Big Rock "I think Big Blue is sick." - my 9-year-old son

[HarveyMushman]

Hello. I'm new to this hobby and this is my first post, so forgive me for not knowing much.

Being stuck at home, my son and I have acquired a small fleet, one of which is a BRCC. It has run fine for a few weeks, then all of the sudden the performance dropped off and the acceleration is terrible. It didn't happen in the middle of a run, but at the beginning. It's super weak at 50 and 75, and at 100, it seems like it needs a runway to get up to near full power. And ever then it seems lacking. Like it doesn't wheelie or blast off like it used to. (It steers fine.)

Here's what I've checked:
- Transmitter batteries (put in new ones)
- Lipo Batteries (I have two. Both 5000mah, one 50c, one 100c. Spektrum. Both fully charged. Same issue on each)
- Spur gear (it's fine)
- Drive shaft (it's fine)
- All spinning parts seem to be ok.

I did a reset on the ESC just because I don't know what else to check. Being new to this stuff, I'm not sure what questions to ask, what to be looking for, or what problems cause what symptoms. I've done searches and have learned some things, but haven't been able to diagnose. Any suggestions or advice would be appreciated. Thx.

 

[Overpowerrc]

Hello. I'm new to this hobby and this is my first post, so forgive me for not knowing much.

Being stuck at home, my son and I have acquired a small fleet, one of which is a BRCC. It has run fine for a few weeks, then all of the sudden the performance dropped off and the acceleration is terrible. It didn't happen in the middle of a run, but at the beginning. It's super weak at 50 and 75, and at 100, it seems like it needs a runway to get up to near full power. And ever then it seems lacking. Like it doesn't wheelie or blast off like it used to. (It steers fine.)

Here's what I've checked:
- Transmitter batteries (put in new ones)
- Lipo Batteries (I have two. Both 5000mah, one 50c, one 100c. Spektrum. Both fully charged. Same issue on each)
- Spur gear (it's fine)
- Drive shaft (it's fine)
- All spinning parts seem to be ok.

I did a reset on the ESC just because I don't know what else to check. Being new to this stuff, I'm not sure what questions to ask, what to be looking for, or what problems cause what symptoms. I've done searches and have learned some things, but haven't been able to diagnose. Any suggestions or advice would be appreciated. Thx.

Check the diffs looks like you stripped one

 

[Yonic]

Slipper most likely got loose, check this thread for info on how to tighten it.

 

[HarveyMushman]

I will explore both of these possible issues. Thx for the replies.

 

[JAM]

This will help. If you have other 3s models you can compare the sound on the ground. Loose slipper will squeal at a higher pitch with less off the line punch.

 

[SrC]

Hope all is sorted out. Welcome to AF

 

[HarveyMushman]

OK, so I checked both differentials. All gears front and back looked fine. No stripping.

It didn't seem like the slipper was loose, but I tried to adjust it. My question is this: If I'm holding the spur gear in one hand (like in pic), should I be able to spin the slipper plates by the sleeve on either side?

If nothing else, I'm getting familiar with the assembly of this thing.

 

[jondilly1974]

OK, so I checked both differentials. All gears front and back looked fine. No stripping.

It didn't seem like the slipper was loose, but I tried to adjust it. My question is this: If I'm holding the spur gear in one hand (like in pic), should I be able to spin the slipper plates by the sleeve on either side?

If nothing else, I'm getting familiar with the assembly of this thing.

No you should not be able to turn that slipper hub by hand.

 

[ph47mf]

don't have to take it out to tighten it either

 

[HarveyMushman]

don't have to take it out to tighten it either

Yeah, I've done an awful lot of unnecessary disassembly.

 

[SrC]

Yeah, I've done an awful lot of unnecessary disassembly.

Disassembly gets you familiar. Ultimately you find/realize short cuts to future disassembly by jumping in and just doing it.

 

[JAM]

Hey it’s out. Time for some loctite. Do you have a vice?

 

[HarveyMushman]

Hey it’s out. Time for some loctite. Do you have a vice?

yep and yep.
UPDATE: Running like new. It was the slipper clutch. I tightened it all the way, then backed it out a turn and a half. Gave a a quick test, now some thread lock.

Even though he has to wait 24 hours to rip, my son is super stoked. So a huge THANK YOU to all.

 

[JAM]

If you ever want to be presice with it you can tighten the screw down inside the slipper then lock the assembly into the vice then back the screw off and monitor your turns as you back it off that way.

 

[SrC]

^^^Yeah TL is useless if it doesn't cure. 24 hours. When uncured it actually loosens faster than if there was no TL. Because when still wet, hardware cant hold its torque well enough...until cured. Been there.

 

[HarveyMushman]

If you ever want to be presice with it you can tighten the screw down inside the slipper then lock the assembly into the vice then back the screw off and monitor your turns as you back it off that way.

That is exactly what I did. Backed it out while in vice, reassembled to test run, then disassembled to thread lock. But all part of the fun. Good to learn this stuff.

 

[Surchaufeur]

I tried @jondilly1974 clutch on my new slipper hub on my kraton 4s it was a bit too tight like was wheelying on 3s backed off a tiny bit on the field and its perfect alwsys monitor the clutch after tightening it up or rebuilded it ilearned there is no perfect number i own a 4s truck. Have put back the 15t i might loosen the clutch sgsinbecsuse i know its going to go into idgaf mode and will wheelie even on water at that gearing