Sick Crankbrothers Joplin 4

[maxwolfie]

I've got a CB Joplin 4 that 's really slow to return.. actually it moves about an inch and stops, it's getting worse. It's the remote version. I've printed off the service manual and I'll have a look at it tomorrow night....... until then.... Any ideas?

EDIT: And no, the seatpost is not too tight

 

[wind ding brutha]

http://forums.mtbr.com/showthread.php?t=665698

All you need right there mate. They are super easy to fix. All you have going on is a bunch of crud in the main sleeve by the sounds of it. Take the seat off first of all, then undo the cable. Using a 10mm socket with a long extension remove the nut at the bottom of the seat pillar then undo the little collar. The post will come apart in two pieces and probably a whole bunch of water and crud will be inside. Clean all of this out super thoroughly and regrease mildly with a good teflon based grease. You dont need tons of it, just a nice film over the guide block and the plastic bushings. I would check the air pressure in the chamber itself too. To do this just use a phillips head screwdriver to take the cover off the bottom of the post where the 10mm nut screws on. Screw a shock pump on and depress the actuation lever at the top of the post and check that you have about 80psi or just over, it might actually be a little less for the joplin 4, check the service guide in the link i posted and what you have too, a little higher pressure means it comes up a bit faster. Thats pretty much it, pretty simple once you know what your doing, not hard at all mate. Good luck...

 

[0psi]

If you are the original owner you may be able to send it back for a warranty service. I know this was the case with the old ones.

 

[maxwolfie]

Thanks, sounds easy enough. Interwebz says that 70-75psi is normal, I'll see how it goes

 

[HAB]

Mine's been brilliant when it's freshly serviced, but does require semi regular maintenance to keep it returning quickly and smoothly. Just give it a once over as per the service instructions above and it should be golden.

I've also found that using a little lighter grease than the stock stuff, (which I think is Finish Line crystal grease) does gain you a little extra time between services. And use liberal amounts of grease on the telescoping bit.

 

[maxwolfie]

Ahh.. OK.. So I've put my shock pump on the end of it to check the pressure and it's dropped a fair bit of oil in the process.. maybe 15mls/ccs?

Do I now have to purchase new oil, syringe, Panadeine Forte etc to fix this thing?

Sort of going off the CB guide and this.

 

[wind ding brutha]

The bleed process or installing new oil is a little more complicated but not super difficult, if it is too low on oil you will find that it will become essentially like suspension when the post is fully extended. They actually take a fair amount of oil inside them, i cant remember exactly but it mentions it in the original link somewhere, around 90ml from memory. If you lost around 15 and the post is spongy get a syringe, remove the valve core from the bottom of the post and fill it back up with a 5 or 10wt fork oil. They are easy to work with, you just need to mess with it and get your head around it, that was all i did!

 

[maxwolfie]

Yeah, it doesn't feel too good now at all.

So now I've got to buy a:

* Syringe - Where from?
* 5/10wt Oil - What brand/type etc? Where from? I've never serviced a fork before so no idea here. I assume there are different makes/models/weights/genders.
* Light grease for greasing bushings etc - Will my Castrol Marine Grease do? I assume it's probably too thick.. some lighter grease would be handy for some other things anyways. Suggestions?

And then I'll need a tool to actually remove the schrader valve, which I've never needed to do before.

*sigh*

EDIT: Would something like this do away with the syringe and the valve removable tool?

 

[maxwolfie]

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 much 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!

 

[maxwolfie]

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

 

[J@se]

LBS?




10 charchar.

 

[maxwolfie]

LBS?




10 charchar.

nooooooooooooooooooo

 

[J@se]

Tight arse.

 

[maxwolfie]

Bump - Any ideas?

 

[0psi]

This will do the trick.

http://tbsm.com.au/index.php?main_page=product_info&cPath=8_26&products_id=751

 

[maxwolfie]

Funny you say that, I've actually got Thomson Elite on there as a backup

Still need to get it fixed though..

 

[maxwolfie]

Any ideas? Might have to take it to the LBS Going once..going twice.. etc.

 

[maxwolfie]

What if I like, use a bit less oil, and stuff? Maybe that will work... yeeeaaaaahh biznatches.

 

[wind ding brutha]

I'd try a lighter oil weight mate... 15 Is pretty heavy going. I even have used hydraulic jack oil in mine and that works a treat, its like 5-10 weight equivalent and its cheap from an automotive store, also works for shimano brakes as its a mineral oil.

 

[Spanky_Ham]

guessing here... sounds like it uses an air spring and hydraulic lock system... well, to the pigs wine addled mind

Adding too much oil (Volume) would mean that the seat could not go down far, as the air space (which can be compressed) has been replaced with the extra oil volume.

Try leaking a bit more oil out, the pig is guessing that will the seat to go down... but let too much out and it won't function

s