Pi (3.1419) x Inner diameter x Length


that will make it right.

Fill near top, insert rod and displace

Edit* I'd use a 3000 psi hose for durability sake..

 

Really? Just fill the whole thing?

 

Push the piston to the fill side of the remote resi, fill the thing up about halfway, then push the piston almost all the way to the hose end to bleed the resi. Then top up the shock and let it displace a little fluid, charge, install, party.

Not sure on the actual Fox brand lines, but 2k should be more than enough. You also don't need shock oil, any hydraulic fluid will work, all mine run cheap power steering fluid, and the race truck runs Mobil hydro fluid which is far cheaper, and a better oil than any of the shock company's house brand oil.

 

You also don't need shock oil, any hydraulic fluid will work, all mine run cheap power steering fluid, and the race truck runs Mobil hydro fluid which is far cheaper, and a better oil than any of the shock company's house brand oil.

Interesting...Is this the general concensus and I didnt get the memo? I have been using dirtbike 5w fork oil at 13 bucks a quart!!

All ears for a cheaper and even better alternative!!!!!

Wayne, any comments on oil???


Thanks,

Rob

 

Cool, thanks

 

Set the IFP in the res 8" from the end of the res with the schrader valve. You will have to take that cap out of the res to do it (yes I know it can be done without removing the cap but for a first timer...). Also get a 24" peice of 1/4" x 20 all thread to help set the IFP, it threads into the IFP and allows you to move it in and out. I set the IFP at 9" and it is usually within an 1/8 once you insert the rod and seal carrier.

Let me know if you need any mor help Pm for my phone # if you don't have it.

wayne

 

You want to use a fluid with a high Viscosity Index (VI). If you use a fluid with a low VI it will be real stiff when cold and soft when hot. This is a good read.
http://www.peterverdonedesigns.com/lowspeed.htm

 

Brian,

What size are the reservoirs? That's what determines the proper location of the IFP.

On a Fox 2.0" series shock, push the IFP approximately 3/4 of the way into the reservoir (8" in for an 11" long reservoir, 6" in for an 8" reservoir).


step by step with photos here:

http://www.pirate4x4.com/tech/billavista/coilovers/Part_2/#TeardownBleedingCharging




on oil...this!

 

I was curious so...

M1 ATF
cSt @ 40º C 36.3
cSt @ 100º C 7.4
Equation (I didn't check it...just cut and paste from the link I posted above)
VI = 100+(10^(LN((EXP(1.0727+0.6175*LN(cSt@100)+0.9744*(LN(cSt@100)^2)+(-0.3764)*(LN(cSt@100)^3)+0.04824*(LN(cSt@100)^4)))/cSt@40)/LN(cSt@100))-1)/0.00715

M1 ATF VI = 176
You could do worse...but you could also do a good bit better. It is sad that Fox/King/et al. won't give out their spec sheet. Anyone have access to a viscometer?

 

What do you recommend, Bill???

I have been using Bell-Ray 5w fork oil from the local dirtbike shop at $13/quart.



Rob

 

Rob,

Bet you were hoping for a short answer eh? Sadly, no dice!

But a few thoughts:

- I don't know that I'm qualified to offer a recommendation. I know quite a lot of theory, and have some practical experience, but would never call myself expert. I will happily offer the following thoughts though, which may help you decide (and if so, colour me happy).

1) I'm not selling, pimping, or advocating anything - just trying to share knowledge and keep some of the more far-out urban myths from taking root.

2) I aknowledge the huge world of difference between the world of science/engineering/theory and the real, practical world. How far apart the two are for you often depends on what your goals are, as below:

3) There is a lot of differnce between "what'll work" and "what is best". Hell, I've poured brown swamp water in a rad, engine-oil in a diff, and ATF in a manual tranny - and it all "worked". Sometimes you do what you have to.

But what are your goals in choosing a shock oil? Tunability, thermal satbility, optimum performnce, price point, ease of availability, longevity? There are many things to consider.

I guess the "safest" bet is to go with what the shock manu. tells you - nothing wrong with that. Not likely to be cheap or as easily available though.

Next option would be to use a quality motorcycle shock or fork oil. I do this when I can't get the OEM stuff. Shock oil would probably be best, as a motorcycle rear shock is very similar to a coil-over, but I have noticed front fork oil is cheaper, and I have used this myself in the past.

Which makes me think of another thing - what are you doing with the truck and shocks, and therefore "how much difference will you notice". I'll be the first to admit, on an average trail ride, you could robably replace my shock oil with used 5w30 engine oil and I may not even notice. Racing is a different story.

Take a look at a racing shock at work, imagine it over hundreds of miles! I can't think of any "hydraulic cylinders" that work anywhere near as hard as that, with a lot at stake too.

So for racing, the oil properties become much more significant - thermal stability, VI, anti-foaming, seal swell agents, antiwear agents, corrosion inhibitors, detergents, dispersants, friction modifiers, pour point depressants, antifoam agents, viscosity index (VI) improvers, and antioxidants to name a few. Some may be important, some not so much, and the tech gets uncontrollably complicate pretty fast.

So you're back to either trusting the oem did their homework, trusting your own instincts / experience / trial and error, or doing an ass-load of engineering.

The other thing to take into consideration is how often you are rebuilding or re-valving. For me, I don't take much pleasure in tearing shocks apart and working on them, so once the tuning is close, I'd choose to use a quality synthetic and hope I don't need to get into them again often enough that the few extra bucks per shock is going to matter much. If you're doing extensive valving tests and going through gallons of the stuff, price is going to matter more. Whether or not one brand's 5wt differs enough from another to upset your valving tuning I do not know. I do know many bike guys "tune" by using differnt viscosities rather than altering valve shims (or sometimes in addition too).

Or go with maxyedor and use donkey piss :flipoff2:

 

No offence to anyone, but If the manufacturer say to use X oil in their shock... shouldn;t you use that... Maybe someone should get the manufacturers of the major shocks in on this so that we don't have 30 people bitching next year that the ATF in their coilover shat the bed cause of a tech thread on Pirate.

 

FOA says to use 5w oil.

5w oil isnt easy to get at 10 o'clock at night in the middle of no where.

 

5-7wt shock oil, or an AW22 hydraulic oil is what we recommend in most instances.
(I personally have used power steering fluid and automatic trans fluid in shocks with no issues however.)

 

Personally I use Bilstein Branded 5W Shock oil. You can buy it by the gallon for about $30 from several places. I have used this oil in Bilstein, Walkers, Foxs, and Swayaways and have not had any problems. A gallon of oil goes a long way unless you rebuilding after every race.

 

Fox 2.0== http://www.foxracingshox.com/fox_tech_center/owners_manuals/RemoteResRebuild.PDF

 

This thread is why most people stay far away from the inside of a shock. I will say 2things and I am done.

Billavista; there is more than one way to skin a cat

maxyedor; even though I don't wholy agree with Bill, I think your explination simplifies things way below where we are as a sport now. I do however agree with most of your message.

Wayne

 

Well said....

Thats all I needed to hear Thanks Wayne:dietsoda:

 

Also agree to well said, without bashing. Thanks Chris for your input also.

On the shelf are old gallons of 10 and 15wt Belray. 5wt are gone.

Some of the old shocks and forks in the 70's were "factory tuned" with 15wt... to others points.

Could be that 5wt disipates heat faster, and seals have become better.??

 

Brian, you probably need to revalve your junk for goin fast anyway Pull em apart and discover the mystery for yourself. It's not that bad, I promise

 

These are the old fox's that I need to sell... When I start playing with my 2.5" FOA's you know I will be calling