Ball Diff Maintenance... how?
 

Ok, I rebuilt my TC5 ball diffs; diassembled it first, cleaned all the parts,
replaced the aluminum outdrive with new composite outdrives, sanded
the diff plates at 1000 grit sandpaper, lubed the thrust bearing assembly
with black grease, lubed the diff balls diff lube, assembled it, and tightened
it to my liking. It still felt gritty. WTF? I assembled it right but it still not
smooth. What do I need to change? Diff plates? Diff balls? Should I sand
the plates more?

Another thing, can I use a silicon sealant between the diff outdrive and
the diff pulley? Just at the small gap where micro dirts can get in.
I know I can just buy a diff seal but I dont have access to that after market
part. I tried the Tamiya diff seal same as what I use in my TA05, but I can
only fit it to one side of diff.

Lastly, how much diff tension is needed on a loose surface? AE manual says
to screw all the way and back off 1/8 turn. If I follow that, it will be a
little tight. Now I read somewhere here that it should be screwed just
enough not to let the diff pulley slip. So which route is better?

Balls are worn (both diff and thrust). If you have a nice little powerful magnifier have a look and you'll see they are pitted and cratered from grit being ground in the diff. You can polish them if you want, but it's way cheaper and easier to buy ceramics which will last forever.

No. No silicone. Cut your own protectors out of sticky label printing paper you can get from Avery. Use an Olfa or similar circle cutter (or a plotter cutter if you have one) and you're set. You can even cut and sell these at your track for 1 buck a pair (people offer me, but I am too lazy and just tell them how to do it)!

I assume the AE manual gives instructions for a new diff with new balls. You need to adapt. Test on the track and you shall find (no really).

you did everythign your supposed to, that shouldve mae it butter smooth.
You may have flat spots on the diff balls, try replacing all the diff balls and do it all again.

I guess it's the diff balls, I will rebuild it again after I source new ones.
The tc5 diff pulley has a blank side so the diff seals are not sticking
properly thats why Im thinking of silicon sealant.

Now, what will happen if I run it like this, a little rough and gritty?

You need to cut the protectors large enough to stick on the outer edge of the pulley and let them rub on the diff joints. To avoid these sticking, you need to cut another ring of smaller diameter that sticks on the inside face (the one facing the pulley), leaving only a ring wide enough on the edge to stick to the pulley. The Avery label paper is pretty good and plasticky and sticks to most surfaces, don't worry. Just make sure you have no grease there and you should be OK.

No big deal runnig gritty diffs. Just annoying to setup and not long lasting. Once the balls are gone, the rings get worn a lot quicker between rebuilds too.

I can only get the Tamiya tungsten diff balls. Are these ok? It's 3mm, it
is standard? I mean will it fit on AE diff pulley without problems?

No, AE (and other american companies as well as Corally, HPI and Yokomo) use imperial size balls.

Tungsten carbide are more expensive, heavier (not a biggie) and harder than ceramics SiN3 (silicon nitride) commonly used. Surprisingly, I found mine were a bit soft (tamiya). They wore down, which was really unexpected and when I checked they were magnetic (so they were probably just ordinary steel) so I might have been stung with a dodgy set from Tamiya, courtesy of poor QC.

Get the silicon nitride balls (they're black so you can see straight away).
Try Kanzen Bearings. They can kit out your entire car and are good quality balls/ball bearings. Also many other shops on ebay sell balls by the pair or in complete sets.

Yup, it's expensive and not the right size. I'll be getting yokomo steel diff
balls for now. Thanks for the advice...

you sanded the rings??

is that good???


:weird:

Yup. It is recommended and it's what the pros do.
About 1000 grit.

wow.

glad i read this thread.


so what your saying is the ring that contacts the balls in the diff gear is what i sand?

i would almost think that would make the diff more "gritty" feeling?

this is good for a 1/10th scale losi or associated offroad ball diff?

(im a newb and just realized this was onroad section) :o

That's what I thought also but when I tried 1000 grit of sand paper,
I ended up with a smooth polished diff ring. But I used the old diff balls
which is already worn and pitted so I ended up with a gritty ball diff.
Gonna rebuild it tonight but with new balls. I still have to seal it though.
My TC4 doesnt experience this.

i think im gettin ya.

so this wouldnt be done if new rings and balls?

Sanding the rings when everything is new will give you the best possible result. If you're careful, you will get the new rings even flatter than they came from the factory.

Some rings don't appear to be 100% flat out of the packet for some reason... maybe they're pressed, not machined ?

;)

I'm surprised that noone has posted this link yet:

http://www.youtube.com/watch?v=YOMu6...layer_embedded

A demonstration from the new European Champion of how to maintain diffs, very informative!

Regards

Neal