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Subject: Ford 8N tractor starter won't disengage, Positive Drive type

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Brad Cobb    Posted 03-08-2020 at 21:01:31 [URL] [DELETE]        [Reply] [Email]  
  • Ford 8N tractor starter won't disengage, Positive Drive type
  • Didn't find anything relevant to what I'm experiencing with my Ford 8N tractor (probably 1949 or '48 model), so decided to post a question:

    Has anyone experienced their starter hanging up on tractor's ring gear, & failing to retract, being driven round by tractor motor once the engine has started?

    I have removed starter, and all the teeth (that I could see) on the ring gear and starter drive looks to be in good shape.

    I took the starter drive off the shaft, then took Bendix all apart to see if I could figure out how it worked (it's very non-intuitive. You don't want to go there: it wasn't easy and it wasn't fun, plus taking it apart didn't make it any easier to understand how it was supposed to work).

    I got everything put back together, used the "wire wheel on a grinder" method for retracting the Bendix, yet whenever I put starter back into the tractor, inertia-engagement Bendix drive doesn't want to retract after the motor starts. Bendix stays extended on the ring gear and gets "powered" by the tractors engine (starter puts out a distinctive dynamo-type whine when engine spins it; to hear this was surprising).

    What bugs me, is that I can't see anything wrong with the unit, but somethings not working correctly, and I haven't the faintest idea of why (my preference is for events to make sense and be comprehendible).

    I suppose I could always just order a new starter Bendix, and that would resolve my problem, but I don't like the mystery of not knowing why a starter Bendix wouldn't retract, when a detailed examination revealed nothing obviously amiss.

    Brad    Posted 03-13-2020 at 12:52:52 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Figured I'd better put this discussion to bed. What was causing starter to continue turning (hung-up symptoms) once the 8N tractor’s engine was running, turned out to be caused by a weak spring and corrosion.

    Symptoms were traced to starter solenoid’s sometimes remaining engaged, due to weak return spring having to work against corrosion inside the solenoid, and simply not being strong enough to overcome corrosion reliably. Intermittently keeping starter contacts energized despite engine running and starter button de-energized (not a happy scenario!)

    Solution was to clean out solenoid, drill small hole in bottom solenoid’s base plate to permit moisture drainage, and providing machine screws/nuts replacing rivets holding solenoid access plate closed, such making allowance for future servicing of starter solenoid if necessary.

    Tim Daley(MI)    Posted 03-10-2020 at 07:42:22 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • 6V or 12V starter will crank but I've worked on a few fellas who had 12V batteries and nothing else was switched over. A 12V battery will spin the starter faster and sometimes will jam up -I've had to work on a few fellas that had done this. The amp draw on cranking a 6V starter is 100-150 AMPs but 12V will draw a bit more. Not a problem if it starts fast but leaving cranked for more than 10 seconds or less will get things real HOT in a hurry. I see this often with guys trying to jump start their tractor with their 12V truck or car battery. Also, a weak or near dead battery will not engage the starter and jam and hang up. Often the solenoid just click click clicks if so and is a good indicator. Both the OEM and the newer Bendix drives have all worked well for me, but I only buy from 2 or 3 suppliers but I suppose some new aftermarket stuff can be poor quality. Meantime you can take your battery and starter to your trusty, local starter/alternator shop and he will bench test under load, usually for free. While he is doing that, go thru the entire wiring system and verify it is correct -SEE LINK BELOW. If you don't already have them, get the essential manuals as well -great tools. Once system is correct and running, another good tool is a float charger like the Battery Tender.


    Tim Daley(MI)

    Brad    Posted 03-10-2020 at 09:15:20 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • I really like pictograms you've linked, they're very helpful and clear/easy to comprehend.

    It's worth noting that many "essential manuals" you've mentioned are available to freely download (One'll have to search/wade past/through merchandisers selling this information).

    I would agree that a float-trickle charger is quite helpful, some are quite reasonably priced (although to be useful, power has to be available), & costing a bit more, are solar battery trickle chargers. Search will be your friend, locating best prices.

