Jeff N.

So I'm following this procedure to change my stock T-bar to a 30 MM tbar.

http://members.rennlist.com/m758/TbarReindex.htm

Question on step 3 & 4:

- I have removed the sway bar as it states.
- Do I need to remove the rear shocks too prior to measuring?

I tend to think so as the shock limits the downward travel of the wheel shortening the measurement (I get like 13" with the shock attached, 16 1/2" with it disconnected).

Appreciate any clarification.

Cheers!

Jeff

kdjones2000

A couple of things here.

1) YES, remove the shocks, as they limit travel in your unloaded state, and will mess up the calculations.

2) You ALSO need to remove the LOWER REAR BOLT on the torsion bar end caps. If you have stock bars on now, these also limit the travel in the unloaded state. This is mentioned in the Clark's Garage writeup, but not in this procedure.

3) I have a modified XLS sheet that can help with setting your new index up using a better procedure than just "Eyeball and try again". PM me.

Cheers,

Keith

mclarenno9

I just did this as you may have remembered and have a few suggestions:

- Measure just as the instructions state, I had 9"/9.25" D/P on the ground and 13"/13.25" in the air WITH the shocks connected. I also wondered the same thing when I was doing mine but said screw it and continued as planned.

- I wasn't sure if I could lower the whole assembly at once with the parking brake cables and such, since I don't think there is any easy way to disconnect it. I actually took the trailing arms off seperately before I dropped the torsion tube. In reality, they will have to come off anyway so you can get the spring plate out to replace the bars, so here is where I thought the instructions were a little misleading. Just make a note of where the trailing arm is positioned on the spring plate, scribe a line around it, and take a look at the hole for the toe adjustment tool and make a mental note of where it is. I would do this because the trailing arm can slide back and forth quite a bit in the spring plate to adjust the toe and depending on where it is, it could affect your measurements.

- Once I had everything apart and the torsion tube lowered I reconnected the trailing arms in about the same alignment that they were on before. I took my measurements at this point from the banana arm down to the hub center. I got around 12" for both of those. So, based on the programs calculation I needed to be around 9.5" for my setup (orig 23.5mm bars to 30mm bars). It is worth noting that my spring plate eccentrics were set to lower the car as much as possible.

- Since I had the eccentrics at their lowest setting I wanted to make sure I went lower than needed so I could use them to even out the sides, so I factored that into my indexing as well (or tried to, didn't do a good job, read below).

- First time I tried I had the passenger side 0.5" higher than the driver's side (25"/25.5" D/P). I was not happy with this so I took it out again and adjusted since I couldn't go down any lower with the eccentrics. So now after settling the car a bit, I have both sides around 25" ground to fender (which I know is the improper way of measuring but you can get more precise with it) with only about 0.125" difference between the sides. If I drive it I'm sure they will lower a bit more so I am hoping no more than 1" or else the eccentrics will not be able to compensate!

- In reality, this job is pretty much a **** shoot, no matter wht anyone else says. Sure, you can get close your first time but you will most likely be doing it again, so just suck it up and get to it. I didn't think it was that bad after the first time taking it out and wouldn't really mind doing again either. I bought an impact gun for this job and man it really makes this procedure go a lot quicker!

- Make sure you have a safe way of keeping the back of the car in the air! I put the front of the car on ramps and used something I saw on the 911 boards for the rear... The rear jackpoints on my car were very mangled and knackered so I didn't feel very safe with them to begin with, so I bought the following:

-About 6' of a 4 x 4 which I bought for about $10 at home depot.
-Craftsman 4 ton jackstands (Sears, http://www.sears.com/shc/s/p_10153_1...e%7CJack+stand). They have much flatter, wider tops than most I've seen (see picture, about 3.25" across IIRC).

First, cut notches into the 4 x 4 so it will fit into the tops of the jackstands better. The 4 x 4 is actually 3.5" wide and you will need to spot the locations along the wood to make the notches. A chisel and a hammer works well for this.

Then, position the 4 x 4 across the car, aligned with the rear jackpoints. I used pieces of plywood on top of the 4 x 4 by the jack points to prevent any stress cracks in the 4 x 4. Once you get the rear high enough you can get jacks under each side of the 4 x 4 and lift the entire rear end. Then, just slide the jack stands under the 4 x 4 where you have the notches cut out (they should be right under the jack points as the best case). The car should be very stable at this point.

The problem I see with most jackstands is they are not meant for a square jackpoint like our cars have, but for frame rails. I did not feel very safe with putting a small block of wood on top of them because they would only be stable in one direction so by using the 4 x 4 you are sort of "tying" them together in the unstable direction.

See the pictures and you can probably figure it out. I am tired of typing.

M758

I did mine with the rear shocks still in place. Maybe I should not have, but it worked out fine when I did it about 7 years ago. I even got it right the first time. Ok I did change my mine and took out the 28 mm bars and put in 30's a year or so later, but that does not count.

I can't remember what did for the e-brakes.

Jeff N.

OK. Those starting measurements dove tail to mine.

Trying to follow this. I have everything disconnected EXCEPT the parking brake cable. I don't see an easy way to disconnect this. How exactly did you do it? Did you disconnect at the wheel hub (pull the caliper + the rotor and disconnect inside) or some other way? I am hoping that you can disconnect at that Y up by the torque tube. First inspection looks like that only disconnects one side, not both.

Hmm...as I look at your pics, it looks like you didn't disconnect it at all. ??

I'll be sure to scribe the spring plate to trailing arm as you recommend + note the position of the toe bolts.

