I'm about the rebuild the front end on my '90 XJS.

The service manual mentions the use of "Mid-Laden" tools. I assume these are used to set the suspension at the correct height or load prior to aligning the caster, camber and toe.

Anyone know the part numbers for these tools? Where can I buy them?

Thanks!

Mark

 

Safari
They are quite un-necessary. If you are using the same springs, just be careful to ensure the same number of height shims (the big plastic rings under the spring in the spring pan) go back in as came out. If you are worried about ride height, this is how it is adjusted. If you are using new springs; take a couple out each side and you should be fine, but it is trial and error, even for Jaguar main dealers!. You want about 6 to 6 1/2 inches under the centre beam of the subframe.

The Great Palm, in one of his few (in my view) errors, makes great play about them. Total tosh.
Greg

 

.Greg is spot on.

The only "special tool" if you really want to platy by the book, it the one to remove the front springs. However, the human race being what it is, has devised many ways of getting them out, and back in again, without losing too many fingers. Those suckers are dangerous.

The only thing to remember is when reassembling, is to place the lower wishbone parallel with the cradle BEFORE tightening that big thru bolt. Failure to do this "preload" will "tear" the Metalastic bushes in about 5 miles once the load is back on the unit, and you will be doing it all again.

I have also refitted the cradle, after the rebuild, with that thru bolt LOOSE, and then with the weight of the car back on the suspension, and I have bounced it a few times, final tighten that big bolt. The steering rack will neeed to be OUT of the way to do this, so access to the head of that big bolt is possible.

 

Advice coming from Greg or Grant never needs backup from me, but, for the record, I agree

Cheers
DD

 

Thanks for the info guys. I have done many, many front suspension jobs but this will be the first one on an XJS and as usual, Jaguar is different.

I normally replace the parts and then take it to an alignment shop but its a challenge trying to find one willing and able to do the job properly.

I might just have to invest in some alignment equipment so I can do the work myself. My shop gets smaller every day. ;-)

Mark

 

Many alignments shops won't work on older Jags be because of all the hoopla and ballyhooing over mid-laden tools, ballast weights, Jaguar mystery, blah blah. Once past all that nonsense.....it can take some arm-twisting to get them to agree to even do the job.....they find that a front wheel alignment is very easy to do on these cars. No tricks or magic at all. Perfectly ordinary job. Probably easier than many other 'ordinary' cars out there.

Now, that said.....

Moving to the rear suspension is a different matter. The only adjustment is for camber and it is a bit of a PITA and the half-shafts must be disconnected to add/remove shims.

Cheers
DD

 

Aha, the mud clears a tad.

Wheel alignment on the Jag is not rocket science, different, yes.

The only trap I have had over the years is the shimming on the upper wishbone inner pivot. These are standard GM style shims. HOWEVER, the only trap I mentioned is that whatever thickness shim/s are place on the front bolt, MUST be duplicated on the rear bolt. This maintains the upper pivot shaft and the lower pivot shaft in a state of parallel. This is the "camber" adjust ONLY.

Most aligners are lazy, and attempt/do the "normal" car adjusting style of camber/caster with diferent thickness shims front and rear. This habit on the Jag will reduce top bush life to months, every time.

The caster adjustment is made by moving the "fixed number" of shims AT the top balljoint, front and rear, until the measurement required is achieved. The number of total shims stays constant, and memory HAHAHA, is 4 shims of different thickness per side.

This is time consuming, and is why the lazy guys do not do it, or have so many excuses about Jags, you walk away.

 

How very strange, landed here from a search engine while looking for information

When it comes to getting an alignment shop to do something "different"
it is sometimes helpful to discuss the job with the technician, and somehow
drop the information that you where all the adjustment points are, and how
they work. A printout would be helpful. This might tip the balance since some
of the reluctance might be due to not knowing where to find the adjustments.

Now, weights or mid laden tools, which is how I landed here ...

the best inside story about adding weight for a wheel alignment seems
to be from a BMW site where it is also a hot topic. However, it all made
sense when a couple of people shared some stories. One came from the
factory BMW wheel alignment trainer for the US dealership network.

According to him, the weight was not used to simulate a load. Rather it
was to position the vehicle to a pre-determined height. The weight totals
something like 700 pounds depending on model and options. People who
have had an alignment done this way claim it is night and day.

I suspect the mid-laden tools do the same job, only differently and
without having to lugh 700 pounds around.

Of course, YMMV.

 

Right, same for Jaguar. The idea is to lock the suspension at xxx-height.....which might be either higher or lower. I think the 'mid-laden' terminology is a little tidbit from the past that Jaguar technical editors couldn't let go of.



Even after all these years I'm not aware of anyone having it done both ways on a Jag and then reporting back. It would be very interesting. We know that it is easy to get good results without the tools. The question is whether or not using the tools ensures optimal results.

I always found it a bit odd to be very particular about locking in an *exact* ride height.....and then giving us a rather wide **range** of acceptable adjustment settings. Isn't the precision of the former negated by the imprecision of the latter?

Personally, I always tell 'em to make the settings at the existing ride height and to get as close to max spec on caster and camber as possible. That is, take the negative camber as close as possible to max allowable spec, and take positive caster as close as possible to max allowable spec. Always been happy with the results.

Cheers
DD

 

I have only recently come across Jaguar technical bulletin 60-5 and it actually states that the sportspack and xjr-s variants should be at their normal ride height rather than use the tools. (interesting that it also gives slightly different alignment specs for xjr-s)
As long as ride height is more or less "normal" I can't see that the tools are an absolute necessity.

 

Thank you Great Francis for the write up about having the load on springs prior to tightening lower fulcrum bolt. The all data manual does not specify that needs to be done. I was driving around with the front end about 1 foot higher than back of car. I hope the bushings are not torn after not doing this correct the first time. I will update if I need to change bushings.