Rockshox Fork Service Tip....- Mtbr.com
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  1. #1
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    Rockshox Fork Service Tip....

    My Rockshox Dart 3 is mishaving and so I have to take it apart and check oil levels and replace the oil. I found an outstanding link over and above the Sram Service PDF manual link that should help many that are considering routine maintainence on their Rockshox:
    http://www.parktool.com/repair/readhowto.asp?id=169

    The beauty of the above link is unlike the Sram service manual which shows complete disassembly of the fork to refurbish oil in each lower leg, this approach allows refilling the lower legs by inverting the fork and not taking the fork completely apart...a big time saver.

    I know there are those on this site that can rebuild a Rockshox fork in their sleep and my question is you please. In your experience, how often do you find the culprit with the Rockshox to be the damper leaking down into the right leg of the shock and not the lower oil level in each fork leg leaking out? For my Dart 3 the manual states to replenish the damper if removing it with 93ml of 5W fork oil. By contrast the lowers each need about a tablespoon of 15W fork oil for lubrication. In your experience, is it the damper that leaks down into the right leg causing the shock to malfunction or do the lowers lose their oil out the bottom bolts causing the shock to not work properly? Is there a way to differentiate by the shock's performance whether its either the oil level in the lowers or the oil in the damper that is the root cause of poor shock performance?

    Many thanks.

  2. #2
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    If you lockout and rebound suffer then it is you damper that is leaking down.

    The issue you will have with loosing the fluid in the lowers is damage to you bushings and stanchions from lack of lubrication.

  3. #3
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    By contrast the lowers each need about a tablespoon of 15W fork oil for lubrication. In your experience, is it the damper that leaks down into the right leg causing the shock to malfunction or do the lowers lose their oil out the bottom bolts causing the shock to not work properly? Is there a way to differentiate by the shock's performance whether its either the oil level in the lowers or the oil in the damper that is the root cause of poor shock performance?
    Having dry lowers will not affect damping, it's just there as an oil splash to keep things wet. Being low on oil in the damper will/might/can affect both compression and rebound damping, as well as lockout if you have one. If the damper oil is low, a faulty oring is likely the culprit (allowing it to flow to the lowers), not the damper itself. Once enough oil moves to the lowers you will lose travel as well...or known as hydrolock, where the fork cannot compress the oil at the bottom of the stroke as the fluid acts as a hard stop.

    It sounds like a big mess I know, but it really comes down to an oring, although I admit I have never serviced your particular fork so I guess I could be assuming too much here.

  4. #4
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    Thanks gents. What you both write makes sense.

    Where do you guys order Rockshox replacement parts?...directly from Sram?

    Eatdrinkride...is the O-ring you reference that is generally the culprit for damper leakage...are they available generically at say a local autoparts or hardware store or perhaps another source?

    Thanks again.

  5. #5
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    is the O-ring you reference that is generally the culprit for damper leakage...are they available generically at say a local autoparts or hardware store or perhaps another source?
    RS will not sell directly to the customer, in most cases. I'd go to the lbs and ask them to order a seal rebuild kit for your fork.

    It's likely the oring on the rebound damper (#10 is the damper), it doesn't look like they sell just the oring as each oring is listed as part of the sevice kit (#16 if you go to the link).

    As far as matching the oring up, you would have to take it with you to a place with a good selection of orings. I do not know the ID and OD of the oring.

    This is the dart 2/3 exploded parts diagram. Link here: http://www.sram.com/_media/techdocs/...20list)%20.pdf
    Attached Thumbnails Attached Thumbnails Rockshox Fork Service Tip....-capture.jpg  


  6. #6
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    The leak in a dart is a warranty issue, take it to a LBS, or have a LBS contact SRAM to get a new damper for it. There is a faulty o-ring in the damper that allows fluid to leak into the lowers. Again, this is warranty, get a new damper for free.
    Quote Originally Posted by sickspeed16
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  7. #7
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    Quote Originally Posted by rvmdmechanic
    The leak in a dart is a warranty issue, take it to a LBS,.
    How do you know how old his fork is? Either you are clairvoyant or I misread his post.

