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Technical Early Ford Banjo Rear End Rebuild

Discussion in 'The Hokey Ass Message Board' started by tdog, Apr 5, 2010.

  1. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    About 6 years ago my dad purchased a banjo rear end for 100 bucks from a Junkyard down by the Kansas Boarder. It was compete with brakes and a torque tube. But what he was really after were the Chrome Bells it had. He brought it home and stored in the garage. Last Nov he was hot rod’n and broke an axle in his 32 Cabriolet. It had been howling for a couple months before he broke it. Dude is 65 years old and still breaking shit. Its likes have a 16 year old kid around LOL. He wanted to upgrade with a set of 3:54’s so He took the banjo rear end (w/ 3:77s?) out of the car and put in the corner. Decided to build the rear end with the Chrome Bells. When he took it apart it was very rusty inside. At some point it must have sat upright with the torque tube standing straight up in the air. So he scrounged around in his shop for some extra rear end parts that we had left over from when I built a Columbia two speed banjo rear end for a 28 Model A roadster that he and I built. He brought over all the parts to my house so I could start the process of rebuilding a rear end that will hopefully hold up to his Right foot.
    Before reading on let me say I work in an office for living. I used to wrench for a couple summers during college. I have a lot of experience building 8.8s in Mustangs and have done some 9” rear ends. I only have one Banjo rear end under my belt before building this one. Also I am looking for input from the folks who are experts on this. I am looking for tips and help for what I may be doing wrong. After I get this one done I have a buddy who needs help with a 46 ford rear end. I am always looking to learn and do better. Also trying to help the guy/gal who wants to run a banjo but may not have any experience in building one and help give some confidence that it can be done.
    My Dad had already had partially taken the rear end apart and I am taking apart two center sections so in the end I can choose which case I like better. One center section was very rusty and the other was very clean and not rusty.
    Taking apart the center section:
    First order of Business was to get the old pinion, bearings and race out. Using a 5/8” deep well socket I used to push up. And a 3 ½” piece of pipe with a cap of ¼ steel welded on top. I got some pressure on the press to hold everything in place and then I used the torch to put some heat into the housing. Not a lot of heat just got her warm. Not even close to cherry red. With some pumps of the handle the whole pinion assembly started moving and she was out. (One picture shows the pinion still in the case about ¾ of the way out) Clean case or rusty case I would suggest a little heat to get the pinion assembly out. As info I will be using all new bearings and a new gear set.
    [​IMG]
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    Next order of business was to get the pinion snout bearing out. If the rear end has not seen lot moisture or a failure where a bunch of shavings and chunks of metal have run through the bearing via the fluid. I would say this bearing could stay in place if the rollers look good. In my case I am planning on have the Center section (Banjo Portion) powder coated. I needed to the have the case completely gutted.
    I drilled both rivets out and pushed them through with a punch and the retainer dropped. Then ready to press the bearing out.
    Using a 36mm socket was used to push the bearing up and pipe used to press against the other side of the housing. On the “clean” case it pushed out cold no heat. (Came out easy). On the rusty case I used heat on the case around the pinion snout housing. Then it came out.
    [​IMG]

    [​IMG]
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    [​IMG]

    ffice:eek:ffice" /><O:p></O:p>
    After getting both center housings stripped I used a 3/8 x 24 thread tap to chase all the holes for the banjo bell bolt holes and where the torque tube bolts up. One of the housings had some messed up threads in the torge tube flange. Somewhere along its life someone took some wrong bolts and tried to make them fit. The tap cleaned them up with no problem. After the tap the Factory Ford bolts went in just fine. For some reason a 3/8 24 dia did not seem to work on the bolts? Ford must have used a none standard thread pitch on the bell and torque tube bolts? Regardless the 3/8 x 24 tap did the job on cleaning up all the holes. The set up on these require a lot of assembly and disassembly so making sure the bolt and holes have good threads is important.

