Bilstein Shock Install Update

DOC4444 · **Posted:** Sun May 03, 2009 6:05 pm

Finally had a chance to install the Bilstein F4-BE5-D917-HO on the rear of the CRD (otherwise stock suspension).

1. I was surprised to find how much slop there is between the mounting bolts and metal bushings on the OEM shocks.

2. Extended and compressed lengths are very similar, so no worries about internal bottoming with the Bilsteins.

3. OEM shocks were not leaking, but (by hand) seemed to have virtually no bump damping and LOTS of rebound.

4. Bilsteins (prior to install) appear to have at least 30% more bump and similar rebound to OEM.

5. Bushings on the Bilsteins are also extremely sloppy using the OEM shock bolts.

6. Harsh bottoming on rear bumpstops has been eliminated over sharp bumps/dips.

7. Despite retightening shock bolts beyond factory limits, at least one side rattles, possibly both.

Have to use shim stock around the bolts or install sleeves to eliminate this.

Somehow, even the "easy" jobs never seem to turn out that way.

Will report after the fronts are installed (much more involved project).

DOC

BioCRD · **Posted:** Fri May 08, 2009 9:44 pm

So, how are the Bilsteins with the rears only installed? I'm looking to replace the rears, at 43000 mi, with a lot of towing, the factory shocks are probably done - and Firestone air bags will be put in too, just to keep things level with/without the trailer.
Any recommendations?

DOC4444 · **Posted:** Sat May 09, 2009 8:57 am

See # 6 above. Other than largely eliminating harshly crashing into the bump stops in the rear over sharp dips, there is no difference in ride/handling with just rear Bilsteins installed. This makes sense because the rebound seems to be similar to OEM (hand shock dyno).

The rear airbags should be good. I have experience with them with other vehicles, but not the Jeep. We tow a 4500 (loaded) pound horse trailer using equalizer bars, so airbags are not needed. However, I took the trailer empty to get hay the other day, skipped the bars, and I could see that in that configuration, airbags would be essential.

Still have not sttled on how to eliminate the rattling. need to do that before installing the fronts.

DOC

DOC4444 · **Posted:** Sat May 09, 2009 3:58 pm

Picked up a spare upper and lower rear shock bolt to facilitate fabricating spacers without disabling the Jeep and found DCJ has "superceded" the lower bolt with one with a much thicker shank.

Voila! Rattle eliminated, no fabrication required!

DOC

mOlson · **Posted:** Fri May 15, 2009 4:10 pm

By "hand shock dyno" are you referring to the piston rod coming back quickly after compressing by hand? If so this is simply the gas pressure moving the piston back and the faster it comes back the LOWER the rebound; ie shock is blown. High rebound damping means the shock more strongly resists the spring once compressed.

-Edit: Also, in comparing the stock shocks to the Bilstein in this way is not going to show you anything. Bilsteins typically run relatively high gas pressures.

DOC4444 · **Posted:** Fri May 15, 2009 9:27 pm

mOlson,

Thought my post was pretty clear, but to further clarify, the only problem we were experiencing with our '05 CRD was inadequate bump damping in the rear so that sharp dips got us into the bump stops way too quickly causing a real pounding. Bilsteins completely cured this problem without changing any other of the ride characteristics (which are fine).

"hand shock dyno" refers to not bothering to put them on our "real shock dyno" and relying on 15 years of experience working with and rebuilding Penske, Bilstein and Koni racing shocks to make a decision. (After a while, you learn to distinguish the difference in "feel" between gas pressure and actual damping.)

I am very confident that a comparison done on the SPA dyno would show that the OEMs with 50K have much less bump damping than the new Bilsteins and similar rebound damping. (Not precise enough for subtle changes done with racecar tuning, but good enough to go ahead and just bolt them on.)

Actual performance after installation on the CRD is also consistent with this assessment.

Happy to send you one of my used OEM rear shocks if you would like to run comparison profiles on your shock dyno against a new Bilstein.

DOC.

jinstall · **Posted:** Fri May 15, 2009 11:20 pm

This thread is so full of WIN!!!

mOlson · **Posted:** Tue May 19, 2009 1:00 pm

Spa? I'll stick with our Roehrig :wink:

(although they look suspiciously similar)

I cheaped out and just replaced the stock units with KYBs and compression and rebound is still way soft. Do you have any idea if the Bilsteins are significantly more firm (than the KYBs) to make the switch?

tonycrd · **Posted:** Tue May 19, 2009 5:43 pm

I think its great someone tried the Bilstein shocks.

Don't want to trade them for my Rancho's though! :wink:

DOC4444 · **Posted:** Tue May 19, 2009 11:30 pm

The Bilstein tech rep I spoke to before purchase indicated that their notes suggest that their Liberty, stock ride height replacement shocks are about 30% stiffer than OEM, but could not be more specific as to whether that is 1/1, B/R, or ??? They also indicated that the bodies F/R are the "crimped" style so that they do not offer the custom revalving option they do for many of their shocks.

