Shim Stack Mod Question (with pics)

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#1
Hello All!

I've got a question about how to put the pieces back together on the valve body in the bottom of the fork legs. I tried to keep track of exactly how things came apart, but there's one piece I lost track of it's orientation (which way is right side up). It's that little piece with holes in it, then a little washer, then the shims, ect. Does it go like this:


OR like this:


The rest is fairly obvious, but I'm not sure on this piece. I've had this apart before, (I'm actually removing a third shim now) but I'm not sure I got it in right the last time. I really need some help on this!!!

Thanks a lot!

Rob
 

blackduc98

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#2
It's been a while since I've done my forks, but I think the valve orientation should be like the top picture.

The spring goes on the bottom, narrow end of spring faces the valve (what you referred to as the "thing with holes"). Then the washer goes on top of the valve, topped off by the shim stack.
 
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#3
OK, so 1 vote for picture number 1. Thanks!

I know a lot of people on here have done this change, so if a few more of you would post what you remember, I'd greatly appreciate it! I'd hate to install that value upside down.

Rob
 
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#4
I'm pondering this mod myself. On a mechanical difficulty level how would you rate it?
 
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#5
As far as getting it done, it's pretty easy as long as you don't loose track of how the little pieces go back on there! :bang:

The main thing is getting the valve body out and back in again, which is where the "trick" to it is. I compressed the forks with a tie down strap and used an impact gun with a 14mm allen socket to loosen it. Then released it and turned it the rest of the way out. It can be tightened back up the same way. Last time I put the impact on the lowest setting and spun it till it was snug, then put the torque wrench on it and was able to get it to 35 ft-lbs before it started to "turn". When I took them out this last time (2 years later), they were still plenty tight in there.

Any more thoughts on how those little pieces go back on there? Better yet, does anyone have the factory shop manual that's willing to scan that page for me????? ;) ;) ;) ;) Pleeeeease????

Rob
 
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#6
There should be an electronic version of the manual out on the interweb somewhere! I'll do some lookin'. A while ago I managed to dig up a factory service CD for my BMW, very cool - includes training videos!
 

blackduc98

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#7
robl: I looked in my manual, but it does not show that level of detail. Sorry.

BTW, manual says 71 N-m (54 ft-lbs) is the right torque for that 14mm allen bolt. Personally I don't really like using an air impact wrench. Instead I made a tool to hold the damper rod from the inside. Go to a hardware store and buy two 27mm nuts. My h/w store didn't have metric nuts that big, so I bought the closest available which I think was 1 1/8 (my caliper says it is 26.4mm) and it works just fine. Also buy a 2-foot steel pipe approximately 15mm I.D. Weld one nut on each end of pipe. Presto! If you can't weld yourself then find a welding shop and I'm sure they'll do it for peanuts. It doesn't have to be pretty.
 
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#8
Thanks for taking the time to look. That's surprising they don't show that. It could be the shops don't mess with the valve assembly when they service forks.

Good idea on the tool! I may give that a try! (I don't actually tighten anything down with the impact - I don't think that's a good idea either)

I'm still fishing for info on the assembly order of the valve assembly if anyone on here remembers. I may have to give Jeff Fredette a call!

Thanks,

Rob
 

blackduc98

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#10
Can you measure I.D. of the shims, and O.D. as well as I.D. of the valve shank? By "shank" I mean the middle protruding part of the valve (in pic 2). I'm thinking if shim I.D. is the same as shank I.D. then pic#1 must be the right way.

And if you can post a pic of the rest of the assembly, that would help to refresh my memory.
 
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#11
OK, that's a good thought - when I get home I can do some measuring with my calipers.

Here's a picture of all the parts:


I got a response on the FRP forum suggesting that the remaining parts on the table go on like this: thin washer followed by the shims, then the rest of the parts from right to left but flipped over.

I'm sure it may be difficult for someone else who has done this in the past to remember such specifics. I removed a couple of the shims already a couple of years ago, but I think I may have put things in there wrong because they never really worked very well. So, I can't be sure I can even trust the way I took them out this last time.

Thanks guys,

Rob
 

blackduc98

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#12
robl said:
I got a response on the FRP forum suggesting that the remaining parts on the table go on like this: thin washer followed by the shims, then the rest of the parts from right to left but flipped over.
My memory recollection agrees with the response you got from FRP forum.

I suggest you post your question with pics to "Suspension Q&A with Jeremy Wilkey" forum here on DRN. Jeremy has done so many forks that he should be able to answer your question with his eyes closed.
 
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#13
blackduc98 said:
My memory recollection agrees with the response you got from FRP forum.

I suggest you post your question with pics to "Suspension Q&A with Jeremy Wilkey" forum here on DRN. Jeremy has done so many forks that he should be able to answer your question with his eyes closed.
I'll do that, thanks!
 
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#14
Shim Stack Mod assembly instructions thread

Many thanks to those who posted attempting to help me get my forks back together. I did get things together right and I think they will be working much better on my 2 day ride coming up this weekend in the high cascades of Central Washington. (pics from last years ride: http://robl245.smugmug.com/gallery/2524046/1/132604732)

To finalize this thread for future reference, the assembly order can be seen in this picture Jeff Fredette himself sent me in an email (what a guy):


all the parts will be flipped over and stuck on there!

Here's the key to putting the base valve back together, which was my major mistake the last time. Make sure you don't tighten the nut down tight. You will notice that the holder "clips" into place and allows the shims and valve to move up and down against the spring. If you tighten the nut too much, it will push the holder down to far restricting valve movement causing the base valve not to function properly. Most likely, you will actually further restrict flow making the forks work really crappy as in my case.

Just put a healthy dab of loc-tite on the threads and turn the nut down until it contacts the collar. Allow the loc-tite to harden and your all set!!!

Thanks again,

Rob
 

blackduc98

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#15
So looks like pic #1 in your first post was correct as far as valve orientation goes, but maybe my eyes are playing tricks on me?