Screw/Nut ID... Gen 7 design flaw?

[pb1592]

Is it just me or has anyone else had this issue... Keep in mind my Gen 7 has very little use, in fact I was testing it in my basement when I came upon it. I noticed that the screw that holds the top of the shock to the chassis is SELF THREADING into a pre-drilled nylon hole. Every single other screw on the Gen 7, RS10, and Everest have a nut to hold any load bearing screws to the chassis. Needless to say one of the shocks just randomly popped off the chassis at this failure point. When I tried to re-attach it the nylon hole was stripped. No I did not overtighten any screws. After inspection I noticed that the other three shocks were loose at this same point and the joint flexes considerably when the shock is pressed. It's just a matter of time till the same thing happens to the other three. Furthermore, the screw appears to be just a little too short to even make it all the way through the nylon mount. Am I missing something here or is this a horrific design flaw? I don't recall making any mods to the shock location on this truck but maybe I did and don't remember (has happened before :mrgreen: )

All of this being said, I would like to purchase some new longer screws and nuts so I can mount the shocks properly so they will not fail and fall out. I have a question... what type of screw holds the shock to the body of the vehicle? I'm referring to the black screw that goes through and mounts the ball joint that the upper joint of the shock rotates on. Is there an identification for the form factor for these screws (diameter, thread size, etc?) I think pretty much every single screw on the Gen 7 and RS10, Everest that has has a nut fastened on it is this type.


Thanks!

 

[brimdogg]

They should be M3 screws, not exactly sure the length you need.

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[nightcrawler48]

The RedCat Gen7 manual shows only a screw mounting the shock to the shock tower. The screw is a 3mm dia. x 25mm long hex button head machine screw, RedCat #80248. The nylon it threads in to is only about 1/8" (3mm) thick. Not Ideal for the forces transmitted from the shock to the chassis mounting point. A 3mm dia. x 30mm long screw with a nut should resolve your problem. One thing though, depending on which hole on the chassis is used to mount the shock, you could have interference with the body mounting post. Just move the shock to a new hole that is clear to mount the hex nut. You'll see what I mean when you start playing around with it.

Pretty much every manufacturer uses 3mm dia. x 30mm long screws (Axial #AXA091, Traxxas #2557, HPI #Z360) so your LHS should be able to help you out if you don't have any of these screws. Depending on manufacturer, usually come in packages of 6 or 10 for about $3.

As far as design flaw, not really anything new as other manufactures have used the same design but maybe with thicker material, 5mm or 6mm, and most use 3mm self-tapping screws rather than machine screws. I usually drill the nylon out with a 1/8" dia. drill bit and use a machine screw with a nylon locking nut to mount the shocks, if I don't make my own metal shock hoops. I guess you could say RedCat kind of got it half right.

 

[pb1592]

Thanks! Those screws in my truck are only 20mm for some reason. Maybe its why they stripped loose. I found some M3 30mm screws and lock nuts at home depot to make the needed modification. Thanks for the info!