A Complete Guide To Removing The R32 Hicas System (inc Looping Hydraulic Lines)

[BNDAIR]

I know there is a lot of debate about Nissan’s HICAS rear wheel steering system and I do not want to start an argument on whether to remove HICAS or not, how good/bad it is etc. I am just trying to put together detailed information about HICAS and a how-to guide which may help others out there who are looking remove it from their R32.

Nissan made two different versions of HICAS, the original HICAS (R32/S13) which used hydraulic fluid to control the rear steering and Super HICAS (R33/R34/S14/some S15) which used electric motors to control the rear steering.

This guide is for removing the hydraulic HICAS system including all hydraulic components and lines from an R32 Skyline (I presume it would be similar on an S13 Silvia) and installing a HICAS Eliminator kit.

HICAS Removal Kits

The two most common HICAS removal kits are the HICAS Lock Bar and the HICAS Eliminator.

The HICAS Lock Bar kit is a simple bar which replaces the HICAS hydraulic steering unit which runs horizontally behind the diff. This kit keeps the existing factory rear tie rods (aka steering arms) and ball joints on the wheel hub assembly. This kit is simpler to install and cheaper to buy (about $100).

The HICAS Eliminator kit allows you to removes the HICAS hydraulic steering unit and also replaces the factory tie rods and ball joints. This kit is more a more involved installation which requires the ball joints to be removed from the back of the wheel hub assembly. This kit is also more expensive (approx. $250-400).

Whichever kit you choose to install, you will need to loop the hydraulic lines that control the HICAS unit. In this guide I will remove the lines and loop them together in the engine bay as well as remove all of the components of the HICAS system. This way we can remove as much of the unused parts and weight from the car.

I have chosen to install the Eliminator kit for a number of reasons:

• The factory tie rods are relatively small and have been known to break under load or if not maintained (see pic below). If this happens your rear wheel will turn sharply and rapidly, causing potentially bad things to happen.
• The ball joints at the ends of each tie rod are removed and replaced with new adjustable bars. These ball joints are another weak point and over time will wear out as ball joints do. Again, if they fail at speed, you are in trouble.

Before we begin

Firstly a word of warning; this information should be taken as advice only. This is a guide and I am sure there are other ways of doing this, so feel free to add anything which I have missed or if there is a different/better way to do it.

Secondly, and more importantly, if you cannot get the rear ball joints out while the rear hub is on the car, you will need to remove the entire hub from the car and have them pressed out.

If this is the case you will need a 36mm socket to undo the rear drive shafts then you will need to remove the hub and take it to a mechanic or mate’s place that has a press.

This will obviously involve a lot more work. Make sure you don’t do anything you cannot reverse until you have these ball joints out!

What you will need

Tools:

• Good socket and spanner set (ratchet spanners are always handy)
• Screwdrivers
• Car jack and stands
• Hacksaw or small angle grinder
• Ball joint splitter
• Bucket/pans/rags to catch the power steering fluid

Parts:

• HICAS Eliminator kit
• 50cm of 10mm or 3/8” transmission cooler hose
• 2 hose claps to suit the hose
• 1L power steering fluid

Step 1: Removing the hydraulics

Jack up the rear end of the car, remove the wheels and make sure you have car stands to support the car. Do not rely on a jack to support it.

Remove the split pin and undo the nut from the ball joint at the rear end of each tie rod. These are located behind the shock absorber and brake disc rotor on each side. Then use a ball joint splitter (or your preferred method) to remove the tie rod arm from the ball joint.

Now remove the ball joints from the hub assembly before going any further. The ball joint has a circlip on the on the back which needs to be removed and then you need to press the ball joint out.

Getting the ball joint out is a PITA as it will be in there tight. You can try using a G-clamp and follow the instructions at http://youtu.be/IVluVuiFnlw

Once it is removed your hub should look like this:

Now it’s time to start removing the hydraulic lines. Go to the HICAS steering unit which is the horizontal part behind the diff, and loosen the two 19mm bolts holding it in place. Do not remove them completely; they provide support while you undo the mounting points for the hydraulic lines.

Follow the two main lines coming from the top of the steering unit and remove all of the mounting brackets from the sub-frame (aka diff cradle) using a 10mm ratchet spanner or socket.

