Re: (ET) Bye bye brakes

["Jim (fiskfarm)" <fiskfarm mediaone net>]

Hmmm, maybe the seat switch is better off disabled. I only have one tractor
with it hooked up. Never missed it and I'd rather have the motor stay 
engaged
during regen braking. Sounds like a personal preference decision.

Jim

Pieter Litchfield wrote:

> I have recently replaced the transzxle (and  rebuilt the original brake) 
> on
> my e-15.  Apparently there were at least two different designs - one in
> which the caliper was fixed but the rotor floated (was free to slide a 
> bit
> on the transmission shaft) and another where the caliper floated on pins 
> but
> the rotor was fixed.  Somehow I managed to combine the two designs so 
> that
> both parts are now floating on mine.  It seems to work as well as can be
> expected of two square inches of mechanical disk brake!  In addition, I 
> use
> a bit of "Never-Seize" graphite/lithum grease to lightly coat all the
> floating points, since as I am sure we ALL have experienced, the brake 
> rotor
> dearly loves to weld itself to the shaft.  Lubing and checking for free
> float should be an annual rite.  In addition the brake power cut off 
> switch
> on the linkage needs to be adjusted so that the motor is not working 
> against
> a fully applied brake, causing wear and ineffective braking.  I allow 
> for a
> bit of overlap - the brake just begins to take effect when the power 
> switch
> kills motor current.  It is, in my opinion, a design which when working 
> well
> is of marginal capacity, and which almost never works "to spec"!  Bill's
> upgrade is surely worth it.  I suspect that the design was an original 
> part
> from the transaxle supplier (Peerless) and is designed to be used on 
> lighter
> gas engine machines.  Nobody envisioned six big batteries headed down a
> steep slope.  If the throttle is not cut, or if you don't bounce a 
> activate
> the seat cut-off switch, the tractor is capable of some effective
> regenerative braking effort.  If however (as I have done) a bump causes a
> power cutoff in the middle of a hill, the mechanical brake may be barely
> adequate to save you!  I always shift to a lower speed range (using the
> mecahnical transmission) for steep downslopes, and then keep my foot off 
> the
> brake pedal so I maintain power.  Of course, we are talking about a 
> brake on
> the input shaft of a differential, so braking is limited by the available
> traction at either rear wheel.  If one rear wheel is unweighted (as when
> traversing across a slope), the available braking traction is limited to 
> the
> amount of force that can cause the lighter rear wheel to slide - 
> sometimes
> not much.  All in all, the E series brake is a weak point!  If equipped 
> with
> two drum or disk brakes at the rear wheels, the brakes would have been 
> far
> more effective, and of course more expensive.  But you could have 
> employed
> brake steeering and traction control as well as do "real" tractors.  This
> would appeal to me because even with a weight box on the back and 
> chains, I
> often spin rear wheels with a full bucket on the front mounted loader.
> Being able to independently brake each rear wheel would be a big 
> advantage
> for me in trasferring power when one has better traction than the other.
> Hmmmm...... winter project?
>
> I used to have an old Jacobson tractor that had a transmission brake on 
> the
> input shaft like the GE, but it was a very simple "outside drum" where 
> the
> pedal linkage pulled tight a lined metal band looped around a drum 
> attached
> to the shaft.  It was very effective, but of course suffered from the 
> same
> limits on brake force generated by sliding a wheel.
>
> -----Original Message-----
> From: owner-elec-trak cosmos phy tufts edu
> [mailto:owner-elec-trak cosmos phy tufts edu]On Behalf Of Jim (fiskfarm)
> Sent: Monday, February 04, 2002 9:43 AM
> To: Christopher Zach
> Cc: Elec-trak
> Subject: Re: (ET) Bye bye brakes
>
> Hey Chris,
>
> The rotor is NOT supposed to "deform" but rather float free on it's keyed
> shaft. I use a combo of air chisel, Breakaway and sometimes heat to free 
> up
> the
> rotor and then remove it , clean up both shaft and sleeve, retighten the
> rivets
> by hammer and anvil (or replacement) and reinstall all with a gentle 
> coating
> (you don't want any on the rotor and pads) of Never Seize. Here, unlike a
> car,
> the caliper doesn't float, but the rotor does. Also you will want to sand
> the
> rotor smooth with either a power sander or rotate the rotor in place with
> the
> motor while sanding by holding the paper against it. Not for the faint of
> heart
> but probably the fastest for the more experienced. DO NOT "grab" the 
> rotor
> with
> the paper , but rather sand one side at a time. New pads (if they are 
> shot)
> go
> without saying. Stainless steel rotors would avoid about 99% of the 
> problems
> with these breaks. That and Never Seize.
>
> Hope this helps you along,
>
> Jim
>
> Christopher Zach wrote:
>
> > Well, I figured out why I have no brakes....
> >
> > No brake pad :-)
> >
> > Seriously, the outboard pad is gone. It appears that the brake lever
> engages
> > a cam which pushes on a metal dowel which pushes on a pad which pushes 
> > the
> > disc into another static pad on the other side. Interesting design, are
> > there any specs for pad clearance on the static pad (if it wears down, 
> > the
> > disc will have to deform more and more for the brake to engage, thus
> > reducing brake effectiveness)
> >
> > Ah well, it looks like the pad disintegrated or something. I'll call 
> > Mr.
> > Gunn and see if he has a new puck.
> >
> > Chris