assembly from the Vehicle:
Step 1: Raise the front of the vehicle under the engine cross-member and place two jack stands under the front jacking lift points (below the hinges on the front doors). Elevate as necessary to gain good access to the underside of the engine.
Step 2: From underneath the engine, locate the high pressure hose connection (from the discharge / rear of the pump) to the steering rack. Using a 14 mm combination wrench (or crows foot if desired), loosen and remove the hose connector from the steering rack. Once the seal is broken the connector should be easily turned. Allow the hose to drain into the oil collector pan so that all of the power steering fluid is removed from the system before you attempt to take off the power steering pump assembly.
Note: It's a good idea to turn the steering wheel from lock to lock a couple of times to expel any old power steering fluid from the rack and pinion unit. You do not need to start the engine, just place the key in the ignition to defeat the locking mechanism.
Step 3: Re-Install the high pressure hose connector to the steering rack with the 14 mm combination wrench. Just snug the connector after it fully seats. The hose connector o-ring will probably be in good shape, replacement of the o-ring is not necessarily required to ensure a leak-tight joint.
Step 4: Remove / loosen the power steering pump suction hose clamp (6 mm socket or flat tip stubby screwdriver) at the pump and slip the hose off the pump. Loosen the suction hose clamp at the fluid reservoir so that the hose can be safely pivoted upward and out of the way.
Step 5: Using a 16 mm combination wrench (stubby 16 mm combination is best), loosen and remove the high pressure discharge hose connector from the rear of the power steering pump. Protect the connector end (and o-ring) with a piece of masking tape or similar material and position it out of the way.
Step 6: If equipped, remove the Exhaust Gas Recirculation Valve using a standard 13 mm combination wrench. Tuck the vacuum line up under the ignition wires. Disconnect the EGR line from the valve body adapter using two 26 mm combination wrenches (or equivalent). If this joint is tight (quite likely), its possible to leave the line connected to the EGR valve body adapter and slip the adapter with line off the EGR valve studs.
Step 7: Remove the five (5) 13 mm exhaust manifold shield bolts. Two bolts are located near front (radiator) side of the shield, two are located near the rear (firewall) side of the shield and the final bolt is located at the middle bottom of the shield. With the bolts removed, carefully remove the heat shield. It's helpful to disconnect the distributor cap and move it to the top of the engine to provide better clearance for shield removal.
Step 8: From the engine bay, locate and remove the upper power steering pump assembly mounting bolt using the 3/8" ratchet with 6" extension and 10 mm socket. There are only three (3) bolts which hold the assembly to the engine.
Step 9: From underneath the engine, locate and remove the lower power steering pump assembly mounting bolt using the 3/8" ratchet and 10 mm socket.
Step 10: From the engine bay, locate and remove the middle power steering pump assembly mounting bolt using the 3/8" ratchet with 2" extension and 10 mm socket. (a wobble head adapter with a 1" extension is best for this task). Be sure to support the pump assembly upon removal of the last bolt.
Step 11: Carefully remove the power steering pump assembly from the engine bay by pushing aside the air conditioning hoses. Leave the plastic coupling disc attached to the engine driven coupling hub.
Pump Coupling Hub Removal / Re-Installation … Pump Shaft Seal Replacement:
Note: It is mandatory to remove the pump coupling hub before you can replace the entire pump or just replace the pump shaft seal. Before you attempt to remove the hub, it is absolutely necessary to determine a hub location reference. Typically, the pump shaft extends beyond the top of the hub by approximately 3 mm or so. The easiest method for determining a reference position is to measure the depth between the top surface of the hub slots and the bottom of the aluminum assembly adapter. Normally, this measurement will be approximately 23-24 mm. Note this depth measurement so that it can be re-produced exactly when re-installing the pump coupling hub. If the hub is not correctly placed on the shaft, it is possible to get an interference (or too loose) fit up with the plastic coupling disc upon re-assembly.
Power Steering Pump Coupling Hub Removal:
Note: There are several techniques for removing the pump coupling hub. The hub is "pressed" onto the pump shaft with a slight interference fit. The technique is very similar to a pressed-on pulley for any auxiliary device … with the exception that this application uses a hub instead of a pulley and access space to the hub is tight.
Method 1: If you have access to a very compact two jaw gear puller, this may be used to grasp the slots of the hub and carefully ease the hub off the shaft. The jaws must be narrow to allow access to the slots. Jaguar dealership service departments have this tool but it is highly unlikely any independent shops will have this device.
Method 2: Remove the three (3) 13 mm head bolts that mount the pump to the aluminum assembly adapter. This action will provide sufficient room to allow a large bearing separator (or two thin steel plates) to be slipped between the adapter and pump. Add shims as necessary to ensure the aluminum adapter is adequately aligned and supported on the press arms. In this configuration, the adapter neck will force the hub off the shaft when force is applied to the end of the shaft via a press. The bearing separator (or steel plate pieces) will rest on the press arms which will ensure all force is applied to the pump shaft. Be careful to support the pump when the hub is pressed off the end of the shaft.
Power Steering Pump Shaft Seal Replacement:
Note: If the power steering pump was noisy or there was difficulty with turning the steering wheel under normal driving, it probable that the power steering pump needs complete replacement. Quality rebuilt pumps are readily available from large auto parts supply chains for a very reasonable price as they are typical GM Saginaw pumps.
