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Discussion Starter · #1 ·
This document was created and written to aid users in converting the OEM Toyota MR2 Spyder steering rack into a Fully Manual, Depowered steering rack. I do not assume any responsibility of any damages which might occur during the installation or use of this conversion.

Caution: Protective eye wear and gloves are recommended. Hydraulic fluid is known to irritate skin and during this conversion you might need the use of power tools.

Handy tools you will need:
3/8” Drive Ratchet and extension
17mm, 14mm, 12mm, 10mm, 9mm, 8mm sockets
15/16” Wrench or socket
19mm Allen Wrench or socket
Flathead and Phillips screwdrivers
Hammer and Chisel
Cutting Wheel
Magnetic tool retriever

This write-up assumes that the user is able to remove the steering rack from the vehicle. In order to do this you will need to perform the following operations per the BGB
1. Place Front Wheels Facing Straight Ahead
2. Remove Steering Wheel Pad
3. Remove Steering Wheel
4. Remove Luggage Compartment Trim Box Cover
5. Remove Tool Box
6. Disconnect pressure feed tube and return hose from power steering vane pump
7. Remove front luggage under cover
8. Disconnect RH and LH Tie Rod Ends
9. Remove PS rack assembly (2 bolts, 2 nuts, 4 plate washers and PS rack assembly)

Now to begin the process of the conversion:

  1. Using a Flathead Screwdriver you will need to remove the clamps holding the RH and LH dust boots to gain access to the rack ends.
  2. Using two large adjustable wrenches, loosen and remove the Driver's side rack end. These are normal threads but are torqued into place.
  3. Remove the adjusting cover by first removing the large lock nut. The cover is a 19mm hex and is fairly easy to remove (not highly torqued). Then using the magnetic tool you'll need to remove the spring and support yoke. The parts are laid out top to bottom in order of their removal below.
  4. To remove the pinion shaft you will first need to remove the pinion shaft housing which is retained by to 12mm hex screws. Be sure to keep the gasket in a safe place as this will be reinstalled later in this procedure. You will also need to remove the pinion shaft retaining nut. This is done by first removing the cover using a 15/16" hex socket and then the 17mm nut.
  5. The Pinion shaft should simple rotate out of the assembly and will look like the below image.
  6. The steering rack is held in the housing by a stop ring and is located at the opposite end to the pinion shaft. Using two flat head screw drivers you should be able to pry out the stop ring. Keep this stop ring as it will need to be reinstalled into the housing.
  7. With the steering rack free of its housing, you will now need to remove the seal. To do so you can simply remove the retaining clip. I was unable to get this clip out so I simply cut the seal and seal groove from the shaft. BE CAREFUL NOT TO DAMAGE THE STEERING RACK ITSELF!
  8. With the internal seal removed, we do not need the lines any more. You can source plugs for these holes or you can simply cut the tube and crimp them shut. They are no longer holding pressure, but are needed to keep dirt and debris out of the system. Alternatively you can weld the plugs shut.
  9. Before reinserting the steering rack and pinion, be sure it's well greased. Once it's reinserted into the housing you will need to reinstall the stop ring from step six. The assembly of the components is simply the reverse of the afore mentioned steps.
  10. The torque specifications for the parts are listed below.

  • Rack End (step 2) - 62 N-m or 46 ft-lbf, ensure weep hole is not blocked
  • 19mm Allen (step 3) - 25 N-m or 18 ft-lbf, adjust (outward) so turning preload is 6.7 - 11.3 in-lbf
  • Lock Nut (step 3) - 28 N-m or 21 ft-lbf, with loctite (be careful not to further adjust the 19mm Allen)
  • 12mm Hex (step 4) - 21 N-m or 15 ft-lbf
  • 17mm Pinion Nut (step 4) - 24.5 N-m or 18 ft-lbf
  • 15/16 cover (step 4) - 59 N-m or 43 ft-lbf
 

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I picked up a spare rack a while ago with the intention of doing this, just haven't got around to it yet. What are your impressions of it? Just curious if it is suitable for a car that is driven real world (low speed parking lots and such) and are you running 0 degrees of toe now or even toe-out?
 

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Discussion Starter · #3 ·
To be honest, I haven't gotten the opportunity to test this out on a rolling chassis. The motor is still being built and it will be early September before it touches the ground. I can comment on the "looped" system, but even then I have never driven the car with the power steering functioning.

From what I've read, my comments are very much in line with what Jack wrote way back when.
 

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When I was younger my ford festiva didn't have power steering, the steering wheel was a tiny bit harder to turn at low speeds but I didn't mind it at all.
 

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It isn't a bulb that can be pulled. It's a soldered-in LED.
You could disassemble the instrument cluster and put some electrical tape over the LED.
Which is why I didn't want to got that route. Seems there would be a way of repining the plug (with a jumper) in the frunk where the PS used to be (if you were to remove it.)
 

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Discussion Starter · #9 ·
Which is why I didn't want to got that route. Seems there would be a way of repining the plug (with a jumper) in the frunk where the PS used to be (if you were to remove it.)
I'm sure there is a way to "fooling" the computer to thinking the PS pump is still there. I simply taped over the light at the cluster. But I'm sure the computer is searching for some sort of signal and set resistance due to the pump.
 

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I'm sure there is a way to "fooling" the computer to thinking the PS pump is still there. I simply taped over the light at the cluster. But I'm sure the computer is searching for some sort of signal and set resistance due to the pump.
I'll dig into the wiring manual to see what I can come up with. I was just hoping that someone had been down this road.

Dev how long have you been running with rack depowered? Did you just loop the lines, install a breather, or go this route and remove the central seal?
 

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Discussion Starter · #15 ·
The below method is simply looping the hydraulic hoses. When I received my car the PS was already looped and it felt great. Very connected. The difference is the fact that the fluid can act as a damper, for better or worse. Also, When my PS was looped, the previous owner used a filter to allow the system to vent to the atmosphere. I hated the look of this and it allowed dirt to enter the system which could cause binding issues.

Looping the Hydraulics is a good way to test it out and see if you want to go to this extreme.

Is this method better than this one?
driftopia.com/2008/03/04/mr2-spyder-power-steering-removal-part-1/
I think that with this method, you still have to deal with some extra resistance due to pumping
PS fluid from either side of the rack piston when you steer.

Dave
 

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So how different (in feel and effort) is the looped-steering or the greased de-powered rack, from what we experience by simply cutting the power to the base power-steering system?

Dave
I have felt the steering without power assist but connected. Extremely heavy. If I where to so this I would loop the fittings and disconnect power to the electric pump-no need to run. The PS warning light is something else to consider and deal with. I would do this if the electric pump where to fail.
 
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