Current height 7 3/4” measured as per photo. 1 inch lower than minimum.
I’d leave it. But then, I think it looks good slightly nose-down, plus I do all my own work, and rotating torsion bars is a LOT of work. Having your shop do it is a cost/benefit calculation.
Jay,
You appear to be using the ride height specification from the ealier 3.8L Series 1 Workshop Manual. By the time the 4.2s came along, Jaguar realized that the specification was problematic as it took no acount of variations in the tyres fitted and inflation levels. They came up with a new specification described on pages J.X.s.1&2 of the Bentley reprint of the Jaguar Service Manual. It involves taking two suspension measurements and subtracting them, thereby eliminating any variability due to the tyres. Before you make any further change you might want to check using the newer specification. To me, the height looks about right - when set according to the early 3.8 specification, the cars always look too high to me, as if they are standing on tippy-toes…
Many thanks. I shall leave it he way it is!
Looks fine to me, same as my 3.8.
Don’t be afraid to do it ,once you know how it’s just your time . The real trick in all of it is to lower the lower wish bone ( A arm) so the Torsion bar is completely unloaded then get everything clean clean clean
It’s usually a dirty greasy job to start but that only has to be once.
I’d have to wash my hands to do it now or I’d make the parts dirty on my car
Balljoints
When you back off the lock nuts do them far enough so the the nylon is not engaged then separate the tapers
Installing new nuts load the tapers with a common nut with no nylock or exercise the nylocks first so the ball joints don’t spin so easy
I don’t really do them tight till I’m happy with adjustment ( easier to get them apart )
Cheers
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Folks, I’m in the same situation. My T/Bs need to be adjusted. I thought there was a good you-tube video of that process.
Any suggestions?
I’d like to tackle that myself if possible.
Thanks in advance,
Nick
The description in the factory manual is the only way I’ll do it. There are just a couple tips to add to it. Read through it several times and ask questions if you’re unclear.
I substitute a large turnbuckle for a rigid setting link. It’s easier and it’s completely adjustable in case the stock setting span yields an incorrect height. It very often does.
After removing both rear bolts, I jack up the control arm so it is at 90 degrees to the car before attempting to tap out the bar. Same with insertion. It is the position of absolute lowest stress.
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Nick, I installed new TBs a month ago. Here are the notes I made for my future self (or my son as the case may be).
The torsion bars on this car are now 0.860″ “performance” ones.
– The teardrop is the key.
– Follow the directions in the manual.
– Remove the exhaust manifold. It ain’t happening if you don’t. [I have long manifolds from Classicfabs]
– When removing the torsion bar have the a-arm about horizontal. For all other procedures have the a-arm slack.
– Pound the torsion bar from the front of the car to the back, but first completely remove the two bolts from the tear drop, not just remove the nuts (this is important). This may involve screwing the bolt out once the nut has been removed.
When installing the torsion bars put the setting tool at 17 7/16″ [I made a setting tool from a turnbuckle and leftover steel. This measurement is what I used; you may want something different.]
– Have the a-arm slack during this procedure.
– Install the torsion bar from the back to the front to the point you can put in the small locking bolt at the front.
– Align the teardrop with the two bolt holes.
– Ease the collar into the reaction plate hole. This may involve levers of sort (screwdriver, small crowbar, etc.).
– Double check that the teardrop bolt holes are aligned (move the a-arm up or down slightly to align).
– If the teardrop bolt holes aren’t aligning with this slight adjustment to the a-arm you need to move the teardrop to another tooth on the torsion bar. Do not remove the setting tool during this procedure. There is enough slop in the setting tool to allow the required movement. If not, then your teardrop isn’t on the correct torsion bar tooth.
– Once the teardrop bolt holes are aligned, and only then, introduce the bolts into the holes. Yes, you may need to do some small amount of tapping with a hammer, but it should not be a struggle.
– It may take some pounding with the small sledgehammer to get the teardrop flush through the reaction plate hole. Drawing it in somewhat with the upper teardrop bolt can be helpful, but don’t over tighten.
