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15071Re: Click of death.........RM Gear-case failure

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  • toolman_d
    Jul 1, 2008
      What's the retail price for gear case assembly? It seems like this,
      2nd to the battery (and possibly the controller for older models) is
      the most replaced part? I'll probably be due in the next year or
      two...

      Also what is part #125 "Gear Frame Support"? How does this work?

      --- In RoboMower@yahoogroups.com, "Bill" <wild_bill_howell@...> wrote:
      >
      > < Yeah I know you're gonna complain>
      > --------------------------
      > Has my reputation preceed me? ;-)
      > ============================
      > > Swapping the gear case is relatively easy- pull the wheels,>
      > ---------------------------------------
      > Not ~THAT~ easy because I have 'dualy-wheels', two knobby wheels
      > bolted together which eliminated the stuck-on-stupid behavior in my
      > sandy soil.
      > First the wheels must be unbolted before I can get to the snap ring.
      >
      > Maybe I wasn't clear, but my RL-800 now has the gear-case robbed
      from
      > my low-hours RL-500.
      > The only original RL800 parts are one drive-motor shroud with the
      > thermistor attaced.
      >
      > Now...........
      > about the new gear-case.....
      > I just want to get it clear in my mind.....
      > the new gear-case has replaced the white plastic bearings with
      > ball bearings?
      > If not ball bearings, then what is it?
      > I understand the plastic composition has changed for the frame,
      > pinion/motor assy and the gears, but I need a clear explanation of
      > what has replaced the white 'bearings' before I plunk my money down
      on
      > a frame/new gear-case/ drive-motor assy.
      >
      > BTW, I'm an engineer and this stuff interests me...........
      > especially now that I have a NEED. :-)
      >
      > TIA
      >
      > WB
      >
      >
      >
      >
      > --- In RoboMower@yahoogroups.com, <dannym@> wrote:
      > >
      > > Ah yes, the click of death.
      > >
      > > Those plastic bushings were recognized as a problem and fixed in
      > later designs. They changed out the plastic bushings with proper
      > bearings, changed the plastic the whole case is made of so the
      motors
      > don't soften it and sag, and changed the type of plastic the motor
      > pinion is made out of.
      > >
      > > You'd think you could just get the plastic gear frame and side
      gears
      > cheap, but really the other problem was motor pinion wear and heat
      > tolerance. Unfortunately the motor pinions are not removable; you
      > need new motors there. So it comes down to just swapping the whole
      > thing out, otherwise the old worn pinions will eat into your brand
      new
      > gears anyways.
      > >
      > > Yeah I know you're gonna complain about how much the mower cost
      > initially, this is a sort of defect, how somebody should fix it for
      > free, blah blah. I *do* feel your pain. But the mower was a
      > completely innovative design when it came out (actually there's a
      LOT
      > in here which is innovative), so it's not surprising that it's not
      > going to be a completely maintenance-free deal in the first 5 yrs.
      > Gas mowers break too and taking one back to the dealer to get fixed
      > would probably run you more than this gear case will cost. The good
      > news is the new gear case WILL be a long term fix. There's enough
      > benefit there to justify the $ to buy a new drive train (gear
      case).
      > It's not a cheap fix but not monumentally expensive either and it's
      > really good.
      > >
      > > Swapping the gear case is relatively easy- pull the wheels, take
      off
      > the tach board, unplug the motor wires, IIRC move some wires going
      to
      > the rear out of the way, pull the gear case out, reverse steps with
      > new one. Test to see if you have the motors hooked up the right way
      > before putting the top back on (hook up controller and drive
      forward,
      > if it reverses or turns them obviously you need to fix that).
      > >
      > > I don't think lubing the plastic is gonna help. In fact it may
      > attract dirt which acts as an abrasive and accelerates the problem.
      > But really the problems are inevitable no matter what you do.
      Getting
      > the improved gear case is essential.
      > >
      > > Danny
      > >
      > > ---- Bill <wild_bill_howell@> wrote:
      > > > Well, it finally happened.....
      > > > part of the gear-case failed after 328 hrs on my RL-800.
      > > >
      > > > It did NOT fail at the drive-motor pinion, although it shows
      some
      > > > wear, there was still plenty of teeth engagement to work.
      > > >
      > > > The failure occured in the gears which are 'supported' by two
      white
      > > > 'bushings'/bearings'.........
      > > > two 'bearings' on each wheel or a total of four on the same
      shaft.
      > > > what a junky POS, crappy-assed design.....
      > > > designed as though it was INTENDED to fail!!!
      > > >
      > > > The 'clicking' came from only one side where the part of the
      gear that
      > > > receives the 'bearing' had worn so badly that it formed a cone-
      shaped
      > > > hole so the gear wobled on the shaft...
      > > > the other side was on the verge of failing in the same manner.
      > > >
      > > > So...
      > > > I cannabalized my $200 Woot RL-500 and swapped out the gearcase.
      > > > I, of course had to remove the drive-motor shroud with the
      thermistor
      > > > pop-rivited to it from the original 800 and put it on the
      replacement
      > > > gear-case and resolder the thermistor leads.
      > > >
      > > > Just for drill, I lubed up those white bearings with "Break-
      Free" oil
      > > > and put it all back together.
      > > >
      > > > While I was already into the job, I decided to make an
      additional
      > > > heat-sink "shade" for the two motors with two pieces of 1/6"
      alum
      > > > angle.
      > > > I cut them so that they will also serve as a 'spreader' to
      prevent the
      > > > drive motors from ever sagging inward from over-heating.
      > > > One angle required cut corners to provide relief for the part
      of the
      > > > plastic frame which have molded gussets.
      > > > I also put TWO layers of heat-shrink tubing over both
      thermistor leads
      > > > to keep them from shorting out...
      > > > In addition, as a further precaution, I glued some 'fish-paper'
      > > > (phenolic impregnated fiver paper) on the 'shade' in the area
      that
      > > > might come in contact with the thermistor as an additional
      electrical
      > > > insulation precaution.
      > > >
      > > > I oriented the drive-motor shroud containing the thermistor in
      the
      > > > 'valley' of the alum angle, then clamped each end of the angles
      to
      > > > the ends of the two drive motors with hose clamps.
      > > >
      > > > Here is my question....
      > > > Why did Friendly use those two crappy-assed white 'bearings'
      instead
      > > > of something more substantial?
      > > > I swear, it looks to me like it was designed to fail in order to
      > > > generate after-sales repair income.
      > > >
      > > > What is REALLY new with the new generation RMs to eliminate this
      > > > failure mode?
      > > > If the answer is 'a better plastic formulation', then it's
      still not
      > > > very satisfactory.
      > > >
      > > > Those white plastic 'bearings' are gonna require periodic PM
      lube to
      > > > keep them from failing....
      > > > and considering what must be done to just get to them for that
      > purpose ...
      > > > really is an unnecessary time-waster and it pisses me off that
      I'll
      > > > have to disassemble the mower just to keep an eye on it.
      > > >
      > > > Grrrrr.
      > > >
      > > > WB
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > > ------------------------------------
      > > >
      > > > Yahoo! Groups Links
      > > >
      > > >
      > > >
      > >
      >
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