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Old 08-19-2008, 12:08 AM   #1
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Default I Took Apart My Buggy and...

Other than replacing stripped screws, worn out parts, relube bearings and relubing the shocks and diffs, what else should I be looking out for? Also, how would I take out the pin that holds the bevel gear inside the diff. housing? I need to relube that bearing because it's getting kind of gritty when I'm rolling it. Thanks...

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Old 08-19-2008, 12:12 AM   #2
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Basically when u strip your car, you should change anything that doesn't look right to u or anything that has been in the car 4 a while. Take my 8ight 4 example, I change the pinion bearings in my diffs every 2 - 3 meets, to make sure that it is right and it will not throw a bearing.

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Old 08-19-2008, 12:31 AM   #3
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Basically when u strip your car, you should change anything that doesn't look right to u or anything that has been in the car 4 a while. Take my 8ight 4 example, I change the pinion bearings in my diffs every 2 - 3 meets, to make sure that it is right and it will not throw a bearing.

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See, I'm a noob so I wouldn't know what to look for. =P lol

You don't relube the bearings? You just get new ones?

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Old 08-19-2008, 01:04 AM   #4
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The diff gears should come right out when you pull on them. Check that there isnt any excessive play in the arms and other plastic parts, considering that a little play is alright.

For the bearings what I would do is remove the shields, clean them out and let them sit for a while in wd40. Next I would blast them out with an air compressor and relube them with hi temp grease. Remember that too much grease in the bearings will slow down the drive train. If a bearing is gritty I would replace it with a new one.
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Old 08-19-2008, 01:13 AM   #5
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See, I'm a noob so I wouldn't know what to look for. =P lol

You don't relube the bearings? You just get new ones?

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Yep, don't muck around with bearings, just get new ones. That's just my way of doing things
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Old 08-19-2008, 02:14 AM   #6
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Also, how would I take out the pin that holds the bevel gear inside the diff. housing?
Depends on the car you're driving.

Knock the diff case onto the floor until the bevel gear just fall off. Then, push the pin to one side, and make sure either end faces the deeper groove. Use the shorter end of a 1.5mm allen key to push the pin out completely

...or, there's a grub/set screw that secures the pin which is located in the diff case itself. Unscrew that and push it out with a 1.5mm allen key or wire.

Hope that makes sense....Sorry I don't write well
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Old 08-19-2008, 05:31 AM   #7
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Depends on the car you're driving.

Knock the diff case onto the floor until the bevel gear just fall off. Then, push the pin to one side, and make sure either end faces the deeper groove. Use the shorter end of a 1.5mm allen key to push the pin out completely

...or, there's a grub/set screw that secures the pin which is located in the diff case itself. Unscrew that and push it out with a 1.5mm allen key or wire.

Hope that makes sense....Sorry I don't write well
I use needle nose plier to slip it out to the side of the diff case with the deep groove.

And +1 on the bearings... just replace them. Avid bearings are $1 each... cheap insurance against failure. www.avidrc.com
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Old 08-19-2008, 01:02 PM   #8
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Thanks for the replies guys!! =)

See... the car I'm working on is an XB8EC. I read the manual and it shows that there's nothing holding the bevel gear from coming out. I should be able to pull it out. Maybe I have to knock it on the table like Razor said. I'll try pulling it out first though like Genius said.

Also, what diff oils should I be using if I want the car to slide more?

Thanks again guys. I'll post the progression of this strip down by me, a noob, as it goes by.

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Old 08-19-2008, 04:24 PM   #9
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Heavier diff oil in the rear will transfer power quicker and make the rear end loose on power if that's what you're talking about. Not sure what you're running now, but 5,000 wt or so in the rear should make it plenty loose.
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Old 08-19-2008, 04:31 PM   #10
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Heavier diff oil in the rear will transfer power quicker and make the rear end loose on power if that's what you're talking about. Not sure what you're running now, but 5,000 wt or so in the rear should make it plenty loose.


LIGHTER diff oil in the rear will loosen it up. Heavier will make the rear more planted, but ALSO it will "upset" the car more over uneven surfaces under acceleration.

Another thing you can do is reduce the toe-in in the rear by changing the rear toe block. If you reduce the rear toe it makes the car less planted in the rear, but also has the effect of making it easier to "catch" when it starts to come around.

A third thing you could possibly do is go to a stiffer swaybar in the rear. That will unload the inside wheel in a turn, allowing it to break traction. If you don't have a stiffer bar you can make one from "Music Wire" from the local hobby shop... if they do model airplanes they'll have a variety of sizes. Also a smaller adjustment can be made by adjusting where the swaybar links are attached... if they are all the way out, it is set as soft as it can be set... moving them in gives it less leverage and acts like a stiffer bar.

You have an XB8EC and you want the rear end LOOSER? You must be "the man" on the drivers stand.

BTW that Xray manual has "the chassis tuning bible" in the back. It is THE best reference. Read it, read it again, then read it again... then look up stuff that you don't remember. Also Xray is the KING of quality... that's a great buggy for those who can handle it.
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Old 08-19-2008, 07:30 PM   #11
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Thanks for the replies guys...

