Kronos How to remove the front drive cup

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Stormwind

Stormwind

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Corally RC's
  1. Kronos
Hi, I'm currently in the process of attempting to replace the input drive cup to the front drive train with an upgraded swiss cup. However, I'm obviously being particularly dense but I can't seem to remove the cup from the gear spindle.
I have removed the grub screw from the side of the cup but I can't seem to see any other screws or anything either on the thing itself or in the exploded views.
Can anyone shed on any light on this please?
1687343807783.webp
 
It's probably got threadloc on the shaft as well, so try a little heat and gentle tapping and levering.
Also try some wd40/gt85 down the hole as this can soften the threadloc.

I'll be replacing mine a little later on as well.
 
It's "stuck".. a little heat could help if you have a micro torch or similar. Otherwise you're gonna have to pry it off with a flat blade screwdriver. A combination of heat and prying will be easiest.
Take your time and use minimal heat/force so you don't damage the bearings or plastic housing. They can be stubborn to remove.
 
I already snapped a screwdriver removing the grub screw from it :P
Thanks for your answers, I'll keep going.
 
Is there a hole through the cup itself where it slides onto the pinion shaft? Might get away with using a punch and hammer to "tap" the pinion out of the cup?
 
Jeffwazz said:
Good to know 👍

How notched were your cups?
Click to expand...
Curious too..
My '21 XTR came with the black XP cups..might as well have been made of copper,LOL.
My brother picked up an RTR Kronos late last year, his don't seem to be wearing as badly as mine's did.. perhaps I got a bad batch? Happens. TC did me right with the swiss upgrades FOC. PIA to change em all out though.. oh well. Swiss cups are holding up great.
 
I had 6 months out of the centre driveline. Centre diff outputs were fairly deeply notched, front and rear input cups are similarly notched and need changing - just need to get around to it later.
 
Jeffwazz said:
I had 6 months out of the centre driveline. Centre diff outputs were fairly deeply notched, front and rear input cups are similarly notched and need changing - just need to get around to it later.
Click to expand...
The center driveline parts aren't as sensitive to the wear since there's minimal movement of connected parts. The outer drive parts are where it gets troublesome. Suspension starts binding..
 
Jeffwazz said:
Good to know 👍

How notched were your cups?
Click to expand...
It looks like I've already binned mine but they were pretty much the same as the centre diff ones depicted here.
I've managed to end up spending about 4-5 hours today changing out just the front cup today, upgrading my servo-saver spring and changed my pinion whilst I was at it. Took so long since I had to keep pulling it apart again since I had used the wrong screw or re-assembled it to find I had two nuts left over which I had no idea where they went so had to pull it apart again :P.

Let's hope that I can do the rear cup in a lot less time although I don't have much hope since I haven't taken anything apart on the rear yet. It's gotta be less right since there is no steering assembly to deal with?!
 
Stormwind said:
It looks like I've already binned mine but they were pretty much the same as the centre diff ones depicted here.
I've managed to end up spending about 4-5 hours today changing out just the front cup today, upgrading my servo-saver spring and changed my pinion whilst I was at it. Took so long since I had to keep pulling it apart again since I had used the wrong screw or re-assembled it to find I had two nuts left over which I had no idea where they went so had to pull it apart again :p.

Let's hope that I can do the rear cup in a lot less time although I don't have much hope since I haven't taken anything apart on the rear yet. It's gotta be less right since there is no steering assembly to deal with?!
Click to expand...
I reckon you can do the rear by removing about 8 bolts. I know the front will separate from the chassis with only 7, just leave the arms and towers attached to the case.
 
Stormwind said:
It looks like I've already binned mine but they were pretty much the same as the centre diff ones depicted here.
I've managed to end up spending about 4-5 hours today changing out just the front cup today, upgrading my servo-saver spring and changed my pinion whilst I was at it. Took so long since I had to keep pulling it apart again since I had used the wrong screw or re-assembled it to find I had two nuts left over which I had no idea where they went so had to pull it apart again :P.

Let's hope that I can do the rear cup in a lot less time although I don't have much hope since I haven't taken anything apart on the rear yet. It's gotta be less right since there is no steering assembly to deal with?!
Click to expand...
They call it dope for a reason!! Sounds like me wrenching after I've gotten myself "tuned up"..😆😁🤣🤣
 
Jeffwazz said:
I reckon you can do the rear by removing about 8 bolts. I know the front will separate from the chassis with only 7, just leave the arms and towers attached to the case.
Click to expand...
Yep, realised that later on after I had removed pretty much everything from the front drive train. I'll "remember" that for the next time. If there ever is a next time. I'd actually have to fix it first and get it running again. I'll probably run out of money before that happens :P.
 
KnowAir said:
The center driveline parts aren't as sensitive to the wear since there's minimal movement of connected parts. The outer drive parts are where it gets troublesome. Suspension starts binding..
Click to expand...
The most wear I've seen is on the center diff cups, then the front input, then rear. These tend to get deep narrow notches.
Front and rear diff outputs aren't wearing that badly, and with the arm movement, it's a wide notch, unlikely to bind.
I did expect the rear axle cup to be the first to get eaten, but that's still unmarked.
 
Jeffwazz said:
The most wear I've seen is on the center diff cups, then the front input, then rear. These tend to get deep narrow notches.
Front and rear diff outputs aren't wearing that badly, and with the arm movement, it's a wide notch, unlikely to bind.
I did expect the rear axle cup to be the first to get eaten, but that's still unmarked.
Click to expand...
Seems to be the ones operating at the greatest angles. Front center definitely chews the fastest.. the "ring" wear marks around the front center shaft tell a tale..
Here's some pics of my cup wear when my Kronos had the XP cups. Front and rear diff outdrives.

20220616_175839.webp


20220616_184007.webp
 
Just submerge the entire differential in water to heat the cup with a flame so you don't melt anything!
I had the same problem with my beloved MT4-G3..
 
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