    Some battery maintainers go a step farther, providing AC frequency riding on top of DC charge value, which can help prevent having to DIY rejuvenate lead acid battery (link). https://www.youtube.com/watch?v=VEnXlZekHD4

    Tim Daley(MI)    Posted 03-10-2020 at 14:32:06 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • We have some in our MANUALS forum for free download. There is the early July, 1947 8N Owner Manual but and the I&T FO-4 manual is an older version. Prices vary on new editions, especially when you start looking on ebay. I listed the two most reliable suppliers many of us use. You do NOT want a trickle charger, a float is different, they are NOT the same thing -see 75 Tips from Bruce(VA). the DELTRAN BATTERY TENDER is a good float charger -$30 at Wally World. Trickle chargers aren't controlled and can overcharge the battery. A float charger maintains a full charge and shuts off automatically. But, get your wiring and starter issues fixed first.

    The worst thing that depletes a battery life is that constant discharging and recharging. Get a FLOAT charger, not a trickle or regular charger. 'Battery Tender' is a brand name, and is a very good float charger. The name gets tossed around incorrectly for any charger so don't get confused and misled. Simply attaching a battery charger means nothing if the cells are depleted and specific gravity isn't met. A starter shop or auto parts store can bench test it. They will test and take your old battery in for the lead/core charge too on a new unit. There is a ton of archived info on batteries here. Most of the cheap, bargain house brands are not worth the time or money as they have poor lifespans. 7 years is a good run for a 6V battery. Briefly in a nutshell, you want a GP-1 6V AG battery -no Deep Cycle or RV/Gold cart type. Use a GRP 25 or GRP 35 12V battery. I suggest you invest in one of the better brands. Those would be DEKA, INTERSTATE, EAST PENN/DURACELL, or EXIDE. I'm not sure who makes the NAPA one but I've heard good things about it. Get at least a 550 - 650 CCA with the average cost at about $125. The best thing you can do to prolong a battery is also invest in a float charger. The DELTRAN BATTERY TENDER JR. is the 6V unit and priced about $30. You also need good battery cables for each. A 6V battery needs thicker cables than the 12V battery. Keep a Float Charger (Battery Tender) for each of your vehicles connected whenever the vehicle is idle. I like the DELTRAN models because they have a built-in fuse and disconnect/automatic shutoff feature if connection is lost.

    You need a strong battery to:
    1. Spin the starter
    2. Engage the Bendix
    3. Provide voltage to the coil.

    The following is courtesy of Bruce(VA), tips on battery care and performance:
    As the battery gets weaker, the first thing to fail is your spark. The more current you use to spin the starter, the less you have for the ignition. If your starter pulls that battery down much below 5.2 volts (ref: 6-volt battery), the module in the EI will not fire. It doesn't really matter much if the battery is "fully charged" until you test it correctly. 4 Volts is an almost dead unit. Bench test under load and specific gravity must be tested. Your trusty local starter/alternator shop can bench test it on their special machine, usually at no charge –no pun intended. No matter what else you do, the battery must be fully charged.

    A float charger is helpful; NOT a trickle charger, but a float charger, like the DELTRAN Battery Tender Jr. ® ™ . A battery charger, even a "trickle" charger, left unattended will eventually boil out a battery. Use a float charger for two reasons: battery longevity and a sure start. Battery sulfation occurs at a specific rate at "X" temperature. Over time, sulfation reduces battery performance and eventually its effects are irreversible. Sulfation of batteries starts when specific gravity falls below 1.225 or voltage measures less than 12.4 for a 12v battery, or 6.2 for a 6 volt battery. Sulfation hardens on the battery plates reducing and eventually destroying the ability of the battery to generate current. Using a float charger significantly reduces sulfation. Your battery loses 33 percent of its power when the temperature dips below freezing, and over 50 percent of its power when the temperature falls below zero. A fully charged battery will not freeze until -76°F; however, a fully discharged battery can start to freeze at 32°F. So……keep the battery fully charged! If you have a digital volt meter, 6.03 volts on a 6 volt battery and 12.06 volts on a 12 volt battery is only a 25% charge!


    Tim Daley(MI)

    Brad    Posted 03-10-2020 at 17:43:49 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Wow, that is a lot of information! Will take me a while to digest it all. :-)

    The battery maintainer pictured in my previous post is indeed a float charger (with automatic cut-off), here is a link to technical data, if desired: https://manuals.harborfreight.com/manuals/69000-69999/69955.pdf

    I've experience with these (there's one permanently mounted to my work truck), I've never had any issues with my float chargers for years, and at less than 10 bucks, it's hard to go wrong (if does eventually go out, they're cheap to replace).

