What is it?
A de-powered rack and pinion is a power rack and pinion that has the "power" part removed. Some of you might add, "We do this all the time. We just loop the lines." At the same time, many also say "it's still hard to turn after looping the lines." I hear this from owners of many platforms that loop lines.
Why de-power?
The purpose of de-powering a rack is for a few good reasons:
- Reduces rack resisitance
- Eliminates power steering fluid leaks
- Cleans up the engine bay (somewhat in the 86)
- Car loses 10-20lbs...?
- Maintains the lesser lock-to-lock ratio as opposed to converting to a manual rack with a higher turn ratio
- Eliminates the frustration of finding a manual rack and the hardware that goes with it.
- More responsive feel at the wheel (in my opinion)
Tools:
- 12mm, 14mm and 17mm sockets.
- 12mm and 14mm combination wrenches
- 14mm and 17mm flare nut wrenches
- Torque wrench and drive adapters, if needed
- Bearing pre-load meter
- Vice grips
- Bench vise
- Needlenose pliers
- Adjustable wrench up to ~2.00"
- Tie rod end puller / ball joint press
- In-car inner tie rod remover tool (Not neccessary but highly recommended because of the simplicity)
- 24mm and 42mm inside hex sockets
- 12" brass drift punch and dead blow hammer
- Optional: Stick, MIG or TIG welder
- Tube cutter
- Grease. I used red synthetic chassis grease available at any parts store. I believe it's intended for most imports and GM, Chrysler and some other manufacturer.
Process:
1) Remove rack assembly from vehicle (not pictured)
- Disconnect the pressure and return lines from the rack and pinion using the flare nut wrenches. If you see they are really tight, use the vice grips to break them loose. Try not to damage the nut too badly. Note: You might want to drain the fluid beforehand and now take the opportuninty to remove the P/S pump if you haven't done so already. Also, be careful not to lose the union seats underneath the fittings. They'll more than likely still be in the valve housing
- Seperate the outer tie rod ball joints from both steering arms using a ball joint press / tie rod end puller. If your car was well taken care and serviced correctly like mine was, you need to remove the cotter pins by un-folding them using needlenose pliers. Remove them and now you can place the 17mm socket on the nut and remove it.
- Loosen the 12mm bolt on the steering shaft universal joint. Disconnect the U-joint from the directional valve shaft.
- Remove the four M10x1.25 bolts (14mm hex head) and two brackets that hold the rack housing to the subframe and it should be free to come out.
This is what you should have on your work area:
I've outlined a few key components just to familiarize yourself with what they're called and their purpose:
Red - This is the outer tie rod / tie rod end. Its purpose is to connect the inner tie rod to the steering arm / knuckle via the ball joint.
Blue - This is know as a bellow or boot. This keeps dirt and foreign objects from touching the rack itself. This part has to be removed in order to gain access to the inner tie rod but can only come off after the outer tie rod has been removed. It is secured by two clamps, one on each side. In some instances the clamps may have to be cut to be removed.
Green - Directional valve / spool valve / control valve. Has many names but I call it the directional valve. What's circled is the whole assembly. The valve itself is inside. This little guy is what makes all the magic happen. This directs the fluid in the appropiate direction for the assist to make turning easy on the driver. Usually, there are 4 lines / hoses connected to this housing. One pressure from the pump, one return to the reservoir or cooler and two directional lines that go to the rack housing.
Magenta - These are the directional pressure / return lines that connect the rack housing to the directional valve. They are either suppling or returning pressure to / from the master cylinder depending on the rack's currect position and which direction the wheel is being turned.
2) Disassembly of outer components.
- Remove the outer tie rods. Note: This is very easy when the rack is still fastened to the car but can be done either way. Also, mark the position of the tie rod ends on the inners that way the alignment is not lost or not too far off.
- Now remove the bellows. Note: The bellows HAVE to be removed in order to gain access to the inner tie rods.
- Remove the inner tie rods. There are flat spots on the rack to place your wrench. Hold the rack uning a wrench and remove the inner tie rods using another wrench or if you have the in-car inner tie rod removal tool you can do this when the rack is still bolted to the subframe. This saves the headache of trying to remove the inners while the rack is out the car.
- Remove the directional lines from the rack. Note: Be careful not to lose the union seats underneath the fittings. They'll more than likely still be in the valve housing.
You should now have this and probably this dirty as well:
At this time I would suggest draining the rest of the fluid from the rack assembly simply by flipping it upside down and turning it left and right. On the left of the picture is the directional valve assembly. On the top, there is a dust boot. Remove it and set it aside. You will now see two M8 x 1.25 bolts (12mm hex head). These two bolts fasten the directional valve assembly to the rack housing. Remove them and the directional valve assembly. If needed take your dead blow and /or brass punch and loosen the valve until it comes out. You will be left with this:
3) Disassembly of rack assembly
- In the picture above, you'll also see a nut (rack guide spring cap) with a hex shaped recess and locknut on the rack housing about 90 degrees from where the directional valve was removed. Behind this plug is whats called the rack guide. It sets the amount of preload or drag on the rack. Loosen the lock nut and remove the spring cap using the 24mm inside hex adapter. Then remove the rack guide spring and rack guide.
