MR2 Spyder Power Steering Removal (Part 2: The Vented Surge Box)

By 240am
In Projects, Toyota MR2 Spyder
April 16, 2008
7 Min read
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(NOTE: This guide adds to part 1 so if you haven’t done so already, read part 1 here.)

Throughout the process of developing this mod, I tried numerous combinations of line routing to find what I believe works best on the Spyder. The final result is a steering system that feels like power steering at any speed over 2mph. And for those wondering about the feel, I will say that this mod passes the wife test with flying colors. Upon driving she stated, “I forgot you had removed the power steering once we got out of the driveway.” and “This is so much easier than the steering on the old crx.”

Theory

When removing the power steering from your car, you want to make sure there is power steering fluid left in the rack for lubrication. In part 1, the inlet and outlet lines were connected together so that as the rack is turned, the fluid remains. However, what it doesn’t address is pressure differences in the rack and as a result, the first method is not ideal when converting the Spyder’s automatic rack to manual because you will have to fight the pressure of the fluid in what is now a closed/non-assisted system. An ideal solution to this is the vented surge box. The surge box (or breather can) is an oil catch can with two lower ports and a vented filter on the top. Basically, by connecting the steering racks fluid lines to the box and filling the box half way with power steering fluid, fluid will be retained in the rack while pressure escapes. And since the box is vented to the atmosphere, the driver will no longer have to overcome the fluid pressure of the closed system shown in part 1. In this manner, the steering feel becomes much lighter.

Parts and Tools Required

    • 1 – small pipe cutter
    • 8 – 10 feet of 1/4″ fuel line
    • 4 feet of 3/8″ fuel line
    • an assortment of wrenches (10mm, 12mm, 17mm)
    • lots of hose clamps
    • power steering fluid
    • oil catch can
    • appropriate adapters to 1/4″ and 3/8″
    • assortment of brass 1/4″ t’s, elbows, unions and nipples for the routing block
    • 1 – 3/8″ brass t
    • zip ties

(See images throughout article for examples.)

Procedure

First, drain the power steering fluid. My preferred method is to place a drain pan under the steering rack and loosen the small hard line from the passenger’s side of the steering rack. Once the draining slows, turn the steering wheel left and right a few times (from lock-to-lock) to force any additional fluid out. Repeat this process on the other hard line directly attached to the rack and then remove all of the hard lines from the system. This includes the two large lines.

Removing the power steering from the mr2 spyder
Loosen and drain the hard line at 1 and then repeat at 2. Afterwards, loosen and remove additional hard lines (4) at the arrow. Set the lines outside of the car for cutting. (Note the power steering pump pictured should already be removed as directed in part 1)

Starting with the larger lines (3/8″) use the pipe cutter and cut the lines at after the U. Make sure the modified lines are free of debris and then reinstall them. I also rotated the lines 180 degrees so that they exit on the other side of the steering column. (These lines strip easily so be careful not to over tighten them.)

The modified hard lines for the mr2 spyder’s power steering removal.
After shortening the larger hard lines, reinstall them into the lower steering column making sure they have been rotated 180 degrees.

Now, taking the 2 smaller hard lines, cut each end about 2 inches in and then reinstall each back into the rack. In the end you will have 4 small steering rack lines that point towards the front cross member.

Image showing the area to cut the hard lines for the mr2 spyder’s power steering.
Cut each end of the small lines to about 2 inches long and then install the 4 pieces into the rack.

You can use a flaring tool on the ends of the new lines but I have found that is not necessary as the 1/4″ fuel line barely fits as it is.

You can use a flaring tool to create new ends on the cut sections. However, due to the tight clearance the 1/4″ fuel line will have, it is actually not necessary and wholly up to you.

Using the 1/4″ brass hardware (you can buy these at the local hardware store in the plumbing section) construct a routing block that will accept lines from the four small ports that were made on the rack on one side and join them to a single line that will run to the surge box on the other side. I used 5 1/4″ nipples, 3 1/4″ t’s and 2 1/4″ unions. All of the pieces were connected together using teflon tape.

The routing block for the power steering removal on the mr2 spyder
This is the configuration of the routing block. This piece will be attached to the underside of the front cross member.

As shown in the previous image, you will need to run a 1/4″ piece of fuel line from each 1/4″ nipple on the steering rack to the highlighted nipples on the routing block. When doing this, make sure to include a little bit of slack in each line and go ahead and secure the lines with the clamps. Then secure a final line to the other side of the block (on the odd nipple) and then zip tie the block to the underside of the front cross member.

Now you will need to mount the oil catch can (or whatever else you will be using as the surge tank) to the car. The mounting can go pretty much anywhere as long as it is above the steering rack so that gravity will constantly force fluid into the rack. I would recommend mounting the tank in the area where the power steering pump used to be as there are a lot of mounting points in this area and access to the unit will remain simple. On my car, I bolted the tank to the upright portion on the front cross member and then place a few zip ties around the unit to prevent any vibration. (see image below)

The vented surge box for the power steering removal on the mr2 spyder
I recommend mounting the surge tank in the same location where the power steering pump sat. Also, no matter what you are using for the tank, make sure that the nipples are on the bottom. (For example, this oil catch can is installed upside down.)

(NOTE: In the image above the oil catch can is installed upside down and the inlet and outlet is used to connect to the modified steering lines. The catch can drain is used as the vent. Also, since this can has a fill level line, I can easily check the fluid level with a quick visual glance.)

At this point, connect the last nipple from the routing block to the first nipple on the oil catch can using 1/4″ fuel line. Secure the routing of this line with zip ties to ensure that it can’t hit the fan. Then, place a short lenth of 3/8″ fuel line onto the 2 large hard lines and then connect the two lines together using a brass T. Run a third 3/8″ line from the T to the other nipple on the oil catch can, once again securing the routing with zip ties. Now inspect all of the new lines and make sure they are securely connected to the nipples with hose clamps. Once done, go ahead and fill the oil catch can 1/2 way with new power steering fluid. Turn the steering wheel a few times from lock-to-lock to make sure the rack is filled and then check for any leaks. Finally, fill the can to about 3/4ths and then install the filter on the port at the top of the can. (I used a 1/4 to 3/8 adapter for my filter, your can may be different.)

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By 240am April 16, 2008

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