Mounted to the chassis rail in front of the rear sub frame is the HICAS cut off valve (pictured below). Disconnect the brown clip which runs the wiring from it up to the HICAS computer in the boot. Then remove the entire valve from the chassis by undoing the 10mm and 12mm bolts that hold it in place.

Follow the two hydraulic lines which run forward along the chassis rail and remove both of them from all the mounting brackets until you get to the solenoid just behind the back of the engine bay.

At this point you will need to break the hydraulic seal on the lines, so have a container ready to catch any fluid which leaks out.

Disconnect the two lines from the back of this solenoid and drain as much fluid as you can to minimise spillage when you remove the lines from the car. This fluid is corrosive so try not to get it on your car’s paint.

Now go back to the HICAS steering unit behind the diff and remove the two 19mm bolts which were loosened earlier. Now the entire system will drop from the car and you will be able to pull it out from underneath the rear of the car.

Step 2: Installing the HICAS Eliminator Kit

Installation of the kit is relatively simple. Firstly put in the new bushes which go where the rear tie rod ball joints once were. These can be quite tight to get all the way through so I used a bit of dishwashing detergent to help get them in. Once the bush is in place, push in the metal sleeve through the middle and it should look something like this:

Now bolt the mounting bracket which comes with the HICAS Eliminator Kit to the diff cradle. This bracket mounts to the sub-frame using the 19mm bolt hole which previously held the original HICAS steering unit. And a second bolt runs through the diff cradle and then through the joint at the inside end of the toe rod.

A third bolt runs through the outer end of the toe rod and through the new bush behind the shock absorber.

Repeat this on the other side. You can undo the exhaust rubber mounts and lower the exhaust to get better access on that site.

Make sure everything is tight and now you can put the rear end of the car back on the ground and raise the front.

Step 3: Looping the hydraulic lines

This part has much discussion and uncertainty. Some people simply block the hydraulic lines however your power steering pump has a section at the rear of it which is designed to push fluid into the HICAS system. If you block the lines, it will put extra stress on your power steering pump and may lead to premature failure.

The best solution is to loop the lines together and bypass all the HICAS parts. Contrary to much information I have read online, you will only need to join low pressure lines together which can be done using standard transmission cooler hose and clamps. Also, the way the lines are looped in this guide will keep the power steering cooling system intact.

Below is a picture of the HICAS pump. It is bolted to the engine bay behind the battery and under the intake manifold. This entire unit will be removed and the line leading to it will be bypassed back to the power steering pump.

Start by undoing the hose clamp and remove the short hose underneath the back of the battery which leads to the HICAS pump.

Now we need to cut the return line to create the loop for the power steering fluid. Under the car, locate the hydraulic line pictured below (this photo was taken from the front of the car, looking back). It is on the driver’s side in front of the engine cross member and next to the oil sump plug.

This line runs from the back of the power steering pump, down the radiator support, along the engine cross member and up to the HICAS pump. Double check you have the right one!

Use a small angle grinder or hacksaw to cut the line just after the connection. Then attach your 10mm transmission cooler hose to it and feed it up through the engine bay. Below is a before and after picture of mine.

Get back in the engine bay from above then cut the your new hose to length and connect the top end to the metal line below the battery, which originally had the short hose leading to your HICAS pump.

Clean up any excess power steering fluid which was spilt and your bypass loop is now done. The back section of your power steering pump will now only push fluid around the transmission cooler and back.

Below is a photo of the bypass loop from start to finish. This photo was taken from above the engine looking down. It should be around 40-50cm of hose leading from underneath the back of the battery to near the engine cross member.

To finish, you need to remove the HICAS pump. Undo all the bolts holding the pump to the engine bay. This will take a bit of mucking about as they are in a tight spot. I had to loosen the fuel filter mount to get them out.

Then follow the two lines down the engine bay, undoing all the mounts holding them to the car. Eventually you will get to the solenoid below the car where you removed the two lines leading to the back. Remove this remaining solenoid and your HICAS hardware removal is done.

Step 4: Removing the HICAS warning light

Now that the HICAS unit has been removed, the HICAS warning light on your dash will turn on. Many people just remove the bulb from the dash. This will work however you will not get a warning light if your power steering fluid gets low.

I have also read some people disconnect or remove the HICAS computer altogether, but this may lead to loss of power steering.