- On the end of the rack housing, you'll see the cylinder cap. This part keeps the rack from flying out of the housing. Behind it are a few seals which keep the rack from leaking. You'll need your 42mm inside hex adapter to remove this bad boy.
Here it is removed:
- Once removed, you can remove the rack from the housing. With the directional valve on the left, (looking at the rack from the drivers seat while installed) the rack will be removed from the right side of the housing. It might be a booger to remove towards the end. If so, take your dead blow and brass punch and strike the rack from the left side. A solid tap should remove it. Once removed you'll see this:
Outlined in white is the rack. Congrats! You've gotten this far!
Once the rack is out the housing, you'll see the seal and the guide. In the above picture, the seal is the black piece and the guide is the one that looks like a timing sprocket... Kinda.. remove both, noting position and orientation. The rack should now be ready to go. At this point, it depends on the available tools and which route you choose to take. Since I wanted to weld the two directional ports (on the housing), I removed the inner seal and spacer from the housing. It's deep inside the housing and is tricky to remove. If you are going to weld the ports or this seal is leaking, I would remove it, otherwise leave it in.
4) De-powerization process
- Essentially the dividing master cylinder needs to be removed and the O-ring has to go. I started off making a small 'V' cut into the divider and just deep enough to cut through both seals.Now they can be removed and thrown away.
Here they are as shown with the red arrows:
I usually cut 4 slots into the M/C to ensure that pressure can never be built regardless of the fluid. I've also removed it completely as well. It doesn't really matter what you do as long as it can no longer build pressure which equates to building resisitance. Once you are satisfied with your newly modded rack, wash it to remove the metal shavings from the cuts. At this time, if you choose to do so, you can go ahead and wash all the other parts. Use any method you like. All that really matters is that the internals and moving parts stay clean.
After a good solvent wash and bead blast:
If you planned on welding the holes shut like I did, the time to do it is now. I fired up the good 'ol Lincoln TIG and got to filling. I also chose to cut them down a little to lower the protruded height from the housing. If a welder is not available, you can reuse the hardware and cut the tubes. Once cut, just smash them flat to seal them. If you want brownie points, braze them shut.
Afer filling, grinding and painting this is my finished product.
Once you are satisfied with the cleanliness of the parts, reassembly can begin.
5) Reassembly
- Install the rack end guide on the rack (timing gear sprocket look alike). I really don't think orientation matters anymore but if you're picky like me, ensure the dots are facing toward the center as they were when removed. The outer seal follows after but make sure to grease the rack and seal before you reinstall it. Don't wanna tear it...
- If you removed the inner seal and spacer from the rack, reinsert those as well and also lubricate the seal so the rack doesn't ruin the seal when reinstalled. Before you finally button everything up, put some grease in the housing before the rack goes in. Quantity doesn't really matter just as long as theres enough to keep everything lubed and make sure you apply to both sides.
Here's how it should look:
- From this position, slide the cylinder cap on the rack, using it to compress everything together and keep things in alignment. Then follow up by tightening it to about 45 ft/lbs using the 42mm inner hex adapter.
- Spin the rack so that the valve assembly can be reinserted. Beforehand, you want to grease the bearing inside the housing and the teeth on the rack. Just pack some more grease in there and you should be good. Theres also an o-ring on the valve assembly. Grease that too to prevent the o-ring from binding up. Reinsert the two 12mm bolts and tighten them down. Torque doesnt really apply because they aren't load bearing bolts and the threads are aluminum. Just tighten them up until snug.
Almost there:
- Now at this point, you need to reinstall the rack guide, spring, nut and locknut. Screw the nut in by hand until you feel resistance, then start tightening with the 24mm inside hex socket. While you're doing this, attach the pre-load meter to a socket that will fit over the steering shaft when it is wrapped with vinyl tape. Now take pre-load measurements until you see around 15-20 in/lbs of preload. Then tighten the locknut to 50 ft/lbs and stake it.
- Most cases, I weld the fluid fittings shut. This time around I was tired and ready to leave so I just cut the tubes, flattened them, and tightened them. Note: Make sure the union seats are in place and not offset. I'll weld them once the car nears completion.
- Now is a great time to reinstall those steering components that you've been neglecting to replace. Otherwise, reinstall the steering components starting with the inner tie rods. Make sure you re-stake the claw washers and apply LocTite to the threads. Torque them down to 75ft/lbs. Reassemble everything else and you should have this:
Now reinstall it onto the car, making sure to re-cotter the castle nuts for the outer rods. If you're good, you won't have to recenter the steering wheel. :D Now enjoy!
I'm sure there are plently of grammatical / punctual errors in the text. I did this as fast as I could. So for all you grammar nazis out there, let me have it and I'll correct any errors as I see fit. Thanks.
