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Old 07-14-2008, 02:13 PM   #16
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Yes those spider gears can be a bear to remove, needlenose pliers and patience required. Under it you will see the pin that needs to be removed then the outdrive can be pulled out to get to bearing, Here is a good writeup on mugen diffs:
Here are some build tips for guys putting together a MBX5T (or buggy)


The biggest tip would be prepping the diff cups and double-gasketing them. Using like 3 different grit sandpapers (I use emery cloth) you want to sand the cups until they’re smooth as glass. I use 320 grit, then 800 grit and finally 1500 grit. Place the paper on a perfectly smooth table and hold the cup on the paper. Swirl it around in a figure 8 pattern. The idea is to get the cup perfectly smooth and flat. When you go up to 800 grit, you’ll quickly see the plastic get very shiny smooth. If you didn’t go long enough on the 320 grit, you’ll clearly see it. I then do a quick run with the 1500 grit and they’re dead straight. What this does is ensures the cup won’t leak against the ring gear or spur gear. Most people blame the leaky Mugen diffs on the o-rings, but 95% are at the cup (just take two cups and face them together and see the light in between them as you rotate them face to face). Remember, the cups are not machined, they're molded. Then double up the gaskets (Part # C0257). I use my screws 2mm longer than the manual and tighten up. They’ll NEVER leak from the cup (Tip comes from Chad Bradley).

I also have thicker 5mm (S5) o-rings for the out drives. These are tighter than the stockers. The real key is to use grease on them (the thicker S5 o-rings or the stock S5 o-rings) and in the slot on the outdrive shaft. Of course, do NOT use the small S3 o-rings.

I use the stock Mugen brake linkages so I put a slight z-bend in the upper rod to get it fit right. You won't be able to easily adjust the rear brake bias with the z-bend, but remove the small 2x10mm screw and twisting it is very easy. I usually get it set right and then adjust the front in or out. I know most guys love the Kyosho linkages. If you’ve had the Kyosho, you may like it and want to fit them on the Mugen. The Mugen uses fuel tubing where the Kyosho has those little springs. I’d like to change mine over to try the springs, but don’t have a Kyosho to see how it goes. Maybe someone else that switches can post pics.

The kit should also have shims to get the ring & pinion mesh set. They go outside the 8x16 bearings on each side and just add pressure to get the ring gear closer or further away from the pinion. They are 14mm x 16mm by .1mm thick. On the buggy, I always used two on the diff cup side to push the ring gear away from the pinion. But I've heard that the new 46/10T ring & pinion on the MBX5T doesn't need them. Regardless of what anyone else uses, always check the backlash on your car.

The rest of the car goes together like butter. New shocks are SWEET!

Best regards,

Tony P.
From truggyracers, written by Tony's Screws
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Old 07-14-2008, 03:24 PM   #17
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that was written by Tony eh, I really respect him so I will try that stuff. I dont know what he mean about the sandpaper part though.

I know what that "spider gear" looks like inside, its still very very hard to get out though.. i think its that sticky black sludge (old diff oil) inside there thats keeping a good grip on it


how do you know when the bearings need to be changed? how often do you guys change yours? how does it effect the buggy when you put 1000 or 7000 weight in the center diff?


thanks.
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Old 07-14-2008, 04:50 PM   #18
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Originally Posted by new to rc cars View Post
that was written by Tony eh, I really respect him so I will try that stuff. I dont know what he mean about the sandpaper part though.

I know what that "spider gear" looks like inside, its still very very hard to get out though.. i think its that sticky black sludge (old diff oil) inside there thats keeping a good grip on it


how do you know when the bearings need to be changed? how often do you guys change yours? how does it effect the buggy when you put 1000 or 7000 weight in the center diff?


thanks.
Ok... to start with, GREAT choice of a buggy. IMHO the best beginner buggy made, period.

A good starting point for a new driver on diff oils is 5k front, 5k center, 3k rear.

Heavier front fluid takes away a little initial steering, but pulls the car out of corners better.

Heavier center fluid make the car more "aggressive" and gives it more AWD effect.

Heavier rear fluid keeps the rear more planted in corners, but can make the car twitchy in the rough.

I liked my Mugen with 5k front 7k center 1k rear... but that is a pretty aggressive setup. I'd start with 5-5-3, and if you want it to rotate a little better in the corners go down to 2k in the rear, or even 1k...

It depends on the car, and the driver. My Losi I ran 5-5-5 because it was so edgy I could barely drive it. It FELT fast, but it wasn't consistant.

In the Jammin I run 5-5-3, or 5-5-5 if the track is very loose.

Since you have an MBX5... I'll also recommend some shock fluid weights as a starting point- 45 front 35 rear. Hopefully you have the grey springs on it.

If the car "pushes" too much put a lighter front swaybar on, with the connecting ends as far out as you can get them. Move the rear swaybar end links in, or go to a bigger rear bar. This will help the car turn better... but intially you probably don't want to do that. (What that does in effect is adds cornering traction in the front, and takes some away in the rear)

Don't buy expensive bearings... Avid Revolutions are GREAT and they're $1 each. Run them "rubber seal out." In other words, the rubber seal toward the side that is exposed to dirt.

