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Unread 07-05-2014, 09:41 PM   #1
Bill_Dunnigan
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Crown Victoria Springs & JK shocks in an LJ

Ok, before you all go on a hate trip, read below!

I finally got around to putting my lift on my 05 LJ Rubicon. I gathered parts for about 2 months for cost savings.

This is my daily driver, and I wheel it about once a month. The trails are challenging but, not extreme, so....

I decided to go with the Ford Crown Victoria Springs in the back and 2" BB pucks in the front.

As for the shocks, the local jeep dealer ship had a set of slightly used (20K miles) JK shocks ( 2" longer) destined for the scrap heap, which they gave me for free.

Here's the cost break down:

New Ford crown Vic springs (police interceptor) : $60 Bucks (napa)
New 2" BB lift pucks : $10 dollars shipped (ebay)
JK shocks: Free! (Jeep stealership)
Rear track bar relocation bracket (teraflex I think): $10 ( craigslist)
Misc hardware (grade 8) : $10 ( local hardware store)

Total: $90 for complete lift!!!


So here's the run down,

Whole install took 4 hrs in the driveway. The back is a lot harder than the front if the 4 upper shock bolts snap, which happen to me and is very common up here in New England. ( the fix: remove the shock after snapping the bolts, Dremel cut the welded nuts or just snap them out with a cold chisel. Replace with grade 8 hardware. Shouldn't take more that 45 minutes to do all 4, and that's the longest I would think it will take!

The rear springs netted me 2 1/2" (2.5") lift over stock (after settling 2 weeks later)

The front pucks obviously gave me 2" in the front.

The rear shocks were bolt in with very minor mods to the bottom bushing sleeve (grind about .080" from each side of the sleeve).

The front shocks needed to have the bottom sleeve pressed out and the stock bar bin pressed in( used the harbor freight u joint tool, some sockets and a vise, took all of 5 minutes to swap them out!)

The ride:

After doing a DIY alignment, and then having NTB make it perfect,...
Thing rides great! The shocks are only slightly firmer than the worn out stock ones I had one there for 120K miles.


Now for those of you who will say the following.......

" that is stupid, why would you mix and match the lift like that...."
" crown Vic spring are only going to give you a $h1tty ride!..."
" You shouldn't have wasted your time, you should have spent tons of money and set your jeep up properly!..."
" you get what you pay for, this is a bad way of lifting a jeep"
" the crown Vic springs bulge to much and don't look safe"
" waaaaa, waaaaa, waaaaa, pout!, waaaaaa, wine!, I'm the jeep god and I know all!!!"
You done?

I'm an electro mechanical engineer with 10+ years with jeeps and engineering, (not gloating, as this isn't impressive compared to some of the other guys on here... Jerry, Blain, both very knowledgable and respected gentlemen)

I deal with springs and shock absorbers a lot.

The crown Vic springs, if cut and installed properly will not bend like a bananna! When installing them, place both the pig tail coils ( top and bottom) towards the front of the spring buckets, also place the coils which are closer together (remember they are variable rate cargo coils) on the axle spring perch.

The crown Vic springs have only a slightly higher spring rate and larger bar diameter over stock rear springs. 140lbs/in vs 167lbs/in. They are also variable rate which admittedly ride firmer than constant rate springs.

Nothing needs to be said about the front lift pucks, everyone knows what they do.

The JK shocks came off a 3900lb 2 door JK. My LJ weighs about 3800lbs.
I know that they are not balanced exactly the same front and back, but let's not be rediculous! The weight bias is very close on both.

The shocks, like I said are noticeably firmer, but not by much, certainly nothing that would bother anyone. It's a jeep not a 70's Cadillac!

And yes, I know I'll need to add 1" extensions to the bump stops, that's coming.

Here are some pictures, I'll post more later.









Crown Vic springs compared to stock.




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Unread 07-05-2014, 09:57 PM   #2
Bill_Dunnigan
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Oh, I should add that there is about a 1.25" rake ( front sits lower than back) after the rear springs settled. It's not that bad, but I'm considering getting some 2.5" - 3" lift coils in the future to level it out. I'm also thinking about replacing the front lower control arms with WJ front lowers, as they allow for more tire clearance while turning and are 1/4" longer which will help with caster once aligned.

