Andrew, stick with the stock CATS struts. Chris of Mina Galleries and Jagbits sell them for $350/each. For some reason, QuartzSTR has a persistant CATS error? Everyone else haven't. The Bilstien "Sport" struts, which mine presently wears, are too soft (inadequate dampening) with the H&R Sport springs.

 

Definitely sounds like the damper(s) are blown,

Try and find the absolute lowest price on two new rear CATS dampers, and go with those.

If you absolutely must run non CATS, change all 4 to V8sport and reuse your stock STR springs. you can try mounting your h/r springs, but like bfsgross reports, he finds them 'too soft' in regards to dampening to suit the lowering springs,

Bilstein is a very popular damper in the aftermarket, and there is a lot of motorsports related companies that do extensive bilstein service, including rebuilds and revalving.
You should try and google for 'bilstein rebuilds' and contact a company who could do a CATS damper.

If they can rebuild most bilstein models, it stands to reason the CATS damper can be rebuilt as well. This might be the most economical and best performing way to run the lowering springs on your STR. The downside being your car will be down for a while as they are shipped out and done; be advised,
turn around during the busy motorsports season is NOT fast, this may not be a suitable option for many STR owners, unless you want to ride on cheap non-CATS replacements for a while to hold you over, as the CATS are off the car and shipped out.

 

I recall a thread by Brizco88 where he had the same issue I did; I don't believe that it got resolved or at least he never updated with a resolution. I thought there was another member as well, but I could be wrong. Personally, I don't think the non-CATS struts are too soft; then again I came from a Mercedes E430 with a much softer ride despite being lowered with sport shocks as well (and a modded e30 M3 before that where I could make the car extremely stiff). You did mention after switching yourself that the car rode much better than worn out CATS struts. Would it be better with new CATS struts over new non-CATS struts? Yes. For 4 times the cost? Not to me. I think my car rides better now with the non-CATS struts + H&R springs than it did with CATS struts and stock springs (with 50k miles), so I feel it is an improvement for me.

 

GT42R makes good sense with either a new or rebuilt strut.

 

Ever since Brutal posted the link for rebuilding the CATS struts I have been hoping someone would try it and report back.

Bilstein is the one doing it so I think the original manufacturer would get it right. Still have not heard a price or time other than the CATS are rare enough that yours are rebuilt, no core so you would be without your car that whole time.
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Andrew, just wanted to add: replace the one rear shot strut ($350). And as others chimed: H&R Sport lowering springs go in with struts.

 

Sounds good guys. Well here's the thing, I might be able to get the left rear strut repaired at no cost. If the job gets authorized, the tech is going to purchase the specific bushing part of the strut assembly to repair, not sure if this is considered a "rebuild". They obviously want to be cost efficient and not buy the whole strut.

At the time of purchase 3 weeks ago, the tech pressed in new bushings for the left and right lower control arms which was needed. Most places advise to get the control arm because of difficulty. They covered cost, but did it economically once again. This tech told me he can order specific parts and "rebuild" almost any assembled components on jags. Only works on high end cars including a lot of jags, so I hope the owner authorizes the work which would be right thing to do. I'll find out the outcome on Monday since the owner is on vacation.

I'll keep you guys posted.

 

Eh, rebuilding/replacing the lower mount bushing on the bilstein damper body is one thing and relatively easy, so I'm sure he can do that.

This should solve the issue relating to the CLUNK you're hearing, no doubt.

If your damper is blown internally though, the ride will still be bouncy, although the clunk will be gone.

Taking apart the bilstein damper internally and rebuilding it, is another matter, and I would ask if he is experienced or equipped to perform that kind of overhaul.

 

^^^ what he said!

 

Ahh, great information right there. I will have the damper investigated. What would you have to do in order to see the condition of the damper? Computer diagnostic or physically look/take it apart?

 

I suspect you bounce it and see how well it works. I guess with IDS you can probably activate it and see if it's a lot stiffer?

Or you look for how badly it's wept oil?

 

Is there any oil or oily film on the body of the strut that might indicate leakage?
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The jag tech said there is no leakage on the strut. I suppose this is a good sign for the condition of the damper.

 

Unless it's empty LOL

 

I just got off the phone with the owner and he won't cover the costs. Says the car passed inspection and we already replaced bushings and now you come back asking for a strut/pads/rotors. Its a used a car and I am not obligated, car was sold as is etc...I was annoyed and argued but nothing I can do. Anyway, not the end of the world.

Moving forward, I want to change all 4 rotors/pads. I was going to go with Premium Dimpled and Slotted Brake Rotors:

Front Two Rotor Set (Silver) #RS-20024 w/premium semi-metallic pads.
Rear Two Rotor Set (Silver) #RS-20022 w/ premium semi-metallic pads.

http://brakeperformance.com/brake-ro...ake-Rotors.php

Let me know if these will be an improvement for braking performance. Anyone who can chime in, greatly appreciated.

 

My take is that dimpled/etc will not give better performance. Just a fashion accessory and probably extra cost.

 

It's up to you but my 2005 STR at 87K miles is still on all 4 factory disc's. I cut the disc's just to clean them up when I install new pads.

Use Akebono pads unless you like cleaning the wheels every week!!
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JagV8 is right.
BUT:
there are OTHER fashion-only accessories on our STR's. Take, for instance, the "spoiler": not functional. aesthetic only. Our cars ARE a fashion statement, to some extent. We like that they LOOK good, in addition to going-good.

It seems a little ironic that we might decide NOT to improve the looks of our Jaguars with a better-looking brake rotor simply because of a couple $$. If we had wanted something without "fashion-accessories", we likely would've bought something other than a Jag, no?

 

That's a very good point you make

 

Ditto. My 03 STR has slotted/dimpled rotor and I don't feel brakig improvement for daily driving. At the track they may make a difference. Ditto again to Achebono ceramic pads.