Torsion Bar End Cap Removal and indexing?
10-18-2009, 10:23 AM
#1
Three Wheelin'
Thread Starter
Torsion Bar End Cap Removal and indexing?
I'm adding coilovers and keeping the tbars (keeping them because I want to, OK?). I have worked out that I only need to adjust the tbar at the outer end by rotating them by 1 spline. What's involved in removing the end caps - ie how much do you need to drop the torsion tube to get enough room? Can you leave the flex brake lines attached?
10-18-2009, 11:09 AM
#2
Drifting
Join Date: Jan 2008
Location: Suburban DC
Posts: 2,641
Likes: 0
Received 0 Likes
on
0 Posts
Search for the three part write up on this site somewhere. I did it about a month ago and it's very comprehensive. Good luck with the job. Be patient (but have a big pry-bar available).
PS: I went about 18 months with t-bars and coilovers before pulling out the t-bars. Re-indexing is as difficult as removing t-bars, so rather than do what you did, I picked up firmer coilover springs and just pulled out the t-bars. If you re-index as you plan to, you'll avoid the one issue I had, which is the coilover springs getting "airborne" when the suspension unloads.
PS: I went about 18 months with t-bars and coilovers before pulling out the t-bars. Re-indexing is as difficult as removing t-bars, so rather than do what you did, I picked up firmer coilover springs and just pulled out the t-bars. If you re-index as you plan to, you'll avoid the one issue I had, which is the coilover springs getting "airborne" when the suspension unloads.
10-18-2009, 12:43 PM
#3
i tok my bars out and he is right, it takes a HUGE prybar. glad i dont ever have to do it again. you can do it with the brake lines on but its not worth it. bleeding them is pretty easy.
10-18-2009, 02:55 PM
#4
Drifting
Join Date: Jan 2008
Location: Suburban DC
Posts: 2,641
Likes: 0
Received 0 Likes
on
0 Posts
I managed with a very big screwdriver but wish I had a big prybar. The torsion bar needs to be tipped but the prybar is needed to get the end cap out of it's spot .
10-18-2009, 03:06 PM
#5
Drifting
Join Date: Jan 2004
Location: Michigan
Posts: 2,023
Likes: 0
Received 0 Likes
on
0 Posts
It takes me about 45 minutes per side to re-index with the right tools. I just had to do this on a car 5 times to get it right. You can lower each side at a time just enough to get the aluminium end cap carrier off and out of the way. It helps to have a second person hold the swing arm out of the way and in positioning it. The brake lines do not need to be removed but the clips holding the brakes line should be, it will makes things might easier and not stress the lines.
The difficult part is pulling the end cap off which either the bar staying in the torsion tube or keeping it in the end cap so you only move one end of the bar. On the other side make sure you move that same end. The splines are different and the index spacing is different depending if you move the inner or outer splines.
Rear 2.25" springs are about $80 new. There's no reason to keep the headache of torsion bars.
The difficult part is pulling the end cap off which either the bar staying in the torsion tube or keeping it in the end cap so you only move one end of the bar. On the other side make sure you move that same end. The splines are different and the index spacing is different depending if you move the inner or outer splines.
Rear 2.25" springs are about $80 new. There's no reason to keep the headache of torsion bars.
10-18-2009, 03:08 PM
#6
i got my end caps off with a small bar, it was tipping the tube that caused problems. the factory undercoating and bushings had it "welded" in place. it took a 3ft bar to move it. she went back easy.
12-10-2009, 08:34 AM
#7
Three Wheelin'
Thread Starter
I'm finally about to do this job. I have 250 lb/in springs with the stock 24mm t bars. I have so far fitted the coilovers (at their lowest possible spring setting - but still in compression (just) when unloaded) without reindexing and they have raised the rear end about 30-35mm, which is pretty close to what I calculated. I'm guessing that by reindexing and moving the inside spline I will drop this by perhaps 67mm (drop without coilovers) x about 75%(note 1) to take into account the additional spring compression in the coilovers - so a drop of around 50mm (which would then be about 15-20mm lower than stock - I am aiming for -20m).
Should I instead rotate by 2 outside splines - or will this put too much preload in the coil springs due to having to raise the perches? I'm trying to avoid errors by moving both inside and outside splines.
Love to hear anyone's experience with similar coil spring rates.
note 1: my logic is that the total effective spring rate is made up of 50% tbar and 50% coilover spring, but the coilover only compresses by around 50% of the total drop (67mm), so the coilover will reduce the drop by 25% of the total.
In retrospect it is more logical to assume a drop (after coilover is initially installed) that is relative to the coilover effective rate. Eg, 250 coilover = 140 effective, tbar = 137, drop = 67 x 137/(140+137) = 33mm
Should I instead rotate by 2 outside splines - or will this put too much preload in the coil springs due to having to raise the perches? I'm trying to avoid errors by moving both inside and outside splines.
Love to hear anyone's experience with similar coil spring rates.
note 1: my logic is that the total effective spring rate is made up of 50% tbar and 50% coilover spring, but the coilover only compresses by around 50% of the total drop (67mm), so the coilover will reduce the drop by 25% of the total.
In retrospect it is more logical to assume a drop (after coilover is initially installed) that is relative to the coilover effective rate. Eg, 250 coilover = 140 effective, tbar = 137, drop = 67 x 137/(140+137) = 33mm
Last edited by Eric_Oz_S2; 12-13-2009 at 08:27 PM.
Trending Topics
12-13-2009, 09:55 AM
#8
Three Wheelin'
Thread Starter
It takes me about 45 minutes per side to re-index with the right tools. I just had to do this on a car 5 times to get it right. You can lower each side at a time just enough to get the aluminium end cap carrier off and out of the way. It helps to have a second person hold the swing arm out of the way and in positioning it. The brake lines do not need to be removed but the clips holding the brakes line should be, it will makes things might easier and not stress the lines.
The difficult part is pulling the end cap off which either the bar staying in the torsion tube or keeping it in the end cap so you only move one end of the bar. On the other side make sure you move that same end. The splines are different and the index spacing is different depending if you move the inner or outer splines.
Rear 2.25" springs are about $80 new. There's no reason to keep the headache of torsion bars.
The difficult part is pulling the end cap off which either the bar staying in the torsion tube or keeping it in the end cap so you only move one end of the bar. On the other side make sure you move that same end. The splines are different and the index spacing is different depending if you move the inner or outer splines.
Rear 2.25" springs are about $80 new. There's no reason to keep the headache of torsion bars.
It took about 8 hours all up (incl 2 hours trying to get the tbar tube back in - figured the easy way how to do it, so next time will be much quicker). I think next time I could do it in about 5 hours. 90 mins seems hard to achieve considering all the bits that need to be removed.
I also discovered that dropping one spline on the inside with coilovers (250 helpers) drops the rear only 35mm (ie about half of the 67mm you would expect for tbars alone). Doh!!! Back to stock - not stock -20mm as hoped. If I get keen I'll do it again and turn the tbars another spline.