Any recommendations?

I'm not going to swap in the V8 ZJ springs. I did that on my last jeep and they were just a bit too stiff!
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Unread 07-05-2014, 10:46 PM   #3
ravenworks
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Been there done this on mine, it rode so bad I took everything out within a week.
I'm not bashing you but you'll have a hard time convincing me how well your LJ rides or drives.
I have a pile of new springs in my shop if you tell me what your looking for up front I probably have them for free but you pay shipping.
For the difference in ride quality your shocks are what's going to make or break you, wait until the bar pins start to rattle.
BTW my LJ is the same color.
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Unread 07-05-2014, 10:50 PM   #4
Bill_Dunnigan
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For my own sake, what made your bar pins rattle? Wrong diameter? Ripped rubber? Can this be avoided? When I did mine, everything looked like a nice tight fit.
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Unread 07-05-2014, 11:12 PM   #5
ravenworks
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The ones I have now are bonded/vulcanized (Bilstein) together to prevent that damn rattle.
The old style bushing just wear out and start to clunk.
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Unread 07-05-2014, 11:15 PM   #6
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As for bump stops you can add length under the cup up front you may need a longer bolt.
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Unread 07-05-2014, 11:21 PM   #7
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I will probably use aluminum extensions for the bump stops. I found some scrap aluminum in my workshop that will be perfect for the job. I also found these... $6

Just need to drill a hole

http://www.mcmaster.com/#1610t12/=sppnhs
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Unread 07-05-2014, 11:27 PM   #8
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I'm going to see if I can put some type of bonding agent between the bar pin and bushing. Guess I'll have to take them out again
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Unread 07-06-2014, 03:42 AM   #9
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Looks good. Maybe the OEM TJ/LJ springs are a better match for Crown Vic springs than you would get from using the V8 ZJ spring up front? Based on the spring rate posted, and the Crown Vic springs being variable rate, it sounds like they would be better balanced, in terms of ride quality, with TJ/LJ springs?
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Unread 07-06-2014, 08:58 AM   #10
ravenworks
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Quote:
Originally Posted by Bill_Dunnigan View Post
I'm going to see if I can put some type of bonding agent between the bar pin and bushing. Guess I'll have to take them out again
Just let them go when they start clunking you'll know what the noise is.
Hell mileage may vary and they may never clunk.
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Unread 07-06-2014, 09:59 AM   #11
rda616
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You could try a set of stock xj springs up front for about an inch more lift and reuse the bb with them. I just scrapped a set last week, or you could have had them for cost of shipping.

Do you have the part# for those rear springs. I am interested in looking up the coil diameter and number of turns to try and calculate spring bind height. The tape looks almost as though they have a 16.5"-17" free length.

I just bought a set of metalcloak 3.5" fronts and don't care for their rears due to the 3" of bumpstop extension they require. Those crown Vic springs could be the answer to my rear spring issue.
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Unread 07-06-2014, 05:21 PM   #12
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They are Moog

CC865 ( I'm pretty sure these are what I got, I know there are one or two other numbers out there for crown Vic springs. I'll measure the bar diameter and confirm tonight)

15.25 free length

See link below:

http://www.moogproblemsolver.com/moo...rings_Spec.pdf

So here's an update. I took out the front shocks today and put some epoxy between the bushings and bar pins. I honestly don't think this is necessary. They are in there really really tight!

While the front shocks were out, I also had a chance to compare the dampening of the jk shocks to the old stock shocks. The jk shocks are much much softer. They are much easier to compress by hand over the stockers.

I drove about 100 miles today and all I can say is that I am very happy with this lift!

I will keep this updated for those who are considering this path.
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Unread 07-06-2014, 05:22 PM   #13
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Are the XJ shocks the same spring rate as the TJ/LJ shocks, just taller/more coils?
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Unread 07-06-2014, 05:40 PM   #14
watkinstj
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I tried the Crown Vic coils but didn't get maybe 1" of lift. Not sure what the difference was but ended up buying springs.
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Unread 07-06-2014, 06:17 PM   #15
joe_jeep
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jeep looks great!
i was gonna do this, but i found a set of lift springs too cheap to pass up.
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