    Using tried-and-true battery Rejuvenation measures (see my previous post), I've managed to avoid having to replace batteries, such that I've been able to make some of the mid-grade batteries last as long as top brands.

    When AGM battery went out on my MX-5 Miata, I did a bit of research, finding Walmart EverStart brand was a top contender in independent battery tests, without paying top dollar for the best brands. Thus far, battery's working out well and I'm pleased for money spent.

    Bruce(OR)    Posted 03-09-2020 at 05:49:52 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Well, if was working one week and not the next and you didn't change anything, I might tend to say it got weak with age and wore out.
    Chances are you can get another one cheap enough to try or continue to play with this one until something more expensive breaks.
    Last bendix I picked up, I believe, was about $15.

    Brad    Posted 03-09-2020 at 09:42:35 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Thank you Bruce, for your reply.

    Searching "usual parts sources" best price could find is $25 shipped, so would appear inflation has since "booted-up" price $10 or so since your last Bendix purchase.

    It's not that I'm so tight "My shoes squeak when I walk" (purchasing replacement Bendix isn't going to break me). Thing is, I don't like to throw parts and money at a repair without knowing what is wrong..

    I prefer to understand "Whys" and move systematically/methodically through troubleshooting, and it bugs me when I can't see anything wrong with the Bendix that I've got (except for not working lol).

    Tim Daley(MI)    Posted 03-09-2020 at 03:15:13 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Model year is irrelevant. Do you have a front mount distributor or the angle (side) mount style? Are you trying to run a 12V switchover system or is it the OEM 6V/POS GRN setup? Either way, have you verified the wiring is all correct? Don't guess and start replacing parts until the true root cause is determined.

    Tim Daley(MI)

    Brad    Posted 03-09-2020 at 09:16:24 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Tim,

    Thank you for your reply.

    1. Front mount distributor.

    2. 12 volt converted system.

    I agree throwing money and parts at tractor is not the best way to get repair results.

    Checking wiring to eliminate electrical (for example, stuck starter solenoid could cause "starter does not disengage") as the cause, so far everything checks out.

    Using search of forums "starter Bendix not retracting" has yielded results of other folks facing the same difficulties, good to find remedies from other's experiences.

    Presently pursuing removing Bendix from starter shaft, meticulously disassembling/cleaning (especially spiral grooves), using dry silicon lubricant (spiral grooves must be spotlessly clean as per "Dell", with no lubricants to attract dirt into spiral grooves), and checking condition of springs (if springs have lost strength, alignment/position or integrity, it is enough to throw inertia off to where Bendix may not retract)

    Some manner of added friction in the wrong place (spiral grooves), and loss of friction (Springs, etc) could adversely effect inertial operation, causing some "tail chasing" and head-scratching.

    JMOR    Posted 03-09-2020 at 04:16:33 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Tim, you are a nice guy and all that, but come on now, his starter bendix problem has nothing to do with 6/12v, side/front distributor, etc., now does it?

    Brad    Posted 03-09-2020 at 11:02:45 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • JMOR,

    Quote: "...starter bendix problem has nothing to do with 6/12v..."

    I believe what Tim is working his way towards with that question about "6 or 12" volts has to do with what I've been reading on repair forums, where everything changes and inertia can get thrown out of balance, when a 6 volt starter is spun by 12 volts, turning too fast with too much torque for optimal design parameters performance (try saying that three times fast! lol).

    One remedy reported successfully implemented, was using part of a spring (from old starter Bendix) as a wire resistor, knocking the voltage down to the starter enough to where it would "inertia" close enough to design parameters to function reliably. This is pretty weird stuff when you consider that it happens to some people, others experienced no problems whatsoever. What could be behind this happening? Never cared much for mysteries, I prefer for things to make sense! :-) lol

    Typically reported, older models of Ford 8N tractors didn't experience too much "whanging N banging" of Bendix drive VS ring gear-meshing dance with a 6 volt starter powered by 12 volts, but not so much with later model 8N's (could be why Tim's asking about side distributor, they were used on later model 8N's?). Not entirely clear why "later 8'ers" would experience more issues (unless something subtle had changed in parts sourced/manufacturing)?

