XJ6 & XJ12 Series I, II & III 1968-1992

xj6 REAR THUMPING, SHOCK TOPS?

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Old 01-21-2009, 07:23 AM
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Default xj6 REAR THUMPING, SHOCK TOPS?

HELLO AGAIN
I forgot to mention one other thing, my 1990 xj6 makes a horrible thumpint noise from the back, sounds like the typical shock tops,
any thoughts?? also a similar noise from the front, if so, what kind of job is it,

thanks
 
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Old 01-21-2009, 03:49 PM
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Default RE: xj6 REAR THUMPING, SHOCK TOPS?

Perhaps transmission mounts......
 
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Old 01-21-2009, 08:44 PM
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Default RE: xj6 REAR THUMPING, SHOCK TOPS?

Greetings,

I'm assuming you have tube shocks in the rear of your car, and not the hydraulic ride levelling system,

The rear shocks have foamisolators above and below the top mounting plate, they do deteriorate but not as quickly as the front. Worse is the urethaneguide bushing that plugs into the top plate: the shock shaft goes through the center of it, and they deteriorate until the shock shaft is rattling against the top plate.

You need one of each of these items for each side on the rear:

CBC 2254 55 lower isolator
CBC 2257 60 upper isolator
CBC 2933guide bush

You have to remove the shock and spring assy from the car, fit spring compressors and remove the top mounting plate to replace these shock mountings. Each side in 1.5 hours is fair.

The parts are maybe $40. total for each side. New factory shocks come with the isolators, KYB DO NOT. You have to obtain the guide bush separately, I've never seen any shocks that come with them.
 
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Old 01-22-2009, 08:04 AM
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Default RE: xj6 REAR THUMPING, SHOCK TOPS?

thanks Jagtech, that helps alot
appreciate your time,
 
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Old 02-12-2009, 02:14 PM
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Default shocks?

OK, so that solves the thumping noise coming from the right front when I hit the sharp Iowa Highway bumps~thanks!

What about shocks? I know one of my left rear shocks is bad as there is oil coated all over it. I am thinking of just replacing all of the shocks-front & rear. From the research I've done, Gabriel is the factory replacement and maintains the best original ride. I've used Bilsteins in my stock car and liked their performance, but have heard that they stiffen the ride up a bit in a Jag. That doesn't sound like too bad of a deal to me though, as I prefer a bit of a tighter feel. What do you guys recommend?

Also, I found that Jaguar Specialties sells a 1" sway bars to replace the factory 3/4" sway bars. I can believe that this stiffens it up when cornering, but are they really worth it? Link: jaguarspecialties

Thanks in advance, Paul
 
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Old 02-13-2009, 01:41 PM
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depends on how fast you can drive around the corners from your house to the grocery store without turning into a demolition derby.

Shocks are a sensitive subject. Bilsteins and Konis are expensive, and they are hard as rock. The XJ was not meant for back-breaking stiffness.

do me a favor and buy the cheapest shocks you can get that fit the XJ, then let me know what you think.

Take one of the rears and one of the fronts to get them matched at any auto parts store. when they ask you "what kind of car?", tell them it's just a chassis you are building, no car as such. Tell them to match them, then install them. Let us know what you found out. I already did.

Jose
 
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Old 02-13-2009, 08:41 PM
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Jose, I'll back you up any time you are right, and you are on this subject. And Gabriel shocks were never OE on a Jag. Girling for early SIII XJ6, Boge for later. The Boges work well for all Series III and are a good value. Cheaper is not.
 
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Old 02-14-2009, 05:42 AM
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thank you JTO, I am as you know, not always right, but sometimes I get close.

you are right about the Girlings and Boges. My '84 came with Girlings, I replaced the Fronts with Boges, bad decision. Fortunately I kept the old Front Girlings. The 4 rear Girlings are still there!

Girlings were the equivalent of American Monroes, in my humble opinion.
Bilsteins suck. Koni suck. Boges suck. Gabriels are decent.

In fact, any cheap American brand is better than any of the above expensive shocks for the XJ. CarQuest, AutoZone, Advance, you name it, they all have their own "Monroe" quality house-shocks. Usually cheap. Buy them with your eyes closed.

Does anybody remember when Sears had an auto parts catalog? 1960's ? They had some
very nice generic shocks back then.

So here's what I have found out:
all shocks wear out, and they wear out fast. The "like new" feeling wears out fast.
Shocks are like oil and filter, like guitar strings, they need to be replaced often, but nobody does.

So if you install cheap shocks whenever you notice they are worn, you maintain that "like new" ride for the least amount of money.

If you want a stiffer ride, you don't have to spend your paycheck in Bilsteins, just buy the KYB and you will get the same for less.

Put your money in wider tires if you want a faster XJ. Use 235/60/15, the difference in red light performance can be clocked. (more rubber on the asphalt equals faster forward acceleration, Car and Driver magazine did a study on that and their conclusion was to add fatter tires). Not like a Mustang 5.0 or Chevy Corvette, but certainly a lot better than before.

Install a K & N Air Filter, you will notice another improvement in forward acceleration.
Part number E-2350 for the XJ.

and here's one that nobody believes:
install SplitFire spark plugs. You will get faster starts, better gas mileage, and a lot more throttle response when you step on it. If anyone wants the part number, I'll post it here.
I use Splitfire plugs in both my 3.8 S type and my 4.2 XJ-6.

Jose
 
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Old 02-16-2009, 02:31 PM
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Originally Posted by Jose
depends on how fast you can drive around the corners from your house to the grocery store without turning into a demolition derby.
Jose
LOL! My "local" grocery store is over 10 miles away, rural blacktops/highways, very little traffic so I could tear it up pretty wildly if I wanted to. I've competed in demo derbys in my past life as well...I'll pass on trying that insanity with my XJ6!

Thanks for the pointers. The service station in town and the NAPA parts store both pointed me toward the Gabriels. I should clarify that they said they were the stock replacement, not OEM. I'm on a first name basis with all the service stations and parts stores around here due to my racing days, so they're all quick to cut me a deal on parts and stuff.

Since noone commented on the sway bars, I will assume those to be a pointless waste of money as well. I just wanted to broach the subject to see if anyone had tried them, or even heard of them or not.
 
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Old 02-16-2009, 03:08 PM
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the problem with going with a larger-stiffer sway bar, is that you end up with a false sense of security, in which you take the car over its limits and end up oversteering or understeering into the closest tree or light pole, which always seems to get in the way.

with stock size tires, I would treat the Starship with a lot of care. I only realized the handling potential of my XJ-6 after I installed Dunlop 235/60/15 tires, (while using stock sway bars and shocks). the fat/low tires make a huge difference in fast turns, in braking, and acceleration.

Gabriels: If the price of the Gabriels is low enough, go for it. Just don't pay a lot because the car is a Jaguar. Otherwise Gabriels are good shocks for 3 years.
 
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