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SRB FRONT SHOCKS IE CHAMP RR SS

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refilled both front shocks on my super champ put new o-rings in them one is working ok and the other i just can not get it to work ..(no resistence at all or pushing back)  what is up with  it i must of done it right cause the other is ok...  so am i doing somthing wrong or is the shock damaged/worn?

thanks for reading .. whould like info thanks

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OK, the pushing back or rebound basically means that the shock has a little to much oil in it, and you run the risk of blowing the seals (again?). To fix, simply push the piston in on that shock, then undo the top cap and allow a little oil (and pressure) to escape.

My first question is, when you rebuilt the shocks, did the shaft slide smoothly inside each of the shocks without any oil. What Im getting at is that the shock that has little resistance may be OK, and the one that you have resistance with, may actually be the one with problems.

Also, What weight oil did you fill them with?

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i thought the rebound is what i want in the shock? the one i have that will not rebound just pulls in and out with no rebound .. it stays were ever i put it..

so turn it upside down with the piston pushed fullly in and let the excess come yes .. then put the end back on..am i right

 

also the piston rod just slide down the shaft ok no resistence .. also i am useing 400 oil in both one works ok with it

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i thought the rebound is what i want in the shock? the one i have that will not rebound just pulls in and out with no rebound .. it stays were ever i put it..

 

A damper by it's self won't rebound, it's the spring that causes the damper to return to it's position, are there springs fitted to your car ?

Also, in relation to the lack of resistance, is the piston on the end of the damper's shaft Ok ?

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i thought the rebound is what i want in the shock? the one i have that will not rebound just pulls in and out with no rebound .. it stays were ever i put it..

 

A damper by it's self won't rebound, it's the spring that causes the damper to return to it's position, are there springs fitted to your car ?

Also, in relation to the lack of resistance, is the piston on the end of the damper's shaft Ok ?

 

 

yes there is springs fitted .. also the end of the pistion looks ok .. but not sure what do i look for? 

neil

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You could visually compare it to the damper that works to see if there is any difference in the parts.

If the problem is happening when the dampers are fitted to the car then perhaps there is some binding taking place in the suspension arms or even in the damper mounting points, or maybe even the spring might be worn out so not returning the damper to it's proper position ?

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it is returning with great spped due to the damper not working the one that works does back gentle so the arms will not break..  this what i am afraid of it doing..  the damper with spring works but there is no.. softley return just flys back and i have the springs set to softest setting the highest notch

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Ah, I see what you're getting at now, at first I thought you meant it was sticking in position and not returning.

I guess it must be down to the internal parts of the damper then, if the oil is the same quantity and type in both sides then I suppose the only thing left to check is the pistons, do they look the same if you hold em side by side ?

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i will check them but will need to strip them down again .. but if they are differant is it knackered?/worn ..nothing else to do?.. the only other way i get it to be differant if i over fill it and the pistion just stays were it is .. i am sure the damper is filled right must of done it 10 times did the first one . at first attemped

 

 

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Just a thought but was the shaft fully extended when you put the oil in ?

If not it could be a big air bubble in there.

If the oil is Ok and the piston is Ok then maybe the inside bore of the damper body is worn out, never seen one like that though but I guess it's possible if the car was run without damper oil for a long time.

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i did to the way the origanel instructions read... the pistion is left in as i fill it up .. or should i try a differant way.. is there another way..

 

neil

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From everything you're saying it sounds like you did it correctly, basically if the right quantity of oil is in there as per the instructions it shouldn't be a problem.

Did any oil escape past the O-rings after you re-built them ?

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it did first time but i put a new o-ring in thought then i was sorted then i got no oil leak but the shaft just pushes up and down..

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First, the shock that is rebounding shouldn't. it has too much oil in it. Loosen the top cap and push the piston in, then tighten the top cap. This damper is now filled correctly.

Now the other damper. First check it is still full of oil, those shocks weren't known for their ability keep oil in them. Top up if necessary. If it is still the same then either the piston or the shock body is worn out. Modern dampers work by having a close fit between the piston and cylinder and the oil is forced through holes in the piston. The SRB dampers work by the oil passing through the gap between the piston and cylinder and the only thing preventing the piston rubbing on the cylinder is the o-ring seal at the bottom. As the seal wears it allows the piston to rub on the wall of the cylinder, which quickly wears the aluminium cylinder. As the gap is larger than the other one you could compensate for it by using a thicker oil, comparing the two dampers until they feel the same should be near enough for an SRB.

