Just bought XJS - question!
Discussion
Hi, I haven't been on PH for a while as I've been trottng around the world.
I've just returned to Jaguar ownership, by buying a 1988 V12 XJS for a 'round of drinks' price. (I was looking for a cheap fiesta-ish runabout until I was tempted by this).
Nearly everything is fine, although there is some non-structural rust. My main worry is that, on braking, the car judders and the steering wheel rocks back and forth by an inch or two at the same time. The car doesn't pull to either side though.
The car also vibrates at 70 - 80 mph, but I suspect this to be worn UJs or out of balance prop shaft. Anyone have any idea, opinions advice?
I've just returned to Jaguar ownership, by buying a 1988 V12 XJS for a 'round of drinks' price. (I was looking for a cheap fiesta-ish runabout until I was tempted by this).
Nearly everything is fine, although there is some non-structural rust. My main worry is that, on braking, the car judders and the steering wheel rocks back and forth by an inch or two at the same time. The car doesn't pull to either side though.
The car also vibrates at 70 - 80 mph, but I suspect this to be worn UJs or out of balance prop shaft. Anyone have any idea, opinions advice?
Sounds like warped brake discs. Just hope its not the back ones - changing those is a 4 hr plus job. And as for non-structural rust, are you sure? check radius arm mounts.
And check the condition of the underbonnet fuel hoses, ht leads and dizzy cap. Fire is not uncommon, especially when combined with round of drinks prices.
And check the condition of the underbonnet fuel hoses, ht leads and dizzy cap. Fire is not uncommon, especially when combined with round of drinks prices.
Thanks. I was rather hoping you weren't going to say that, but I suppose facts have to be faced! Trip to the garage, pretty sharpish, methinks! 
Radius arm mounts were among the first things I checked, but I'll have a closer look at the other stuff as well. Thanks for the advice - I'll get on the case!
Radius arm mounts were among the first things I checked, but I'll have a closer look at the other stuff as well. Thanks for the advice - I'll get on the case!
Check the inner wings too down past the air intakes!
the general rule for the back brakes btw, can get quite extensive, as if you are doing them it generally involves dropping the subframe, and if youre doing that you may as well overhaul the calipers and fit new handbrake pads whilst their out, and if youre going to do all that you dont want oil dropping onto them from the diff above it so better overhaul that too
Get the idea? scary stuff!
down past the air intakes! the general rule for the back brakes btw, can get quite extensive, as if you are doing them it generally involves dropping the subframe, and if youre doing that you may as well overhaul the calipers and fit new handbrake pads whilst their out, and if youre going to do all that you dont want oil dropping onto them from the diff above it so better overhaul that too
Get the idea? scary stuff!
First things first: Jag Lovers XJS Pages. Not knocking PH, but the guys on the XJS forum are very good with helping out (PH Jag forum can be a bit quiet).
Secondly: I'd have a four-wheel tracking/alignment done (along with re-balance each wheel). This may well clear the vibrations at speed.
Third: The judder under braking is almost certainly the front disks. Rear disk would give vibration, but not give the steering-wheel shakes.
Finally, the V-12 fire issues are related to the Marelli ignition. You may or may not have this system. Get the under-bonnet electrics serviced, and if the engine ever loses power suddenly, stop immediately (The power loss is because one bank isn't getting spark, but fuel still gets injected. Thus the engine is pouring fuel into the exhaust system, and this then catches fire!!!).
Hope this helps. Kitty is an expensive mistress, but would you really rather be in a fiesta?
Sheepy
'86 XJS 3.6l
Secondly: I'd have a four-wheel tracking/alignment done (along with re-balance each wheel). This may well clear the vibrations at speed.
Third: The judder under braking is almost certainly the front disks. Rear disk would give vibration, but not give the steering-wheel shakes.
Finally, the V-12 fire issues are related to the Marelli ignition. You may or may not have this system. Get the under-bonnet electrics serviced, and if the engine ever loses power suddenly, stop immediately (The power loss is because one bank isn't getting spark, but fuel still gets injected. Thus the engine is pouring fuel into the exhaust system, and this then catches fire!!!).
Hope this helps. Kitty is an expensive mistress, but would you really rather be in a fiesta?
Sheepy
'86 XJS 3.6l
Just thought I'd resurrect this thread to give you an update and ask more daft questions. The juddering under braking turned out to be warped front discs. The vibration at 70-80 mph disappeared after the discs were changed, which was a bit of a surprise, but not to be complained about.
Next job is the steering rack, which leaks like a New Labia MP. My long term plan is to upgrade the car's handling and performance after I've done all the more routine jobs, and this includes the steering. I was thinking about stiffer rack bushes and something to quicken the steering and/or reduce the power assistance. I understand there was a valve that could be fitted to the rack to reduce the assistance, but a quicker rack from a late model car would have much the same effect. As I probably have to replace the rack anyway, I may as well fit a late rack now. Can anyone advise on the wisdom of this and whether a late rack will fit directly to an 88 XJS?
Apart from all that, the car is behaving impeccably. So much more satisfying than the miserable hatchback I was going to buy!
Next job is the steering rack, which leaks like a New Labia MP. My long term plan is to upgrade the car's handling and performance after I've done all the more routine jobs, and this includes the steering. I was thinking about stiffer rack bushes and something to quicken the steering and/or reduce the power assistance. I understand there was a valve that could be fitted to the rack to reduce the assistance, but a quicker rack from a late model car would have much the same effect. As I probably have to replace the rack anyway, I may as well fit a late rack now. Can anyone advise on the wisdom of this and whether a late rack will fit directly to an 88 XJS?
Apart from all that, the car is behaving impeccably. So much more satisfying than the miserable hatchback I was going to buy!
Hi Bruce,
I'm having a rack rebuilt right now. Dunno about mods to valves etc, but make sure you have a true XJS rack and not an XJ6/XJ40 rack as these give a poorer steering response (but are cheaper and hence a common PO fit). Uprated bushes on the rack mounts will help too (so I'm told, until I get my new rack I won't know!!).
The JEC have a technical advice line which may be able to help, alternatively my supplier is very good with advice(Derek Watson). Speak to Terry or Ken (if he's in a good mood!!).
Sheepy
I'm having a rack rebuilt right now. Dunno about mods to valves etc, but make sure you have a true XJS rack and not an XJ6/XJ40 rack as these give a poorer steering response (but are cheaper and hence a common PO fit). Uprated bushes on the rack mounts will help too (so I'm told, until I get my new rack I won't know!!).
The JEC have a technical advice line which may be able to help, alternatively my supplier is very good with advice(Derek Watson). Speak to Terry or Ken (if he's in a good mood!!).
Sheepy
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