As for getting that gear (the one down in the bottom of the diff case) out... I usually just lay a towel down and tap it on the towel so the gear falls out. Yours sounds like it might be stuck a bit... maybe spray some WD40 and let it sit for a bit... then tap on a towel to get it out.

And the Mugen DOES have those shim washers behind the spider gears, although they may be stuck to the gears on yours. Be sure you have ONE on each of those gears. It also has a shim behind the pins that hold the larger gears...
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Old 07-14-2008, 05:02 PM   #19
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+1000000000000000000000000000000000000000000000000 00000000000
Avid Rocks! With the rare exception when I run out, I try to use them exclusively in all my Bug's. Can't beat em, and FWIW, unless you're Drake/BK/Masami/Truhe/etc etc etc...you won't likely notice a difference between "standard" and ceramic bearings...especially in offroad.
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Old 07-14-2008, 05:04 PM   #20
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Carb cleaner...bad choice, leaves a residue. Try brake cleaner. I use the same Wal-Mart brand stuff...Super Tech, I think it's called. $1.78/can!
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Old 07-14-2008, 06:03 PM   #21
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Originally Posted by DOMIT View Post
Ok... to start with, GREAT choice of a buggy. IMHO the best beginner buggy made, period.

A good starting point for a new driver on diff oils is 5k front, 5k center, 3k rear.

Heavier front fluid takes away a little initial steering, but pulls the car out of corners better.

Heavier center fluid make the car more "aggressive" and gives it more AWD effect.

Heavier rear fluid keeps the rear more planted in corners, but can make the car twitchy in the rough.

I liked my Mugen with 5k front 7k center 1k rear... but that is a pretty aggressive setup. I'd start with 5-5-3, and if you want it to rotate a little better in the corners go down to 2k in the rear, or even 1k...

It depends on the car, and the driver. My Losi I ran 5-5-5 because it was so edgy I could barely drive it. It FELT fast, but it wasn't consistant.

In the Jammin I run 5-5-3, or 5-5-5 if the track is very loose.

Since you have an MBX5... I'll also recommend some shock fluid weights as a starting point- 45 front 35 rear. Hopefully you have the grey springs on it.

If the car "pushes" too much put a lighter front swaybar on, with the connecting ends as far out as you can get them. Move the rear swaybar end links in, or go to a bigger rear bar. This will help the car turn better... but intially you probably don't want to do that. (What that does in effect is adds cornering traction in the front, and takes some away in the rear)

Don't buy expensive bearings... Avid Revolutions are GREAT and they're $1 each. Run them "rubber seal out." In other words, the rubber seal toward the side that is exposed to dirt.

As for getting that gear (the one down in the bottom of the diff case) out... I usually just lay a towel down and tap it on the towel so the gear falls out. Yours sounds like it might be stuck a bit... maybe spray some WD40 and let it sit for a bit... then tap on a towel to get it out.

And the Mugen DOES have those shim washers behind the spider gears, although they may be stuck to the gears on yours. Be sure you have ONE on each of those gears. It also has a shim behind the pins that hold the larger gears...
damn you know a lot about rcs!

Yes, I love my mugen, its an awesome buggy.

I think I might put a 7000 fluid in my diff. I dont race so I dont really notice that much, and I usually drive on gravel back roads, the car usually floats ontop the stones so the steering isnt the greatest anyways.

I will go and see if I put the rubber side out, I just threw them in without even thinking it made a difference.

I have tried tapping on the cup thing to get that gear out, I tapped quite hard and it wouldnt go anywere. Im sure that black sludge acts like a glue, its very thick and sticky. I will let some wd-40 sit overnight and see if that loosens it up, would laquer thinner or 99% iso alcohol work better? it wont ruin the plastic cup?

I will check for the shim, Ill admit, I dont know exactly what im looking for, is it like a spacer or a washer?

thanks.

Quote:
Originally Posted by NitroOB4You View Post
Carb cleaner...bad choice, leaves a residue. Try brake cleaner. I use the same Wal-Mart brand stuff...Super Tech, I think it's called. $1.78/can!
I will need to pick some of that up, pretty cheap by the sounds of it.

thanks.
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Old 07-14-2008, 07:13 PM   #22
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damn you know a lot about rcs!

Yes, I love my mugen, its an awesome buggy.

I think I might put a 7000 fluid in my diff. I dont race so I dont really notice that much, and I usually drive on gravel back roads, the car usually floats ontop the stones so the steering isnt the greatest anyways.

I will go and see if I put the rubber side out, I just threw them in without even thinking it made a difference.

I have tried tapping on the cup thing to get that gear out, I tapped quite hard and it wouldnt go anywere. Im sure that black sludge acts like a glue, its very thick and sticky. I will let some wd-40 sit overnight and see if that loosens it up, would laquer thinner or 99% iso alcohol work better? it wont ruin the plastic cup?

I will check for the shim, Ill admit, I dont know exactly what im looking for, is it like a spacer or a washer?

thanks.
The shims are like a VERY THIN washer. handle them gently, you don't want to bend them. I don't mean they are fragile, they're not... just don't be rough with them.