I have no idea how KYB valving compares to Liberty Bilsteins or OEM. Refer to my previous posts. I am very satisfied with Bilsteins on the rear (fronts not installed yet).

Before ditching a new set of KYBs, I'd be inclined to try a set of incoil rear airbags. They are cheap and I hear they work well. Since we only tow with equalizer bars we don't have a need for them, but I would definitely go with them if towing without bars.

DOC

mOlson · **Posted:** Wed May 20, 2009 11:39 am

DOC, that does help to clarify things a bit for me. Good to know also that I can't open up the shocks as well. My parts supplier describes the KYBs as "OEM replacement" so if that means the Bilsteins are 30% stiffer I may go that route. And there is no way I am towing with this thing and not having anti-sway and load equalizing bars; good to know you are having good towing results.

DOC4444 · **Posted:** Thu May 21, 2009 7:39 am

The Bilstein tech rep I spoke to before purchase indicated that their notes suggest that their Liberty, stock ride height replacement shocks are about 30% stiffer than OEM, but could not be more specific as to whether that is 1/1, B/R, or ??? They also indicated that the bodies F/R are the "crimped" style so that they do not offer the custom revalving option they do for many of their shocks.

I have no idea how KYB valving compares to Liberty Bilsteins or OEM. Refer to my previous posts. I am very satisfied with Bilsteins on the rear (fronts not installed yet).

Before ditching a new set of KYBs, I'd be inclined to try a set of incoil rear airbags. They are cheap and I hear they work well. Since we only tow with equalizer bars we don't have a need for them, but I would definitely go with them if towing without bars.

DOC

ribbon · **Posted:** Thu May 21, 2009 3:23 pm

The Bilstein tech rep I spoke to before purchase indicated that their notes suggest that their Liberty, stock ride height replacement shocks are about 30% stiffer than OEM, but could not be more specific as to whether that is 1/1, B/R, or ??? They also indicated that the bodies F/R are the "crimped" style so that they do not offer the custom revalving option they do for many of their shocks.

I have no idea how KYB valving compares to Liberty Bilsteins or OEM. Refer to my previous posts. I am very satisfied with Bilsteins on the rear (fronts not installed yet).

Before ditching a new set of KYBs, I'd be inclined to try a set of incoil rear airbags. They are cheap and I hear they work well. Since we only tow with equalizer bars we don't have a need for them, but I would definitely go with them if towing without bars.

DOC

ribbon · **Posted:** Thu May 21, 2009 3:24 pm

i wanted to be part of the double post club too

DOC4444 · **Posted:** Thu May 21, 2009 10:03 pm

I have not made a post on this thread since the 19th. What on earth triggered a repost two days later (i.e. on the 21st)?

DOC

jinstall · **Posted:** Thu May 21, 2009 11:13 pm

jelousy(spmsorry I haev had a few too many) LOL.

kjfishman · **Posted:** Fri May 29, 2009 11:35 am

DOC4444 wrote:

Picked up a spare upper and lower rear shock bolt to facilitate fabricating spacers without disabling the Jeep and found DCJ has "superceded" the lower bolt with one with a much thicker shank.

Voila! Rattle eliminated, no fabrication required!

DOC

I called the local dealer parts and they didn't know anything about superceded lower bolt. Do you have a part number?

Thanks
----------------

DOC4444 · **Posted:** Fri May 29, 2009 7:06 pm

Actually, it turns out I was misinformed. The only superceded bolt is the UPPER one. I ended up using 4 of the NEW upper bolts in all 4 positions on the rear shocks. They are both larger in diameter and longer than the original ones. The part number is 6506147-AA.

I am sure if you have access to a really great selection of bolts with mostly "shank" and few threads, you would not need these, but they aren't that horrible compared to AN (about $4 each).

This should take care of your rear shock rattles.

DOC

kjfishman · **Posted:** Fri May 29, 2009 10:01 pm

DOC4444 wrote:

Actually, it turns out I was misinformed. The only superceded bolt is the UPPER one. I ended up using 4 of the NEW upper bolts in all 4 positions on the rear shocks. They are both larger in diameter and longer than the original ones. The part number is 6506147-AA.

I am sure if you have access to a really great selection of bolts with mostly "shank" and few threads, you would not need these, but they aren't that horrible compared to AN (about $4 each).

This should take care of your rear shock rattles.

DOC

I wonder if a really good hardware store would have them for less? Did you happen to note the diameter and length of the new bolts?

dieseldoesit · **Posted:** Wed Sep 14, 2011 8:32 pm

bringing this back up,

Doc, did you ever get the fronts for the Jeep? What have been your impressions of the shocks?

Bilstein Shock Install Update

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