I have a buddy doing a 32 5 window with a strong flat head. He has both a 36 and 40 rear. Will be an open driveline with a T-5. Any strength difference between the two? The 40 axle bells/tubes are quite a bit larger in diameter, but it appears the axle O.D. and end bearing size is the same. Any info will help. Thanks
I thought the '36 & '40 bells the same, the '36 may be a bit narrower. The '36 would have been closed driveshaft only with the tubular driveshaft headers were made from. I think the '40 could have been open drive but conversion kits available for either banjo to open drive. Far as I know there is no difference in strength. It just occured to me the V8-60 might have had a less durable rear, I don't recall exactly when they were made but it would have been around 1936 or so. Time to research a little.
Thanks. Significant difference in diameter of bells , from center section to ends[taper]. Center sections are the same. Didn't think about V8 60.
People will argue both ways but in truth a stock flathead will break a Banjo rear if you hammer on them. The real weak point is the axle keys that shear off in the hubs. If you are going to the trouble of converting to an open driveline then do it complete.
Both the 36 and 40 have a closed drive line. The open banjos came on trucks from in the later 40's, 46 47 i believe. you can improve the strength of the banjos weak link the, the axle keys. First replace them with the right keys, not just keys from the parts store. Most early Ford parts joints sell them. The Key is only part of whats holds them the axle. The taper between the hub and the axle itself holds it also, when torqued down properly. Check the fit between the hub and the axle taper. clean the axle taper and inside of the hub as good as you can get it. There can be no knicks or rough spots for the hub to seat properly. Polish the axle taper and the inside of the hub with emery cloth, then Use a little bit of valve lapping compound to true them together by spining the hub on the axle taper (axle key removed) until they are a perfect fit. I check the fit by putting a light coat of layout fluid (Dykem) on the axle taper then lightly spining the hub one revolution on the axle. Once it has perfect complete contact, clean it then clean it again. they have to be spotless to seat properly. Then install the new axle key and hub and torque it down to 200 ft lbs first the to 250 ft lbs. Remember guys were running banjos and quick changes on slicks back in the day with some pretty nasty drag motors and they didn't break axle keys and axles all day long. The above way is how i was taught to do it by an old timer that had a blown olds powered digger with a Halibrand quick change banjo in it. it worked for him, and i have not had one break that i did doing it that way.
^^^^^ Read this and memorize it! (I also learned and practiced this, from an old timer drag racer, in 1953) Lapping the tapers is NOT 'overkill'. It is paramount. The V8 60s were used in Ford cars from 1937-1940, used the same rear ends as the 85's.
If you have the hubs that were on the rear when it was made, they are generally pretty close. But you would be surprised how much different it can be when using a hub from another banjo. Yeah they should be the same but time and wear and hack mechanics beating on shit can make them not as precision a fit as they should be. Ever head of guys saying "we just loosed up the nut and drove it around the block the the hubs would pop right off!" That tends to make shit not fit right after a while. If you are piecing a rear together or putting 40 hubs and brakes on wide five rear YOU NEED to lap them together!. It does make a difference.
Yep...key trouble means hub/axle fit is loose, either from taper mismatch or simply not enough torque on the nut, which should be SCARY TIGHT. there are TWO 1936 rears...most got same rear as '35, except for hubs, of course. This has the forged spring hangers made integral with radius rods, the whole thing bolted to the axle housing. The late 1936 rear is pretty much the '40 rear, with spring hangers forged as part of tube ends. I think only significant changes in this period are different tooth counts on spiders (I don't see any advantage either way, but of course your spider gears and axles must match) and different spline counts on pinion. I think all overall dimensions are the same.
What about a 9 inch axle conversion? Nice strong axles, and the diff is up to it. Needs a bit of machining, but Hot Rod works can do this for you and supply all the parts you need, which was what I had planned to do on mine, but the above tech has got me thinking. One of my keys has been really chewed, and the taper doesn't look to good, would I need to get another axle? And where do you get the 'good keyes' from? . Also, I may need to 'narrow' my rear to get my Kidney Beans under the fenders, can you get narrower OEM style axles?
