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Discussion Starter · #1 ·
You're cruising down the road in your 5th gen, listening to VTEC sing, and all is right with the world. Suddenly the peace is shattered, you hit a minor bump just the wrong way and you hear it, the dreaded "shock knock". The moment isn't quite ruined but the mood is lost....

If this sounds like you chances are you've tried Matt Hyder's shock knock washer fix at http://www.prelude.clara.net/prelshok.htm . Maybe it worked for you, maybe not. Honda acknowledged the problem in TSB 99-084 which called for some pretty drastic measures to fix it, and in November of 2000 released an updated TSB 00-090 which replaces 99-084. This new TSB calls for the simple replacement of two steel collars which sit around the shock shafts in the rear suspension.

Disclaimer
I take no responsibility if you destroy your car or stab yourself with a screwdriver. If you have any concerns about what you see here, just take your car to Honda as they should do the repair under warranty. I'd rate this as a 2.5 on a difficulty scale of 1-10, 1 being an oil change and 10 an engine rebuild.

I should also mention that I STILL have some knock even after doing this but it is definitely better than before (and better than having the washers installed). Matt was on the right track with the washer fix though, as you will see. For me the next step will be to install some firmer bushings if I can find them.

On To The Procedure

What You'll Need

* (2) Honda part# 52728-S30-004, replacement collars
* Flat head screwdriver
* Pair of channel locks/pliers
* Silicone (or equivalent) lube, preferably aerosol
* Metric allen wrench set
* 14mm box wrench
* Band-aids (for skinned knuckles)

I got the collars from http://www.handa-accessories.com. They're about $4.50 each and Trevor was nice enough to add them to the "Maintenance" section of their www page so you can order them online.

Step 1
Take the light bulb out of your trunk light and remove all the trunk trim, jack, etc. You can leave the spare. I'm not going into detail here and if you have any problems this early in the game you should probably just take your car to the dealer.

Step 2
Pick a side to do first. Looking at the shock mount, you should see something like this (you can't see the collar yet):



Notice I already have washers installed per Matt's fix.

Step 3
Using your hex set and 14mm wrench, remove the top locknut like so:



You'll need to hold the shaft still with the hex set while you loosen the locknut as the shaft will rotate otherwise. Put the locknut and top plate aside.

Step 4
Pry out the upper bushing. Carefully work your screwdriver around, prying from several angles carefully until it pops out:



You should now see something like this:



The collar is that brassy-looking steel piece around the shaft.

Step 5
Remove the collar, pulling it straight up with your channel locks/pliers. Get a good grip on it and just wiggle it out. Nothing is holding it in place except the lower bushing which is gripping it.

Now that the old collar is out let's compare the old with the new. They both have the same OD (14mm). The ID is also the same (10mm), but the new collar is 2mm shorter than the old one, 39mm vs 41mm:



If you visualize everything put back together with the new collars, you will see that by installing them you will be allowing the top plate to come down further before it contacts the top of the collar, compressing the top bushing further than with the stock collar length.

Step 6
Lube the new collar up on the outside (spray some lube down the shock shaft for good measure) and install the new collar. Just put it over the shock shaft and push down on it with hands/screwdriver/etc. You may find that the shock shaft is now off-center in the hole in the lower bushing. If this is the case you will have to put some lateral pressure on the shock shaft to center it better while you push down on the collar to get it seated. When you are successful it should look something like this:



Step 7
Lube the edge and inside of the upper bushing and replace it over the old collar. Reinstall the top plate and locknut, remembering to hold the shaft in place with the hex wrench while you tighten down the nut. I believe this is supposed to be torqued down to ~25ft/lbs but I had no way of doing this due to the need to hold the shock shaft with the allen wrench. Just tighten it down good, not too tight (don't strip anything).

Step 8
Do the other side (rinse, lather, repeat....)
Step 9
When you're all done with both sides reinstall the trunk light bulb and all trim pieces.

Drive around and be sure to hit a few bumps. Hopefully your knock is now gone, or at least greatly reduced.

Good luck!

KrautLude
 

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Hmmmm if 39mm was good I wonder if 37mm would be better. I might want to try to shave a tiny bit off the passenger side just for the hell of it. Yes I'm a glutton for punishment.

BTW thanks for the great write up...and let me be the first to suggest this ends up in the FAQ's!!
 

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*hint* *hint* i need a new job real soon.... hehehehe

very nice write up... now, let's see if i'm actually going to fix it.
 

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I really enjoyed that. But I find it hard to believe that just 2mm shaved off of that collar would really fix it? O.K., if enough of you guys say it works, I'll take your word for it.

Thanks for the nice writeup and CLEAR PICTURES! Good work!

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Discussion Starter · #7 ·
No problem guys, glad you like it. I wanted to give a little something back to the most mature 'lude forum around.

KrautLude
 

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Originally posted by KrautLude:

No problem guys, glad you like it. I wanted to give a little something back to the most mature 'lude forum around.

KrautLude
Not to sound like a sap, but stuff like this really makes this forum head and shoulder above the rest.
 

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I now know what I'll be doing on Sunday afternoon.

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"and on the seventh day, God created VTEC"
 

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Why not just shave a few mm off the stock one, rather than buying new ones?

What would be the problem with this?

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Originally posted by BRacing:
Why not just shave a few mm off the stock one, rather than buying new ones?

What would be the problem with this?

I'm sure that'll work as well but no one knew the difference in the parts until Krautlude did the fix and write up.
 

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Discussion Starter · #16 ·
Originally posted by Neur0sis:
Done. http://www.sonic.net/~danm/shock for now, until I get the re-direct URL working.

Great writeup KrautLude! Send me your info so I can credit you on the webpage!

Looks good, though you cut off my first paragraph. KrautLude is fine for giving credit, you can also link my email address to it if you want in case people have questions I can answer.

Most importantly, please put that the writeup was done for the fine members of the honda-acura.net Prelude community and place a link to the Prelude forum here and to the original FAQ article once the mods put it up.

Thanks!

KrautLude
 

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Discussion Starter · #18 ·
Still a bit of noise but noticably better than before; I'm happy so far. I'll bet for most people who haven't tried the washers this will fix it completely. I think playing around with the washers was a mistake as I might have overdone it and put too much stress on the bushings at some point. Rubber bushings compress and deform if pushed beyond their limits, hence Matt's warning about putting too many washers. There seems to be a fine balance between not enough pressure (like stock, causing movement and noise) and too much pressure (much beyond 2mm of washer thickness, causing damage to the bushing).

My next step will be to find very firm bushings (polyurethene w/graphite?) and replace all four. Maybe that coupled with the new collars will finally eliminate the noise completely!

KrautLude
 

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Originally posted by KrautLude:

Still a bit of noise but noticably better than before; I'm happy so far. I'll bet for most people who haven't tried the washers this will fix it completely. I think playing around with the washers was a mistake as I might have overdone it and put too much stress on the bushings at some point. Rubber bushings compress and deform if pushed beyond their limits, hence Matt's warning about putting too many washers. There seems to be a fine balance between not enough pressure (like stock, causing movement and noise) and too much pressure (much beyond 2mm of washer thickness, causing damage to the bushing).

My next step will be to find very firm bushings (polyurethene w/graphite?) and replace all four. Maybe that coupled with the new collars will finally eliminate the noise completely!

KrautLude
Thanks again for your input...I might try and shave the passenger side collar just a tiny bit more to try and get it just right. The worse that happens is I re-use the stock collars and shave them down the 2mm to the TSB size.
 
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