    The Bells:
    I knocked out the old axle seals. The first one I used a punch and taping on the seal in a circle. It was not a good method for me. The seal came apart in three pieces. And was a fight. On the other bell and the second seal I used a 15/16 impact socked with an extension to tap on. This method work great. Pushed the seal out in one piece.
    The chrome bells seemed to looked rusty on the inside. I ran a telescoping magnet down the inside of the bells and same out with a bunch of rusty flakes. I took the bells to the car wash and sprayed as much as the grease out 2 bucks would allow. Then took brakleen and rags and a pipe to get the bells clean enough to get them in my buddies blasting cabinet. My friend Josh owns Trails performance coatings located in Papillion Ne. Josh and his right hand guy Jeremy are the guys who are going to powder coat the center section when its time. After I taped up the outside of the bells the insides were ready to blast. (Tape was used to protect the already not so perfect chrome during the media blasting process) After the inside of the bells were clean from rust I used compressed air to get most of the media out and then back to the car wash to spray out the last of the blasting media.
    [​IMG]
    [​IMG]
    Remove the bell diff bearing races:
    With a pieces of 4’ long by ½ rebar we used to tap out the old races. There is “groove” on the inside of that exposes the edge of the race. This is where you need to have the rebar rest while the other end gets taped. In one of the pictures I am using a hammer handle to keep force on the rebar so it will not jump out of the “groove” while my dad hits on the other end. Rotate the bell around while tapping to spread the force. After that I used race installer I made from an old race and tapped the races in place. I will not install the new seals until the end of the build. The axles going in and out of the bells during set up could cause damage to the seals if installed now.

    [​IMG]
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    [​IMG]

    <O:p></O:p>
    That’s it for now more to come. I almost have it together. It’s all set up and I used a rope to hold the spider gears and set up the preload on the diff bearings with an inch lb torque wrench with one axle installed. Worked out great. Just need to find the time to put together the write up.
    <O:p></O:p>
     
  2. bct
    Joined: Apr 4, 2005
    Posts: 1,445

    bct
    Member

    looking forward to the rest....
     
  3. butch27
    Joined: Dec 10, 2004
    Posts: 2,278

    butch27
    Member

    Great help. I'm changing from 4:11 gears to 3:25 right now.
     
  4. Fred A
    Joined: May 3, 2005
    Posts: 152

    Fred A
    Member
    from Encino CA

    One Mistake! Those tight bolts are supposed to be that way from the factory. That's what keeps them from leaking when the assembly is all together. Hope you don't get it all together and curse the design that leaks when you are the cause. Banjo's are cheap as dirt and might be worth the effort to head off any problems. Even the Late Great Richard Johnson of Burbank didn't know about the tight holes until I had him do some machine work on my Model A banjos and told me what he'd done. Luckily the A banjo is even cheaper than the V8 style and easier to pull the pinion. Good Luck: Fred A
     
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  5. cvstl
    Joined: Apr 15, 2009
    Posts: 800

    cvstl
    Member
    from StL MO
    1. H.A.M.B. Chapel

    Perfect timing.... getting ready to rebuild one w/ 3.54s. Thanks.
     
  6. fab32
    Joined: May 14, 2002
    Posts: 13,984

    fab32
    ALLIANCE MEMBER

    Great timing on this. I'm in the process of changing the rearend in my '38. going from 4.11's to 3.54's. the tip about the factory interference fit of the bolts is especially timely as It has been a practice of mine for over 40 years to chase the threads on everything that I'm reassembling.

    Frank
     
  7. hotrod40coupe
    Joined: Apr 8, 2007
    Posts: 2,561

    hotrod40coupe
    ALLIANCE MEMBER

    Thanks for the tech, this one is getting saved.
     
  8. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Fred A, Thanks for the knowledge that is great help. At least I wont screw up the next one. I did add a dab of sealant on all the banjo bolts during final assembly so hopefully this thing wont leak like siv when my ol man fills her up.
     
