Tech Tuesday - Fox Lower Leg Removal And Service

Dec 7, 2010 at 0:07
Dec 7, 2010
by Mike Levy  
 
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Spending a few minutes to remove and clean the lowers of your Fox fork will not only keep it running smooth, but also act as preventative maintenance for down the road. Today's Tech Tuesday shows you how to drop those lowers and replace the all-important lube oil to keep your fork silky.

Check out the tips and video inside to see how the job is done,







Your Fox fork may feel like a million bucks, but if it's been awhile since you've performed any maintenance than there is a good chance that a little love will have it working even better. This job won't require rebuilding the damper, a repair that some will find intimidating, but only removing the lowers for cleaning and reassembling with new lube oil. How do you know when to get your hands oily? Fox says to slide the lowers off once every 25 hours to inspect the seals and foam rings, but this is also the time to clean everything thoroughly and treat the fork to some new lube oil as well. Riders who spend a lot of time in nasty conditions or doing laps of the bike park will want to do it a little more frequently, but it never hurts to be an eager beaver when it comes to maintenance.

What exactly does that oil in there do? It's pretty simple actually, it acts as lube oil to keep your fork running smooth and active. The oil breaks down over time and loses its ability to lubricate the bushings, but it also gets contaminated from the elements. Small pieces of grime, water from hosing your bike down after a ride, and even tiny bits of rubber from your seals all pollute the oil, with the result being that nasty and thick gray sludge that you're about to pour out of your fork lowers. This sludge can not only have a negative effect on performance, making the fork feel sticky and unresponsive, but can also damage your stanchions in the long run. Think of that nasty oil as sand paper, because that's essentially what it is, with millions of invisible grits slowly working away to scour the finish right off of your stanchion tubes. Doing this repair will not only keep your fork running smooth, but it's also preventative maintenance that can save you money in the long run.


Some pointers before you begin...

• There is a good chance that you're going to make a mess during this job, especially if it is your first go at it. Not only do I recommend wearing gloves and eye protection, but it also doesn't hurt to put down an old towel on the floor to soak up any spills. Be sure to properly dispose of your old oil as well, not by just pouring it down the drain!
• You'll be dealing with some small parts during this job, including the foot nuts and the very small detent ball and spring tucked up in the high-speed compression knob. Don't lose them! Having a small dish or container to put these bits in after removal can save you from spending a lot of time on your hands and knees scouring the floor.
• The video shows me removing the fork from the bike, this makes the job much easier, but isn't 100% compulsory.
• Both foot nuts, 10 mm on the spring side and 15 mm on the damper side, are aluminum. This makes them light, but more fragile than if they were steel. Use the correct size tool (not an adjustable wrench) and take your time so as not to damage them during the repair.
• In the video you'll see that I'm using a rubber mallet to tap the foot studs lose from the lower leg assembly. I can't stress enough to never use a standard hammer for this.
• Once you have the lowers off, take a few minutes to inspect your stanchion tubes to be sure that they don't have any fatal scratches or dings in their finish.
• With your lowers off and the upper assembly in the upright position, stroke the fork's damper rod through its travel. It should take effort to stroke, but move freely and not feel notchy. If it feels as if it momentarily loses damping you'll need to service the cartridge, which we'll cover in a future Tech Tuesday.
• There is no point doing all this work and then not properly cleaning the inside of your lowers before putting them back on. You can use a rag and a long screw driver (just be sure not to scratch the bushings inside the leg), or the long plastic handle of a kitchen utensil, to push the rag in and out of the fork. Spraying some non-corrosive cleaning solvent down the legs will help as well.
• When reassembling take note of the flat surface on the adjuster rod that the low and high-speed adjuster knob's setscrew tighten down onto. Be sure to line this up with each setscrew.
• If either of the foot studs spin when reinstalling the foot nuts, a bit of pressure on the fork can help a lot.


Putting in the correct amount of lube oil is vital in order to have your fork working properly. It's all about volume - too much oil and you won't be able to attain full travel, but you need enough in the lowers to lubricate the bushings. Our 180 mm travel 36 VAN RC2 requires 40ml of lube oil in both the damping and spring side, but it will vary depending on the fork model. Be sure to have a close look at the Fox oil volume chart to determine the correct amount that your fork requires. Fox also recommends using their own special 10 wt. fork oil on models featuring gold Kashima equipped stanchion tubes.


