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02-28-2010, 12:51 PM

#1634

Timmie

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Quote:

Originally Posted by SoCalGuy

Hi all,
Another boring day at the office!
To date I have only been running my car outside my work with a few fellow employees on the asphalt street. For some reason after half a dozen or so runs, the rear diff seems to loosen up and feel "gritty" when it is turned. Is dirt somehow making its way into the diff housing? Is this a common problem on the TB-03? I would hate to think I need to tear it down and clean it out every week or so

Any thoughts would really be appreciated.
SoCal

Hi there SoCalGuy,

I never really had issues with dirt getting into the diff case of a TB03, but its not entirely impossible depending on how dusty the street you are driving your car on is. I'm thinking the gritty feel you are getting is actually coming from the thrust bearing assembly which is somewhat exposed in the diff half. A easy solution to this would be to rebuild your diff. Then before you install it into your car again, seal off the thrust bearing.

There are a few ways to do this. Just to make sure you are following what I'm saying to do, you will be sealing the side of the diff assembly that has the thrust bearing and diff adjustment bolt. You can push in one of the red rebound foams from the shocks in that end of the diff to help keep the dirt out. You can cut a ear plug (may take a few cuts to get it to fit just right) and push it in. And the last thing I have done is get the right size o-ring.(sorry don't remember the mm size) The o-ring should fit between the inner diff half bore, and the diff adjustment bolt head coming up through the o-ring. This will allow you to adjust tension of your diff without having to remove a piece of foam.

You can basically use anything you like. But the end result you are trying to achieve is, seal the thrust bearing from dirt, have something that is easily removed when you need to work on the diff, and something that won't come flying out.

I'm not sure if you are running the factory plastic diff or the hop up aluminum diff. You mentioned that you felt the differential had loosed up on you. This is a characteristic of the factory diff unfortunately. Every time you tighten the diff, the plastic nylon lock nut holder, and the diff half itself weakens. Also driving the car heats the plastic up during runs that also leads to needing to re-adjust the diff to compensate. The diff does not retain its tension because of this. You can just keep adjusting the tension to compensate, but that gets old fast.

Best solution is the aluminum diff assembly. When built correctly, you should be able to go a really long time without rebuilds....even if you run the car often. To build a almost bullet proof diff you will need...

Aluminum diff joint set - Tamiya #54056
Ceramic diff balls - 3mm in dia.
Ceramic thrust bearing assembly

All these items are available at speedtech under this link http://www.speedtechrc.com/store/ebp...?catmainid=716 If you can't locate the ceramic stuff look under racers corner.

With these parts, sanding your diff rings so they are flat, Associated stealth lube and black grease, and sealing off your thrust bearing, you will have a solid differential that will give you less headaches and more performance.

Quote:

Originally Posted by SoCalGuy

I hope everyone is having a great weekend!
Yet another rookie question regarding shock assembly. What position should the shaft be in (extended, pressed in, or somewhere in between) when the bladder is put in place and the end cap is screwed down.
SoCal

I was having a pretty good weekend until i realized tomorrow is Monday

What you are referring to is shock rebound settings. A lot of that is left up to personal preference. And is one of the things that makes this hobby so involving...is trying different things out Some people prefer no rebound...or a "dead shock." You would be doing this by building the shock with the shaft all the way in. Building the shock with the shaft halfway in would be building to 50% rebound. And a shock shaft fully extended would be 100% rebound. A general way of looking at when you would want to use different rebound is on what kind of a surface you will driving on. No rebound will usually be used on a smooth, higher traction surface. Full rebound would be used in a bumpier track, 50% rebound splits the middle. But it's still driver preference. It gets even more involved with weight transfer, sudden changes in direction, etc etc. So I will stop there haha. Hope I've explained this well enough for you

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