    Is the Dart damper different than a Pike or Lyrik or Totem? On those forks the damper sits in the oil. In fact you pour oil in the upper before you even install the damper. There is no damper oring to retain oil. If you remove the rebound damper rod then the oil will leak out the bottom leg. Like I said, I've never serviced a Dart so maybe i'm off base.

    At any rate you are correct if it's under 2 years. OP: how old is the fork?

  8. #8
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    It's a really simple fix.
    When the damper o-ring starts leaking, the damper oil starts leaking into the lower right leg, which eventually fills up and starts leaking out the bottom rebound knob or bolt.
    Sometimes the fork hydro-locks, and won't travel very much......or at all.
    Once you see oil on the bottom right leg, or your lockout stops working, or your fork won't travel very far, the damper seal needs to be replaced.
    It takes about 15 minutes, and is pretty basic.
    You need a set of snap ring pliers, large cresent wrench or correct sized socket, a long wooden dowel, some fork oils, some measuring device like a syringe, and a hex key. I forget if it is 5 or 6mm. Oh, and a small hammer.
    Bring your fork into a local shop and ask them if they can get the part covered under warranty.
    Sram is really good about helping with this.
    Look, whatever happens, don't fight the mountain.

  9. #9
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    I can't thank you guys enough for providing a road map of what the possible cause and effect is when this shock works less than optimally for what it is. I know it isn't the greatest shock but its reasonably simple and for XC trail riding it is adequate. You have given me a lot of good advice to likely restore its function.
    As the age of the shock, it is almost new...from an '09 Trek 6000...almost 1000 miles on the bike though. The thing is, I am a DIY'er as many of you guys are that know your way around tearing things apart (and why I have come to you for advice) and I got a great deal on this bike off ebay. The bike was pristine an virtually new when I received it. Btw, its been a great bike again for what it is. Since I bought the bike off ebay, I am not sure if my local bike shop could get the warranty honored through Sram or not. I do have the bill of sale from the original owner however I figured learning about the internals of this shock would pay dividends down the road if I continued to ride it or perhaps I upgraded to another of similar design.

    What you guys have taught me is:
    - A good telltale of damper leaking is the lockout feature starts to fail. This makes sense because there is insufficient oil in the damper to freeze the shock in position when the porting is closed off by rotating the lock out knob.

    - If the damper in the RH stantion of the shock starts to leak, this can fill the lower leg beneath the damper which gives the shock no where to displace which is often called hydrolocking.

    - The approx. teaspoon of oil in each lower leg is purely for splash lubrication to mitigate wear as the shock strokes.

    Above simplifies what is going on. Further thanks very much eatdrinkride for the service kit #16 to order and a clarification that this has to be done through my local bike shop. Even if they won't warranty the shock through Sram since I didn't buy the bike through them, they will likely still order the kit in my behalf. I honestly would prefer to tear the shock down and service it because that is the way I am and will likely be preforming routine service on it periodically anyway to replace the oil. The Park link of replacing the 15W splash oil in the legs without taking the top of the shock apart is very easy and likely a good PM measure to keep the shock from wearing. I may order some oil on my own and do this anyway before even talking to the lbs. Word is from other accounts I have read is that these shocks many times come in almost dry into bike shops on production bikes like my Trek.

    Thanks again everybody for sharing your knowledge.

  10. #10
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    Another tip for ya is to get fork oil from your local motorcycle shop. It is way cheaper than buying bicycle specific oil.

  11. #11
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    Since I bought the bike off ebay, I am not sure if my local bike shop could get the warranty honored through Sram or not.
    FWIW I've sent 2 RS forks in for warranty service a total of 3 times. Not once did anyone at the lbs ever ask me for proof of purchase. SRAM simply checks the ser# or a stamp under the crown for a manufacture date and goes by that. A receipt would be handy in a case where your forks date stamp shows it to be several years old but maybe you just bought it brand new a few months back (new old-stock or something). In that case, with proof of purchase SRAM can warranty from your purchase date.