What's needed: 2 mm hex wrench, 10 mm socket, 15 mm socket, rubber mallet, oil pan (an old Tupperware container works great), measuring cup, 7 wt. suspension fluid



Want to keep your Fox fork running smooth? Watch the video:

Views: 70,203    Faves: 353    Comments: 38



While I didn't need to replace the seals on my fork, if you need to, follow the same dis-assembly procedure as stated above in order to remove the lowers. Once the lowers are off you can use an 18 mm open end wrench to pry the seal up and out of its bore, being careful not to score the inner surface of the leg. Don't worry about damaging the seals, you'll be replacing them anyway. Now remove the foam ring that was hidden under the seal. To install the new seals, first slide them up the stanchion tube, not into the fork lowers. This limits that chance of damaging the new seals during installation. After dipping the foam rings in your new oil, slide them up into position under the new seals. Now you can reinstall your lowers, sliding them up onto the stanchion tubes. Use your fingers to seat the new foam rings and seals into the seal bore. If the fit seems tight you can use a socket or another blunt tool on the seal's outer edge to push it in place. Never push on the dust wiper lip unless you want to buy another set of seals.
While I didn't need to replace the seals on my fork, if you need to, follow the same dis-assembly procedure as stated above in order to remove the lowers. Once the lowers are off you can use an 18 mm open end wrench to pry the seal up and out of its bore, being careful not to score the inner surface of the leg. Don't worry about damaging the seals, you'll be replacing them anyway. Now remove the foam ring that was hidden under the seal. To install the new seals, first slide them up the stanchion tube, not into the fork lowers. This limits that chance of damaging the new seals during installation. After dipping the foam rings in your new oil, slide them up into position under the new seals. Now you can reinstall your lowers, sliding them up onto the stanchion tubes. Use your fingers to seat the new foam rings and seals into the seal bore. If the fit seems tight you can use a socket or another blunt tool on the seal's outer edge to push it in place. Never push on the dust wiper lip unless you want to buy another set of seals.


Need more info or some help? Check out the Fox Racing Shox website to see their service guides.


Have you done this job? Want to add a tip or hint of your own? Put it down below!



Past Tech Tuesdays:

Technical Tuesday #1 - How to change a tube.
Technical Tuesday #2 - How to set up your SRAM rear derailleur
Technical Tuesday #3 - How to remove and install pedals
Technical Tuesday #4 - How To Bleed Your Avid Elixir Brakes
Technical Tuesday #5 - How To Check And Adjust Your Headset
Technical Tuesday #6 - How To Fix A Broken Chain
Technical Tuesday #7 - Tubeless Conversion
Technical Tuesday #8 - Chain Wear
Technical Tuesday #9 - SRAM Shift Cable Replacement
Technical Tuesday #10 - Removing And Installing a Headset
Technical Tuesday #11 - Chain Lube Explained
Technical Tuesday #12 - RockShox Totem and Lyric Mission Control Damper Mod
Technical Tuesday #13 - Shimano XT Crank and Bottom Bracket Installation
Technical Tuesday #14 - Straightening Your Derailleur Hanger
Technical Tuesday #15 - Setting Up Your Front Derailleur
Technical Tuesday #16 - Setting Up Your Cockpit
Technical Tuesday #17 - Suspension Basics
Technical Tuesday #18 - Adjusting The Fox DHX 5.0
Technical Tuesday #19 - Adjusting The RockShox BoXXer World Cup
Technical Tuesday #20 - Servicing Your Fox Float Shock
Technical Tuesday #21 - Wheel Truing Basics
Technical Tuesday #22 - Shimano Brake Pad Replacement
Technical Tuesday #23 - Shimano Brake Bleed

Visit Parktool.com to see their entire lineup of tools and lubes.
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90 Comments

  • + 10
 To me, this particular tutorial is a total Godsend! Thankyou so much. Before I was able to maintain everything on my bike other than my Forks, I just didn't have the confidence to do it. Just given it ago following step by step and now it's a piece of cake!
[Reply]
  • + 2
 This video is great, and explains the job really well. My only question is why do you say to use 7w oil when FOX clearly states that you should use 10w green for the lube oil and 10w red for the cart. oil? The 7w oil is only used in the earlier 32 forks. You never mentioned the different colored oils that fox has either.

