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  1. #1
    Big Mac
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    Joplin oil change

    Forgive me if this has been discussed before, but my search wasn't helpful. I have a 2 yr. old Joplin R that I have tried to change the oil in. The result is: with the recommended oil amount the post is locked. No movement at all. The lever has no effect at all. When I remove a small amount of oil, the post is spongy. And again the lever has no effect. I also noticed that when I air the post up and activate the lever, there was no drop in pressure as all I have read said there would be. Any ideas? This should be simple right?

  2. #2
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    I haven't had to do this operation yet, but here is all the info I have collected for that eventuality... maybe it will help you out?

    --------------------------------


    Crank Brothers Bros Joplin 4 4r seatpost service instructions

    Good internal pictures: **http://www.pinkbike.com/news/crank-b...view-2008.html
    ***** Great general info in this review!! *Tips, info on fixing it, etc.


    Haaa haa what a piece of junk! Hey I just serviced my junklin following instructions on line.The post is working better than new.It could be done in 30 min. The title of the thing is Grrrrrr! CrankBros Joplin 4 issues. Help! on singletrack forum.Great instructions. Very well written. Wear gloves & safety glasses.


    http://www.singletrackworld.com/foru...-4-issues-help


    -------------------


    Joplin's, at least mine, do require disassembly and cleaning , relubing fairly often. But it's a really quick job. Pull out the post, unscrew collar by hand, undo nut inside the bottom of the post and that's it. Clean and relube and reassmble. Ten minute job. The real guts of the mechanism will be different. I haven't taken that apart yet. I believe it has nitrogen instead of air. My buddy has taken his Maverick apart all the way and he uses air. Crank Bros took over the Maverick design but did they change anything? The post head is weak though. The one bolt has to be really tight to hold the saddle in place. Mine keeps sliding back. Last night I put a paint dab on the rails and by the end of an hour and a half ride it had moved a millimetre.


    -------------------






    maybe an airlock in it??? Lil' Joplin may need a burping!!!

    undo the gold collar and pump post up and down a few times, then tighten gold collar finger tight and see if that makes a difference.
    ...
    this can happen if you "pull" the seat post up without using the leaver/remote to activate the return by all accounts, thus creating an airlock and stopping the post from fully extending back, and if you "pull" it up it will extend but drop down again if you get my meaning??? *So "burp" and the problem is solved not ideal but works






    If it's a cable remote it may be that the cable tension is too high and the button is being pressed all the time.

    The problem I've had with mine is that when it's up it's fine but when I put it down it won't come back up again. I've sent it back (3 months old!)




    does it not need some air adding via the schraeder valve in the bottom of the post? What pressure should it be - anyone know?
    ...
    mine was sluggish to return to its top height also...called Crank Bros...technician said 70psi on both sides of the valve...so using shock pump, pump it up to 70psi, activate valve which will equalize pressure...pump it to 70 psi again and activate valve again..repeat untill 70 psi is equal on both sides of the valve.
    Crank Bros Joplin Seatpost air pressure
    ...


    ------------------------- Service Instructions


    Brilliant bit of kit but no good in the UK dirt and grime. 3 tips for anyone thinking of buying one:*


    1. Buy the remote, infinite adjustment without looking away from the trail.*
    2. Buy some Lizard Skins neoprene suspension fork boots, cut one of them down and use it to protect the moving parts of the seatpost from dirt and grime - this will save you hours of maintenance and keep the seatpost functioning properly. In the UK it will need stripping and servicing after one wet and muddy ride.*
    3. Service the seatpost from time to time, don't waste money sending it away, just follow these instructions:*


    Crankbrothers Joplin Oil Change*


    *For just setting air charge - see below instructions Holding in remote lever or hand actuated lever, cycle post upside down several times. Let go of lever.*
    Remove 10mm nut at bottom and unscrew Crankbrothers engraved collar.*
    Remove outer tube. (Slides off)*
    Remove micro Schrader valve cap at bottom of compression shaft (flat head screw driver). Cover Schrader valve with paper towel and release any pressure still in post.*
    Remove Schrader valve core. With post right side up, aiming bottom valve into an oil bucket, release remote lever or squeeze hand lever.*
    ***This will release any pressure left and oil. Holding release lever in, cycle compression shaft (gold color bottom shaft) up and down, allowing oil to drip into oil bucket.*
    ***This will cycle out all the left over oil inside. At this point there should be no pressure and virtually no oil left in the post.*