    Order the seal kit. Download the instruction manual. Look on Youtube for a tutorial if you want and just go for it.

  12. #12
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    Quote Originally Posted by eatdrinkride
    FWIW I've sent 2 RS forks in for warranty service a total of 3 times. Not once did anyone at the lbs ever ask me for proof of purchase. SRAM simply checks the ser# or a stamp under the crown for a manufacture date and goes by that. A receipt would be handy in a case where your forks date stamp shows it to be several years old but maybe you just bought it brand new a few months back (new old-stock or something). In that case, with proof of purchase SRAM can warranty from your purchase date.

    Order the seal kit. Download the instruction manual. Look on Youtube for a tutorial if you want and just go for it.
    You have really helped me out a lot. Thanks for all the great advice and participating here.
    How about fork oil? I have read that Sram fork oil is really Maxima oil or virtually one and the same. Do you pick up your fork oil on line for your rebuilds?
    Thanks again.

  13. #13
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    Sram will honor their warranty under 2 conditions.

    1. Within the standard 2 year warranty time frame.

    2. Its not customer damage - but sometimes they will fix it under warranty if it could be come a customer service issue.

    Now at the shop I work for, I use the Sram fork oil because I'm not paying for it. But yes, there are fork oils on the market that you can pick up at motorcycle shops that are the same. But I'm not 100% on the compatibility.

  14. #14
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    Quote Originally Posted by dirtrider7
    You have really helped me out a lot. Thanks for all the great advice and participating here.
    How about fork oil? I have read that Sram fork oil is really Maxima oil or virtually one and the same. Do you pick up your fork oil on line for your rebuilds?
    Thanks again.
    RS oil was re-branded Torco, It very well may be Maxima now, I've read that it is. I use Torco or Red Line.

    You can use other oil, just make sure to match up the "reported cSt value @40c (first column below). Don't ever go by the 'weight' listed on the bottle. There is no standard to speak of and two 5W oils of different brands may have a very different cSt. SEE BELOW: the RS5W is the same cSt as Torco 7W....although in this case they are one in the same oils but you get the idea. I.E. Suzuki W-15 has a lower cSt than Bel Ray 5W and Maxima 5w is nearly identical to Torco 7W/RS 5W.

    Take a look at THIS CHART (scroll to bottom of page) and match up an oil that is as close as possible to the oil you may be looking for. It is a bit outdated as it shows RS and Torco on the same line. RS used to use Torco (re-branded as RS oil) but I believe they now use Maxima. Anyhow I have mixed different weights of Red line oil to achieve that of the stock RS damper fluid with nice success.
    Attached Thumbnails Attached Thumbnails Rockshox Fork Service Tip....-screenhunter_01-feb.-06-15.19.gif  

    Last edited by eatdrinkride; 02-06-2010 at 05:32 PM.

  15. #15
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    Quote Originally Posted by eatdrinkride
    RS oil was re-branded Torco, It very well may be Maxima now, I've read that it is. I use Torco or Red Line.

    You can use other oil, just make sure to match up the "reported cSt value @40c (first column below). Don't ever go by the 'weight' listed on the bottle. There is no standard to speak of and two 5W oils of different brands may have a very different cSt. SEE BELOW: the RS5W is the same cSt as Torco 7W....although in this case they are one in the same oils but you get the idea. I.E. Suzuki W-15 has a lower cSt than Bel Ray 5W and Maxima 5w is nearly identical to Torco 7W/RS 5W.

    Take a look at THIS CHART (scroll to bottom of page) and match up an oil that is as close as possible to the oil you may be looking for. It is a bit outdated as it shows RS and Torco on the same line. RS used to use Torco (re-branded as RS oil) but I believe they now use Maxima. Anyhow I have mixed different weights of Red line oil to achieve that of the stock RS damper fluid with nice success.
    Couple questions for you Eatdrinkride, wondering your opinion:

    I see that the 5w is pretty similar between the Maxima and RS, but the 15wt is different by about 3 points. What is an acceptable difference in cSt to acheive similar feel? (ie, is there a big difference between 42.8 and 46 cSt?)