You can see the chart here: service.foxracingshox.com/consumers/Content/Service/oil_volumes.htm
  • - 1
 GET ENDURO SEALS!!!!
[Reply]
  • + 1
 So basically an avid rider should do this once a month or more? If I hadn't been stuck inside all summer I'd have been really behind. As it is I barely rode since august and I already should do all this. Problem is that oil is expensive; as if I didn't pay enough for my fork to begin with.
Well I guess that's the cost of performance. . .
  • + 6
 Not going to lie, 25 hour service intervals seems pretty quick... I'm betting that most riders don't follow that rule too closely. I like to tell people to just use common sense, meaning that if you're riding in shit weather and pressure washing the piss out of your bike all the time you'll need to do it more. This nice thing about this job is that it only requires a small amount of both oil and time in order to keep your expensive fork running smooth. Mike
  • + 1
 yeah i usialy change the oil and clean the insides after every two races so i do it at least once a month.
  • + 1
 good to know. Thanks mike.
[Reply]
  • + 1
 hello Mike,
one question about my Fox 40 rc2 2010.
is spilling oil from the left leg(spring side). the fork is pretty new , I used it maybe 15 hours. But the bike has been stored hanged on the wall (front tire up) for the last 2 weeks. can this being the problem? what should I do now?
[Reply]
  • + 2
 just an interesting piece of information; the bigger the fork, the easier it is to service. my 07 40 is super simple to service, but then i opened up my dads f100 and needed to look at some guides to get it right.
[Reply]
  • + 1
 Doesn't fox recommend their "Green" 10w Fluid for all 2008+ forks oil baths? I also recommend to all new Fox fork owners to do this service as you pull the fork out of the box. My 2011 Float 36 came with 5ml of oil in the baths and 30+ml in the air chamber.
[Reply]
  • + 1
 Mike, I have a question for you. I have an 2007 66 RC2x, but I think this applies to most other forks aswell. How will a different weight oil change the characteristics of the fork? I am a pretty light rider, would it make sense if I tried out 5wt instead of 7,5wt?
  • + 1
 the weight of the oil affects the speed at which a fork can move through its travel. putting in 5wt instead instead of 7.5 will just make the fork easier to bottom out since theres less resistance from the thinner oil
  • + 1
 Ok, so in theory, I can make the fork "plusher" by adding more bottom out compression, decrease rebound damping and maybe add some air preload? Won't that (in theory) make the hsc and lsc (even) smoother?
  • + 1
 no. that doesnt have much to do with the oil weight. the oil weight wont affect the rebound damping significantly, so i really dont see what decreasing rebound damping would do. adding more compression just lets more oil into the damper, which makes the fork less smooth.
  • + 1
 On my fork I have lsc, rebound, bottom out compression (not hsc) and air preload. I think you're mistaking the bottom out for high speed compression. The bottom out is not the same as hsc, what it does is that it just works in the last 1,5" of travel and prevents the fork from bottoming.
  • + 1
 When you are referring to the oil in the stanchions it won't do much but move through the inside lubricating everything at a slower rate. You need to change the oil inside the damper to see a difference in damping. I went to a 7.5wt oil inside one of my older forks and found that the rebound didn't need to be as engaged as before. If you move to a significantly heavier weight I would think you would be faced with bottoming out the fork often because it wouldn't have time to rebound as quickly.
  • + 1
 Lighter oil weight equal less damping, both rebound and compression. If you went with lighter oil, but wanted to keep the same damping characteristics, you'd need to add some clicks on the dials. Keep in mind though that a Marzocchi fork uses the same oil for both lubrication and damping duties, whereas the Fox I'm working on separates the two. Lubrication oil in the fox fork does not effect damping. Mike.
  • + 1
 I see! Thanks for the replies. Smile
  • + 1
 I used to put 10wt oil in my Marzo's and I'm heavier, so it would do the same for you if you're lighter and use 5wt. I've done it for other people before and it's fine.
[Reply]
  • + 2
 Hey Mike great TT! Question: (Specific to a fork that has a double bushing system before the foam ring) Do you recommend packing the space between the double bushings with grease?

Cheers,
S
  • + 1
 i usually use SLICK HONEY and pack a small/moderate amount into the concave ridge in the seals....makes the fork extra buttery!
[Reply]
  • + 1
 the best thing i have found is to use Automotive ATF oil in substitute of Fox Fluid Atf is a very thin lubercant used in automotive transmissions its about 7.5 weight if you get the right stuff Oh and it works GREAT!
[Reply]
  • + 1
 ^^ had the same thing happen, sent it to Fox.. they said lack of maintenance; dirt in the oil like said above so they refused to fix it. Kinda wish I saw this video before then!
[Reply]
  • + 1
 great tutorial mike, just in time for the offseason tear down. question - i'm assuming the process is the same with the float, but decompress the air spring first. anything else to note?
[Reply]
  • + 0
 this may be a dumb question, but a guy at a bike shop once told me that fox air forks such as a 32 talas 150 rlc don't need oil because they're air shocks... this can't be true... is it? Thanks,

