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Author Topic: How to Remove Nissan Front Subframe  (Read 2259 times)

SlaterRacingNZ

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How to Remove Nissan Front Subframe
« on: June 18, 2015, 12:23:40 PM »
Hello SDU community, I hope all is coming along well with your new years resolutions.

Now I suppose your wondering why on earth you need a guide to remove your front subframe?
That my friends I have no answer for, as it's really a case by case basis.
Maybe you would like to go a bit mental and move your rack forward 25mm for the purpose of steering big lock......
Or possibly you've smashed a curb and bent your existing subframe........

In this guide I've incorporated not removing your steering rack, as re-bleeding it for no reason is totally unnecessary.
Suppose I should stop blabbing and get straight to the good stuff then huh.

Last weekend I decided to remove my subframe and switch back to a factory one, as the previous one had the rack moved forward by 25mm. This caused some slight ackerman changes, which induced a fair amount of understeer in our setup. Very similar to the ackerman changes of the parts shop max steering rack eccentric solid bushes.
In order for the car to be a competitive circuit car, we had no choice but to switch back to a factory setup.

You will need the following tools:
-1/2 Drive 12,14,17 & 19mm Socket, Short & Long Extension Incl a Flexi Joint, Power Bar & Rachet.
-10,12,14,17,19 Ratchet Spanner or Open ended spanner
-A jack and Axle Stands
-A flat piece of ply wood the same size as your sump.

First things first, Jack the car up and lower it down onto axle stands supporting the chassis rails.
Having the rails supported will give you that much more room to work underneath the car.
I'd recommend removing the wheels, as this will save a struggle when putting the subframe back in.



Then dismount the sway bar links from the LH & RH lcas, if they're stock it'll be a 14mm nut underneath the lca.
In my particular case it's a 19mm nut underneath the lca. (Ratchet, Short Extension & the relevant Socket)



Once both links are unbolted, swing the sway bar so it faces upward.



This next step differs depending on if you have adjustable castor rods or factory ones.
Get your 19mm spanner and tuck one end inside the subframe, and slot the other end overtop of the castor bolt.
Doing this trick will make the removal process of lock nuts very effortless.
Grab your 19mm socket extension and ratchet, and proceed to undo the bottom castor rod nuts.
Bare in mind once the castor rod is removed, it will dangle and be in the way.
unless you either remove it completely, or cable tie it up out of the way like I did.



Move onward to the inner lca bolt. Support the right nut using a 17mm spanner.
Then use a power bar with a 17mm socket on the bolt to crack it off, then completely undo the nut.
once the nuts off you may need to push the arm back, just so you can slide the bolt out without hitting it with a hammer.



Move the arm downward, and swing it out of the way so it completely clears the subframe.




Complete the same process again on the other side.



Once both lcas and castor rods are dismounted and out of the way, you'll need to dismount the power steering lines.
On the front left and right side of the subframe you will see two brackets holding them in.

Take your 10mm spanner or ratchet with 10mm socket, and unbolt the nut in order to release the lines.
Do not forget this step, or you could ruin the lines when removing the subframe.



After the lines are free to move, grab your 19mm socket - short extension & power bar.
Proceed to unbolt the 19mm bolts holding the rack in, there is two on each side to loosen.
Once they're loose switch to using the ratchet in order to remove them quicker.




Once the bolts are out, remove the brackets that were holding the steering rack and put them aside.
The left bracket will require a 10mm bolt to be removed, this holds the shield to the subframe.



Grab your jack and a piece of ply that is the same size as your sump.

Raise the jack and insure the plank is nicely covering the sump, jack on the plank till it touches off on the sump.
Raise the jack further more by Only One Stroke, so the engine will be supported for when the subframe is removed.

Double check your jack is locked, as having your engine fall on you won't be to fun.



Now it's time to unbolt your engine mounts, the nut size is normally 14mm.
Either use a long extension with a flexi joint on the end along with a 14mm socket & ratchet, or a spanner will do just fine.
Completely undo the nuts & put them aside.



