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simalarion

To get the Oil Dampers Perfect?

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Hi,

I try to do exact the same, assemble the Oil damper itself correctly ofc then i fill the oil all up, then i slowly push the pin up and down until bubles are gone, then i attach the rubbe cap that has Oil all the way up to the cap. 

Then when the Oil damper`s is complete there is always some that will kick back right away and go back right back all out, while some pins go slowly out and many do not go completely out again. 

So what is the correct reaction for oil damper?, and if they do not do exaclty the same should i open them and do it again?, i presume that the correct is that the pin kicks right out again all the way (?).

I am finishing up the Agrios build and that seg have 8 Oil dampers :), not a kit for beginners i must say (specially this is not for "kids" to build like The Grasshopper etc) ... 

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It will be interesting to hear what some of the experts have to say about this (specifically any proper racers here ;) )

In theory all dampers should behave the same way once assembled.  Do you lubricate the o-rings before you assemble?  Some could be sticky.  The push-down from the reservoir is minimal, it would only take a sticky o-ring to stop it.

Also there could still be air bubbles.  You will notice this as a squeaking in the shock if you pump it up and down once sealed.  After I've filled my dampers with oil I will pump the piston gently just once to get oil down through the holes, but after that it's best to wait until the bubbles come to the top.  The instructions say to move the piston slowly, but if you're not careful you can chase the bubbles back down the holes.  Once the oil is clear I do another few gentle pumps to get any last bubbles.  Sometimes rotating the piston shaft helps to find a few more trapped under the piston.

I have a car stand with space to put shocks, after I've filled them with oil I can leave them to stand for a bit until all the small air bubbles come out.  I wait 5 - 10 minutes per shock.  If I start the dampers early on in the build process (before I need the stand for the chassis) I can move on to do other things while I wait for the oil to settle.

I have heard that some people assemble the damper with the piston in the middle position (or specifically the position you want it to be in when it's fitted to the car and the battery is loaded).  I think I did this once and was surprised how evenly all the shocks wanted to return to the same position.

Finally - I recommend Associated Green Slime (other brands are available) to lubricate the piston shafts.  This stuff is like nothing else.  It must be made of the same stuff that Chevy Chase put on the bottom of his saucer sled in Christmas Vacation (which reminds me, it's nearly time to watch that film again).

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2 hours ago, Mad Ax said:

 

In theory all dampers should behave the same way once assembled.  Do you lubricate the o-rings before you assemble?  Some could be sticky.  The push-down from the reservoir is minimal, it would only take a sticky o-ring to stop it.

Also there could still be air bubbles.  You will notice this as a squeaking in the shock if you pump it up and down once sealed.  After I've filled my dampers with oil I will pump the piston gently just once to get oil down through the holes, but after that it's best to wait until the bubbles come to the top.  The instructions say to move the piston slowly, but if you're not careful you can chase the bubbles back down the holes.  Once the oil is clear I do another few gentle pumps to get any last bubbles.  Sometimes rotating the piston shaft helps to find a few more trapped under the piston.

I have a car stand with space to put shocks, after I've filled them with oil I can leave them to stand for a bit until all the small air bubbles come out.  I wait 5 - 10 minutes per shock.  If I start the dampers early on in the build process (before I need the stand for the chassis) I can move on to do other things while I wait for the oil to settle.

I have heard that some people assemble the damper with the piston in the middle position (or specifically the position you want it to be in when it's fitted to the car and the battery is loaded).  I think I did this once and was surprised how evenly all the shocks wanted to return to the same position.

Finally - I recommend Associated Green Slime (other brands are available) to lubricate the piston shafts.  This stuff is like nothing else.  It must be made of the same stuff that Chevy Chase put on the bottom of his saucer sled in Christmas Vacation (which reminds me, it's nearly time to watch that film again).

No, i did not lubricate the o-rings so that can be the problem i have, they will not get lubricated when used?. I believe i pulled the piston all the way down. Thanks for the tips, very helpfull. 

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A good question, I always get the same thing with Tamiya shocks. Build all the exact same way and always get 2 or 3 that spring back and the others will return slowly or slower. I have tried oiling the o rings and using slime. 4 shocks NEVER behave the same!

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I have always built mine the same way, I lubricate the o-rings before assembly, fill up 3/4 with oil, work up and down to get the air out, leave them stood up for a while until all air is gone. Then fill up with oil, some in the cap, then fit the cap but leave it loose, push the piston until it pushes the air out and it will push spare fluid out then tighten the cap. If I want a bit more rebound, I tend to tighten the cap just before its pushed all the way in.

That may not be the perfect way, but I have never had any issues in 20 years of race use.

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33 minutes ago, Matty36 said:

I have always built mine the same way, I lubricate the o-rings before assembly, fill up 3/4 with oil, work up and down to get the air out, leave them stood up for a while until all air is gone. Then fill up with oil, some in the cap, then fit the cap but leave it loose, push the piston until it pushes the air out and it will push spare fluid out then tighten the cap. If I want a bit more rebound, I tend to tighten the cap just before its pushed all the way in.

That may not be the perfect way, but I have never had any issues in 20 years of race use.

Thanks, i will test. You do also lubricate o-rings, im thinking thats the main thing i missed out (even though i se Gazzaline over hear did that to but with same result as i have).

 

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Yeah, if you dont oil the o-rings, they may get damaged as the edge of the o-ring will be dry when moving in the shock body, but also when assembling the shock cartridge they generally get caught then leak over time. I usually put a bit of shock oil on some kitchen towel and rub the o-ring in it.

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7 hours ago, Matty36 said:

I have always built mine the same way, I lubricate the o-rings before assembly, fill up 3/4 with oil, work up and down to get the air out, leave them stood up for a while until all air is gone. Then fill up with oil, some in the cap, then fit the cap but leave it loose, push the piston until it pushes the air out and it will push spare fluid out then tighten the cap. If I want a bit more rebound, I tend to tighten the cap just before its pushed all the way in.

That may not be the perfect way, but I have never had any issues in 20 years of race use.

Just a comment: Your method is mentioning aeration shocks, right? The other ones talked about shocks with a bladder for separating oil and air. Just to not confuse any newbies here...

Nothing wrong with your method in my eyes...:lol:

Kind regards,

Matthias

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5 hours ago, ruebiracer said:

Just a comment: Your method is mentioning aeration shocks, right? The other ones talked about shocks with a bladder for separating oil and air. Just to not confuse any newbies here...

Glad you mentioned that, as I was thinking that method would surely end up with a rock-solid shock :s  

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Yes build as per manual, except always rub the o-rings in green slime, the residue I wipe around the top bladder and the shock thread.

When tightening the cap, I do it in quarter turns, to hear air escaping a couple of times during attachment.

Just helps reduce leakage

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12 hours ago, Mad Ax said:

Glad you mentioned that, as I was thinking that method would surely end up with a rock-solid shock

Sorry to confuse anyone, but the shocks wont be rock solid as all the extra fluid is pushed out the top before fully tightening the lid, basically with the piston fully pushed in, so just leaves oil and no air in the body. Some shocks have a small screw to let the air out, and a bladder inside.

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