I'm taking a vacation day Thursday and swapping rear torsion bars on the S2. I'm using the drop the whole suspension approach which is a little more work up front, but much more likely to be accurate with the indexing. While I'm in there the axle seals get replaced and brake lines.

I'm armed with the outline and spreadsheet from the board.

Any advice from the been there done that crowd.

Jeff

 

Take Friday off too! Take your time and enjoy!

 

You guys rock... I managed to take last Friday off for a track day... but if I tell em I want to take one off to wrench on suspension, the boss man would probably laugh up his lunch!

I'd get the days though

 

Hey Jeff,

Hope everything arrived in good shape. Although is sounds like it's a bit more work to drop the whole assembly, trust me it's not. I have tried the tilt it down one side at a time (that's how I got the bars out to send to you) method, the disconnect the trailing arms and then drop the assembly down method, and then dropping the whole assembly down with the trailing arms attached method per the Spreadsheet and that is the easiest in the long run.

I am about half way through with a detailed write-up with some pics based on the Spreadsheet method, but I am tired and headed to bed. I will finish it up tomorrow and post it.

What did you decide to do about the bushings?

 

I just did this last weekend to index the bars on the 968. All told, excluding the lollygagging, it took less than 6 hours of actual work time. I had done it before on the '84, but I was being a little more careful this time.

Go ahead and cut the exhaust bolts behind the cat and get the entire rear half of the exhaust out of your way. I was able to unbolt the lower two, the upper two were victims of the sawzall.

Take the abs wires off by removing the bolts holding the two little brackets onto the trailing arm, then you can get them out of the way.

You mentioned the brake lines; just remove the rubber hoses, you can leave all of the hard lines in place.

When you go to remove the 12 point bolts holding the half shafts on, take a bit of stiff wire and clean the gunk out of them first. Make sure you get the bit seated in there very well. I only had to remove the outers; I left the axle connected to the tranny and tied them up with a bit of wire through the upper shock mount. Stick a quart size baggy on the end to keep the grease off everything.

I didn't have to remove the parking brake cables; in fact I didn't mess with the brakes at all except the hoses. I left the calipers and rotors on the trailing arms. Once I dropped the trailing arms, there was enough slack in the parking brake cables to lay the entire trailing arm down and get it out of the way underneth the car.

Once the trailing arms are off and the bolts holding the spring plates to the body are removed, you will need to pry the entire assembly out; basically the bushing in the forward body mount for the spring plate will be holding the torsion tube in. A big crow bar works well for this. Set a couple of jack stands just under the torsion tube (just in case) and work from side to side; you can pry the top of the spring plate against the body (it doesn't take that much force) Once you get it about an inch or so lowered, the goofy bracket at the center than hooks it on to the torque tube will be holding it up from coming out any more. You'll need to get the pry bar in there and pry the points past each other.

To get everything back in place, you will need a couple of jacks; one on each side. Some time ago, I cut up a bunch of 2x4's to make cribbing to support a jack or jack stands or whatever. I found that these came in really handy. Just concentrate of getting the forward body mount and bushing going in straight and you should be OK; once that's started, you can jack further back on the end plate to get the top end of the bannana arm into the right spot.

Good luck. In all, nothing about the job is particularly difficult, it just takes a bit of time and patience. Nothing in the procedure requires a hammer, so if you find yourself reaching for one, stop, take a break, have a beer, then look at it again.

 

Unless you are changing the ride height, make sure you measure the angle of the spring plate after you droped the rear (before you remove t/bs.) You can put a piece of cardboard against the spring plate and trace with a Sharpie.

 

You may want to do the spring plate bushings and TT mount bushings while you're in there. Paragon has the Weltmeister and Delrin bushings. They are not expensive, but extra work to get the old rubber off the spring plates.

 

When I did this, I used the tilt one side at a time method. I did screw up the indexing though. I tried to adapt the spread sheet with the method on Clarks garage and screwed up the angle. So I did have to do it twice.

However, the second time took half the time the first shot did. (First Time = 8 hours, Second Time = 4 hours), and it came out right.

If I was to do it again, I would still do the tilt method, but just find a better way to calculate the spring plate angles.

Seems to me dropping the suspension requires a lot of jacks and two people. I had neither of those.

 

Thanks Guys

Skip - WOW, Everything arrived in perfect shape. The way you packed that stuff up it could have been air dropped from 2 miles up without a scratch! I'm ordered new bushings from Paragon. Really wanted the Elephant stuff, but my "budget" toy is way over budget. Thanks again for all the help and the "new" suspension.

I'll shoot some pics during the process and post.

 

OK – here it is. I plagiarized liberally from OZ951’s procedure and picture as he has a very nice write-up on his website: http://www.oz951.com/public/usefularticles.htm

However he didn’t drop the whole assembly in one piece and use the Joe Paluch’s Spreadsheet http://944spec.org/944SPEC/content/view/42/25/ which is key to getting the ride height set the first shot. Any extra time involved with dropping the whole assembly is more than made up if you do not have to reindex.

The whole job is not necessarily difficult it is just long and tedious, so take your time, plan on the fact that it is going to take 8+ hours your first time, and bag and tag all the bolts using zip lock baggies.

1. Remove cat-back exhaust if it is a type (ie aftermarket) that goes under the CV axles.

2. Remove the rear sway bar - leave the eccentric bolt (C in pic below) that goes through the spring plate alone

3. Lower the car and take measurements per steps 2-6 on the Spreadsheet write-up.

4. Jack car up and put it on stands and take the rear wheels off.

5. Disconnect brake lines at the caliper end of the rubber hose (Pic - item 5) – remove the clip that holds the brake line connector then use a 17mm spanner and a 11mm brake line wrench to undo the connection. Tie wrap a baggy over the end of the brake line to keep from making a mess and tie wrap it up and out of your way.