The easiest way to fix this is to simply unplug the wire which sends the signal from the HICAS computer to your dash. To do this go to the boot and locate the HICAS computer, it is mounted under the rear parcel shelf to the right of centre, and unplug the smaller of the two harnesses located towards the centre of the car (see pic below).

Step 5: Finishing the job

Now top up the power steering fluid reservoir (do not put the cap on yet) and start the car. It will most likely make noises from the power steering unit because there is air in the system. Turn wheel from side to side while someone watches the fluid level and keeps it topped up if necessary. Continue doing this until the noise is gone then replace the cap.

Last but not least, get a rear wheel alignment done from your local tyre place. It should cost you around $50 for them to do the job and is well worth the peace of mind knowing your wheels are pointing in the right direction and not wearing out your tyres prematurely.

I have also heard that removing the HICAS may be defected in some states/territories if it does not have an engineer’s report because it is a modification to the steering system. I am not 100% sure if this is true but thought it was worth mentioning.

[D.I.Y. Mik]

Good write up.

No photos? Looks like there are sposed to be some but they arent there.

With the warning light, you can cut the green wire with the white trace from the hicas computer, and the light still comes on if your fluid is low.

[GH05T]

save this for later

[Jordy32]

Bookmarked this!

While my HICAS is locked, i want to remove all the lines and stuff from the car while my engine is out to clean it up a bit

Will post results, thanks for a great writeup

[BNDAIR]

Re-posting with images

Sorry guys n gals, I had images in my original article, but they were not visible once it was posted to the forum. Hopefully they will work this time...

Nissan made two different versions of HICAS, the original HICAS (R32/S13) which used hydraulic fluid to control the rear steering and Super HICAS (R33/R34/S14/some S15) which used electric motors to control the rear steering.

This guide is for removing the hydraulic HICAS system including all hydraulic components and lines from an R32 Skyline (I presume it would be similar on an S13 Silvia) and installing a HICAS Eliminator kit.

HICAS Removal Kits

The two most common HICAS removal kits are the HICAS Lock Bar and the HICAS Eliminator.

The HICAS Lock Bar kit is a simple bar which replaces the HICAS hydraulic steering unit which runs horizontally behind the diff. This kit keeps the existing factory rear tie rods (aka steering arms) and ball joints on the wheel hub assembly. This kit is simpler to install and cheaper to buy (about $100).




The HICAS Eliminator kit allows you to removes the HICAS hydraulic steering unit and also replaces the factory tie rods and ball joints. This kit is more a more involved installation which requires the ball joints to be removed from the back of the wheel hub assembly. This kit is also more expensive (approx. $250-400).




Whichever kit you choose to install, you will need to loop the hydraulic lines that control the HICAS unit. In this guide I will remove the lines and loop them together in the engine bay as well as remove all of the components of the HICAS system. This way we can remove as much of the unused parts and weight from the car.

I have chosen to install the Eliminator kit for a number of reasons:

• The factory tie rods are relatively small and have been known to break under load or if not maintained (see pic below). If this happens your rear wheel will turn sharply and rapidly, causing potentially bad things to happen.
• The ball joints at the ends of each tie rod are removed and replaced with new adjustable bars. These ball joints are another weak point and over time will wear out as ball joints do. Again, if they fail at speed, you are in trouble.

Before we begin

Firstly a word of warning; this information should be taken as advice only. This is a guide and I am sure there are other ways of doing this, so feel free to add anything which I have missed or if there is a different/better way to do it.

Secondly, and more importantly, if you cannot get the rear ball joints out while the rear hub is on the car, you will need to remove the entire hub from the car and have them pressed out.
If this is the case you will need a 36mm socket to undo the rear drive shafts then you will need to remove the hub and take it to a mechanic or mate’s place that has a press.

This will obviously involve a lot more work. Make sure you don’t do anything you cannot reverse until you have these ball joints out!

What you will need

Tools:

• Good socket and spanner set (ratchet spanners are always handy)
• Screwdrivers
• Car jack and stands
• Hacksaw or small angle grinder
• Ball joint splitter
• Bucket/pans/rags to catch the power steering fluid

Parts:

• HICAS Eliminator kit
• 50cm of 10mm or 3/8” transmission cooler hose
• 2 hose claps to suit the hose
• 1L power steering fluid

Step 1: Removing the hydraulics

Jack up the rear end of the car, remove the wheels and make sure you have car stands to support the car. Do not rely on a jack to support it.

