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Author Topic: 1985 R180 Diff Removal, Welding, and Re-installation For Mk. I Hatch  (Read 615 times)

Offline snakezulu7

  • n00b
  • **
  • Location: DFW, Texas
  • Posts: 44
  • I'm too drunk to taste this chicken.
Good afternoon, everyone, and welcome to another post regarding my '85, KA swapped, mki hatch. This thread will consist of the removal, welding, and re-installation of the R180 diff broken up into 3 main posts with as many images as I can take. Also, I will explain my troubles and failures so y'all can avoid my screw ups and not smash your fingers like I did...still getting the feeling back in it and it's been over a week. I'll be having a friend that's welded many a diff do the welding while I spectate, take pictures, and note what settings he uses on the mig welder we'll be using. The goal is to have the diff back in the car, welded, this week and driving on Friday before I go innawood with my friends and some guns for my bachelor party.  :yes:

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1985 KA N/A 200SX

Offline snakezulu7

  • n00b
  • **
  • Location: DFW, Texas
  • Posts: 44
  • I'm too drunk to taste this chicken.
Howdy howdy! It's time to go over removing the R180 diff without removing the axles from the car. This was the first time I've ever dropped a diff that didn't also contain a solid axle, so by no means am I telling you that this is the way to do it. Understand that this is meant to open dialog and provoke meaningful conversation to help future owners do this with less headache. Also, I did this without dropping my exhaust because I'm fucking dumb, so please also excuse any possibly incorrect terminology.

What you'll need:
Wrap around eye protection
Jack & jack stands (or a lift if you're smart, but you'll need something to prop up the diff)
Pry bar
Breaker Bar
Short and long ratchets
Usual ratchet extensions
12, 14, and 17 mm sockets
12 and 17 mm wrenches
Hammer (a mini mallet is fine, don't break out mjolnir)
Penetrating (lol) spray
Good pliers
Strong mind
Sound soul
A friend to help with popping the first axle out

What to do:
0. Go ahead and crack the lug nuts on your wheels.
1. Jack up the rear of your car high enough to fit yourself all the way up to the driveshaft and give yourself enough room to be able to turn a wrench.
2. Place your jack stands in a safe spot and set the car down on them.
3. Pro-tip - Put some cardboard down where you'll be working so you can slide in and out easily if you're like me and you spread tools out all over the damn place. This will also make sliding the diff out from beneath the car a piece of cake when you have it completely disconnected.
4. Since my car has a KA engine and trans swapped in from an S14, there is also a different drive prop, but I believe the end linkage is the same. Using a 12 mm wrench, remove the 4 nuts on the end of the drive shaft and push the bolts through.
5. Place your jack in such a way that you can jack the cross member that the diff bolts to up ever so slightly to allow the 4 long bolts (that you'll be removing with a a 17 mm wrench, socket, ratchet, and cheater bar) to drop through with little need for finagling.
6. Pro-tip - Now that your bolts are out, support that cross member with something that wont move while you're working.
7. Now would be a good time to pull the wheels off
8. Remove the Parking brake bracket's retention spring with your pliers and then disconnect the parking brake cable from the bracket
9. Using your 14 mm socket and ratchet, disconnect the two bolts holding the caliper on and lift it out of the way.
10. Pull the rotor off of the hub and set it out of the way.
11. Prop up the shock mounting point on the control arm with your jack and pull that bolt connecting the shock to the arm.
12. Go ahead and prop the arm up in a semi permanent state when you lower it and pull your jack away. If you have lowering or cut springs, you'll be wise to prop it high enough so the spring doesn't fall out.
13. Repeat the above process for the other side and have a beer or six. You'll need to be buzzed for what comes next.
14. Crack the nuts on the studs at the back of the diff with your 17 mm socket and ratchet. Depending on where the car came from, penetrating spray may be needed.
15. Get your jack under it to cradle it, give it one more quarter pump so that it is supporting the diff and not the rear mount.
16. Remove the two 17 mm nuts and don't fucking lose them or the retaining plate when you pull it off. The jack is now supporting the diff.
17. Lower the diff ever so slightly and slowly, making sure that you don't hear any popping of any kind. You want to have the back of the diff just lower than it's mount point.
18. Steadily pull the diff back about an inch so that the drive prop disconnects. You're going to want to push it to the side or ziptie it out of the way.
19. Push the diff forward so that it is further forward than it was while jacking it up to its original height.

Here is where the experience may differ...
20. Depending on the climate your car has been in, you may be able to start pulling the axles out the sides of the axle without much problem. But if you can't, some prying may be in order.
20a. If you need to pry it, this is where you need to pay attention. Do NOT remove the 5 bolts from the sides of the diff even if someone else has mentioned it as a way of making the axle prying easier. Those bolts hold the bearings in the diff that the internal diff gearing stick into and putting these back in is a huge pain in the ass from what I've seen. The place that you want to stick your pry bar is between the plate of the bearing housing that I told you not to remove and the hard lip of the axle. Because of the way the axle is constructed, you'll be fine prying it outward because it is spring loaded.
21. I found that it was easier to remove the passenger side axle first, so you may want to push the diff further forward and then to the driver's side.
22. While you're under the car, hold onto the lip of the axle mentioned in sub-point 20a and pull while your friend tugs on the diff from the driver's side. With all of the leverage, you'll be able to get the axle free from the diff.
23. Go ahead and prop the axle on something out of the way so that nothing gets damaged.
24. Slide the diff to the passenger side and the driver's side axle should come out in the process, though some prying may be necessary to get it started.
25. Now you can slide the diff out, lower it down, and slide the diff off of the jack and onto your cardboard.

Now rejoice in your success because you have successfully removed the R180 diff from your car! Next up will be on opening, cleaning out, welding, cleaning out again, creating the gasket with gasket goop, and putting oil in your diff!
1985 KA N/A 200SX