Step 1: If the power steering pump is operating correctly, the leak is likely due to a worn or defective shaft seal. This specific part (or a seal kit) is readily available from large auto parts supply chains for a very low price as this is a GM part. With the part in hand, compare it with the existing seal and continue with the following steps if they are identical.
Step 2: Drill a small (1/8") hole in the metal top of the seal to allow access for a seal puller or small screwdriver. Be very careful not to touch the pump shaft … best to tape the shaft as a means to protect it during seal removal.
Step 3: Using a seal puller or screwdriver, grasp the seal through the hole and lever the seal out of its housing. Once the puller engages the seal, it will pull out of the housing easily.
Step 4: Thoroughly clean the pump shaft and the seal recess areas. Cleanliness is very important when installing the new seal. Inspect the pump shaft seal area for damage or wear. A slight scoring from the old seal will likely be visible and will not cause any problems when the new seal is installed. However, if you can feel any groove in the shaft from the seal, purchase a rebuilt pump assembly.
Step 5: Lubricate the shaft with a small amount of power steering fluid or silicone o-ring grease. Carefully locate the seal on the shaft and move it into position over the seal housing.
Step 6: Using a small hammer / block of wood or large deep well socket the same outer diameter of the seal, carefully tap the seal into place within its housing. The top of the seal should be slightly recessed (1 mm) below or flush with the top of the seal housing when properly seated.
Step 7: Re-install the power steering pump to the aluminum assembly adapter using the three (3) 13 mm head bolts. Torque these bolts adequately and use thread-locking compound if desired.
Power Steering Pump Coupling Hub Re-Installation:
Note: There is only one general method for re-installation of the pump coupling hub. Force cannot be directly applied to the pump shaft as this action risks damage to the internal pump thrust bearing. The pump shaft is internally threaded to allow the shaft to be supported / restrained while the hub is installed.
Note: Return the power steering pump assembly to the machine shop. The machinist will utilize a press device with threads matching the internal threads of the pump shaft. The device uses a "thrust bearing with lead nut" to ride down on the press threads to force the hub back flush onto the end of the pump shaft. It may be necessary to place a large socket with an internal diameter greater than the pump shaft outside diameter. This action will allow the "thrust bearing with lead nut" to drive the hub beyond the end of the shaft. Be exceedingly careful to ensure the hub is correctly positioned to the pre-determined depth … press the hub very slowly.
If a machine shop with proper tools is not available, the following method can be used.
Step 1: Procure an approximate 4" long bolt (and nut) with identical thread type as the internal threads of the pump shaft.
Step 2: Lubricate the shaft and initially position the coupling hub.
Step 3: Install the lead bolt, flat washer and nut onto the pump shaft via the internal threads. Lubricate the top and bottom of the flat washer with grease to ease the thrust forces acting on the hub.
Step 4: Place the lead bolt head into a vice to support the pump assembly. Carefully rotate the lead nut downward on the bolt threads to force the hub onto the shaft.
Step 5: It will be necessary to install a large socket with an internal diameter greater than the pump shaft outside diameter below the lead nut on the bolt to allow the hub to be positioned beyond the end the pump shaft. Be exceedingly careful to ensure the hub is correctly positioned to the pre-determined depth … press the hub very slowly.
Re-Installation of the Power Steering Pump Assembly into the Vehicle:
Step 1: Carefully re-position the power steering pump assembly into its fit up area. Rotate the pump shaft such that the hub "ears" engage the plastic coupling disc. When the fit up is correct, the pump assembly will easily slide forward where the mounting surfaces are flush with each other with no misalignment.
Step 2: While supporting the pump assembly with one hand (after fit up to the drive coupling), fasten the middle mounting bolt with the other hand to secure the assembly in place.
Step 3: Fasten the upper and lower mounting bolts. Snug all three mounting bolts but be careful not to over-torque as the female threads are aluminum.
Step 4: Install the high pressure hose connector to the rear of the power steering pump. The connector should easily thread into place. Just snug the connector after it fully seats. The hose connector o-ring will probably be in good shape, replacement of the o-ring is not necessarily required to ensure a leak-tight joint.
Step 5: Install the pump suction pressure hose to the pump inlet port. Snug the clamp as necessary to ensure an oil tight seal. Re-torque the suction hose clamp at the fluid reservoir to prevent leakage.
Step 6: Power approximately one liter of power steering fluid into the fluid reservoir.
Note: If your XJ40 still has the rear self-leveling system, use hydraulic system mineral oil (HSMO) as the power steering fluid. If this system has been removed or was never installed, Dexron III is the suggested power steering fluid.
Step 7: Re-position the exhaust manifold heat shield and install the five (5) mounting bolts.
Step 8: Re-install the EGR valve and body adapter if equipped. Tighten fittings as necessary to prevent exhaust leaks. Be sure to re-install the gaskets or procure new ones if the originals are in poor condition. Re-connect the vacuum hose to the EGR valve.
Step 9: Start the engine (while still on jack stands) and rotate the steering wheel several times from lock-to-lock position to vent air from the pump / rack assembly.
Step 10: Stop engine, remove jack stands and lower the vehicle. Check fluid level in the power steering fluid reservoir. Additional fluid will likely be needed to ensure the fluid level is between the "cold and hot" markings. Total volume is approximately 1.5 liters.
Step 11: Test drive and check for leakage.