  9. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Remove old pinion and diff bearings:
    If you are opening up the rear end to inspect, re-adjust the bearing preloads and/or replace gaskets you may not have to replace any bearings. If the bearings look to be in good shape and the rollers are NOT blue in color (Been Hot) and your not sure if they are good enough to run?. A rule of thumb I have followed: If you can feel an imperfection on the rollers or the race with your finger nail the bearing should be replaced.
    On the pinion gear the one bearing by the splines should slide right off and then the race will come off. The bearing next to the gear end of the pinion needs to be pressed off.
    [​IMG]
    To remove a good pinion bearing for re-use: Take an air chisel and get the point down between the Bearing race and the base of a tooth on the gear. Give the trigger on the air chisel a couple pulls. Get the race to move about an 1/8 of an inch or more. You are making room to get the bearing splitter to grab the back side of the race. After the splitter fits down in the space you just made tighten it up using the big nuts on the threaded shafts. Make sure the cage of the bearing cage still spins. If it does not spin you may need to use the air chisel again. In some cases you may need to grind a little meat off the splitter to make clearance. Then take it to the press. While its in the press keep checking to make sure the cage rotates freely if you bend the cage. You will ruin the bearing.
    [​IMG]
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    To remove a bad bearing: I cut the cage off with a cut off wheel and put a little heat on the race this will really get it moving. Then use the air hammer to make room for the splitter. Then put in the press and fire up the torch again and put some more heat on it. Don&#8217;t go crazy with the heat. (Not cherry red) it will not take much to make a big difference once its in the press. I like to use heat when I am removing junk bearings so I do not have to put a big strain on my bearing splitter when I don&#8217;t have to. I figure the less strain the longer it will last. And with the cost of a good bearing splitter I need to make mine last a long time&#8230;&#8230;&#8230;Tip: Don&#8217;t by the Harbor Freight Bearing splitter. I tried to go cheap and broke it on its first use. Got mine at Napa. Spent close to $200. Try to find a friend that has one you can borrow. Save all your old races. They come in handy for installing the new bearings and on other projects you may come across in your press.
    [​IMG]
    [​IMG]
    Remove the bearing on the None ring gear side of the differential: Just use the bearing splitter to catch the back side and get in the press. . I used a deepwell socket to go between the press and the diff. If saving the bearing no heat. If the bearing is junk, cut the cage and get some heat in it.
    [​IMG]
    I did not have to remove the bearing on the side of the ring gear. I made a Gear change and purchased new bearings. But if I had too I would repeat the above instructions.
    More to come...................
     
  10. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Next thing to do is the get the bearing on the ring gear and the bearing on the big half of the diff. To press the bearing on the ring gear I used some wood on the press to protect the teeth of the ring gear. I also took rear end oil and lubed up the inside of the race and the ring gear portion where the bearing presses on.
    Never install bearings or races dry. I think I may have not mentioned that above in the bell race installation section? Sorry
    Then with an old race flipped upside down to push down on my new bearing I pressed it on. Pay close attention. I had to readjust the bearing a couple times before it was exactly square. (I started pressing and had to stop right away and pull the bearing off and re-adjust)
    [​IMG]
    [​IMG]
    Then I repeated the above steps to press the bearing on for the big half of the diff.
     
  11. Fordguy321
    Joined: Oct 16, 2009
    Posts: 412

    Fordguy321
    Member
    from Arizona

    Im lookin for a banjo for my sedan and probably gonna have to go through it like this, do they have bearing kits? How much does a overhaul cost on these?
     
  12. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Fordguy321 I think the Bearing kits are around $325 -$340 and a ring and pinion if you desire to change yours I believe are around $350 and then there are some seals and gaskets. I heard have you can spend around $800 for parts. My dad scored a whole rebuild kit of ebay for $415 that included everything new with a set of new 3:54 gears. So guy bought the stuff and decided he did not need it. So we got lucky. I seen on a web page a company will go through a banjo for $465 just for labor. A guy could buy a press and bearing splitter and build some race installers and be money ahead. good luck
     
    Last edited: Apr 6, 2010
  13. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Temporarily bolt together the Differential with ring gear for set up:
    First thing I did was get one of the bells to mount vertically on a my rolling work Cart. Got it mounted with a wide jaw vise grip and a ratchet strap.
    [​IMG]
    I pushed two diff bolts through the back side of the ring gear and took the small half of the diff and tapped it into the ring gear with a rubber mallet.
    [​IMG]
    Then I set the other half of the diff (Big Half) with the bearing in place and set it in the vertical bell on the Cart. Slid an axle in it (Down into the bell) and placed the spider gears in the diff. I took a ¼ nylon rope with a knot on each end. (Burnt the ends so it would not fray and untie). Total length measured about 5”.
    [​IMG]
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    Took the knots and wedged them in between the spider gears and the axle end. Make sure this does not hold up the spider gears from fitting down in the correct position. This rope will temporarily lock the one axle into the diff while I set the preload on the diff bearings.
    [​IMG]
    With the 8 diff bolts, bolt the two diff halves and ring gear together and tighten it up.
    [​IMG]
    Take the assembly out of the bell (Axle was pointing down) and set in back in the bell so ring gear is on the bottom and the axle is straight up in the air. This the time to make sure the roller in the bearings and the races have plenty of oil on them. When the preload is being set up its important to have them saturated
    [​IMG]
    [​IMG]
     