Sort of but not really. What you want to do is rotate the entire bar and that will require removing the setting link and propping the arm out to the side again. You rotate it in the direction you need the closest holes to go in order to line up. Yes the torsion bar bracket will end up on different bar splines, as will the front splines, but this time when you reinsert the rear bracket, the holes will line up better or hopefully be perfect.
Ideally you don’t want to have to raise or lower the control arm even a smidge from your desired setting span for the bolts to pass through. You keep rotating the bar until the bolts simply slip through. The farther they are from fitting, the more splines you need to rotate it. If the closest hole is 50% masked, you’d rotate the bar 180 degrees. (I think)
This is the only systematic way to do this job. It’s systematic because you know exactly what the setting span is. If the car is too high or low, you can adjust that span by a sensible amount and retry. Done this way, it can never take more than 3 tries and it can generally be done in one or two, plus you have a reference for future adjustments.
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Nick
step one
get a manual and check the archives
Make an adjustable setting link
Step two
Disconnect the tie rods
Step three
Jack the front of the car up and remove wheels support clear of suspension
Report back
Cheers
Angus why did you set your torsion bars at 17 7/16" when the manual states 17 3/4". Is it because you have up-rated bars? The reason I asking is that I’m rebuilding the front suspension on my 69 FHC at the moment and have got everything removed from the car and will be re-setting mine when all my parts come in.
I was planning on setting it at 17 3/4" but now wonder if I should set it a little lower. When I removed the TBs the setting were at LH 17 3/8" and RH 17 1/2" and I always thought the front was a little low.
Andy
Indeed. I knew the car was going to naturally ride a bit higher.
When I installed .86 bars Andrew shared this chart that shows comparative setting spans for different diameter bars. It was shockingly accurate. One side was perfect on the first try, and the driver side needed an extra 1/16 or so of setting link span to match it.
That is a much better/kinder way of responding than I was about to! 
All I can say is if Angus was able to achieve the correct ride height using the procedure he described, it’s time to buy a lottery ticket! As Erica indicated, it is fundemental to the correct procedure that the torsion bar be rotated both at the front (A-Arm) and rear (“teardrop”/“rabbit’s ear”). To get the correct ride height there will only be one angular position of the bar within the A-Arm, and one angular position of the bar within the Teardrop that works. This is because there is a different number of splines at each end of the bar.
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Well…to get any specific height that’s true, but there are a range of acceptable ones so long as it’s level to the eye and suits the driver’s style of driving.
Hi Nick not too difficult at all ……Erica and others have told you ….follow the manual…… do make sure everything is clean ……once you get the bars out throughly clean the teardrop, brackets and inside the reaction plate etc …this is essential. As is cleaning at the A wish bone .
I’ve just done this myself ….one thing no one has actually mentioned here is that you should use anti seize copper grease on the splines both end to ensure that if you ever need to do it again it will come apart more easily and stop you swearing ……and r ember as Erica pointed out each time you adjust the position of the tear make sure the a frame is parallel to the ground so everything is easy to move ….it should just slide
Good luck
Hi Nick…top tip…dont be tempted to use a hammer on the torsion bars to remove them…you will damage the splines and then adjustment will be more difficult…use a mallet and brass drift…then clean up all the splines and make sure you can slide the splines together easily…if they dont fit easily then clean them more and a smear of anti seize. …Steve
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Andy, bravo for measuring before. very logical. To raise the car by half an inch add 3/8 of an inch to your setting link.
Obviously Erica has done this job once or twice before. Her excellent tip on removing the TB - once you have split the ball pin, lowered the A-arm and removed the bolts at the rear, raise the A-arm to near horizontal and the TB will slide out of the front splines easily once the small locking bolt is removed. Otherwise there is enough tension on the bar that makes it difficult to get it out of the splines in the A-arm.
For tying off the hub carrier / brake disk assembly when separating the top BJ, I used a length of Romex house wiring. It’s strong enough to support the assembly yet soft and flexible enough to tie into a crude knot and not harm anything. I couldn’t find an old wire coat hanger to cut up. I used the angled tube of the subframe as my support point.
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