RCCrawler Forums

EZap · 06-14-2010, 09:57 AM

Rear wheels won't turn if I'm going forward, but grab like hell if I put it in reverse. wtf?

The front axle was doing the same, so I replaced it with a new one. This could get old.

LittleE · 06-14-2010, 12:00 PM

That sounds electronic, most likely, and this has happened to me with my slash, is there's something wrong with your ESC, it's not wanting power to flow threw it. It's unlikely that it's your motors, if they go reverse they should go forward. So ya, i would be looking for a new ESC.

jsowens · 06-14-2010, 12:39 PM

What do you mean "grab like hell" when in reverse? Does that mean if you hit reverse your crawler actually moves or what? Here's the first thing you should do...remove the dust cap cover thing that sits above your motor pinion, unscrew the screws from the motor, remove the motor and make sure the screws don't fall into the gearbox...then see if you can spin your rear wheels freely. They should spin without any interference at all. If they DON'T spin freely...your best bet is to disassemble the entire rear axle and check all of the individual gears to make sure no teeth are damaged since that's likely a gear issue or something binding in the axle housing.

If the rear wheels DO spin freely try powering up your crawler with the motor still removed and see if the motor will function outside of the crawler...if it doesn't spin your pinion on the rear motor, but the front one works fine that's when you should start tracing the wires from the rear motor. You'll want to make sure there are no cuts or loose connections in the wiring. If the wiring is fine, then you can try putting the "rear" motor in the front axle and see if it works or not...if it doesn't, you likely have a bad motor and should replace it. I would try all of these things before you actually buy anything...buying a new motor is a lot cheaper than buying a new ESC so start checking the little things first. I would say your motor is most likely the problem...seems like if the ESC is dying it would take both motors out instead of just one. Check these things out and post up what you find and I'll try to help you further.

jwo · 06-14-2010, 07:57 PM

try what jsowens has advised. do you have a servo type dig possibly? my dig switches stick from time to time and cause the front and or rear to not work. it could also be your esc as well like littleE mentioned. i had an esc that kinda got fried. yeah kinda. they usually work or they dont. mine had forward that would come and go with a huge lack of power and no reverse. also i would maybe check out the condition of your motors. i have had a few seize up on me before in other rigs. once broken free they were fine. also the magnets can pick up tiny nuts, debris that can cause issues. sometimes the pieces can go in between the magnets and let the motor function again til the next time throttle is applied in the other direction. with moa's its a strong possibility that stuff will get in them seeing they are mounted on the axle. keep us posted on your findings.

dgna5 · 06-17-2010, 01:41 PM

Quote:

Originally Posted by EZap

Rear wheels won't turn if I'm going forward, but grab like hell if I put it in reverse. wtf?

The front axle was doing the same, so I replaced it with a new one. This could get old.

Did you figure this out ???

billybob13 · 07-05-2010, 07:02 PM

have the same problem with mine. took the motor cover off to verify the pinion gear turning the other gears. took the axle apart to see that all gears were in perfect shape. not one thing visibly wrong and everything feels fine. i thought it might be the shaft turning freely in the spool, but it felt solid. this is a huge mystery to me and i guess i'll have to buy a whole axle instead of wasting any more time trying to figure it out.

Ripperfi · 08-21-2010, 07:15 PM

I gotta throw this out there. Have you considered clod stall? Its normal on a dual motor rig with one esc. Do a search. Also, have you tried going foward and reverse with all wheels off the ground? If it works fine, then theres a good case there is nothing wrong with your crawler. There are ways to help with clod stall, one easy and quick way is by using different pinions in the front and rear.

major94 · 08-21-2010, 07:39 PM

ok this may seem too easy. Did you adjust the throtle trim forward? It could help.

dudegetabike · 08-22-2010, 04:57 PM

Sometimes when I break that spool pin it will grab in one direction and spin in the other direction because of the way the pin sheared off. Take it apart and check it / replace it with a 3/32 pin from Ace Hardware for $0.31. While you're at it get rid of those sissy screws that hole the spool together and use 3-56 screws with nuts on the back side and loctite it up. New axles would be nice but usually people who but these rigs are on a budget.

06-14-2010, 09:57 AM	#1
EZap Rock Stacker Join Date: Mar 2010 Location: Seattle Posts: 59	Axle problems Rear wheels won't turn if I'm going forward, but grab like hell if I put it in reverse. wtf? The front axle was doing the same, so I replaced it with a new one. This could get old.

