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Full Floater

Discussion in '40- & 55-Series Tech' started by 72cruiser, Oct 12, 2003.

  1. 72cruiser

    72cruiser

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    sup y'all,

    wonderin, what's the big deal with a full floating axle? i'm gonna search and look though the tech stuff, but i figure i'll need some of it explained anyways :D.

    also, what's the difference between an FF from a 60series and an FF from a 70series?

    and, 1. prices 2. advantages 3. disadvantages.

    thanks guys,
    jonathan
    jmalphr@clemson.edu
     
  2. 3_puppies

    3_puppies SILVER Star

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    Main advantage of FF is strength. You have two bearings supporting each wheel, like a front axle assembly with out the knuckle. If you break an axle shaft, the wheel stays on the rig. If you flat tow it, you can install hubs on it, instead of disconnecting the driveshaft.
     
  3. cruiserman

    cruiserman

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    [quote author=3_puppies link=board=1;threadid=6232;start=msg50104#msg50104 date=1066007402]
    If you flat tow it, you can install hubs on it, instead of disconnecting the driveshaft.
    [/quote]

    Not without custom axles.
     
  4. Mike S

    Mike S

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    With locking hubs on RE FF, towing is a breeze. Also, if you wreck the RE, you can ulock and drive out with the FE engaged.

    Mike S
     
  5. tclndcrz

    tclndcrz

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    how nifty. now i am jealous of ferg.
     
  6. 72cruiser

    72cruiser

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    thanks guys,

    anybody got one? Got pics?

    also, what years/models did these guys come on? the only ones i have seen are off of 60/62s.

    would y'all consider it a worth while conversion to try (especially b/c i am goin to have to repair/replace the majority of my rear end)?

    jonathan
    jmalphr@clemson.edu
     
  7. Dan_J-spec_fj62

    Dan_J-spec_fj62

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    Jonathan,

    The 60/62 ff are a bit more wide than the 40 axles... i know you can get a 40 ff rear axle here in japan and probably austraila... but i am thinkin shipping would be a PITA you clould try man-a-fre they have some every now and then. i guess if i were going to convert to 60/62 ff rear i would add the front as well and just have a wide a$$ 40. I think that would look pretty good.

    dan
     
  8. theferg

    theferg

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    Though I have no first hand experience with them yet, I have been trying to learn about them as much as I can. Full floats seem to be (debatedly) a stronger assembly than a Semi-float assembly. Here's a good quote I found when I searched the LCML archives: "A full floating rear axle is VERY similar to your front axle. Unlike a semi-floating rear axle which has the tires bolted to an axle shaft which rides on bearings and is held in place by a C-clip, a full-floating rear axle has a spindle which the tire is mounted to, an axle shaft with (or without) a flange goes to the differential and mates to the spindle through either direct mounting or a hub." and "Currently, if you blow the rear end or break an axle shaft, your day is done. With a full floater, you can break an axle shaft, disconnect it(or remove it) and continue on. The tire is held on by the spindle NOT the axle shaft." -J. Stone (whoever that is...) Sorry, I'm tired, so I thought this guy kinda summed it up alright.

    Anyways, there has been continual debate on whether or not the FFs are actually stonger and actually have advantages and whatever--every one has their own opinion. But there are some facts to see there.

    One thing to note is that the FFs seem to require a bit more maintainance than SFs. Supposedly the cone washers work loose and the nuts have to be re-torqued quite a lot... :p More so if you run an auto-locker (like a deroit or a lock-right or somethin') in it 'cause the auto unlocking and locking just loosens those nuts right on up. A selectable locker (Electric, cable or ARB or somethin') is the only way to go for a FF. (IMO of course, some people have probably never had trouble runnin' an auto-locker in a FF, I just don't think it's a good idea--that's why I'm gonna run the J80 electric in mine :D )

    Price? Who knows. MAF just had a sale blowing them out for $495 plus shipping :-X . SOR has them for ~$450 again plus shipping. I called MAF and SOR when I was first lookin' for one and SOR qouted me $350 for shipping (from LA to Northern Utah :eek: ) Anyway, I am getting mine for around $450-500 (including shipping) from a local guy (shipping was cheap 'cause five of us went in to get them). They are kinda hard to find though--if I were doin' mine again for an FJ60, I would just swap in a whole 80 series rear--they're gettin' a little cheaper and are usually easier to find than the others ('cause they were an available factory option here in the US)