    Brad    Posted 03-09-2020 at 21:50:02 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • There are noted to be several different designs of inertia starter Bendix, which causes a bit of consternation, because not all Bendix designs lock in the extended position like Ford 8N tractor starter Bendix do. "After I have learned the answers, they change the questions" ;-) Linked is video of Bendix that doesn't "lock open" on a vehicle. Nice as everything is out in the open and you can see how Bendix drive works.


    On N Ford tractors "Locking open function" was an effort to improve conditions where the Bendix would try to disengage prematurely, before the engine was thoroughly running. Dell, Sound Guy, Hobo and others have commented on this topic on various repair forums, providing further information/explanations for those who want to search & know more details.

    One helpful thing they've pointed out: you can put a starter back into an N series tractor with the drive extended (locked position), and when engine starts running, Bendix will retract from locked open position. They have further expounded that if drive pinion gets hung up on ring gear and Bendix won't let go, you can put the tractor in 4th gear and use big back wheels to rock tractor back and forth and sometimes it will get the Bendix to release from the ring gear, without resorting to starter removal. Nice shortcut, if it works.

    Also shown on various forums: an angle grinder with a cup wheel spins Bendix fast enough on starter to unlock pawls so Bendix retracts. Good to know, not necessary to remove Bendix from starter then having to use screwdriver and wire brush with a bench grinder (method I've used before).

    Brad    Posted 03-09-2020 at 20:43:17 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Case anyone wants to know, lots of repair forums have debated 12 volt dropping resistor for 6 volt starter to death.

    Kind of reminds me of a professor who could mathematically prove a bumble bee doesn't fly. Poor bee never studied math? ;-) doesn't know any better lol

    When something works, it works; whether we understand or approve or not :-)

    People are sure weird in that they only see what they want to see. "If all you have is a hammer everything looks like a nail"

    Bottom line, if using a dropping resistor works on your tractor, make use of it, and don't let anybody know whose belief system would be offended by your successful application! lol >8'-D

    I'll tell you this much, if thoroughly cleaning and using dry silicone on the internals of my starter's inertial Bendix Drive doesn't give me positive results I want, I know where some old fencing wire would make a nice wound dropping resistor, and I would try that before I spent the money for a replacement Bendix Drive.

    But hey, that's me. I'm enough of a free-thinker, that I really don't care all that much about other's "sacred-cow beliefs" (mostly when their opinions are proven at odds with reality).

    Good example: "Law-abiding Criminals" https://www.youtube.com/watch?v=BYVqmBaqgPU

    JMOR    Posted 03-10-2020 at 00:27:00 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • What was so bad about the bendix the Ford used originally that we now have the "new & better" that causes all this trouble? I'm still using the original, myself & on 12v no less! Have been for about 3 decades!

    Brad    Posted 03-10-2020 at 08:31:55 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • A lot of older equipment was designed to last, constructed such that consumers could work on and repair items by themselves; whereas today, we're often dealing with engineered obsolescence.

    When I was combing my way down through layers of problems on 8N tractor and obtaining necessary repair parts, I noticed that many of the aftermarket parts were of lesser quality/precision and flimsier/cheaper construction than OEM.

    The replacement brass float was quite reasonably priced but I had to get some pliers and do a lot of reshaping/tweaking to get hinge pin to go through float and to fit properly.

    It's necessary sometimes to utilize whatever replacement parts are available; in this case, original brass floats were leaking/filling with gas, had previously been soldered numerous times to repair spreading/enlarging cracks, and consequently solder added sufficient weight to render floats ineffective.

    Henry Ford reportedly espoused the opinion that the Model T was perfect, needing no improvements, yet progress stands aside for no man, and few today would prefer a Model T over a MX-5 Miata.

    So it is, we're dealing with improvements in old technology, whether we find that advantageous or not. Manufacturers have pretty much moved away from inertia Bendix, preferring solenoid activation instead.

    I will be going through my Ford 8N starter Bendix today, and if I must replace it (as I have some other parts), it would not surprise me too much to find aftermarket replacements of lesser quality/reliability. Doubtless, one would prefer and expect to be better served by having an OEM repair part, but even good quality parts eventually wear and require replacement.