And I don't know that much... I just pay attention and remember what I've learned, and try to pass it along to help others. There are a lot of folks on here with tons more knowledge than I have.
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Old 07-14-2008, 07:28 PM   #23
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The shims are like a VERY THIN washer. handle them gently, you don't want to bend them. I don't mean they are fragile, they're not... just don't be rough with them.

And I don't know that much... I just pay attention and remember what I've learned, and try to pass it along to help others. There are a lot of folks on here with tons more knowledge than I have.
awesome, thanks a lot for all the help man.

I figured out what shims are now, I have all mine, they are all nice, clean, straight, etc..

the wd-40 trick also worked in getting that one damn spider gear off, and I dont think either of the bearing even needed changing!!!

How do I tell how to put the bearing on? I dont know how to find the rubber seal, they look identical on both sides. I am using cheap advantage bearings.

the ones it had on before it took it off had black caps and looked nice and fairly new, are those the stock ones or aftermarket ones? I can take pics if you dont understand.
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Old 07-15-2008, 08:24 AM   #24
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awesome, thanks a lot for all the help man.

I figured out what shims are now, I have all mine, they are all nice, clean, straight, etc..

the wd-40 trick also worked in getting that one damn spider gear off, and I dont think either of the bearing even needed changing!!!

How do I tell how to put the bearing on? I dont know how to find the rubber seal, they look identical on both sides. I am using cheap advantage bearings.

the ones it had on before it took it off had black caps and looked nice and fairly new, are those the stock ones or aftermarket ones? I can take pics if you dont understand.
If they look identical on both sides, then there are no worries. I like to use the AVID Revolutions, they have a yellow rubber seal on one side. Metal shield bearings have less friction, but they get dirt in them easier... sounds like you have metal shield bearings... or ones with rubber on both sides... either way, those don't matter what direction they are installed.

As for what kind of bearings you had before... there's really no way to tell. But if the diff oil was like you describe, it is probably time to change all the bearings in the car- sounds like it wasn't maintained recently. No worries, just change them to be sure.

Good luck with your buggy... that Mugen is tough as nails, stable and forgiving, and an all-around great car.
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Old 07-15-2008, 06:33 PM   #25
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If they look identical on both sides, then there are no worries. I like to use the AVID Revolutions, they have a yellow rubber seal on one side. Metal shield bearings have less friction, but they get dirt in them easier... sounds like you have metal shield bearings... or ones with rubber on both sides... either way, those don't matter what direction they are installed.

As for what kind of bearings you had before... there's really no way to tell. But if the diff oil was like you describe, it is probably time to change all the bearings in the car- sounds like it wasn't maintained recently. No worries, just change them to be sure.

Good luck with your buggy... that Mugen is tough as nails, stable and forgiving, and an all-around great car.
allright, awesome.

they look identical on both sides, both the new and old ones do. I think thy are metal shield bearings too, I only paid like 90 cents each..

youre right, I have owned the car for almost a year now (3 gallons throug it) and it hasnt bee maintained, I dont know if the original owner did anything to it either.

I went to my LHS today, last expericnce with him was kinda bad, today was pretty good. I got a new JR 9001 servo, some diff oil, and glowplugs, im good to go now!

and yes the mugen is a tough car, its really the only one Ive ever seen but I love it, my next car will def be a mugen, im not even gonna give anything else a chance!!

thanks.
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Old 07-15-2008, 07:40 PM   #26
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another noob here......

So you should only fill the diff to the top of the cross pins?
- its ok for the top of the diff gears to be out of teh oil?
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Old 07-15-2008, 07:44 PM   #27
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another noob here......

So you should only fill the diff to the top of the cross pins?
- its ok for the top of the diff gears to be out of teh oil?
just above the cross pins yes...

the top of the gears should be out of the oil, that space will be taken by the other crown gear attached the to ring gear..
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Old 07-16-2008, 12:45 PM   #28
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As for what kind of bearings you had before... there's really no way to tell. But if the diff oil was like you describe, it is probably time to change all the bearings in the car- sounds like it wasn't maintained recently. No worries, just change them to be sure.

It turns out it had TKO bearings in... 5$ each.

and I put 7000 oil in m centre diff, well see how that goes.

thanks a lot for all the help guys, I got my center diff cleaned, bearings and oil replaced, brake pads cleaned, and put back together with no problems. (I couldnt believe it either!).

I am thinking of changing my brakes/brake pads and getting these http://www.carolinasrc.com/webstore/...idproduct=4854, are they any good? I had old blue junk pads like these: http://www.carolinasrc.com/webstore/...p?idproduct=79 I scrapped the black stuff off them that was built up from the brake disk, is that good or bad? it seems they ont work as good now when I do it manually, but maybe that will change when I throw an engine in and actually drive it.
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Old 07-16-2008, 01:25 PM   #29
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hmmm...suspended again, huh?

Well, welcome back...not that it will take long before people realize your new name.
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Old 07-16-2008, 02:13 PM   #30
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hmmm...suspended again, huh?

Well, welcome back...not that it will take long before people realize your new name.
till 07/22
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