Remove the split pin and undo the nut from the ball joint at the rear end of each tie rod. These are located behind the bottom shock absorber mount and brake disc rotor on each side. Then use a ball joint splitter (or your preferred method) to remove the tie rod arm from the ball joint.

Remove the ball joints from the hub assembly before going any further. The ball joint has a circlip on the on the back which needs to be removed and then you need to press the ball joint out.

Getting the ball joint out is a PITA as it will be in there tight. You can try using a G-clamp and follow the instructions at http://youtu.be/IVluVuiFnlw

Once it is removed your hub should look like this:




Now it’s time to start removing the hydraulic lines. Go to the HICAS steering unit which is the horizontal part behind the diff, and loosen the two 19mm bolts holding it in place. Do not remove them completely; they provide support while you undo the mounting points for the hydraulic lines.

Follow the two main lines coming from the top of the steering unit and remove all of the mounting brackets from the sub-frame (aka diff cradle) using a 10mm ratchet spanner or socket.

Mounted to the chassis rail in front of the rear sub frame is the HICAS cut off valve (pictured below). Disconnect the brown clip which runs the wiring from it up to the HICAS computer in the boot. Then remove the entire valve from the chassis by undoing the 10mm and 12mm bolts that hold it in place.




Follow the two hydraulic lines which run forward along the chassis rail and remove both of them from all the mounting brackets until you get to the solenoid just behind the back of the engine bay.

At this point you will need to break the hydraulic seal on the lines, so have a container ready to catch any fluid which leaks out.

Disconnect the two lines from the back of this solenoid and drain as much fluid as you can to minimise spillage when you remove the lines from the car. This fluid is corrosive so try not to get it on your car’s paint.

Now go back to the HICAS steering unit behind the diff and remove the two 19mm bolts which were loosened earlier. Now the entire system will drop from the car and you will be able to pull it out from underneath the rear of the car.




Step 2: Installing the HICAS Eliminator Kit

Installation of the kit is relatively simple. Firstly put in the new bushes which go where the rear tie rod ball joints once were. These can be quite tight to get all the way through so I used a bit of dishwashing detergent to help get them in. Once the bush is in place, push in the metal sleeve through the middle and it should look something like this:




Now bolt the mounting bracket which comes with the HICAS Eliminator Kit to the diff cradle. This bracket mounts to the sub-frame using the 19mm bolt hole which previously held the original HICAS steering unit. And a second bolt runs through the diff cradle and then through the joint at the inside end of the toe rod.

A third bolt runs through the outer end of the toe rod and through the new bush behind the shock absorber.




Repeat this on the other side. You can undo the exhaust rubber mounts and lower the exhaust to get better access on that site.

Make sure everything is tight and now you can put the rear end of the car back on the ground and raise the front.

Step 3: Looping the hydraulic lines

This part has much discussion and uncertainty. Some people simply block the hydraulic lines however your power steering pump has a section at the rear of it which is designed to push fluid into the HICAS system. If you block the lines, it will put extra stress on your power steering pump and may lead to premature failure.

The best solution is to loop the lines together and bypass all the HICAS parts. Contrary to much information I have read online, you will only need to join low pressure lines together which can be done using standard transmission cooler hose and clamps. Also, the way the lines are looped in this guide will keep the power steering cooling system intact.

Below is a picture of the HICAS pump. It is bolted to the engine bay behind the battery and under the intake manifold. This entire unit will be removed and the line leading to it will be bypassed back to the power steering pump.




Start by undoing the hose clamp and remove the short hose underneath the back of the battery which leads to the HICAS pump.

Now we need to cut the return line to create the loop for the power steering fluid. Under the car, locate the hydraulic line pictured below (this photo was taken from the front of the car, looking back). It is on the driver’s side in front of the engine cross member and next to the oil sump plug.

This line runs from the back of the power steering pump, down the radiator support, along the engine cross member and up to the HICAS pump. Double check you have the right one!




Use a small angle grinder or hacksaw to cut the line just after the connection. Then attach your 10mm transmission cooler hose to it and feed it up through the engine bay. Below is a before and after picture of mine.