Regarding oil, most oil used at the time was usually ordinary lubricating oil, such as 3 in 1, or the Tamiya damper oil which was only about 10-15W. The dampers weren't really designed for performance, more for scale appearance. When racing quite often the dampers were empty at the end of the day anyway and it never made much difference to the handling. The banging of the suspension is more to do with the SRBs having the springs too strong as standard, mainly so the car could cope with jumping without damage. The suspension is designed so it can handle the loads of the strong springs and little or no damping so I wouldn't worry about damaging the car.

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First, the shock that is rebounding shouldn't. it has too much oil in it. Loosen the top cap and push the piston in, then tighten the top cap. This damper is now filled correctly.

Now the other damper. First check it is still full of oil, those shocks weren't known for their ability keep oil in them. Top up if necessary. If it is still the same then either the piston or the shock body is worn out. Modern dampers work by having a close fit between the piston and cylinder and the oil is forced through holes in the piston. The SRB dampers work by the oil passing through the gap between the piston and cylinder and the only thing preventing the piston rubbing on the cylinder is the o-ring seal at the bottom. As the seal wears it allows the piston to rub on the wall of the cylinder, which quickly wears the aluminium cylinder. As the gap is larger than the other one you could compensate for it by using a thicker oil, comparing the two dampers until they feel the same should be near enough for an SRB.

Regarding oil, most oil used at the time was usually ordinary lubricating oil, such as 3 in 1, or the Tamiya damper oil which was only about 10-15W. The dampers weren't really designed for performance, more for scale appearance. When racing quite often the dampers were empty at the end of the day anyway and it never made much difference to the handling. The banging of the suspension is more to do with the SRBs having the springs too strong as standard, mainly so the car could cope with jumping without damage. The suspension is designed so it can handle the loads of the strong springs and little or no damping so I wouldn't worry about damaging the car.

 

 

GREAT MATE THANKS FOR THAT  i am useing 400 oil it is half way between the oils .. or is it 40.  will try a thicker one.. or use mobel 1  haha.. i mean even if i do get them runing ok i will be going through oil for fun even if there new 0-rings.. thought they whould of been a better damper than that.

so even if i do not gt the damper right the arms should be ok hitting the front and will not break (well hope not)

also have seen some upgrades that other people have done (differant shocks) what type of shocks are if you no..

i did try my shocks of the FF01 whitch i just upgraded but they were to fat .. dam pitty that one

neil

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Terry, that is some EXCELLENT information on the SRB dampers, I really found it to be useful.

I wonder if you smear black Molybdenum DiSulphide lubricant MdS2 (I have a huge tube of it, brand and model called ROCOL "MTS 1000") over the inside of the damper walls with a stick, would it stop the wear on the aluminium cylinder when the 'O' ring starts to wear out?  The oil wouldn't "wash" it away, surely?

BTW I have found that my own dampers DON'T leak at all, they're really quite effective and nice. That's probably because I used Silicone Sealant on the end caps as per the manual, and importantly, I let the sealant dry for 24 hours after I had put the bottom caps on, and then after I had filled them with oil I then used the same sealant on the top caps, and let them dry for 24 hours again before I used them, and I made sure that I did not mark the damper piston shafts with any sharp objects by mistake because then the abrasions / nicks in it will then quickly wear the 'O' ring out! I used the original shock oil that came in the NIP damper set.

Also, I softened the spring tension on the rear torsion bar springs by quite a lot so that the dampers played more of a role in the suspension performance. 

Also to Tamiya's credit, when I softened the rear suspension, AND built my shocks properly, I found that when I dropped the back end of my XLT down onto the table under it's own hefty weight, from 10 inches height approx., the car hardly bounced at all, the suspension torsion springs / semi-pneumatic tyres / dampers combination is really quite effective.

Cheers,

Alistair G.

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Terry, that is some EXCELLENT information on the SRB dampers, I really found it to be useful.

I wonder if you smear black Molybdenum DiSulphide lubricant MdS2 (I have a huge tube of it, brand and model called ROCOL "MTS 1000") over the inside of the damper walls with a stick, would it stop the wear on the aluminium cylinder when the 'O' ring starts to wear out?  The oil wouldn't "wash" it away, surely?

The problem with that idea is that the oil goes around the edge of the piston in SRBs, the gap is only around 0.5mm wide. Smearing the inside walls of the damper would fill in this small gap, which would effectively lock up the damper.

Regarding replacement dampers that are more effective some people have tried shocks designed for the losi mini-T that seem to be about he right size.

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