Grant
[Reply]
  • + 1
 question: so my stanchion turned like silver? i had it serviced befoer i went to whistler and this happened over the time riding at whistler. is it the oil? or a defect?
  • + 1
 means your bushes have worn/something inside is rubbing on your stanchion. You will need a new stanchion and new bushes and seals for your fork. A very costly job
  • + 1
 how much you thinking? i was thinking like 250?
  • + 1
 dont know in dollars but i known someone who paid 190 euros just for the bush change, and fox wont let you buy the outer stanchion on its own i reckon, they'll make you buy the whole leg
[Reply]
  • + 2
 I probably sound stupid but by 25 hours they mean every 25 hours of riding right?
  • + 5
 yh i guess. Other wise you'll be serviceing your forks everyday pretty much....
[Reply]
  • + 1
 Mike,
I take it that for the plain-jane 36 Van, w/o the rebound on the bottom that I can just remove the two footnuts and slide the lowers off?
[Reply]
  • + 3
 they forgot to mention to never use water to clean the inside of the fork.
[Reply]
  • + 2
 Do these steps apply to fox 40 rc2s? might be a stupid question, but im not gunna risk it for a chocolate biscuit...
  • + 2
 Pretty much though the amounts of oil will be different, as mentioned. Go earn that choccy bic!
  • + 1
 yeah its the same basic steps its not any harder its a piece of piss the only differance is i do the whole procedure with the forks upside down pouring the oil out and in the stantions. i just find it easier that way.
  • + 1
 yea thats what i do. its pretty much the same procedure, just be careful around the low/ high speed compression knobs, ive broken them before by being a little less gentle with them.
  • + 1
 Cool, cheers for the help guys, Big Grin
[Reply]
  • + 3
 Why does Levy look completely blitzed in every video?
  • + 3
 If by "blitzed" you mean that I look like I just drank three Monsters in a two hour period...
  • + 2
 dude, you seriously have to lay off the Monsters.... that s*it can't be good for you
  • + 2
 That would probably explain it.
[Reply]
  • + 1
 oh do you think you could post a vid of you draining oil from the damper? if you leave it in it means your oil levels will be off.
  • + 1
 Nope, the cartridge is sealed meaning that the damping and lube oil are separate. You can drop the lowers and do this job without needing to touch the cart.
  • + 1
 Mike, when do I know its time to service the cartridge itself ? (with the shox mounted)
  • + 1
 mike, is that just your model? mines an 09
[Reply]
  • + 2
 Good one Mike Levy. You are a natural teacher. Keep the Tech Tuesdays coming!
[Reply]
  • + 2
 great tech tuesday now I can do that myself
[Reply]
  • + 3
 Great Tech Tuesday Wink
[Reply]
  • + 1
 hey mike, how exactly do i pour the oil in without it draining ? do i have to put the fork upside down?
  • + 1
 oh right its fine , i skipped that part accidentally
[Reply]
  • + 1
 Why do you have to change the crush washers ? Can't you do an oil change and keep the old ones ?
[Reply]
  • + 0
 Mind doing the 2008 Boxxer WC at some point? There are thousands of the 32mm chassis and the 2008 was a big seller, it would be good to see how to do a rebuild on that.
  • + 9
 pretty much the same idea, take the lowers off, clean them, put new oil in, done
  • + 11
 I would never say it's the same thing, be careful with that actualy. Nearly every fork has an area where you can break it very expensively with a small mistake. I would say follow these rules:
1.If you are a brute force guy with a poor "technical culture" do not service your forks, or at least do not reassemble them yourself! Some people are like that - accept that before you loose lots of money.
2.If you have never took a CERTAIN fork apart, always ask for guidelines someone trusted who did (i.e a bike mechanic)
3.NEVER OVERTIGHTEN! All parts in forks do not require high torque, they will never get loose.
  • + 6
 people...give ur bike some love
  • + 0
 no gloves, no love!
  • + 3
 WAKI, i never said they were the same, all i said was that it was the same idea, to remove the lowers, give everything a clean and reassemble with the addition of new oil
  • + 2
 I didn't mean anything wrong Wink Just to meant be careful. For example with lower legs service you can screw up pre 09 Rockshoxes equipped with dual air spring. The plastic slip ring issue and placing it in the outer leg not under on shrader valve. But well maybe it was just me that was stupid...
  • + 1
 Marzocchi offers service manuals. I have always just downloaded the proper service manual and followed that. Because you are 100% right Waki, you really should not go into a fork blind, you can really screw it up.
  • + 2
 ArmyFork, Great idea. There are still loads of those forks out there so it makes sense to do that. I'll see what I can do. Mike.
  • + 1
 If you do one on 32mm boxxers, make sure you stress that 35mm boxxers are the same but the bottom screws are just slightly different since the adjusters are differeent
  • + 2
 I believe if you go hover around sramtech youtube channel there's boxxer overhaul vid
  • + 1
 This was a great tech tuesday ! Did exactly what was said for my 2010 Fox 40 and the result is excellent ! Amazing how much silver can come out :p
  • + 1
 is it pretty much the same idea on an inverted fork?
[Reply]
  • + 1
 what the fuck! where was this video last week! i did this for the first time.. o well pretty sure it went fine
[Reply]
  • + 1
 Any one got a video on how to service 2010 Boxxer Teams?? Just looking for seal change and spring change.