Nows a good time to clean up your work area, organize your removed bolts & nuts including your tools.
Grab your short extension & power bar including a 19mm socket, and proceed to undo the 4 nuts holding the subframe in.
Bare in mind it will drop slowly, and you should support the frame with one arm so it doesn't bend the bolts once it drops.
At some point you'll be able to loosen the nuts completely by hand, making sure you're still holding the subframe up.

Lower it down slowly, making sure the power steering lines are all un-snagged.
The rack will droop down once the subframe is removed, so make sure to lower it down slowly & not just drop it on the floor.




While my subframe was out I took the liberty in replacing the Rack to column bush with a solid unit.
And also replaced the racks bushes with Super Pro Nolathane bushes.




These replacement items were inexpensive, and by far one of the best things you can do to improve sloppy steering.
I also did some research on Solid Eccentric bushes that parts shop max make, and if you read the fine print it makes a mention of moving the rack up and forward slightly. This is also the same case on various other solid eccentric rack bushes for s chassis / skyline. So unless you plan to drift your car, then this is very bad for handling performance as it slightly modifies your ackerman angle. (You will notice this change)



I didn't take any pictures of fitting the solid steering column bush, as I thought at the time that this guide is solely for removing your subframe without removing your rack.

How ever I can say it's very easy to do:

While the subframes removed it's a perfect opportunity to replace the column bush.
Unbolt the 12mm bolt that holds the union to the rack, and be careful as the rack will drop even more again.



Don't let it fall to it's death, slowly lower it down until the tie rods support it. (This will avoid damaging the lines)
Slot a medium size flat head screw driver through the union, so it stops the column from spinning freely.
Grab your 12mm spanner, and slowly but surely undo all the nuts holding the bush in.



The union and shaft will completely come off, so you can just remove the old bush.
I put my union / column shaft in the vice, and slotted the solid bush on and tightened the two nuts down.



Then make sure the steering wheel was dead straight, and proceeded to fit the column shaft back up.
On the unions face it's self it has a vertical line, and on the rack spline it has a dot.
Line those two up and slot the union back onto the rack, but only after you slotted the new bush back into the column first.

Tighten the whole assembly back up again and it should look something like this




And of course we can't forget about the new steering rack bushes.




Once all that was done, it was pretty much the complete reverse of dis-assembly procedure to fit it back up.
It's a bit of a mish to push the subframe back up with the rack sitting ontop of it, and having to line up the engine mounts.
But once you get it in place & get a couple of nuts threaded on to hold the subframe, you should be away and laughing.




Button up the subframe to the chassis rails using the power bar, and be sure when you're fitting the subframe back up that no lines are snagged. Bolt down the rack to the subframe using the respective brackets and bolts. Remount the lines to their brackets, bare in mind the right one won't work if your rack is moved forward.



Bolt the lcas back up to the subframe, but don't tighten it fully yet. Grab your castor rod bolts and proceed to fit up the rod again, you'll need to force the lca forward to line the castor rod bolt holes up. Bolt the castor rod up fully and snug the nuts up, then snug up the inner lca bolt using the power bar. Swing the sway bar back down, and bolt it back up to the lca. At any point once the subframe is buttoned up, go ahead and lower the jack & bolt your engine mounts back down. (DON'T FORGET)

At this point once everything was fitted back up & tightened down, I swapped my knuckles out for factory ones.

This is where a hammer becomes your best friend

Using a 32mm socket and a power bar, I removed my wheel bearing nuts.
And then using a 19mm ratchet spanner, removed the brake calipers and rested them on the lcas.

Since I'm running spacers up front the whole rotor & wheel hub came off in one unit, just leaving the knuckle exposed.



Next I carefully removed the split pins from both the lca ball joint, and the outer tie rod end.
And proceeded to remove lca ball joint 22mm nut, and the 17mm outer rack end nut.
Using a hammer I knocked around the area that the lca ball joint seats, eventually they brake loose & the lca drops slightly.
Once again using the same method for the outer tie rod end, to release the joint without breaking any boots.
After the two 19mm bolts that hold the strut to the knuckle were removed, it was just a matter of sliding the knuckle out.

It was the complete reverse again to fit the new one, minus the use of the hammer.
 


I hope you enjoyed this guide :)