All this for a screw pin...
It's been more than a week since my last outing with the ERBE because of a stripped screw pin.
On my last outing in the sandpit I broke a drive-axle and since I bashed all winter long and went through mud, water and snow I decided to go ahead and do a little spring cleaning / tune-up on the ERBE.
But... when I tried to remove the screw pin that secures the hex-hub to the drive-axle I stripped the head of the screw pin like a noob... too much crud + trying to go too fast = stripped screw pin head.
I tried my best to drill the head-off so I could push the pin out but to no avail, after 3 drill bits and a ton of curse words I decided it was time for me to get a new set of 17 mm hex hubs just to make sure it would never happen to me again.
Went to 3 LHS and none of 'em had the parts so I had to order on ebay, it'd be at least a week before I get the parts.
Since I had no way of using my ERBE I started the spring tune-up...
Checked all the wheel bearings on the axle carriers and sure enough, most of them were in dire need of some TLC ... so much so that I went on and changed all of the axle carriers for brand spankin' new ones ( since I had the spare parts ) and I rebuilt the old ones with new bearings, so I still have 4 spare axle carriers.
Changed a lower A-arm wich had a crack in it. Greased up a few bearings and so on and so forth.
Mounted, taped, glued and even went as far as fish-lined ( from the inside ) and sealed the air holes of my new Pro-Line Badlands.
Took the skid plates off to check on the drive shaft and to see if any wear was apparent but everything seemed A-OK ... and Friday I got the package I was waiting for.
Early morning yesterday I installed the hex hub and was more than ready to go. I was eager to try the Badlands in the sand pit and they work great !!! But after only 3 minutes of light bashing I found myself with a FWD ERBE ... After all I went through as far as maintenance I couldn't believe what was happening. I immediately thought "Rear diff" although I had checked if it had any clicking or slop or anything else when I went through the driveline "check" ...
Took the car back home, put it on the stand and started by turning one wheel by hand, the opposing wheel turned the opposite way as supposed so everything was ok but then I grabbed both wheels and turned them by hand and it didn't make the transmission - motor - front wheels turn ... ohhhh so that's the problem. ( or so I thought )
Took the rear diff out ( and found out the rear bulkhead had 2 hairline fractures I hadn't seen ) and went ahead and opened it up to see what was fudged in it... Nothing, everything's perfect in the diff, no stripped gears, no bearing failure, nothing !!! I went ahead and changed the bearings anyway since I had a bunch and re-installed the rear-diff. I was puzzled, what could cause this ??? Turning the front wheels by hand would make the rear wheels turn but seemed to slip a bit... Turning the rear wheels by hand didn't make the front wheels turn. Checked the drive shaft, seemed ok, no twisting nor breakage, nothing !!! Decided to double-check it so took it off and there it was... The screw pin was missing from the diff yoke. It had fallen off so the inside of the yoke stripped in a second. So when I turned the front wheels by hand it would turn the rear wheels even though it seemed to slip a bit but when I turned the rear wheels by hand they wouldn't move the front wheels since it had to turn the transmission and it was slipping too much to do that.
So I got screwed by 2 screw pins
Last edited by Imprez; 04-29-2012 at 11:17 AM.
How can I avoid getting screwed like that in the future? Really though what test did you miss? Yank and pull on the shafts?
Or was it because your tool tip is wore out and stripped the first pin?
It needed the maintanence by the way it sounds anyways.
You can avoid having trouble by ensuring hex screw heads are not packed with debris, and by taking your time during disassembly of your truck. The trouble I've had in the hobby stripping screws and having compounding problems has always been due to me doing something impetuously or too quickly.
RC Turnbuckle Jr.
You can also save yourself alot of hassles by doing the clean up BEFORE the truck sits for a long time. That way the crud doesnt have a chance to set in for a long period of time.
For the center-driveshaft's screw pin the thing that kept me from doubting the yoke's pin is the fact that the ribbed portion of the driveshaft slid right off the outer-tube and stayed attached to the diff when I slid it out the bulkhead even though the pin had fell off. Had the diff's output shaft slid off the yoke while I was pulling on it would've shone a light on the culprit.
Originally Posted by BL-Bob
But it's all my fault, I should've been more thorough in my trouble-shooting...
And for the wheel hub's screw pin it's 100 % my fault too.
As stated in my first post I wasn't paying attention and did not take the time to do the job right. I've changed a few drive-axles on my ERBE and it's a repair that usually takes about 5 minutes to do in the field. But not this time. The screw's head had too much crud in it and instead of using Traxxas' hex key to brake the lock-tite's grip on the treads I used my Dynamite driver with a hex bit so I put too much stress on the head of the screw since the bit wasn't all the way in ... To take off lock-tited screws I always use the Traxxas hex key cause it flexes and twists thus not putting too much torque on the head.
Just make sure to clean the screw's head properly if it's full of crud and what not and take your time with it.
ps : Hope it all makes sense to you guys... english' not my first language
Last edited by Imprez; 04-29-2012 at 06:25 PM.
What size is the screw pin?
I keep a good supply of pins around. Most of them obtained from buying multiple shaft sets and CVDs.
The trick I use when they get crud encrusted and always part of my tool kit is an ice pick to dig out the crud before I put a tool to it. Most of the time though Im very picky on keeping things clean and my RCs get the air compressor treatment thoroughly within hours of a run. If I get it mudded up they get torn down far enough to get all that out too. Im not one to leave them crud encrusted and often get accused of having nothing more than a nice fleet of shelf queens. Im so bad that I replace the skids when they get more than just a little gouged up.
Me too. Have plenty of spares. I take my 1.5mm hex and a drop.of water and clean it out then a little more water. Then hit it with some air
Air compressor is a must have! Drives the wifey nuts when she hears it kicking on in my man cave in the basement. 1000 sq ft of basement all to myself! Sometimes when Im setting up the trucks I do laps around the basement! LOL
Originally Posted by 50togo