R/C Tech Forums - Serpent 811 Cobra Buggy

If you email Serpent they should be able to help you out with the damaged parts. As for the diff shimming, there should be an addendum in the box that shows how to build the V2 diffs. But in short, there are no shims on the spider gears.
Here is something Paul has posted before. Lots of good tips for the build.

1) All the screws and machined parts have oil on them. Its best to clean them with a rag and brake cleaner before you put the cars together and use loctite. Loctite does not stick to oil ;-p
2) for the nitro and ebuggy 2- .2 shims on the pinion coupler seem to do the job quite well in the front and rear. One .2 shim on either side of the diff is also very close in most instances. The kit come with .1 shims also for fine adjustment.
3) Before you assemble the diffs its best to test fit the shimming with no oil, gears or outdrives in the diffs. Just add the gasket, and the 4 screws to bolt the diff together and put a .2 shim on each side of the diff, then put on the bearings. Put the diff in the diff cases and bolt them together with the center shaft and pinion all together. Check the mesh and side to side play then add or remove shims, fine tune with .1 or .2mm shims. If you have a .2 on each side and the mesh is too tight, before you just take a shim completely off the ring gear side and add it to the case side take off the .2 on the ring gear side and add a .1 then add a .1 to the case side.
4) For the gear coupler and pinion make sure all the oil is cleaned off and use red loctite for the pinion. Tighten the set screw almost as tight as you can.
5) A lot of guys like to use a 3x20 cap head screw for the camberlinks and use and 3mm nut on the end so they do not loosen up for extra saftey on the towers.
6) on the out drives when they go into the diffs, there is a grease groove in them. I use a LOT of grease on the whole shaft and work the grease in. I let the remaining grease ooze out the outside for a little seal, so dirt does not get in between the outdrive and diff/ring gear. This is a little different than most guys are used to, other brand diffs leak, but ours do not leak so essentially the outdrives are not self lubricating. I would repeate this process after every 3 day race, maybe sometimes more if you run in really dusty conditions. I use Maxima Blue grease found in MX shops. Lucas oil Red tacky grease is also decent. No grease = locked up diffs, accelerated wear and a bad handling car.
7) Filling the diffs. when all the gears are in you want the oil to be about 1.5 to 2mm below the top of the diff case. If you over fill them like other cars, since they do not leak the diffs will actually hydro lock from the heat and you'll be doing donuts out there!
8) I never ever ever ever think about hosing my car off. The only time I may slightly think about it and probably not do it still, is if I ran in a mud race and the whole car is completely coming apart that day. It destroys all the bearings, makes things rust will cause diff issues getting off the grease off the out drives and having handling issues. I air my car off and wipe with a rag, if I decide to shine her up a little I will put SC1 on a brush and scrub the car. Spraying SC1 all over the car will change the handling because it gets on the drive pins and outdrives making the car handle differently than when it was dirty.
9) When you put the center couple in the diff cases its best to tighten the screws in the case all the way and back them out a little so the coupler can move back and forth slightly and the bearings will spin more free. The kits used to come with huge phillips for the 3 screws in the diff case but now it comes with 3 small phillips head screws, We use to have to only run 2 screws so the 3rd did not hit the ring gear. I still run 2 with the new screws.
10) Brakes. Our brake system is a bit unique and different than what you are normally used to but when set up right it works very well. what I would do is tighten the brake pad bolts with the measurement the manual says. Then use the 50/50 spacer. You will need a small open end 5.5mm wrench to adjust the bolts when they are in the car. When rebuilding my car I like to adjust them with no engine or tank in the car but the center diff and brakes completely assembled. I will pull the brake lever forward just until the brakes start to engage, while moving the spur gear. Then see which of the brakes engages first, if its the rear first loosen the back bolts evenly until the front and rear engage and have the same pressure. Then you will have 50/50 brakes. Using the shims can get you close but adjusting the bolts is the best way to fine tune. When Im at the track and feel I need to change any thing I take out the tank and use my 5.5mm wrench but usually once I have the brakes adjusted at 50/50 they stay that way. Also make sure you sand off the shiny side of the disks with sand paper. They will work much better!