    Refilling post:*


    Remove seat clamps from post and clamp head into smooth jaw vice, with compression shaft facing up, for easy filling. With a 60CC volume or more syringe (you can use smaller and just fill it several times) fill syringe to 55cc of 5wt or 10wt oil.*
    ***Oil weight does not matter but the volume does. Put plastic syringe tip into Schrader hole, slightly screwing it in to create a seal. Push oil into post at the same time releasing post lever. Cycle the compression shaft at the same time.*
    ***Your doing a couple of things at once here! The lever needs to be opened up, as well as being cycled, to allow oil into the lower chamber past the valve system and accept all 55cc of oil. Put a paper towel around bottom of syringe and Schrader valve to keep oil from spitting when pressure is release by removing syringe tip.*
    ***As you inject oil you build a small amount of air pressure. After all 55cc of oil is into post, install Schrader core (light torque). With standard shock pump pressurize to 70psi. Hit release lever, pump pressure will drop, pump back to 70psi and hit release lever. Continue to do this till it stays at 70psi when release lever is pushed. Remove pump. Reinstall micro cap, reverse installation of outer tube.*
    ***removal of outer tube in post instruction manual included with post.*


    Cycle post several times with lever squeezed to activate valve system. Check for firmness at top and holding at bottom. If it continues to be squishy at top, more oil is needed, only 2 - 3CC max more is needed.*
    *****Get post situated back into vice.*
    *****Hold lever and cycle compression shaft 5+ times with release lever squeezed. This will be tough as you are pushing against high pressure.*
    *****Undo micro Schrader valve cap, cover valve with paper towel and release pressure. Safety glasses on!*
    *******DO NOT SQUEEZE LEVER FROM THIS POINT ON. Oil will shoot up if you do!*
    *****Add 2 - 3CC of oil to Schrader hole. (Schrader core removed)*
    *****Close up system, follow above procedure for this.*


    This will do it! Go ride!*


    Setting air pressure in Crankbrothers Joplin seat post:*


    Holding in remote lever or hand actuated lever, cycle post upside down 5 -6 times. Let go of lever.*
    Remove 10mm nut at bottom and unscrew Crankbrothers engraved collar.*
    Remove outer tube. (Slide off)*
    Remover micro Schrader valve cap at bottom of compression shaft (flat head screw driver). Cover Schrader valve with paper towel, Face Upwards, push Schrader valve to release any pressure still in post.*
    Remove seat clamps from post and clamp head into smooth jaw vice, with compression shaft facing up, for easy filling.*
    With standard bicycle shock pump, pressurize Schrader valve to 70psi.*
    **Max pressure = 75Ppsi.*
    Leave pump on post. Hit release lever, pump pressure will drop.*Pump back to 70psi and hit release lever.*
    Continue to do this till it stays at 70psi when release lever is pushed.*
    Remove pump. Reinstall micro Schrader cap.*
    Grease glide rings and guide block & install outer tube.*
    Tighten 10mm nut at bottom to 40in/lb*
    Tighten Maverick seal head collar, hand tighten, over tightening this will slow the post down by crushing to rubber seal.*
    Cycle post several times with lever squeezed to activate valve system. Check for firmness at top and holding at bottom.*
    Done! Go ride!

  3. #3
    Big Mac
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    "mine was sluggish to return to its top height also...called Crank Bros...technician said 70psi on both sides of the valve...so using shock pump, pump it up to 70psi, activate valve which will equalize pressure...pump it to 70 psi again and activate valve again..repeat untill 70 psi is equal on both sides of the valve".
    Thanks Okie! This might be my issue. It may be that I'm not able to pressurize the top side of the valve. Anyone know why? And the fix?

  4. #4
    Big Mac
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    Somebody here has surely had and fixed this problem before. Seriously, I've had 3 rides on my squishy bike with a rigid post. I don't want many more. I would really like to fix this thing. A little help?

  5. #5
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    If I had the problem I'd do the full oil change and repressure.If it still doesn't work send it back or use it for target practice.Best thing to do is buy a Reverb and be done with the endless frustration.

  6. #6
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    Are you sure the seat tube clamp is loose enough? I use a lube on the seat post with abrasive in it so you dont have to clamp so hard.

  7. #7
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    I increased the pressure (70 PSI both chambers) and backed off the seat clamp pressure and in dry conditions it's all good.

    However, after a wet/muddy ride, I have to remove the outer sleeve to remove gunk from the guide blocks, as the Joplin bushings don't keep the mud/water out!

  8. #8
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    Thanks for this, the really long post in the middle which details specifically the 55cc of fluid is the key! Make sure you get all the fluid into the thing and its gold. I just replaced my guide block too and it was cheap and cuts all the slop out. I think the Joplin is all in all a little bit involved but once you get the hang of maintaining the thing its not bad at all and being able to get my seat away from snagging on my sack is gold!

  9. #9
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    Quote Originally Posted by Oracle
    I increased the pressure (70 PSI both chambers) and backed off the seat clamp pressure and in dry conditions it's all good.