  14. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Shim the Bells for correct Differential bearing Preload:
    Make sure all banjo flange surfaces are free of debris.
    [​IMG]
    Bolt the center section to the bell with no gasket.
    [​IMG]
    Now slide the other bell over the axle (Do not use gaskets at this time) and put about 4 bolts in to get it square and measure the gap. My gap measured about .020. So I took the bell off and I placed three gaskets shims .007, .007 and .005 back on the center section and bolted the bell back down tight.
    [​IMG]
    [​IMG]
    I threaded an axle nut on the axle threads at the top. And put my inch pound torque wrench on the top of the axle I jumped up on to a stool to be able to read the top side of the torque wrench. The rotating assemble measured 10 in lbs. Not being able to find any preload specs for the diff preload I used the preload specs for a pinion bearing from some Ford Motorsports read end instructions. With new bearings I was shooting for a number between 16 in lbs and 28 in lbs. I needed to take more shim out. Took the top bell off and removed the .005 shim gasket. And the left the two .007&#8217;s Bolted the bell back on and came up with 22 in lbs of for the preload on the diff bearings. That sounded good to me. The two .007,s shim gaskets gave me the total shim of .014 total to achieve the preload I was looking for.
    [​IMG]
    [​IMG]
    Side note: My bells are have been chromed and the chroming process added a thickness of .005 to each bell flange. (I had a piece of chrome flake off in it measured .005) If my axles were bare steel I would have added .010 to all my numbers
    Another side not: I have read posts about checking the preload on diff bearings by assembling the rear end with both axles and then loosing the pinion and doing it by feel. Probably works fine I did not think my arms would reach to turn both axle ends at the same rate to get a feel for the rotating resistance.
    When I built my first banjo. I used the by feel method but I had the pinion out and did not have the axles in the bells. I spun the ring gear through pinion hole with my fingers to get a feel for the rotating resistance. &#8220;Bearing Preload&#8221; It works good too. I just decided to use the rope because it was an idea I came up with so I would be able to use inch pound torque bearing specs.
    I am use to working on are Ford 9&#8221; and Ford 8.8s I have not seen preload bearing specs for differential bearings on these rear ends. That&#8217;s why I had to use specs from a pinion bearing chart.
    On the 8.8,s you set the diff preload up by shimming the bearings If you can get a cast Ford shims in without breaking a shim (Tight fit) your good. And the spanner rings on the 9&#8221;s are done by feel with no real way of check the resistance. However To get the&#8221; feel&#8221; of a 9&#8221; and the 8.8s you can put your hand on the ring gear itself to get a good &#8220;feel&#8221;. In a banjo style rear end is either through the pinion hole if the pinion is out and using a finger to turn the ring gear or turning a tiny axle end. So I tried the rope. And I liked the way it worked. Sorry if I am getting off track just trying to explain why I used the rope idea.
    Still more to come&#8230;&#8230;&#8230;&#8230;&#8230;.
     
  15. -Brent-
    Joined: Nov 20, 2006
    Posts: 4,175

    -Brent-
    Member

    Wow... informative tech! But really, all I learned is THAT I WANT CHROME BELLS! Beautiful!
     
  16. ss34coupe
    Joined: May 13, 2007
    Posts: 3,184

    ss34coupe
    ALLIANCE MEMBER

  17. Better subscribe to this. I have about 10 rear ends in the shed that need help.
     
  18. dirtbag13
    Joined: Jun 16, 2008
    Posts: 2,522

    dirtbag13
    Member

    nice tech ! saving this one
     
  19. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Prepare the pinion to install in banjo:
    The gear set I am using is brand new and a problem I found with the pinion is that the pinion was not machined enough from the factory to get the bearing on the splined end to slide freely. This bearing needs to be able to move back and forth during the preload set up. The bearing on the Gear end needs to be pressed on.
    I needed to take some material off the pinion gear to make the bearing slide back and forth. (See red arrow in picture)
    [​IMG]
    This could have been done by hand with some emery cloth but it was much faster chucking into my small lathe. I would take some material off with emery cloth and check. This was back and forth process. As soon as the bearing would slide I was good. You do not want to take too much off.
    Then it was time to press on the bearing on the gear end of the pinion. Using an old bearing race a piece of pipe and some gear oil I pressed it on.
    [​IMG]
    [​IMG]
    Side Note: To my knowledge these pinions were not shimmed from the factory and shims are not available specific for this application? The only time I would add shim or machine material off the pinion is if your final pattern check showed the pattern running off the toe or the heal of the drive side or coast side of the teeth of the ring gear. But will go more into that later.
    I slid the race on the pinion and then slid the other bearing that now slides freely into place. I installed the round washer and big nut. The assembly is now ready to take to the powder coaters along with the freshly cleaned and blasted center section.
    [​IMG]
    <O:p[​IMG]</O:p>
    <O:p</O:p<O:p</O:p<O:p</O:p<O:p</O:p<O:p</O:p
     
