Friend gave me two B3s!!!

[roor]

My friend is moving and he asked me if I wanted his old b3s. Hell yea I wanted them! It’s only been like 15 years since I last played with my long lost b4 (RIP, you were in near perfect condition ). I barely had enough to even finish a kit with decent electronics.

Now with some money to burn (NOT!) I could splurge a little on new modern electronics. I’m keeping one classic, the factory team version and modernizing the electronics on a team kit. They were pretty well beat up and the brushless motor blew the diff anyone know where to find a rebuild kit or any other tips on finding parts or any must have upgrades when going brushless? The 3s battery and brushless motor was AWESOME until the differential blew out.

Thanks in advance! Feels great to be back!!!

Vintage B3 with brushed motor


Modernized b3 with surpass hobby esc, reedy 3300kv motor, and 3s brushless motor.


The two of them side by side


Getting a little creative with the body for the esc

[1911Colt]

A friend indeed!

[radioactivity]

Hi there roor

If what you have is a 2.4 trans and it needs diff gear and/or rings, it looks like muddslidemotorsports will have you covered.
Super nice people there.

Chuck

[Frankentruck]

I think you need to disassemble the gearbox and see what is up with the ball diff. If it was installed flipped the wrong direction, it will loosen itself up during runs. You might not need parts, just cleaning and reassembly.

[JosephS]

My friend is moving and he asked me if I wanted his old b3s. Hell yea I wanted them! It’s only been like 15 years since I last played with my long lost b4 (RIP, you were in near perfect condition ). I barely had enough to even finish a kit with decent electronics.

Now with some money to burn (NOT!) I could splurge a little on new modern electronics. I’m keeping one classic, the factory team version and modernizing the electronics on a team kit. They were pretty well beat up and the brushless motor blew the diff anyone know where to find a rebuild kit or any other tips on finding parts or any must have upgrades when going brushless? The 3s battery and brushless motor was AWESOME until the differential blew out.

Thanks in advance! Feels great to be back!!!

Vintage B3 with brushed motor


Modernized b3 with surpass hobby esc, reedy 3300kv motor, and 3s brushless motor.


The two of them side by side


Getting a little creative with the body for the esc

I'm not 100% certain but I have heard that the customworks 2.4 parts, diff gear, rings and outdrives are drop in for the associated parts on the b2&b/t3.

https://www.customworksrc.com/product/diff-rings-for-2-4-diff/
It looks like the gears and outdrives are no longer stocked, but the diff rings should be a help.

[roor]

I ordered two sets of rebuild kits. Thanks @radioactivity!

I tightened down the slipper, still nothing. I disassembled the gear box and the diff feels GRITTY!!!!! Does not turn smoothly at all. Later today I will try to get it a proper disassembly and cleaning to see what the real damage is.

Despite being bashed a lot they should have been built properly but now that I think about it, my friend built this one so it could be built wrong. His dad would take his time and use calipers to measure everything. I’m leaving this one alone.

Thanks for all the tips! I thinking about trying to find the b4 slipper assembly. Seems like it handles extra brushless power. I’m itching to get back!

[Frankentruck]

The thing that seemed to make diffs the roughest/grittiest for me is when the 6 ball bearings and 2 washers around the tension bolt need cleaning and greasing, or replacement.

[R6cowboy]

The thing that seemed to make diffs the roughest/grittiest for me is when the 6 ball bearings and 2 washers around the tension bolt need cleaning and greasing, or replacement.

Speaking of the thrust bolt bearing and washers. Has anyone used the ProTek thrust bearing set? See link below.

https://www.rcplanet.com/protek-rc-2.5x6x3mm-associated-tlr-precision-caged-thrust-bearing-set-ceramic-ptk-2026/p469099?gclid=CjwKCAjw0dKXBhBPEiwA2bmObQ3OIc6cBiGa6RgBR8_FNe6ozCCyTSjuPYlAA-aYzcxqXCRu_pXIyxoCmIcQAvD_BwE

[GoMachV]

I have not, but I have bought some from Avid- and the quality seems great! Not ceramic but very smooth

[Frankentruck]

I bought bulk from McMaster, same with diff gear balls. I notice the thrust bearing balls making the biggest difference. Just my limited experience though.

[jwscab]

On a well maintained diff, you should be replacing thrust parts at a 2 or 3 to 1 ratio with the diff rings and balls. By far the biggest source of notchiness or grittiness is the thrust assembly.

The rings can be sanded smooth.

[roor]

I rebuilt the diff and followed instructions exactly. Still huge loss of power across the board. I’m doing a fast or slow acceleration, the buggy still tops out a slow speed with a loud screeching sound. Never anything close to max speed. I checked the pinion and that’s tightened down properly. I guess it’s the slipper then? I tightened it as tight as it would go, but when I took it apart the pads felt like they had lost a lot of grip/texture. It felt really smoothish with a light grip/texture. I think I remember when I built my b4 the pads felt almost like a fine sandpaper.

I checked out a post and it seems like I just get the nut, spring, disc x2, pads x2, gear, and certain long gearshaft.

I feel like I’m going to end up paying as much in shipping as I’m parts

[juicedcoupe]

Few questions.

Are you trying the brushless or brushed car? Brushless motor require different gearing than brushed.

You mentioned 3S. Are you using that? Those vintage transmissions and slippers weren't designed for that kind of power.

On the slipper, is the spring solid? Or the nut just bottomed out? If it's just the nut, a #4 washer can be used to shim it.

[roor]

Few questions.

Are you trying the brushless or brushed car? Brushless motor require different gearing than brushed.

You mentioned 3S. Are you using that? Those vintage transmissions and slippers weren't designed for that kind of power.

On the slipper, is the spring solid? Or the nut just bottomed out? If it's just the nut, a #4 washer can be used to shim it.

1. All changes are being done on the brushless one. The 100% vintage brushed b3 is running well, although a clean up wouldnt hurt it.

2. lol ya. It did handle it, but only for about 5 minutes until this problem came up. must have been the hard turns and sudden take offs this is the one i got https://www.amazon.com/5200mAh-Battery-POVWAY-Helicopter-Airplane/dp/B07TS2GVS3/ref=sr_1_2?crid=F5SDX8PFS2ZJ&keywords=3s+car+battery+deans&qid=1660339486&sprefix=3s+car+battery+deans%2Caps%2C121&sr=8-2

3. The sporing looks solid. I held the gear while tightening it TIGHT. I know its not good for normal running but i wanted to see if I could tighten it enough to become as non-slip if possible.

[juicedcoupe]

Yeah, those old diffs and slippers aren't going to live with 3S brushless power. Honestly, 2S brushless is probably pushing it.