6. Disconnect the brake pad wear sensor cables near the torsion bar housing to give you some slack.

7. Cut the tie wraps holding the ebrake cable to the tbar carrier to give you more slack.

8. Carefully clean the heads of the cheese-head bolts that attach the CV joint to the transmission, remove the bolts (prevent the axle from rotating witth a jackstand against a wheel stud), place a plastic bag over the exposed CV joint. Suspend the CV joint from the transmission support bracket.

9. Remove the lower shock absorber bolt (24mm)

10. Loosen (but do not remove yet) bolts E, F, G, and H as labeled on the picture below.

11. Remove bolts J, I, and D as labeled on the picture below – impact gun really helps for J.


Photo courtesy of OZ951

12. Repeat steps 10 and 11 on the other side.

13. At this point I put jacks under the tbar housing – one on each side so that the assembly doesn’t fall when it come loose.

14. Now use a pry bar – I found a long 1-1/2 pipe works good – to pry the assembly loose. I would pry down on the tbar end cap (item 2 in pic). You will need to do several iterations of prying on each side to get it loose and you will have to put some **** into it. Keep an eye out to make sure the crash tabs on the tbar housing does not hang up on the corresponding tabs on the torque tube.

15. I left the assembly sit on the jacks once it was free as there wasn’t enough slack to let it sit on the ground.

16. Remove the lower rear bolt of the torsion bar end cap, this will allow the spring plate to be in its unloaded position (bolt F in the pic)

17. Follow steps 11 - 19 on the Spreadsheet write-up.

A couple more notes:

If you are going to RR the spring plate bushings refer to Chuck Moreland’s writeup https://rennlist.com/forums/924-931-944-951-968-forum/147665-how-to-spring-plate-bushing-replacement-part-2-a.html

INDEXING

The torsion bar has 40 splines on one end and 44 on the other end. That means that the splines on the 40 spline end are separated by 9 degrees. The 44 spline end is separated by 8 degrees and 10 minutes (60 minutes = 1 degree). That means that the rotation of the torsion bar can be set to within 9 minus 8o10’ i.e. 50 minutes of angle. A 50 minutes of angle change in the torsion bar will give roughly a 6.5mm change in the ride height. So, to lower the car by 6.5mm (a 50 minute of angle change) you would pull the torsion bar out from its inner mount, rotate it one spline counter clockwise (CCW) and re insert it, then you would put the end cap on 1 spline further in the CW direction.

If you wanted to lower the rear 20mm you could rotate the inner torsion bar by 3 splines CCW and you would rotate the end cap by 3 splines CW. Ie 3x50 minutes change = 3x6.5mm = 19.5mm overall change)

So indexing the torsion bar involves rotating both the inner and outer torsion bars in order to get small changes of angle.

REASSEMBLY

Reassembly will involve a partial reassembly to determine ride height and then a raising of the vehicle again and final assembly of all remaining parts.

The partial reassembly is necessary since there is no guarantee exactly what ride height will result from a new torsion bar installation. You may find yourself having to index the torsion bars more than once. It is typical to have to remove and index the torsion bars 2 or 3 times (although you should be able to hit it the first time using the Spreadsheet).

Unfortunately it is necessary to reassemble the torsion housing and trailing arms and wheels and lower the car, and settle the suspension before the ride height can be measured. If the height when back on the ground is not within the adjustable limits of the spring plate then it will be necessary to remove the torsion housing again and re-index the bars based on the measured ride height and spring plate positions. The good news is that all the bolts will be loose and some things can be left disconnected when checking the ride height (CV joints, exhaust, shocks, sway bars & links). Only reinstall these items after confirming that the ride height was where you want it.

Reassemble in reverse order with note to the following points. The easiest method to get the torsion housing back in is to lift it with a jack under each end, raise it a little on each side. The housing may have to be shifted left or right slightly so that it and the cantilever arms do not bind on anything as it is raised. It is important to not that the driver side carrier mount bolt hole in the frame (bolt J) is slotted, so it is very important that you line up the bolt J hole on the Passenger side first, get the bolt in, and then seat the driver’s side.

 

Skip

Thanks! Thats perfect! I'll let you know how it goes.

Jeff

 

Here is a link to that same spreadsheet, but with more detailed pictures.

http://944spec.org/944SPEC/Technical...25A84779A.html


I devloped that spreadsheet a few years ago when installing 28 mm t-bars in my 944 spec car. I got it right the first time so I was pretty happy. Then I went to 30 mm t-bars inplace of the 28's and it also went smoothly.

The key is taking very carefull measurments. Get sloppy and it will not turn out right.

 

So far so good. Skip - Your write up was dead on. Took all the guess work out.

It has been a lot slower than I had hoped. I lost some real time getting the exhaust bolts off, and even more time shopping for the 12 point I needed for the CV bolts.

All in all not a difficult job, but labor intensive and time consuming. I say that with the caveat that after 6 working hours I'm halfway there with the suspension dropped and T-bars ready to be indexed. If I do it again I can cut out a lot of time. Not in a hurry to do it again though.

I'll let you know how the rest goes.

Jeff

 

This is a very timely article as I will be doing this very soon. I have all the parts ready to go including cleaned up torsion bar ends, new bushings, and new torsion bars. I will have to go a bit further as I blew up the transmission yesterday, so that needs to be pulled in the process. I have not taken it apart yet but expect to find the ring and pinion in a bunch of pieces. Anybody have an S2 Transmission?

 

Good to hear that it is going ok - the first time is always the hardest. Keep us updated.

Joe - thanks for the updated link. Terrific spreadsheet btw, huge time saver.