  20. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Make sure to check the hole that runs though the housing in the pinion race area is clean. This hole feeds the pinions bearings with gear oil as it flies off the top of the ring gear while it is spinning.
    <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p> [​IMG]</o:p>
    On the flange where the torque tube goes there is an extra hole on the bottom. This is the drain that lets the oil that makes its way into the torque tube back into the center section. If you cutting a torque tube down make sure the drain hole on the torque tube flange matches up to the center section hole.
    [​IMG]
    Josh and Jeremy up at trails powder coating took care of my while the pinion was put into the freezer and the banjo was masked to keep powder out of the insides and out of all bearing races and bell attachment areas. After two coats of kick ass red powder the center section was removed at 400 degrees and the cold pinion assembly with a skim coat of oil was slid right into the hole while it still hung from the wires. UUUUNG! Talk about a pretty site!
    [​IMG]
    If you not going to powder coat you center section a torch will work. (Not cherry red) just some heat just like was needed to get the pinion bearing out. Still put the pinion assembly in the freezer. You may want to wait to paint you center after the pinion is installed. Don&#8217;t want to burn the paint.
    I did take off all the over spray on the areas where the bells mount. Don&#8217;t want it to interfere with my set up.
    <o:p> [​IMG]</o:p>
    Stil more to come..........
     
  21. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    Thanks for all the positives on this guys. I am glad your finding it helpful. I will try to add more tonight
     
  22. HellsHotRods
    Joined: Jul 24, 2009
    Posts: 867

    HellsHotRods
    Member
    from So Cal

    EXCELLENT TECH ARTICLE!!!!, very detailed. Thank you for posting this. Everyone building a traditional-period correct hot rod has to rebuild one of these at some point.
     
  23. tinmann
    Joined: Nov 11, 2005
    Posts: 1,548

    tinmann
    Member

    Well written, excellent photography...... and good timing as I need to have peek into the '39 banjo under my '32. Thank you sir!!!
     
  24. butch27
    Joined: Dec 10, 2004
    Posts: 2,278

    butch27
    Member

    Where did you buy the gasket(shim) kit?
     
  25. thesupersized
    Joined: Aug 22, 2004
    Posts: 1,355

    thesupersized
    Member

    awesome tech, thanks! i will definitely be using this in the near future!
     
  26. RDR
    Joined: May 30, 2009
    Posts: 1,173

    RDR
    Member

    Me too...want this one handy..thanx MR tdog
     
  27. 392_hemi
    Joined: Jun 16, 2004
    Posts: 1,739

    392_hemi
    Member

    Nice tech, but the side bell gaskets are supposed to be used to adjust the gear lash and there's a specific procedure for doing that. The early manuals have specs for pinion preload and gear lash.
     
  28. tdog
    Joined: Nov 15, 2009
    Posts: 125

    tdog
    Member
    from Omaha, NE

    392 Hemi I have done all that I just have not had time to post it all up yet. I m going to try to get some more up tonite. I am about 2/3 done with the post. I dont have the old Ford specs. I set the pre load on the pinion between between 16 and 28 in lbs (New Bearings) This is the same as 9" or an 8.8 Ford rearend. My Gear lash is .006 on the splines on the pinion but I figure the actual gear back lash at the teeth of the gear is at .009 or .011. These are also within the specs of a 9" and 8.8

    Does the old Ford manual spell exactly how to measure the backlash? I would like to the point the old books say to measure from. Since you can not see the ring gear when a banjo is all together you can't measure the actual back lash like you can on a 9" or 8.8

    If you had the pinion info from the old manauls to share that would be great

    Thanks
     
    Last edited: Apr 8, 2010
  29. rustymetal
    Joined: Feb 18, 2003
    Posts: 413

    rustymetal
    ALLIANCE MEMBER

    just what i was looking for .
    tdog do you have some more to add
     
  30. butch27
    Joined: Dec 10, 2004
    Posts: 2,278

    butch27
    Member

    Yeah: That WOULD help us all.
     

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