92' Rear Shock Help

[sgilbert14]

I've pulled and drained the oil in my rear shock but the oil got tip over in my shed and I have no clue as to how much goes back in ? What would be the best type of oil to use ?? Questions I should asked before I pulled the shock but I got caught up in the "Why I am here I will do ................................" mode.   

[MetrickMetal]

I've pulled and drained the oil in my rear shock but the oil got tip over in my shed and I have no clue as to how much goes back in ? What would be the best type of oil to use ?? Questions I should asked before I pulled the shock but I got caught up in the "Why I am here I will do ................................" mode.

There's nothing mentioned in the factory service manual about the oil volume in the rear shock, but through some searches I did I found out it's should be around 9.5 ozs. I will be checking out the rear shock and suspension shortly on the C10, and although it shows no signs of leaking it will be interesting to see how much oil drains out, but I'm sure someone on the forum who knows more about it than what I've found will chime in.

I also found that the weight range was from 5w to 10w, and as far as what brand oil to use, I have been using Bel-Rey on my bikes for many years which is very good suspension oil. I don't know what weight oil is in the shock from the factory, and unless I hear anything different I'll probably go with 10w to start.

A good tip to make sure that you get the old oil out of not only forks or shocks if your not doing a complete teardown is to place them out in the sun for a couple of hours to warm up the oil so that it drains out more easily.

Like every bike I have ever owned I have always at some after riding them for awhile modified the forks and replaced the rear shock(s) and  I'm already going to be installing new straight wound fork springs to start with on the forks along with a complete tear down and rebuild and go from there as well as changing the shock oil, but at some point I will most likely replace the rear shock with an after market unit. 
 

[sgilbert14]

Thanks for the help. I was at a lost because I have 2 books for the bike and neither say a word about this...

[Rick Hall]

As metrick mentioned changing the rear shock oil is not in any of the books.

The quantity to refill is what you drained out. Any more and it could be real bad mojo.

My memory what it is, 8 oz is the refill quantity. But make double sure you have all the old oil out. Unscrew the hose tip/hang/warm the shock to make sure it's all out.

Though people use all sorts of oil to refill, it's not a fork. Use shock oil, AKA suspension fluid. Since there's a Kayaba sticker on the side, use Kayaba weight suspension oil. And I recall this is the 175-225 'weight'. Note it may not necessarily be equal to SAE/API oil weights (I know it's not).

But a lot of people can't tell, so refill with a quality suspension/fork oil of your choosing. Also keep in mind the ports (holes) the oil passes through have probably enlarged over the years/miles, a heavier oil may work just fine.

If you do the math, the rear shock is pretty precision inside. If the rear wheel moves 2" over a bump, the rear shock moves around 1/2". The oil takes a beating. So don't "cheap out".

Rick

[T Cro ®]

I've pulled and drained the oil in my rear shock but the oil got tip over in my shed and I have no clue as to how much goes back in ? What would be the best type of oil to use ?? Questions I should asked before I pulled the shock but I got caught up in the "Why I am here I will do ................................" mode.

Don't Murph sell a complete kit with oil and filler thingie for the rear shock?

[Ken]

FYI: A buddy of mine just replaced the oil in his 2002 C10 rear shock.  It takes SPECIAL OIL.

[sgilbert14]

I'll check out Murph

[sgilbert14]

Thanks, I just ordered the kit from MUrph's

[MetrickMetal]

Its strange that the shock oil change kit that Murph's sell says that is comes with Maxima shock oil that has a viscosity index of 385, as Maximax doesn't sell a shock oil with that viscosity index rating.

http://www.maximausa.com/shopping/index.php?main_page=product_info&cPath=7&products_id=43

Maxima is in SoCal, so latter this morning I'm going to give them a call and ask them a few questions about their shock oil viscosity index ratings.

[RFH87_Connie]

Shock oil is a special fluid not to be even remotely compared to fork oil.  On the page you linked, it says right in the text they start at 350+.  Shock oil is a completely different type of oil than traditional "fork" oil when discussing viscosity.  It has all kinds of modifiers and anti-foam agents.  Since it is such a small volume, it gets an extreme work-out all the time.  Both of my shocks only needed 8oz of fluid with no signs of ever having any leakage.  I used 10w because I have a passenger on many rides.  You can buy two different weights and blend your own viscosity.

And yes, Murph sells a handy kit.  The hardest part of this task is getting the fluid back in.