@neilswheels I don't know how or where to go for narrowing banjo axles but it has been done. Look at old pictures of front engine dragsters. Those ran narrowed rears and lots had early ford hubs on them so it can be done. Although the cost may end up being the same, or more now, than just going to 9 inch axles. I have used keys from the Early ford store several times with good success. they sell a kit that is for drum and hub installation. comes with new nuts,cotter pins, washers and gaskets as well as new axle keys. For 8 bucks its worth it , but save your old nuts and washers if you can. I never throw those out. Ford stuff is always the best stuff to use if you can. here is a link to the axle key kit. http://lbcunited.com/earlyford2/pro.../9578?osCsid=f30bef49fb79236de2d8acb7020188e3
Install an 8 inch rear instead of a nine inch. It weighs less, looks better and has all the strength you will need. Converting to open driveline using the 36 or 40 rear will require the use of a torque arm since you will be eliminating the torque tube. The rear radius rods of the 36 and 40 are NOT, by themselves, strong enough to to the job of the torque tube. They will crack and break. An 8 inch open drive line will work nicely with use of parallel rear springs. Chassis Engineering has all the arts you need. PS: The wheel mounting surface to wheel mounting surface of a 40 Ford car is 59 1/2 inches. Plus, the bolt pattern is 5 x 5 1/2. Tons of info. is on HAMB about this conversion.
Thanks, but this car is a mint original paint 5 window. Hot flat head with a T-5. Banjo rear, dropped front axle,46/48 bones. Very basic. 48 Lincoln brakes. We've done a 32 highboy sedan with open drive and third link. Looking like we'll go with the 40 rear and use the tricks you guys offered.
Original keys have a taper bottom on one end...Home Depot one (yes, they have them!) are straight generic keys and so will be shortened or hand-ground to fit. If your originals are good, there's no reason to replace. I was looking through magazine pics of dragsters at the time they were getting past 180 in the quarter. Nearly all used Ford rears, mostly with quick change. Many used normal Ford axle setup (obviously shortened and re-tapered), clearly visible by the long snout at center of wheel. Others used floater conversions, not the 3/4 ton type but the type used on many old sprint cars with Ford axle splined and a special hub sliding over it. The place that made various parts for dragsters and rebuilt Ford trans and rears for dragster use, Chassis Research, supplied axles both ways and placed great emphasis on the quality of their work on the tapers in axles and hubs. I haven't seen a clear pic of their safety floater hubs but I'm pretty sure they are just like the ones detailed in various 1930's-1940's how to build a sprint car books.
Thanks Jason, good info. Having seen Chassis Engineering mentioned, I did a little 'googleing' and found this thread on another forum. the pictures are well worth a look, Chassis engineering knew their stuff! Splined axles for Banjo's, safety hubs, here's a few pics I copied, check out the price of a built rearend with quick change center section, wish i could buy that now! Also thought the diff locator was interesting, i've seen this before on the HAMB as a performance upgrade. I winder if any of the info in how to make ths stuff still exists, I'm sure there would be a market for it.
And I'm sure you can buy new posts (I think they were brass capped) for some of the many trucks that used that idea. For more on Chassis engineering, their custom parts and their many reworked Ford parts and assemblies, hunt down the various Fawcett and Arco publishing hot rod books from the 1950's and 1960's...Griffith Borgeson was obviously fascinated with their stuff and there are good articles in practically every volume.
I'm having a hard time visualizing the "Snubber" assembly. This would keep the ring gear from walking away from the pinion under load, right? So is it a stud/jam nut of sorts protruding into the axle bell, or???? Is there a small clearance between the "Snubber" and ring gear under normal loading? Could this be made at home without too much fuss?
It is just a post reaching in to a very close clearance to the back of the ring gear. This was very common stock on trucks, even Ford trucks bigger than the pickup, and these OEM snubbers had brass ends. On a Banjo you would need to weld up some kind of flat on the bell, because all the stock surface is curved.
The 40 rear end is stronger than the 36. In 1939 Ford went from 18 side gear teeth to 16 on the axles and spider gears. The fewer gears are larger and stronger! The widths are the same and can be interchanged as long as you use matching axles and spider gears.
383deuce has around 35,000 miles on his deuce 3 window with a Winters center and a 39/40 differential, tubes and axles. No problems to date. Assembled by the legendary Jelly out of Wichita Ks. sadly now deceased.
Bruce, this is the best pic I have of a Chassis Research floater axle. It was splined, and retained by an external snap ring.
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