    Also, if Rockshox is reportedly using Maxima now, will just using the Maxima 15wt (which is heavier than the Rockshox 15 and Torco 20) be best or should a person go as close to the Rockshox 15w cSt?

    Basically, should we be basing our cSt comparisons off the Maxima oil values for 2008 and newer RockShox?

    I am riding a 2009 Sid Race for what it is worth.

    Thanks for your insight,

    Jon

  16. #16
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    First time posting. I've been struggling with a Dart 3 a good bit myself (just got off eBay, it was taken off a new bike, supposedly: no extended rides yet). Hydrolock: seem to have some. A quick fix is to remove the preload, and GRADUALLY push the fork all the way down until the oil works its way back into the uppers; of course, then the 15 wt lower oil pollutes the upper 5 wt, and vice versa. Now, how the oil gets down there. It absolutely, positively, does not go through the damper. Any oil that goes through the damper would just come out the bottom of the fork, there is no possible opening into the lowers. The only possible routes are the two o rings, outer and inner, on the nylon bushing at the end of the stanchion. Having done a complete teardown, they seem pretty tight to me, maybe they could be tighter. I'm thinking going with slightly larger generic o rings; don't want to order Rock Shox o rings given all the problems they've had. I've heard that on at least one other model, Rock Shox had produced an undersized nylon bushing that they were replacing under warranty (hope that's not the case here). It's probably unrealistic to expect no leakage into the lowers. Main point: why have different weight oil in the uppers and the lowers if they're going to mix anyway? Fork oil is awfully expensive to allow different weights to pollute each other willy nilly, so I'm thinking of using the same weight in the uppers and lowers. The spring side has no oil at all, using lighter weight in the damper side lowers shouldn't be a problem. My Duke has essentially the same damper, but with a big hole near the bottom so the uppers and lowers share the same oil (the Duke damper also has a plastic hat that diverts the resulting oil spray to the sides). The damper itself has a o ring in it also, but it can't be totally oil tight, or the inner plastic shaft won't move. My Dart leaked from the rebound adjust knob; replaced that o ring with a larger generic from Home Depot; no more leak.

  17. #17
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    Quote Originally Posted by stephenghowe
    It's probably unrealistic to expect no leakage into the lowers.
    It's not.

  18. #18
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    Thanks for the advice. I'll try. Until fixed, same weight in the top and bottom. I've got some 2.5 wt on order (with 5 wt, I got cold freeze).

  19. #19
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    Quote Originally Posted by stephenghowe
    First time posting. I've been struggling with a Dart 3 a good bit myself (just got off eBay, it was taken off a new bike, supposedly: no extended rides yet). Hydrolock: seem to have some. A quick fix is to remove the preload, and GRADUALLY push the fork all the way down until the oil works its way back into the uppers; of course, then the 15 wt lower oil pollutes the upper 5 wt, and vice versa. Now, how the oil gets down there. It absolutely, positively, does not go through the damper. Any oil that goes through the damper would just come out the bottom of the fork, there is no possible opening into the lowers. The only possible routes are the two o rings, outer and inner, on the nylon bushing at the end of the stanchion. Having done a complete teardown, they seem pretty tight to me, maybe they could be tighter. I'm thinking going with slightly larger generic o rings; don't want to order Rock Shox o rings given all the problems they've had. I've heard that on at least one other model, Rock Shox had produced an undersized nylon bushing that they were replacing under warranty (hope that's not the case here). It's probably unrealistic to expect no leakage into the lowers. Main point: why have different weight oil in the uppers and the lowers if they're going to mix anyway? Fork oil is awfully expensive to allow different weights to pollute each other willy nilly, so I'm thinking of using the same weight in the uppers and lowers. The spring side has no oil at all, using lighter weight in the damper side lowers shouldn't be a problem. My Duke has essentially the same damper, but with a big hole near the bottom so the uppers and lowers share the same oil (the Duke damper also has a plastic hat that diverts the resulting oil spray to the sides). The damper itself has a o ring in it also, but it can't be totally oil tight, or the inner plastic shaft won't move. My Dart leaked from the rebound adjust knob; replaced that o ring with a larger generic from Home Depot; no more leak.
    It's simple, the oil is leaking past the orings in the nylon bushing.
    It's a cheap, easy and quick fix.
    RS has updated the part, it's cheap if not free.
    Go to a shop and ask them if they can get you the part.
    Look, whatever happens, don't fight the mountain.

