XRAY - Model racing cars

I have a problem with the pinion gear bearings collapsing mainly on the rear, I do use Xray bearings. Does anybody have any suggestions on how to overcome this problem.

Thank you

Are you using the updated collar/spacer between the bearings?

yes i am

If your rear chassis stiffner is tight at both ends & radio tray including box are tight & bearings have the metal shield facing the gears & those 3 little screws are tight the only thing you might try is grind a little claerance on the end of the dogbone where it would hit the center diff out drive & even grind the slots in the center diff out drive a little deeper.I did both of those when I first got the car & never had any problems but,my buddy that has had his 808 a few races longer than me never did anything to his & he has never had a problem either. All the above is assuming your gear mesh at the diffs is correct if its too tight then nothing you try will help the bearings & inspect closely to make sure the bulkhead where the bearings sit is not damaged from the first time the bearings went.Those Hudy gears can withstand some severe punishment so even with no shims tightening up the gear mesh they will not be harmed if it fixes your problem.

BTW how long are your bearings lasting & how do you maint them?

Thanks for your help,
all the bits you said are tight and bearing are in the right way. The bearing are lasting about if lucky 2 race meetings, bulkheads are damage most of the time so new is fitted. Bearings are just fitted no oil or lubricant on them. I will have t try grinding down the dogbone and the outdrive.

The annoying things is I have had the car 12 mouths and I have only just started to have this problem in the last 3 mouths

If thats the case it would make a difference. I ASS U MEed you were new to the car.12 months is a long time on a chassis,at least round here where we race 50 weeks a year.That could be over 20 gallons. Take out some of the diff screws & hold them up to new ones. If the old screw heads are much smaller in diamater than new ones its because your chassis has worn down(& screw heads along with it) to the point that it flexes too much causing your problems with the dogbones slamming into the center diff & trying to explode your pinion bearings.I went almost 20 gal on my stock chassis & looking back should have replaced it around the 10 gal mark but it just drove so well with a thin chassis that I got lazy till the spur & flywheel started hitting the dirt & stalling the motor then a flexy chassis wasnt so good anymore.

Here I go again assuming you drive on dirt where the chassis wears fast,I have really no idea how long the chassis lasts when raced on grass or astro turf. Checking the screw head diamater will still give you a good indication though.Just dont see anything else that will just start causing it to happen. Sorry for making a ass out of u & me by assuming in previous posts.

The rear stiffner/brace might be bent or too soft after a lot of use. It might allow too much chassis flex. Replace it or upgrade to aluminum one. The radiobox also stiffens the chassis a lot. The screws tend to become loose and unthread the holes of radiobox. Consider getting a new radiobox for the reason or put loooooonger screws in (you have probably done it already).

I check, clean, relube (Hudy Premium Grease) and sometimes replace the diff pinion bearings before every meeting. I tighten the 3 screws holding bearings completely and then loosen them only about 1/4 turns. I also put a lot of grease around the bearings and then few drops of motor oil, so there's a lot of lubrication going on So far 1 bearing failure during 45-min final but it lasted till the finish. Can't complain!

Hope you'll find what's causing the problems! But for the first thing stiffen up the chassis!