    However, after a wet/muddy ride, I have to remove the outer sleeve to remove gunk from the guide blocks, as the Joplin bushings don't keep the mud/water out!
    Use a Lizard Skins fork boot to cover the post. It looks pretty good and works well to keep the gunk out.

  10. #10
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    Quote Originally Posted by G.A-Line
    Thanks for this, the really long post in the middle which details specifically the 55cc of fluid is the key! Make sure you get all the fluid into the thing and its gold. I just replaced my guide block too and it was cheap and cuts all the slop out. I think the Joplin is all in all a little bit involved but once you get the hang of maintaining the thing its not bad at all and being able to get my seat away from snagging on my sack is gold!
    No problem man - I'm glad it is helping people out. I didn't write it, I just copy & pasted all of it.

  11. #11
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    Hey guys,

    A bit of an issue - Basically my post was a little slow to extend and it didn't go up all the way, so I decided to change the oil.. I only have 15wt fork oil but as it says in the guide above, it's the volume that matters not the weight so much.

    Anyway - I've measured out exactly 55mls/ccs, and, even with no air, it will not compress (I.e. simulating someone sitting on it) hardly at all, maybe an inch at most. It just seems like too much oil.

    Am I doing something wrong? Sort of urgent as I've got parts strewn across the garage!

  12. #12
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    Bump - Anyone? Need to get it fixed this morning, if possible!

  13. #13
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    Bump - Any ideas?

  14. #14
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    Last bump... Surely someone knows a bit about these posts?

  15. #15
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    I'm gonna try 5wt fork oil, I'll have to go to Supercheap and get some Fuchs Silkolene..

  16. #16
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    is there any video tutorial on Joplin 4 R complete manteinance (oil & air)?? I'm a little confused on "two air pressure chambers"...

    My CB Joplin4r doesn┤t lift without aid on pulling up.

    Thanks in advance, from Spain

  17. #17
    kneecap
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    I sorta got the idea that if you pump the scrader valve at the bottom & then cycle the post a few times that the pressure will equalize both sides?

  18. #18
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    Quote Originally Posted by kneecap
    I sorta got the idea that if you pump the scrader valve at the bottom & then cycle the post a few times that the pressure will equalize both sides?

    I've pumped upside down, and reverse.

    Pressurized air goes mixed with oil on it?? Isn't it a separation betwen chambers?

  19. #19
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    Kind of funny, I have been saving this info for a while and actually ended up needing it today.

    My schrader valve core was leaking. Luckily I have a spare one from a Rockshox rebuild kit that I am going to use. Cleaning out the leaking one might also work.

    Also I found that Crank Brothers sells the Joplin maintenance kits on their website:

    http://cart.crankbrothers.com/access...tance-kit.html

    Doesn't look like they include a schrader valve core in the kit. I need the kit anyway to replace the guide blocks. My post rotates back and forth quite a bit - it is past time for needing new blocks.

  20. #20
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    Sorry to drag this back up. I just finished changing the oil in my Joplin. The seat is nice and solid in the up position and goes down and returns fine. However I can't get the full seat post drop - there's maybe 1" left that it should go down. I put right at 55cc of oil in the post per instructions. Is there too much oil? Too much air? Thanks!

  21. #21
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    Just a tad

    take out a littlle oil. You might have had some still in your valve.

  22. #22
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    How do you take just a little oil out? If you remove the air/schrader valve will oil just pour out if you tip the post? I can't remember from when I took it all apart before. Thanks for the help!

  23. #23
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    When I rebuilt mine 3R, I used 20/50 motor oil...figuring the heavier oil will help things seal better. I also overfilled it slightly (5cc?) on the thinking that pure oil at the valve will seal better than an air/oil mix.
    The post is a bit slower, but so far no leakage and is holding position. However, it's only been out on a couple of rides, but sitting around for a few months (was riding DH, then winter in CO and all).

    Edit: found my old post: Joplin 3R rebuild - reliability experiment
    Naysayers never apologize. Critics go to their grave thinking everyone else is wrong.
    ╭∩╮( ║.║ )╭∩╮

  24. #24
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    Pau11y, well I refilled mine and it holds position with no sag but it only lowers maybe 2". I'm trying to figure out how to get my full travel back. I used 5-30 Mobile 1 (it's what i had).

  25. #25
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    Quote Originally Posted by mtskibum16 View Post
    How do you take just a little oil out? If you remove the air/schrader valve will oil just pour out if you tip the post? I can't remember from when I took it all apart before. Thanks for the help!
    Tilt it slowly like pouring a beer. Did mine last night, found that you have to experiment to get the oil volume right. Just keep at it!!

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