Maybe it’s just my experience, however nobody seems to mention the issues related to threaded rods method. Taking the springs out is a long, long joy. Assembling it - joy again… Until the spring pan is getting close to the wishbone. Then, you will face all sort of crap so be prepared for it - all our folks in here seems to put some censorship on what’s below.
Make sure you have two bottle jacks available and able to extend to the height of assembled spring pan, able to be used on the surface where you’ve started your operation.
Make sure you have ratchet straps as well
Threaded rods are more likely disposable after completed change - so grab at least 10 of them.
Unless you’ll use steel compression olives (tapered) on each rod - your spring pan may try to shear the threads off the rods while both - winding out and winding in again. That may mess up your nuts and take much of the strength out of them.
The biggest problem hits the fan when you’ll unscrew one of rods and try to insert the bolt to finish the job. You have zero chance to align pan and threaded holed for the first time. Good luck with fiddling
It is worth to mention - I would never trust geniunie compressor (which is now non-genuine made in Hungary by the way) being used on rusty turret mount. However with rods - it makes perfect alignment tool.
There is also a website called eBay. My grandson told me how it works and I’ve managed to hunt down designated compressor for £60…
In reading the posts, if you are putting in new springs, you can use a oxy/acetaline torch to heat up a few spots on the spring rosy red and it will bend. Do this in a few spots and the tension will be relieved. This is what we do on used cars. So much quicker and safer. Do not cut the spring, just heat. That way, you only need the factory tool once. If you are ever planning on using the springs again, then this procedure is not recommended.
Just curious, I know these larger XJS springs are more dangerous, but I’ve done many large McPherson strut coil replacements on the bench, putting the standard two clamps on each side and compressing that spring down to where it almost can’t compress anymore. All while staring it in the face. Are dealing with the XJS springs that much worse? Is it because of the spring pan?
I think that is the fact that the XJS springs are very compressed, I would say that installed are less than half of their uncompressed height.
BTW, I have used the big centre threaded rod and smooth (not threaded) guides. I’ve used an 5cm tall nut and oil/grease to preserve the threads. Did the job many times and it’s still ok.
I also used a lock nut on the top so it would stay put, a bronze wedge washer on the bottom because the pan is on an angle and many big fat washers.
On reassembly it helped a lot to have the guides slightly bent inwards.
Aligning the pan to insert the bolts will be a big pain regardless.
I managed to strip a thread as one bolts did not go in straight, so rethreaded all of them and put 8mm, if I remember correctly, metric allen bolts. Easier to get them in straight as they have a slightly coarser thread.
Also be prepared to do that job more than once and with the subframe in place as you will not know what your final ride height will be with the aftermarket springs and might have to add or remove packing rings.
The external clamps work on the bench. The XJS spring does not allow that kind of access. Even if it did, once you remove the lower plate, how are you going to remove the spring with the clamps on each side. They do compress a lot so releasing the external clamps will not work.
Been reading a lot of the archives, is the fulcrum bolt through lower wishbone gonna be an ordeal? (I’m also replacing lower bushings)
I’m hoping some penetrating oil and a 5lb sledge hammer should work? Or is it only the horror stories that get posted?
On my zero rust car, it was easy. But I can imagine on a car exposed to road salt that it would be a bear. It’s big, with lots of surface area to rust and seize. I reinstalled mine with lots of antiseize.
I have changed out Jag front springs quite a few times, and we have the correct tool in our Jag club, however the main thread is worn, and when I checked some engineering tables, the yield of that one main rod thread is less than using 3/8" threaded rods.
I use the threaded rods, and do not feel it is unsafe.
when you think about it, who has ever heard of the 5 screws failing in situ, when they are subject to extra force imposed by bouncing up & down on the road.
even if you have a badly rusted spring pan, I do not see how the OEM tool would be safer
I use ratcheting ring spanners, lubricant and make sure it is even.
the rods need to be 30cm long
once the majority of the force is released from the spring you can use 3 rods instead of 5 if you feel lazy
If someone could point out exactly how it is more unsafe, I am always up for learning
And just for the record, there are 4 threaded holes on wishbone for rods to screw into, not 5.
If the oem tool is used, there are two guiding rods used in conjunction on the two non-threaded holes on the wishbone (secured underneath with nuts)
And a good safety tip Kirby pointed out in archives, strap a bicycle chain lock tightly around spring/frame.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
34
Ugh. Never did it myself, but have reports of people (including dealer service departments) having to do a lot of heavy framming to get those things out. I have wondered if the heavy hitting is swelling the shaft a bit, making it harder to move. It might be a good idea to begin with lighter tapping.
You may want to see if they are free to turn before removing the sub frame form the car. Mine were in solid and required two days of hammering twisting and penetrating oil. Would never have managed it without the sub frame anchored to the car to resist all that force.
Regarding ride height, on my xjs 94 2+2, the replacement springs were “blue stripe” with a wire diameter of 0.69". The OEM were 0.65". Both the old (when removed) and the new were 12" tall. When you run the math, that should amount to about 1" difference in compressed spring height for just the thicker wire diameter (neglecting any old spring sag), assuming 1000# on each wheel. Mine had 5 spacers, 3 lower and 2 upper. The result of installing the new spring raised static height by 3/4" (measured floor to bottom of wheel well). I expected more, given the color code on the new spring indicated a firmer wire. However, happy with the result.
There are 6 bolts that hold the lower plate in place. 4 go into threaded holes in the a-arm, two are bolts with nuts. Also, I have found that when calculating spacers required to change the height, 1/8" of spacer changes the height about 5/8".
When I changed my front springs, the ride height was low by approximately 3/4”; I installed the spacers as they were. Initially the ride height was high by about an inch, but settled to the specified height within a few hundred miles. So don’t rush to start adjusting spacers until your new springs settle.
, the breaking strain on these zip ties is miles over the the spring compression.