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UTV's Off Road ( RZR, YXZ, Mini Buggy, Carts,etc.) => UTV Chassis and Suspension => Topic started by: SCDL Guy on January 22, 2009, 08:38:57 AM

Title: Adding oil to Fox Airs
Post by: SCDL Guy on January 22, 2009, 08:38:57 AM
Can I add oil with the shock fully extended, or does it have to be compressed.  With a stock shock how much oil can I add before I should be concerned?
Title: Re: Adding oil to Fox Airs
Post by: dsrace on January 22, 2009, 07:20:19 PM
you can add with shocks fully extended but let the pressure out first! then remove the schrader ( valve stem tit  ;D ). with stock 2.0's you can only add 30cc's of oil over stock level. I add in 5cc increments, but you can add in 10 cc increments if need to.
Title: Re: Adding oil to Fox Airs
Post by: SCDL Guy on January 23, 2009, 07:31:08 AM
I added 30cc and could still feel it bottoming, barely. So a few nights ago I added another 30cc. Whats going to happen if I drive it like this? Any idea why I was still bottoming? How would I remove the excess oil?
Title: Re: Adding oil to Fox Airs
Post by: Admin on January 23, 2009, 07:48:17 AM
what stroke is the shock, as far as i was aware, every shock was different as to the amount of oil that could be added... Maybe there was not the intended amount of oil to begine with? is the shock bottoming out, or is the chassis bottoming out not letting the shock work as it should?
Title: Re: Adding oil to Fox Airs
Post by: Yoshi on January 23, 2009, 08:55:26 AM
Title: Re: Adding oil to Fox Airs
Post by: dsrace on January 23, 2009, 09:26:53 AM
"is the shock bottoming out, or is the chassis bottoming out not letting the shock work as it should?"  bugpac's and yoshi's question x3


As I was told (by the fox shock rep) number of years ago, 8.5 - 14 stroke air 2.0's will accept an additional 30cc's of oil before re-valving. anymore than that could and/or will damage the shock. you could call whoever you purchased the shocks from and find out factory fill amount then empty yours and start over.
Title: Re: Adding oil to Fox Airs
Post by: Doug Heim on January 23, 2009, 03:54:01 PM
Do not over fill as I was told by FOX that it will cause seals to blow.
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 23, 2009, 04:55:07 PM
I was looking at a chart today that showed the oil capacity @ approx 5-600 cc depending on stroke.So in reality you don't add much to them total and you'd better have the right amount to start with so I'd say you need to totally drain and start over.
Title: Re: Adding oil to Fox Airs
Post by: SCDL Guy on January 23, 2009, 05:07:15 PM
I called FOX today, was told my 10" travel shocks should come from the factory with 260cc, and I could add up to 30cc more oil for a total of 290cc. I drained them after work and found they had 280cc, which included the 70cc I had previously added. So they came low from the factory(210cc).  Thanks for the help.
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 23, 2009, 08:53:28 PM
You bought them new and they were THAT far off?
Title: Re: Adding oil to Fox Airs
Post by: Engineer on January 23, 2009, 11:08:27 PM
You bought them new and they were THAT far off?

Might depend on how long they were left to bleed out.  What viscosity is this oil?
Title: Re: Adding oil to Fox Airs
Post by: plkracer on January 24, 2009, 12:20:56 AM
The oil is pretty thin. I've heard it's 5w at some places, and 7wt at others. I know my fronts are way off from what they should have been. When I had the n2 out, I could feel them cavitating about 1.5 inches before the shock would bottom out. I haven't added any, but I want to pull the oil out to see how much is actually in there.
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 24, 2009, 09:00:01 AM
I use 5W Amsoil shock oil in the coilovers. I can't see it being an issue when draining.No way there was that much still in the shock after draining. I mean 80CC? No way IMO.
Title: Re: Adding oil to Fox Airs
Post by: odypilots on January 24, 2009, 09:19:33 AM
Make sure to cycle the shock a few times upside down after you start draining it. If you don't, the shock will hold some oil.

When filling, I added half my oil, then cycled the shock some to work the oil through the shock.  Be slow and sure, otherwise you can shoot oil all over the place. After that, to determine the maximum oil I could add, I slowly compressed the shock all the way and added until it was full.

This was with Fox Airs 2.0, by the way.
Title: Re: Adding oil to Fox Airs
Post by: Yoshi on January 24, 2009, 09:41:22 AM
On the FOX airshocks, aren't you able to fully compress the shock, then fill it all the way up with oil for the max usable in the shock?  I know if you have too much oil, the shock will not bottom out, it will hydrauloc lock and actually bottom out on the piston inside instead of fully collapsing, so if the shock is fully collapsed and you fill it with oil, then you should be able to top it off and be safe.  Adding the nitro won't effect anything, the nitro will compress as much as it needs too, the oil cannot.

