S13 Suspension Conversion
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Safety
Tie Rod End Ball Joints
One issue I might raise... my friend has that setup on his aussie 31 and went to get a wheel alignment the other day. The guy told him that the tie rod ball joints were at absolute maximum tilt because the car is so low (perfect stance imo!) and its really dangerous...
Picture this: with the steering rack sitting level, the tie rods are pointing upwards towards the steering arms. then in order for the ball joint to go into the steering knuckle they have to be aimed outwards as far as possible. This becomes more extreme as the suspension compresses (i.e. over a bump). seeing as the ball joints are at max to start with, when it compresses there's no movement left so all there is to do is bend stuff...
- Decs
I ended up using Hyundai S Coupe rack ends and Toyota Lite Ace rod ends. All brand new and cost me $110 for both sides. The reason you don't want to use the R31 rod end is because of the angle it sits at when lowered. The part numbers are rack end: RE1888 and the rod end: TE3722
- are31
Tie Rod End Engaged Thread
Depending on what combination of parts you use for the conversion, if you retain the R31 TRW rack, you may find that there are now only 5 or 6 threads engaged on the tie rod end, as opposed to the 14 or so before the conversion. There are various ways around this.
Personally I used the stock rack but welded the locking nut to lengthen the arm and then retapped the thread to clean it out. All I need now is a new locking nut. - DrifterDan
S13 vs S14 Ball Joints
Converting AUS SPEC R31 suspension to S13
The Front
Intro:
This is a how-to on installing S13 suspension and coilovers into an AUS spec R31.
Further info can be found here: http://forum.r31skylineclub.com/index.php?topic=18558.0
You do this at your own risk, I do not take any responsibility for any damages to persons or property as a result of these instructions, this is just how I did it.
When you have a chance it is a good idea to spray all the nuts and bolts you are going to remove with pentrene, WD40 or some other thread loosening penetrant. Try and do this a day in advance, also spray them once more when the car is on jack stands. The whole conversion should only take around an afternoon, if everything goes smoothly.
Parts Required:
Set of 4, S13 height adjustable coilovers (standard struts are too short) 2 x S13 front hubs and knuckles 2 x S13 lower control arms 2 x S13 front brake disc rotors, callipers and pads (with bolts to bolt callipers to hubs) 4 x S13 front strut bolts and nuts (to bolt front coilovers to hubs and knuckles) Split pins Brake fluid Penetrene or other thread penetrant 2 x S13 front brakes lines (optional) Angle grinder with grinding disc (optional) Drill 10mm metal drill bit
Front Suspension:
1) Loosen front wheel bolts (both sides).
2) Jack up the front of the car and rest it on jack stands.
3) Remove both front wheels.
4) Loosen the nut where the tie rod end meets the rack end, be careful not to round the nut (penetrene comes in handy here).
5) Remove the split pin on the castle nut where the tie rod end meets the strut.
6) Remove the tie rod end castle nut.
7) Using a tie rod end separating tool or a rubber mallet remove the tie rod end from the strut. This takes persistence as it is really wedged in there. You can wind the castle nut back on a few threads and try hitting the nut if you wish but bear in mind that this may cause damage to the castle nut threads or the tie rod end threads if a metal hammer is used. Also try not to hit the tie rod end bolt/threaded area directly with a metal hammer as this can mushroom the tip and stop the castle nut from threading back on.
8 ) Remove the nut where the swaybar meets the lower control arm and remove the long swaybar bolt altogether.
9) Remove the two nuts holding the castor rod (tension rod) to the lower control arm.
10) Remove the bolt and bolt holder where the lower control arm meets the cross member.
11) Put a bucket or tray under the brakes and undo the nut attaching the rubber brake line to the metal brake line, drain the brake fluid.
12) With some pliers, remove the bracket/clip holding the rubber brake line to the chassis (take note of how it sits).
13) With an assistant holding the whole strut and brake assembly, undo the 3 nuts in the engine bay holding the strut top in place. Slowly lower and remove the whole strut assembly.
14) Adjust the height of the S13 strut so when it’s all together it is slightly shorter than the R31 strut assembly, adjust the other S13 strut so that the spring and the height of the strut is the same, you can fine tune this later.
15) Install the S13 strut and put the 3 strut top nuts back on, this should be fairly loose at this stage, tightening can be done afterwards.
16) If not already done so, attach the S13 hub and knuckle to the S13 lower control arm. Put a split pin through the castle nut and twist it with pliers so it will not work loose.
17) Attach the S13 hub/ lower control arm assembly to the S13 strut with the 2 big bolts and nuts, no not over tighten them at this stage, this can be done later .
18) Attach the castor rod (tension rod) to the S13 lower control arm with the two nuts, do not tighten it up completely.
19) Taking note of the setup on the other side, re-attach the sway bar bolt and bushes to the S13 lower control arm, do not tighten it up completely.
20) Tighten up the three nuts in the engine bay holding the S13 coilover top in place, then tighten the strut to hub bolts, castor rod to lower control arm bolts, then the swaybar to lower control arm bolt.
21) Attach the lower control arm to the cross member with the bolt and bolt holder (nut which looks like a bracket).
22) Install the S13 brake rotor onto the S13 hub.
23) Attach the S13 brake calliper to the S13 hub with the two calliper bolts. (R31 calliper bolts will not fit as they are too long and will hit the rotor).