Thanks
[Reply]
  • + 1
 come on mike !!! Tomorrow its tech tuesday day .... show us the cartridge re haul
[Reply]
  • + 1
 Should I put blue locktight on the footnuts?
  • + 0
 That's a good idea. I know about many adjuster nuts that have rattled of.
  • + 2
 I would say it is not a good idea. Using the lock tite could require extra torque to remove the footnuts once it sets, which can damage the rods they screw onto.

Which leads me to my main point. Echoing Waki, be extra careful to the torque you are using on those footnuts, as overtorquing them can damage the rods they screw onto, which are part of the rebound cartridge assembly in the right leg, and the spring assembly in the left leg. They are VERY expensive to replace.

I did this last summer after the shop told me to just screw the footnuts "good and snug". I guess I erred on the side of caution (didn't use a torque wrench), and paid the price. I had to buy a new rebound assembly for close to $400 (for the RC2). In speaking to many mechanics about this issue (including the former Fox Warranty guy for Western NA), this is not an uncommon occurence, even for experienced pro mechanics.

So, my point is, pay VERY close attention to the torque specs of the footnuts. VERY close attention...
  • + 2
 Canadmos,

Don't put any blue on the foot nuts. Both the nuts and the studs are aluminum and don't require and thread locking compound. You are better off to put a small dab of grease and torque them both to the proper spec, that being 50 in/lbs. It isn't the end of the world If you don't have a torque wrench, just use common sense. Think of it this way: 50 in/lbs means that the torque required is 50 lbs on a 1" handle, which is bit weird to relate to.. but if you do the conversion you'll find that it is just a hair over 4 lbs of force on a foot long tool, which is a bit easier to think about. Don't over do it!
  • + 1
 Thanks for video and tips!

How about the bushings? Do you know what the tell tales signs of wear in them are and how long they should last before I should get a shop to check them out?
[Reply]
  • + 1
 do i soak my foam rings in my 7wt oil??
[Reply]
  • + 1
 Very interesting and useful. nice writeup
[Reply]
  • + 1
 how can i change 100 mm to 120 mm on the fox 831 ?? thanks !!
  • + 0
 Why would you do that???
  • + 1
 In the air spring remove spacers?
  • + 1
 There are spacers above the spring??
  • + 1
 Yeah you just pull the the spring back from the air piston end and insert/remove spacers

service.foxracingshox.com/consumers/index.htm#service/forks/40/40rc2.htm

It mentions that the F-Series forks can NOT be increased to 120mm of travel. However the 831 is neither and looking at the FOX site it mentions that the fork's travel is internal adjustable to 120mm of travel so you should be fine, still you should check with FOX before going ahead.

The process should be very similar if not the same as the FLOAT/F-Series procedure.
[Reply]
  • - 3
 Can you also teach how to professionally open and service 2007 Bomber 66 ?
  • + 0
 Watch part I and II of this. www.youtube.com/watch?v=XeNZr5dA4Q4
Marzocchi is actually the trickiest to rebuild as they are open bath, but still with a bit of patience really not that bad.
  • + 0
 I were going to post the same link, haha. Smile I've taken my 07 RC2x apart, it's not that big of a deal, really easy if you just use common sense. Good luck.
[Reply]
  • - 2
 Yeah a video for 2008 Boxxer WC would be great Smile
[Reply]
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