  20. #20
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    The fork cost $56 on ebay. It's the 120mm version. Petra has something they call a Dart 2/3 damper (presumably includes the nylon bushing and o rings) for $26.90 (not including taxes, currently out of stock, might not work with 120mm). Not cheap. Two shops tried to get a RS part kit for me recently, neither succeeded. One never returned my phone calls, I had to call the other to find out what happened (they'd ordered and received an unacceptable substitute without asking). Not easy.
    Last edited by stephenghowe; 02-10-2011 at 05:43 AM.

  21. #21
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    Doubt I'd get free parts, labor and/or shipping.

    "SRAM warrants its products to be free from defects in materials or workmanship for a period of two years after original purchase. This warranty only applies to the original owner and is not transferable. Claims under this warranty must be made through the retailer where the bicycle or the SRAM component was purchased. Original proof of purchase is required."

    http://www.sram.com/_media/pdf/warra...rranty2009.pdf

    The date stamp on my crown is 07, the month dot is at 1 o'clock (January). The ebay description said "hardly used, took off a 2009 GR I-Drive mountain bike." The ebayer lives on the other side of the country.
    Last edited by stephenghowe; 02-10-2011 at 06:38 AM.

  22. #22
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    Just figure out the size o-rings you need (a call to SRAM tech support might be helpful here), and then buy them from www.mcmaster.com. Also, use Mobile 1 5w-20 for the bath oil. Only spend the money for suspension oil for the damper. Fairly easy and cheap. Then, once it's fixed, sell the Dart and buy a fork which will actually perform.

  23. #23
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    Seems that the term "damper" probably includes both the metal shaft, the nylon bushing and associated parts. So if the oil goes past the nylon bushing to the lowers, that is technically going through the damper (like everybody was saying).
    Got a cheap digital micrometer.
    http://www.amazon.com/gp/product/B00...ef=oss_product
    Disassembled the fork and performed various measurements. The oring at the top of the shaft and the oring on the lockout both have a diameter of 26mm (when installed). The outer oring on the nylon bushing seems to be 25.5 installed. Pulling that oring, it appears to have an inner diameter of 18mm, and a wall of 1/8" (approx. 3.2mm). Guess the wall is supposed to be 3.5mm. There's plenty of space in the groove for a larger oring. Hopefully will have replacement part(s) soon.
    Last edited by stephenghowe; 02-14-2011 at 08:00 PM.

  24. #24
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    A member kindly offered to get the repair kit from Rock Shox, but nothing happened, so ordered an o ring assortment from Amazon that included an 18mm x 3.5mm. When placed on the nylon bushing, the resulting diameter was 25.9mm (not quite 26mm, still a big improvement). Reassembled fork (with an 80/100 firm spring and a pvc spacer under the spring shaft spring), put 2.5wt in the damper side upper and lower, and a lot of Pennzoil Platinum 5w20 in the spring leg (over the top of the spring shaft). Took it for its first trail ride, it was ok (nice to have damping, there's a bit of stiction the 1 doesn't have).

    Got myself a pair of inside calipers, to get a measurement on the inside bores of the 3 and the 1, to figure out the thickness of the stanchion walls. IMHO, the Dart 3's stanchion walls are 1.25mm thick; the Dart 1's walls are 1.625 (.375mm thicker). Personally, I don't think the 120mm Dart 3 should have ever been produced; its got way too much flex/twang. I have reduced the travel to 80mm with a pvc spacer, reducing flex to tolerable levels.

  25. #25
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    Hi everyone, I have a 2014 RS revelation 120mm fork and am wondering on service intervals? I've been riding it for a year and have also scratched one of the stanchions too(slight scratch). I can't really find guidelines on how frequent the forks should be serviced.

    thanks!

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