    Oh and the difference between a 70 series and 60 series one is pretty much just width--though some 70 series ones came stock with rear disc brakes and some with dums, and 60 series never go disc brakes (also somewhat debated, but no factory disc brake 60 series axles have surfaced yet). If you are unfamiliar with the models, 70 series axle assemblies are a tad bit wider than 40 series axle assemblies and 60 series axle assemblies are a tad bit wider than 70 series axle assemblies and 80 series axle assemblies are a tad bit wider than 60 series axle assembies...

    That reminds me, with all these rumors tha float around about how the FF rear takes so much more maintainance, it makes me wonder if the 80 series ones are like that as well? Any of you 80 series gurus wanna fill me in? Do they take a lot more maintainance than a SR rear end? Ya obviously the e-lock diff takes a bit more, but what about the axle assembly itself? Is the FF design of an 80 series rear the same (or extremely similar) to it's predecessor's FF rears? Any design changes any one is aware of?

    Anyway, tclndcrz, nobody can be that jealous of me yet--mine still isn't here ::) .... I'll be sure and post a pic of it when it finally arrives though--then you can be jealous and drool all you want.

    Incidentally, look what was just on EBAY. It's a factory 60 series FF rear end with cable locker. Went for $1600 USD. (Yes, of course I bid, but it went WAAAAY out of my range.) I do know a place that'll get you one of these cable lock axle assemblies (front and rear), but it ain't cheap. They want $2000 USD for EACH assembly. Considerin' how RARE they are in the US, and how hard it is to get 'em, and how far they have to be shipped, that ain't too bad or a price for a complete assembly...
     
  9. Dan_J-spec_fj62

    Dan_J-spec_fj62

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    thaferg,

    thanks for the pic that is EXACTLY what my rear axle looks like!!! and i've got a front one to match!!

    LOCKERS RULE!!!!!

    dan
     
  10. woody

    woody unhelpful spotter Staff Member Admin

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    Some searches on the LCML archives might net you some great discussions on the fullfloat strengths...can be found at http://www.birfield.com

    First off, fullfloat axles are 30 spline inners, same as the semi floats. However, the semi NECKS DOWN greatly to meet that 30-spline size. Full floats are smaller diameter their entire length. The LOAD placement of a fullfloat is much nicer, since it's on tapered bearings like the front, but there is zero strength gain, and perhaps even a loss. A vehicle that carries a lot of weight will benefits from a full float...the vehicles weight rests on the bearings and housing, the axle only need to provide the drive. Note in American rigs how a 1/2 ton has a semi-float rear and a 3/4 or 1-ton has a fullfloat....it's more weight carring capacity than strengty (tho they also upgrade axles sizes as a rule too)

    fullfloats are reported to not like automatic or welded diffs. You either run an ARB or an electric if you expect to not perform near constant maintenance. Something about the hub flange loosening the bolts/shearing pins.

    They are great if/when you break an axle...pull and keep driving. However, semi's rarely break, and if you are running a rear disc conversion, that system will keep the axle in place for you to reach either a repair point or camp.

    Full floats are great for "bush" conditions, where you may be on the trail for an extended time, and the ease of changing the shaft is nice. Plus the ability to still get out should you break and not have a spare. However, VERY few of us, especially in the US, fall into a situation where we are not a short trip back to a trailhead.

    I looked long and hard into a fullfloat a few years back, and the more I read, the less I want one. I've been unable to break a rear axle despite 38.5 tires, fuel injected V8's, welded spiders, etc...
     
  11. rick_d

    rick_d

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    I have a few FF so I can speak from ownership...

    FJ40's got two FF, an early 1975/6-1980 and a late 1981+.
    The early are the same as Canadian spec FJ45's, they have a 3 nut
    lock system for the hub which is rare to source as the axle is so old.
    These all have dual cylinder drum brakes and the Fj45 style have 3"
    wide drums vs 2 1/4" standard.

    Late Fj40 FF are rarely seen, they have 100% identical brakes (bendix) to a US issue FJ40 or FJ60- never north american delivery. Use 3 pin tool for nut system from here on out.