What amount of drop did you want in the rear? With my front fender lips (bottom lip) at 25", I have my rear drop at just between 1.25 and 1.5".

Is this factored into your 9.5" measurement? Would it make sense that if you had set your eccentrics in the middle, you would have planned for a 10" span?

I'm thinking I want to plan for a 25 1/8" fender lip (the 1/8" is to assure the car has no rear bias in the rake) with the eccentrics set in the middle. From here, I could drop it as low as 24 5/8 or as high as 25 5/8 with the target again 25 1/8.


Why was this? Did you 'mis index' the bar on one side or do something else?
What is the ending height of your bottoms of your torsion caps? They started at 9" right? What are they now?

Hehe...but you will save me here! Thanks for being the pioneer!
I actually have those stands and have small wood 2x4 wood blocks I sit on them between the jackpoints. I don't like metal to metal on those things. As you mentioned, it knackers them up + I just don't trust the friction coefficient.

The 4x4 solution looks better. I may go that way!

I really appreciate the input... THANK YOU!

mclarenno9

Sorry I wasn't clear here. I thought I would have had to disconnect the cables but you do not have to at all!

The rear of my car had already been lowered with the eccentric but it was roughly 25"/24.75" D/P so I tried to even them out a bit. So, I actually wanted to add a quarter inch to the passenger side and keep the drivers side the same.

All I was trying to do was to make sure the spans were as the program gave me (~9.5") and maybe even a little less, which would put the car lower than originally, because the eccentrics were at their lowest setting. They were not factored into that 9.5" target, though. That is what the spreadsheet gave me. I knew I could always go up easy, but going down more would require a reindexing. That's the part I underestimated.

It's likely I was off a bit on the one side with my indexing. It is not a very precise science as I have learned. The only way to really do it is to try and redo if it's not to your liking because every car is a bit different. Also, things tend to settle differently on each side and there are many factors that can throw off your measurements, like how the trailing arm is attached to the spring plate. If I indexed both bars exactly the same on each side I would bet the ride heights would not match up.

I will tell you in a few hours, the front of the car is in the air ATM.

Yeah, I didnt like the fact that it would only be stable in one direction since the top of the jackstand is not square so by putting the 4 x 4 in there it makes it stable in that direction as well!

Jeff N.

OK - this is really good. You're going to likely increase my chance of getting this right the first time by about 3000%.

Maybe one last round of Q's before I dive back under the car. Can you confirm the numbers you used for the calculator?

1 - starting bar was 23.5mm correct?
2 - new bar diameter was 30mm correct?
3 - 'ride height adjustment' figure was ?
4 - 'loaded height' was ?
5 - 'unloaded height' was ?
6 - the calculated 'trailing arm distance change' (the delta) was ?
7 - your final distance "H" was 9.5 right?
8 - your planned / target rear fender lip height was 25 right?
9 - what size tires do you have mounted in the back?

...and when you did all this - the car was ... correct @ 25" one side and a half inch too high on the other right?

TIMM BALDAUF

If you have a track only car & your not changing the swing arm bushings, this is the way to go!
A plastic plug covers the hole.Fast & easy!
http://9magazine.com/files/Issue_30.pdf
page 25

mclarenno9

1 - Yes, but you will easily be able to check when you take it out. Use an open end wrench.
2 - Yes
3 - D/P 0" / +0.25" ride height of 25.00"/24.75" originally
4 - D/P 9.25" / 9.00" loaded
5 - D/P 13.00"/13.25" unloaded, shocks connected
6 - D/P -2.34"/-2.40" delta H
7 - D/P 9.79"/9.35" final H
8 - Yes, planned height was 25" but if anything I wanted to be lower because I could go up with the eccentric.
9 - 225/50/16

Yes, the first time that was the case. Make sure you roll the car back and forth a bit and bounce it once back on the ground to try and settle the suspension. The bearing flange to upper mount (it is a stud coming out of a rubber mount with a 17mm nut) I left loose so it could slide up into there. This has not happened quite yet. I am thinking if I drive it a bit and hit some bumps it might pop into place.

Unfortunately, I am waiting for new Koni yellows and I need to put new CV boots on the joints before I can give it the final shakedown. Hopefully it will not settle more than 3/4" or so, that way the alignment shop can use them to bring it up a bit.

IMO, once you have everything out the first time, it shouldn't take you more than 2 hours thereafter to reindex if you need to (most of that time was spent jacking up the car!). Just leave the axles, brake lines, and exhaust disconnected / off and it will be cake, esp. since everything is loose. The hardest part is when you are raising the assembly back into the car and it always catches on something (both of these points were noted in the pictures).

Jeff N.

OK.

Got the t-bar dropped tonight but ran into some problems. The 24mm nuts on the spring plate are way frozen on. Note to self - loosen next time when the unit is in the car. We did get them loose with a huge breaker bar and jack handle but the bolt is turning. Need a big a$$ end wrench to get on the inside and hold the bolt.

Also, when trying to initially pop the subframe loose from the forward mounts, one of the rubber bushings tore a bit as it hooked on the bolt hole. That sucks. Will need to replace that as well and will likely to both sides to keep it even.

Have to travel this week for work and then out of town next weekend. *sigh* This job is going to take a while.

mclarenno9

Yes, that also almost happened to me as well. You have to make sure those bushings are going in/out squarely. I caught mine on those holes a few times but somehow they did not rip. Mine were actually quite pliable and seemed to be in good shape, which is odd because every other rubber bit on the car has basically been replaced cause of deterioration!