    It is what it is: today one does what one may, using whatever's available with which to effect repairs.

    TheOldHokie    Posted 03-10-2020 at 14:13:50 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Just invest in a modern gear reduction starter and you won't have to worry about this terribly complicated and worrisome bendix.

    Ford 8N Denso Starter


    Brad    Posted 03-10-2020 at 22:09:06 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • You're not going to believe this ... I don't want to believe this, but I was there and it happened ... I'm wondering if a previous owner was a lawyer named Murphy? ... Possibly headquartered out of Sioux City ...Murphy's Law

    I worked the starter over, checked everything out thoroughly, did a complete detailed cleaning of Bendix Drive, lubed spiral grooves with dry silicone lubricant, make sure everything was functioning as well as was practical to determine ... got the starter & everything installed back into 8N tractor and everything hooked up ...

    I had just finished cleaning the battery terminals, once the starter was in place, last connection was battery ground cable ... Soon as ground cable made contact with battery terminal, there was a big spark, and starter began turning the engine over! ... Glad I was being cautious as a matter of habit and keeping all of my bits and pieces out of Harm's Way! ... That surely wasn't expected...

    Removing the ground cable and troubleshooting wiring with ohm meter, I quickly determined starter solenoid was faulted in the "on" condition! ... Puzzling, I know I checked this before, and solenoid wasn't shorted, but there you go ... not my best work in that ... it would surely explain the symptoms of starter hanging up and failing to retract from ring gear ... due to a faulty starter relay keeping starter turning ...

    Oui! ... If we learn from our mistakes, seems I'm bound to be a bloody genius!!! ;-D lol ... Oh well, at least problem's resolved :-)

    JMOR    Posted 03-10-2020 at 17:40:35 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Surely, Shirley...that starter gear doesn't remain engaged with flywheel gear 100% of the time!?

    TheOldHokie    Posted 03-10-2020 at 18:02:51 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • No, it uses the much more reliable electrically actuated solenoid that extends the gear forward in the fashion Brad likes better.


    JMOR    Posted 03-11-2020 at 09:23:03 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Duh! I should have seen that in the picture! Whack! Up side of my head.

    TheOldHokie    Posted 03-11-2020 at 11:53:17 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • Careful Jesse - at our age we need to reserve such admonishments for the moments truly deserving of them. I just got my first pair of "real" glasses ;-)


    Brad    Posted 03-11-2020 at 15:44:03 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • I've done eye exercises before and was eventually able to get rid of my glasses ... Unfortunately, like exercise equipment in the closet ... When you lose motivation and stop doing your "Bates Method" eye exercises, vision reverts back to what it was before lol ...

    15 minutes eye exercises twice a day is what it takes ...http://www.seeing.org/techniques/ ...

    Then there is the opposing Theory: ... "Beauty is in the eye of the beer-holder" ... ;-) With Dr. Eric Berg's"Healthy Keto" and intermittent fasting, I don't even get to drink a beer nowadays >;'-@ wwwhhhiiiiiinnnneee lol ...


    But I have lost 30 lb and my test results are much improved (even if my humor has not ;-D ) ... I used to say the only way I was going to lose 10 lbs was in a thrift store in London! lol ... because, I never had any trouble losing weight ... it just always found me again! :-)

    Too bad we can't just get repair parts for our bodies, like we can do for our old classic N Tractors :-) ... Henry Ford would be proud to know that his N Tractors, over 70 years later, are still doing work that they were designed for, also that replacement parts are plentifully/economically available.

    Brad    Posted 03-10-2020 at 19:07:50 [URL] [DELETE]        [Reply] [Email]  
  • Re: Ford 8N tractor starter won't disengage, Positive Drive type
  • "The nicer the nice, the higher the price" ... That is one fantastic-looking solution! ... Unfortunately, between jobs at the moment... champagne appetite on a beer budget ...


    If I have to, $27 shipped for new starter Bendix replacement is manageable, in comparison to spending $249.00 of food & part of rent budget on Denso starter ... Tough decision, eat or buy parts & work on tractor? lol ;-) HHHhhhuuummmm.... "Classic Tractor Fever" no cure in sight lol


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