Get back in the engine bay from above then cut the your new hose to length and connect the top end to the metal line below the battery, which originally had the short hose leading to your HICAS pump.

Clean up any excess power steering fluid which was spilt and your bypass loop is now done. The back section of your power steering pump will now only push fluid around the transmission cooler and back.

Below is a photo of the bypass loop from start to finish. This photo was taken from above the engine looking down. It should be around 40-50cm of hose leading from underneath the back of the battery to near the engine cross member.




To finish, you need to remove the HICAS pump. Undo all the bolts holding the pump to the engine bay. This will take a bit of mucking about as they are in a tight spot. I had to loosen the fuel filter mount to get them out.

Then follow the two lines down the engine bay, undoing all the mounts holding them to the car. Eventually you will get to the solenoid below the car where you removed the two lines leading to the back. Remove this remaining solenoid and your HICAS hardware removal is done.

Step 4: Removing the HICAS warning light

Now that the HICAS unit has been removed, the HICAS warning light on your dash will turn on. Many people just remove the bulb from the dash. This will work however you will not get a warning light if your power steering fluid gets low.

I have also read some people disconnect or remove the HICAS computer altogether, but this may lead to loss of power steering.

The easiest way to fix this is to simply unplug the wire which sends the signal from the HICAS computer to your dash. To do this go to the boot and locate the HICAS computer, it is mounted under the rear parcel shelf to the right of centre, and unplug the smaller of the two harnesses located towards the centre of the car (see pic below).




Step 5: Finishing the job

Now top up the power steering fluid reservoir (do not put the cap on yet) and start the car. It will most likely make noises from the power steering unit because there is air in the system. Turn wheel from side to side while someone watches the fluid level and keeps it topped up if necessary. Continue doing this until the noise is gone then replace the cap.

Last but not least, get a rear wheel alignment done from your local tyre place. It should cost you around $50 for them to do the job and is well worth the peace of mind knowing your wheels are pointing in the right direction and not wearing out your tyres prematurely.

I have also heard that removing the HICAS may be defected in some states/territories if it does not have an engineer’s report because it is a modification to the steering system. I am not 100% sure if this is true but thought it was worth mentioning.

[kingtube69]

Great guide Phil!

I'm going to revive an old thread - My kit came with some extra nuts (see the 4 identical nuts in the image below). Has anyone had these come with their kit also? I can't see where they would be used at all but maybe I'm just missing it 

[BNDAIR]

Damn, it's hard for me to remember if those came with my kit or where they belong... It looks like TAS Autosports kits come with those, but others, like the SuperPro ones do not.

Hopefully you will find an obvious spot where they belong when you go to fit the kit... and if you do, please share for others on here :-)

[kingtube69]

6 hours ago, BNDAIR said:

Damn, it's hard for me to remember if those came with my kit or where they belong... It looks like TAS Autosports kits come with those, but others, like the SuperPro ones do not.

Hopefully you will find an obvious spot where they belong when you go to fit the kit... and if you do, please share for others on here :-)

Hi Phil, 

Thanks for your reply! I posted this on R33 OA on Facebook and someone confirmed that they are used to lock the toe adjustment on the arms which would line up with the nut size and thread pitch but I'm yet to test it. 

Cheers 

[duz10s]

Morning, not sure if this was covered I cant find it mentioned anywhere however on a R33 GTR, the subframe has all this bracing that attaches to the body etc, I cannot get to the tie rod to undo at the HICAS without removing this bracing, however I am concerned the whole rear subframe will drop???

Can anyone help.

[eppyfish]

Reviving an old thread here...but for those who have removed the HICAS solenoid on the drivers side, you disengaged the wiring which included the speed sensitive power steering assistance, which is tied into the HICAS system.  How did you manage keeping the power steering system functioning without heavy steering?  My understanding is that when disconnected, the power steering computer no longer receives a speed input and puts the power steering into fail mode.  My car is not fully together right now, but we did recently pull the HICAS system, so hoping to resolve this before she's back up and running. 

thanks

[GTSBoy]

I don't understand the question. The HICAS solenoid in the engine bay has nothing to do with the front steering. There is a (very small) solenoid on the power steering rack. That remains connected. So long as the HICAS CU in the boot remains connected to the larger of the two loom plugs, PS continues to work.