Brake Lines
24) It is easier to use the S13 rubber brake lines, if you could not get these however, it is possible to use the existing AUS spec R31 brake lines with some modification. First you need to dummy fit the lines so that you don’t end up grinding the wring side. You will find that the AUS R31 line will hit the pronged part of the S13 calliper. You will need to grind one side of the brake line about 1 to 2 mm so that it wont hit and will then fit, grind it bit by bit checking as you go as you don’t want to grind too much off.
25) Attach either the modified R31 or the S13 rubber brake line to the metal brake line.
26) Reattach the bracket/clip holding the brake line to the chassis, easily done with light tapping of from a hammer, just make sure you put it on just as it was before hand.
Brake Lines Alternate
Alternately, you can remove the lugs on the S13 caliper that position the banjo fitting.
Put an M10x1.0 bolt in the caliper to stop swarf and shit getting inside the caliper, and hacksaw the lugs almost through. When they're almost through, hammer them off - the point being so the hacksaw blade doesn't touch the area the copper washer seals on.
Give them a minor touch-up with the angle grinder to bring them level with the caliper body, again being careful that the copper washer sealing area is left unmarked.
Now they're flush. After this can give the raw cast iron a spray of caliper paint to stop it rusting.
You can use a standard unmodified R31 brake line this way.
Tie rod end
27) You can use the existing tie rod end from the R31, it will be held on with only 5 or 6 threads as opposed to the standard 14 or so. Also the R31 tie rod ends taper in where it goes into the steering knuckle/hub. It tapers so much that the you wont be able to get the castle nut all the way on so a split pin can go through, the castle nut will have to be installed upside down so a split pin can go through. this can be seen as a dodgy way of doing so, I have had my coilovers on for 9 or so months now and they are fine, hit many a ripple strip sideways and no problems whatsoever. There are other alternatives of doing this such as using steering racks from different cars, having tie rod spacers fabricated etc. - Make up your own mind.
28) Undo the tie rod end and take note of how many complete turns it takes to completely undo. Wind the tie rod end back on 5 or 6 threads depending on how much toe out you want, do not completely tighten the adjusting nut at this moment (NOTE: If you wind the end back on the standard amount of times eg. 14 or 15 you will have MASSIVE amounts of toe out).
29) Slide the tie rod end into the S13 steering knuckle/hub assembly as far as it will go. Hit it gently from the underside with a mallet to help it go on.
30) Install the castle nut upside down as far as it will go and line up the holes so you can put a split pin through.
31) Put in a split pin and bend it with pliers so it wont work loose.
32) Repeat all the above steps for the other side.
33) Tighten up all nuts and bolts on both sides making sure everything is secure. Double check all nuts and bolts.
34) Put wheels and nuts back on.
35) Jack up the rear and install the rear coilovers as below:
36) Bleed the brakes.
37) Adjust front and rear ride and spring heights so the car sits level.
38) And you're done.
-Killabeez
The Rear
Before I start, I thought about this and found there is not a single "how to" for this process, and thought it might make it easy for some people to read if it is on its own not mixed up with other information. Some people might not like the way I have gone about the process so please don’t bag me out.
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Ok first get your hands on a set of coil overs, my ones are second hand off a mate but still all good minus a slight knock in the lower part of one of them.
They're Tein coil overs, apparently they are old HRs
- This is a pic of my new coil overs next to the R31 setup, you might notice they are smaller , my R31 setup is Monroe shocks with King springs (stock height springs).
Now on the bottom of the coil overs you will notice that one side is tapered and they're slightly bigger
What you can do is measure them against the stock shocks and cut off a part of the tapered section like so in next picture (red section is a rough guide of what I did). I cut off around 2-3mm.
Just keep checking to make sure you don’t cut off too much.
Next part can be a bit hard and some people don’t agree with this method. The top hat of the coil overs is smaller and doesn't fit in the holes already in the strut top, and if you use one of the holes then the other hole that you have to drill (due to S13 rear suspension only having 2 bolts on the strut top) will be to close to the centre hole. So we decided to drill two new holes in the strut tower, to do this we pulled the coil over apart used the top of the strut and marked it with something. To leave a mark on the inside of the strut tower we used bright orange paint (it was what we had at hand at the time) we just made sure it was centre and not too close to the other holes. Then you need to drill these holes. We ended up using a drill bit that was slightly larger then the stud so a 13 or 14 mm drill bit (just measure it up to the stud before hand). And this is what it looks like after:
That is the hardest part of the process over, if you haven't already, reassemble the coil over used to mark the holes. Now you can place the coil over in the car and see how it sits. Just check to see if the strut top holes are big enough, if not get a round file and file the hole a bit. And this is the same for the bottom just use a flat file to get it to the right thickness.
- view of the bottom of the coil over bolted in.
- view looking up at the coil over installed
Now as you have noticed the studs in the coil overs are smaller, I used 13mm nylock nuts with a washer. Also be careful because it's on the edge of the raised section but the washer I used just bent into place
- not done up yet in pic.
That is basically it, only thing to do is to adjust the coil overs up to the desired height and lock them in. This is a picture of the end result on my car:
-Garlo
For anyone that doesn't want to redrill tower holes, Cusco make pillowball 3 stud tops for R31/R30 that should be easily adaptable to any brand of coilover. Its also possible to use the original hat in some instances if you use an alloy spring seat. - Dave 31GTSR
Compiled by: Killabeez, Garlo, Dave 31GTSR, Decs, Lach, are31