    J70 FF's USE THE SAME AXLE SHAFTS as a late FJ40, so there is no difference in size. These now come in 3 styles, Drum brake (bendix), disk (1995+ for north american mine trucks), and HZJ79's have 5 lug gusseted tube with 3" brake drums but were robbed and are fitted with 2 1/4 brake shoes (use for heat?)

    J60 FF USE THE SAME SHORT SIDE as a late FJ40 or 70 FF. Never in north america. Some european spec has 3" drums AND 3" shoes, but sadly those 3" shoes are discontinued worldwide and no aftermarket exists. NO DISKS EVER.

    J80, offered as option in US 1993-1995, but were not standard until 1995, disk (very similar to J70) axle shafts wrong length.

    #1 downer, the spindles are welded to the axle tube and MANY of the used axles from mines and Australian sources are worn to the point of not holding a seal. I have seen mine truck speedy sleeved, but why pay top dollar for a FF you need to speedy?

    #2 You must inspect the wheel bearings on a regular basis. If there is slop in the 3 pin nut OR the 3 nut system you will get a wobble that destroys the axle studs. If it's tight, you have no issues, loose, you are breaking studs often.

    #2a) the axle seals should be checked as well and just replace them. E locker's have different seals so buy the right ones.

    Woody may be right about some lockers, but ARB, Cable, or E locker seem to hold up fine. The mines in Canada bust long sides most often (70 series) but these guys do love the trucks they just want the f$#^%&king rice burners to die ASAP- but the miners don't realize that their above ground Chevy, Dodge or Ford's would not last 3 months at -50C average winter operating temps (they tried Dodges and the bodies fell off!) while the jap trucks last 3 years.
     
  12. bjowett

    bjowett Supporting Vendor

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    I went FF for many reasons.... the above mentioned servicability is vey nice. One can change/repack/pull/install just about anything on the rear axle quickly and easily. For example, the 3rd member can be on on the ground in about 30 minutes or less w/o even jacking the truck up or removing a wheel. Most consumable parts are shared with the front end... at least on the mini 8" 1 ton. The housing on the mini has a larger diameter tube, and supposedly has thicker metal used (?).

    I love mine... the coolness factor alone is worth it... they really don't cost much these days.

    Woody is correct, though. The semi floaters rarely break.... you can argue both all day long (but the FF will always be sweeter! :beer: :beer: )
     
  13. theferg

    theferg

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    I coulda swore I read the 70 series axles were a bit wider than the 40 series axles.... But, Rick D is the end all, know all for sure--so listen to him. :) Maybe it's the perch widths or something that's off a bit?
     
  14. mustardfj40

    mustardfj40

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    I have one, here's 2 cents.
    Pros:

    Easy to swap out diff
    Coolness: everyone is able to spot it even jeepers.

    Cons:

    Parts are hard to find in US and expensive you can find it.
    My axle nut loosen twice and almost screwed the threads on the spindle.

    /td
     
  15. Bradass80

    Bradass80

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    Yeah the cone washers do work themselves loose and once loose the studs are prone to getting sheared off, it happended to my 80 series and wasn't too bad to fix just had to drill new holes and retap them, but other than that i want to put a set of 80 series axles under my 40 some day.
     
  16. rick_d

    rick_d

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    Ben- about 40" center to center for 40 series spring perches, about 41.25" center to center for 70 series. Older FF 40 series are slightly shorter shafts (like +/- 1/4").

    again, the cone washers will grenade if the wheel bearings are not tight- check them!
     
  17. 72cruiser

    72cruiser

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  18. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    I love my full float rear...

    Dana 60, ARB, 4:88, Warn 35 spline axle kit with disc brakes...

    :D
     
  19. woody

    woody unhelpful spotter Staff Member Admin

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    [quote author=Poser link=board=1;threadid=6232;start=msg50511#msg50511 date=1066099100]
    I love my full float rear...

    Dana 60, ARB, 4:88, Warn 35 spline axle kit with disc brakes...
    [/quote]

    cheater.... :flipoff2: lol
     
  20. 72cruiser

    72cruiser

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    wasn't there somebody who just finished an SOA on their 60 with a FF rear?