Again, this is a question, I believe I was told you can do that from a shock seller, although i've never tried.....
Title: Re: Adding oil to Fox Airs
Post by: Admin on January 24, 2009, 10:26:42 AM
Thats how the pirate 4x4 guys do it, the weight of the oil isn't going to effect the spring rte, but changiing from 5 to 10 w is a easy fix for some tighter dampening etc... As Odypilots said it doesn't run out, you have to cycle that shock a few times, its amazing what will still come out doing so...
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 24, 2009, 10:58:08 AM
Not 80CC worth tho.
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 24, 2009, 10:58:47 AM
The point tho is that you have to be ACCURATE in the volume and consistent from side to side.
Title: Re: Adding oil to Fox Airs
Post by: Admin on January 24, 2009, 11:06:17 AM
Dont be surprised if there is 80ccs worth...
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 24, 2009, 11:08:27 AM
Well I would be. But if in doubt disassemble and refill correctly with base amount of oil and go from there.
Title: Re: Adding oil to Fox Airs
Post by: Admin on January 24, 2009, 11:13:06 AM
dont forget wes, were not talking a small shaft in a large tube like coilovers here, were talking a big shaft in a just bit bigger tube, oil does not just run out of them....I cycled mine 4 or 5 times before i had it all out when i did oil change....
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 24, 2009, 11:50:05 AM
I guess I'm missing something here.
Title: Re: Adding oil to Fox Airs
Post by: odypilots on January 24, 2009, 12:29:02 PM
On the FOX airshocks, aren't you able to fully compress the shock, then fill it all the way up with oil for the max usable in the shock?  I know if you have too much oil, the shock will not bottom out, it will hydrauloc lock and actually bottom out on the piston inside instead of fully collapsing, so if the shock is fully collapsed and you fill it with oil, then you should be able to top it off and be safe.  Adding the nitro won't effect anything, the nitro will compress as much as it needs too, the oil cannot.

Again, this is a question, I believe I was told you can do that from a shock seller, although i've never tried.....

I believe you need to work some oil through the valving first.
Title: Re: Adding oil to Fox Airs
Post by: odypilots on January 24, 2009, 12:36:04 PM
The point tho is that you have to be ACCURATE in the volume and consistent from side to side.

Very true. I had to start over because as I emptied the second shock, I realized that it still had oil in it, and I had already measured and refilled the first shock. Not sure how much more came out, but it was quite a bit.
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 24, 2009, 12:37:17 PM
I believe we must need some word from the source.Too bad they(Fox) don't post a freekin thing on their site about it.
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 24, 2009, 12:40:13 PM
I forgot about the oil trapped below the piston after just draining.Duh.
Title: Re: Adding oil to Fox Airs
Post by: Admin on January 24, 2009, 12:41:38 PM
I forgot about the oil trapped below the piston after just draining.Duh.

Duh, do you believe there could be 80ccs trapped?
Title: Re: Adding oil to Fox Airs
Post by: fabr on January 24, 2009, 12:56:52 PM
Title: Re: Adding oil to Fox Airs
Post by: plkracer on January 24, 2009, 10:21:42 PM
When you release the pressure, the negative spring will hold the shock partway compressed, so there will be more oil hiding behind the piston than one believes.
Title: Re: Adding oil to Fox Airs
Post by: Admin on January 25, 2009, 07:54:48 AM
When you release the pressure, the negative spring will hold the shock partway compressed, so there will be more oil hiding behind the piston than one believes.

Someone gets it...
Title: Re: Adding oil to Fox Airs
Post by: dsrace on January 26, 2009, 08:39:57 PM
I called FOX today, was told my 10" travel shocks should come from the factory with 260cc, and I could add up to 30cc more oil for a total of 290cc. I drained them after work and found they had 280cc, which included the 70cc I had previously added. So they came low from the factory(210cc).  Thanks for the help.




when you have drained the n2 out of the shocks in the past has a small amount of oil shot out too? has this happened a few times? the reason I ask is a little bit of oil to you might actually be more than you think, especially if it has happened a few times or so. this would account for low factory level you spoke of.
Title: Re: Adding oil to Fox Airs
Post by: dsrace on January 26, 2009, 08:43:20 PM
Title: Re: Adding oil to Fox Airs
Post by: SCDL Guy on January 27, 2009, 07:19:44 AM
Yes when releasing the N2 a few times a little oil did come out, doubt it was much more than a cc. I took a close look at my shocks the other day and noticed that the bearing caps were a little marred like someone had been into them prior to me getting the buggy, so possible they weren't brand new.
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