ZX-5 center drive shaft rubbing the servo mount

[Jelico]

Hi guys,

Just got my ZX-5 RTR a month ago and had a bad accident the first time I took it out. The ground was wet and the car skidded and hit a boulder on the front end. I did not have the aluminum suspension holder. So the plastic holder and the bulkhead were shattered. I just finished rebuilding the car and noticed that the center drive shaft is rubbing the servo mount. The front drive bevel gear shaft seems to be straight still. Could anyone tell me what is the problem with the car now? Could it be the plastic drive joint.

By the way, would the carbon fiber chassis help in the frontal impact situation? Would anyone recommend the 3racing carbon fiber chassis? Sorry, many question!

[Scouser]

The servo rubbing on the centre drive shaft is not uncommon. I had to trim some of the mounting bracket off my Futaba servo to stop this happening. If you have a read of Jimmy's review of the ZX-5, I believe he mentions it aswell.
The chassis of the Kyosho is extremely strong, I doubt you will benefit from changing it to a carbon fibre version. Carbon fibre will be stiffer but it will alter the handling of the car which might not suit your driving style. Hope this helps a bit.

[Jelico]

Thanks for the reply. I haven't upgraded anything, so everything is completely stock. The thing is, I don't know if the center drive shaft was already rubbing the servo mount when I bought it. I just assumed that everything should be assembled perfectly from the factory. It was only after the crash that I noticed the car sounded louder than before. After a closer look at things, I found the center drive shaft rubbing the servo mount . It seem like it's from the front because the drive joint wobbles when I squeeze the throttle. Is it normal for the drive joint to be wobbling?

[RogerM]

The driveshaft wobble is a by-product of Kyoshso trying to make the drive train as adjustable as possible (in terms of 0ne-way / fixed drive options) with as few bespoke components as possible. The shaft rubs on my car too, nothing to worry about as it only does it when reving high with no load on the transmission.

The front brace that you need to prevent similar damage again is LAW31.

[SimonW]

Try and check the front gearbox input shaft also ( la202 i think), it's made of ally and one BAD front ender is all it takes to bend it just enough so that the centre shaft wobbles at the front, they are quite cheap to replace just a pain, for the size of it, it would of been better to have a steel one IMHO. Look at the blue shaft and see if it's worn all the way round or just on one side, another way to check is to remove the shell and rev it up and watch for wobble. HTH

[DanW]

You have to remove the washer from the top screw on the inside servo post, otherwise it rubs. Some servos you may also have to file a very small amount off.

As simon says the front input shaft is only aluminum and can get a slight bend in a big crash.

Its also possible, but less likely, for the main centre propshaft to get bent.

If you have installed new gearbox and bulkhead parts check that the gear box top is screwed down nice and tight otherwise the input shaft can wag. Sometimes with the cross-head screws its difficult to judge when the screws really bite.

[Jelico]

Thanks for the help guys. After checking the blue center shaft, it appears that the shaft has developed the a silver spot on just one side. I will check the screws on the bulkhead and order myself a front bevel gear shaft (LA 202).