Quote:
Originally Posted by cjtamu View Post
Heavier diff oil in the rear will transfer power quicker and make the rear end loose on power if that's what you're talking about. Not sure what you're running now, but 5,000 wt or so in the rear should make it plenty loose.
This was what I was told at one of my LHS's. Although he was very honest in telling me that he doesn't run too much offroad and usually just put's the standard 7/10/3 oil's. I got some 5k wt.

Quote:
Originally Posted by DOMIT View Post


LIGHTER diff oil in the rear will loosen it up. Heavier will make the rear more planted, but ALSO it will "upset" the car more over uneven surfaces under acceleration.

Another thing you can do is reduce the toe-in in the rear by changing the rear toe block. If you reduce the rear toe it makes the car less planted in the rear, but also has the effect of making it easier to "catch" when it starts to come around.

A third thing you could possibly do is go to a stiffer swaybar in the rear. That will unload the inside wheel in a turn, allowing it to break traction. If you don't have a stiffer bar you can make one from "Music Wire" from the local hobby shop... if they do model airplanes they'll have a variety of sizes. Also a smaller adjustment can be made by adjusting where the swaybar links are attached... if they are all the way out, it is set as soft as it can be set... moving them in gives it less leverage and acts like a stiffer bar.

You have an XB8EC and you want the rear end LOOSER? You must be "the man" on the drivers stand.

BTW that Xray manual has "the chassis tuning bible" in the back. It is THE best reference. Read it, read it again, then read it again... then look up stuff that you don't remember. Also Xray is the KING of quality... that's a great buggy for those who can handle it.
LMAO at the comment about being "the man" on the stand! I've just started out. Regardless of me playing video games or driving in real life, I like the back end to swing out more and be looser. I find that I drive faster and more stable like that. I like the back end to swing out even more if it's a 4WD or AWD car.

Like I said above, I was told by one of my LHS's with little experience in offroad that a heavier diff oil will make the rear slide more. So I bought some 5k wt. I'll be getting some 1k and 2k wt's tomorrow. Right now, what I'm going to put in my car is 7/10/5 oils.

After the oils, I'll start playing around with the other settings like toe in and sway bars as Domit said. I don't even know what oils were in the shocks and diff's, and what springs and swaybars are on the car currently.

Also, what shock oil's should I be using if I want the rear looser?

Thanks,

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Old 08-19-2008, 09:20 PM   #12
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Also, what shock oil's should I be using if I want the rear looser?
Other than oils (diffs and shocks) you might want to try excessive camber gain

Try to run with the rear camber link (upper arm) set to the shortest. That will force you to install it at the lowest hole in the shock tower, and the most inner hole in the rear hub. As DOMIT suggested, look into your excellent manual
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Old 08-19-2008, 10:26 PM   #13
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Think about diff oil like this. Thicker will lock the diff up more, lighter will allow the wheels to move more freely at different speeds.

It's a little more than thick makes it more planted and thin looser.

Thinner will turn in better - it will allow the car to rotate better, hence it can feel "looser" as the faster it rotates the more inclined the car will be to break grip.

Thicker will "push" the car more, and be more progressive in breaking grip and of course will not turn in so much initially into a corner. Thicker will "square" the car up quicker as well, so if you are for example having trouble coming out of a corner and getting on the gas for a jump because the rear is loose and the car is squirriling about under power, thicker is generally the answer... however bear in mind every time you affect the handling of the car in one way, it will be affected in some other way as well.


Of course, people will tell you all sorts of things and what feels one way to one person can feel completely differant to another, playing with them is the answer of course.

The Xray manual is as stated, superb. Here is another good piece of text on diff oils:


http://www.rc411.com/pages/howto.php?howto=24&page=3
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Old 08-20-2008, 12:18 PM   #14
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Holy cow, 7k front 10k center 3k rear?

7k is pretty heavy for front, it will take away steering to a certain extent. 10k in the center will give the car a LOT of AWD effect... makes it very aggressive. 3k in the rear is a good starting point on most cars.

I'm not certain on the XRay, but most other cars people run something more like 5k-7k-3k or 5k-7k-2k. I suggest maybe downloading some setup sheets from the XRay factory drivers (now since they have the new 808 it may be harder to find the ones for the older car) and use that as a starting point for suspension settings, shock oils, and diff oils.

On my Jammin I went to 5k-5k-5k (don't laugh, it's very neutral and "lazy" i.e. easy to drive, and our track is usually loose and dusty, and pretty bumpy.) I was running 5k-5k-3k prior to that, and going up in the rear helped keep the rear end planted. I also did the "7th hole mod" to plant the rear end. Longer camber link = less camber gain = lazy and forgiving. Short camber link = more camber gain = loose and aggressive.

Almost everything affects something else... don't assume your car is not aggressive enough in the rear. With 7k in the front you are losing some steering... going down to 5k there will make the car turn in better and not push as much through the corner... so the rear will try to come out more... it is all about balancing traction between the front and rear to make the car behave the way YOU want.

I know people who ran 5k-7k-10k in the XRay... for the opposite reason you stated: They thought the car was too loose in the rear with a "conventional" setup, so they put 10k in there to tame it down... and it worked somewhat.

As for sliding being faster... that is a misconception. It FEELS faster and it is a lot of fun (and a lot of work!) to drive, but your corner speeds will be higher if you can keep all 4 wheels planted.
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Old 08-20-2008, 05:33 PM   #15
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10k in the centre will push more drive to the rear... Brad is right, drift may feel fast but not always the way by a long shot.
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