06-14-2010, 12:39 PM	#3
jsowens RCC Addict Join Date: Jul 2009 Location: Blacksburg, VA Posts: 1,882	What do you mean "grab like hell" when in reverse? Does that mean if you hit reverse your crawler actually moves or what? Here's the first thing you should do...remove the dust cap cover thing that sits above your motor pinion, unscrew the screws from the motor, remove the motor and make sure the screws don't fall into the gearbox...then see if you can spin your rear wheels freely. They should spin without any interference at all. If they DON'T spin freely...your best bet is to disassemble the entire rear axle and check all of the individual gears to make sure no teeth are damaged since that's likely a gear issue or something binding in the axle housing. If the rear wheels DO spin freely try powering up your crawler with the motor still removed and see if the motor will function outside of the crawler...if it doesn't spin your pinion on the rear motor, but the front one works fine that's when you should start tracing the wires from the rear motor. You'll want to make sure there are no cuts or loose connections in the wiring. If the wiring is fine, then you can try putting the "rear" motor in the front axle and see if it works or not...if it doesn't, you likely have a bad motor and should replace it. I would try all of these things before you actually buy anything...buying a new motor is a lot cheaper than buying a new ESC so start checking the little things first. I would say your motor is most likely the problem...seems like if the ESC is dying it would take both motors out instead of just one. Check these things out and post up what you find and I'll try to help you further. Last edited by jsowens; 06-14-2010 at 12:45 PM.

06-14-2010, 12:00 PM	#2
LittleE Pebble Pounder Join Date: Aug 2009 Location: Northridge, CA Posts: 127	That sounds electronic, most likely, and this has happened to me with my slash, is there's something wrong with your ESC, it's not wanting power to flow threw it. It's unlikely that it's your motors, if they go reverse they should go forward. So ya, i would be looking for a new ESC.

06-14-2010, 07:57 PM	#4
jwo Rock Crawler Join Date: Jul 2009 Location: waterville Posts: 525	try what jsowens has advised. do you have a servo type dig possibly? my dig switches stick from time to time and cause the front and or rear to not work. it could also be your esc as well like littleE mentioned. i had an esc that kinda got fried. yeah kinda. they usually work or they dont. mine had forward that would come and go with a huge lack of power and no reverse. also i would maybe check out the condition of your motors. i have had a few seize up on me before in other rigs. once broken free they were fine. also the magnets can pick up tiny nuts, debris that can cause issues. sometimes the pieces can go in between the magnets and let the motor function again til the next time throttle is applied in the other direction. with moa's its a strong possibility that stuff will get in them seeing they are mounted on the axle. keep us posted on your findings.

07-05-2010, 07:02 PM	#6
billybob13 Newbie Join Date: Dec 2009 Location: lakeside Posts: 1	have the same problem with mine. took the motor cover off to verify the pinion gear turning the other gears. took the axle apart to see that all gears were in perfect shape. not one thing visibly wrong and everything feels fine. i thought it might be the shaft turning freely in the spool, but it felt solid. this is a huge mystery to me and i guess i'll have to buy a whole axle instead of wasting any more time trying to figure it out.

08-21-2010, 07:15 PM	#7
Ripperfi Rock Crawler Join Date: Aug 2008 Location: Tucson Posts: 625	I gotta throw this out there. Have you considered clod stall? Its normal on a dual motor rig with one esc. Do a search. Also, have you tried going foward and reverse with all wheels off the ground? If it works fine, then theres a good case there is nothing wrong with your crawler. There are ways to help with clod stall, one easy and quick way is by using different pinions in the front and rear.

08-21-2010, 07:39 PM	#8
major94 Quarry Creeper Join Date: Nov 2006 Location: omaha Posts: 323	ok this may seem too easy. Did you adjust the throtle trim forward? It could help.

08-22-2010, 04:57 PM	#9
dudegetabike Pebble Pounder Join Date: Apr 2010 Location: Brighton, MI Posts: 175	Sometimes when I break that spool pin it will grab in one direction and spin in the other direction because of the way the pin sheared off. Take it apart and check it / replace it with a 3/32 pin from Ace Hardware for $0.31. While you're at it get rid of those sissy screws that hole the spool together and use 3-56 screws with nuts on the back side and loctite it up. New axles would be nice but usually people who but these rigs are on a budget.

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