Rear end axles and gears

J

jrd-28

Member
Hi all. I'm working on reassembling the rear end of my '28. I had to replace the carrier assembly and axles because they were badly galled (somebody ran it with no oil, I think)

When I assemble the carrier, the axles bind against the spider gears. There's no end play at all in the axles, and while I can turn them, they're way too tight.

I don't think I've assembled it wrong, there's only one way that set of stuff can go together. Maybe the axles were matched to the carrier parts? Maybe the dimensions changed for different years? The carrier I found is used, and I'm pretty sure is the correct one for a '28. It's in pretty decent condition. I don't know the vintage of the axles I found; they also seem good, teeth barely worn and bearing surfaces clean and smooth.

I have the machine tools available to take a few thousandths off either the inside faces of the carrier halves, or the back sides of the axle gears, but I didn't think I should be needing to do that. I hope I'm just doing something wrong, and somebody here can point me in the right direction.

Thanks in advance . . .
 
Welcome to the challenges of repairing 89 year old parts. Without knowing what you have, many of these parts look the same but have subtle differences. Some times the best thing is to carefully/thoroughly measure a known good Model A axel, carrier, and gears. The carrier housings are mated halves and should be serviced as a unit.
Many of the Model A differential assemblies were put together with the axel housings bolted to the banjo with no shims/gaskets. This process usually ends badly for the parts.
 
How is the fit without the spyder gears

Are the parts original Ford---or repro gyp

How are you supporting the assembly to "test"

Don't remove any metal till you find which part is out of spec--

Have you tried without spyder gears, on old spec I found is .003 -.006 end play, ,010 gear backlash ---spyder gear to shaft --.005-.008

post some pictures of the parts

I have painted gears and shafts with spray paint , assembled, moved and diss to look where the "contact" is--perhaps this will help

how are you holding the assembly to check it
 
I have encountered reproduction axles of yesteryear that are not correct and do not fit inside the carrier properly. This will cause it to bind.

A number of years ago I overhauled a rear axle assembly for a fellow club member. I found his carrier was extremely worn. There was a good 1\16" or more cut into the carrier where the gear end of the axle had worn it. I replaced the carrier and found the assembly would lock up when bolted up. Comparing the two axles I saw the difference. I asked the owner if he had any knowledge of the axle. He said that he had installed the axle years ago. It probably locked up then, but eventually wore its way into the carrier. I replaced the axle with an original and all was well.

When assembling the carrier and axles, after all nine bolts are torqued. Grasp the axles one in each hand next to the carrier and lift it clear of the work bench and rotate the axles in opposite direction to determine that it is free and not binding.

Tom Endy
 
Thanks all.

I spent some more time working with it. I had been using a set of blocks to support the carrier and the ends of the axles. I think my biggest problem was that my blocks weren't holding everything in alignment.

I tried my other carrier (the worn one) and it bound the same way. I then started looking harder at alignment. I made a wooden cradle to hold the carrier firmly, and then cut new blocks for the axle ends after carefully leveling the axles. With my new jig, it's much better. I can rotate the axles without binding, and the action is fairly smooth. On one axle the end play is .006, which is not bad. On the other there's zero end play. So I may still have to take a few thousandths off the face of the carrier on that side. I'm going to take everything apart again, and put some bluing on the gear teeth to see how I'm doing before I make any further decisions.

Kurt, the axles and carrier are old Ford parts. The spider assembly is new replacement.

Growley, when I disassembled this unit, there were no gaskets or shims or anything. That may have contributed the the wear I found.

I forgot my camera when I last worked on it, I'll get some pix for the future.

Thanks again...
 
Before you go cutting metal flip the spyder over and try end play again---or take it off the spyder thrust pad
 
Contact Tom Endurance on this website he will forward the procedure for working on rear ends. He's my Guru.
 
Thanks all for your advice so far.

After correctly supporting the axles and carrier assembly, I determined that my end play *is* ok on the axles, so I proceeded.

I followed the procedure for getting the carrier bearing preload set up, and keeping track of all my axle housing gasket thicknesses. I installed the driveshaft and got the pinion-to-ring mesh more or less sorted out, and the lash in the ring gear within spec.

I'm not sure whether I still have a problem. I put dykem on the pinion to check the mesh. The marks on the ring gear look reasonable to me, but the marks on the pinion look like it's engaging toward the end of the gear, rather than in the middle. The red book on page 1-95 refers to moving the pinion in and out. I couldn't figure out how to accomplish that. Should I be thinking in terms of shims behind the driveshaft bearings?

Here are some pix. Yes, I used too much, dykem, and my camera doesn't do a great job that close up, but maybe you can get the idea.
 

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jrd-28 said:
Thanks all for your advice so far.

After correctly supporting the axles and carrier assembly, I determined that my end play *is* ok on the axles, so I proceeded.

I followed the procedure for getting the carrier bearing preload set up, and keeping track of all my axle housing gasket thicknesses. I installed the driveshaft and got the pinion-to-ring mesh more or less sorted out, and the lash in the ring gear within spec.

I'm not sure whether I still have a problem. I put dykem on the pinion to check the mesh. The marks on the ring gear look reasonable to me, but the marks on the pinion look like it's engaging toward the end of the gear, rather than in the middle. The red book on page 1-95 refers to moving the pinion in and out. I couldn't figure out how to accomplish that. Should I be thinking in terms of shims behind the driveshaft bearings?

Here are some pix. Yes, I used too much, dykem, and my camera doesn't do a great job that close up, but maybe you can get the idea.
Click to expand...



I would not be concerned with all this bluing business that is often recommended. It is of no consequence. The only way you can move the pinion forward or aft is to put a shim between the gear end of the pinion sleeve and the first bearing installed. This will move the pinion aft. To move it forward you have to machine material off the bearing stop on the pinion sleeve. I have seen no evidence that Ford ever did either of these.

A number of years ago an article appeared in the Restorer written by someone that rebuilt one rear axle assembly. He sent his pinion sleeve several times to some guy in Florida who was an expert that convinced him that he needed a cut on the pinion sleeve. They had to make several cuts and it required several shipments. I believe that this article of dis-information was a dis-service to the Model A hobby as it just created more needless confusing information.

Henry put enough meat on the gear teeth and engineered the assembly so well that the pattern will be just fine where it ends up fore and aft.

If you follow my dissertation you can set the backlash by feel as described. Backlash is the least setting to be concerned with. It is done by shifting banjo gaskets left and right. Sometimes the backlash may seem too much if you are installing a used R&P with considerable wear on the teeth. You may not be able to get it as close as you would like, but it will be fine.

More important is to make sure that you do have some backlash. You should check it at a number of places around the 360 degrees of the ring gear to make sure there is clearance and there is no binding which is an indication that teeth on the pinion are bottoming on the ring gear. This you do not want. In this case shift banjo gaskets around to move the pinion out slightly.

I have rebuilt somewhere around six or seven hundred rear axle assemblies in the past 30 years and this is how I do it and I have never had a problem with this procedure.

Tom Endy
 
Thanks Tom, very encouraging :)

I won't worry about the offset of the pinion, then.

I have been following your very helpful howto doc. At this point I think I'm ready to start final assembly. I'll check all the fits and clearances one more time, safety-wire the diff bolts, button it up, then check the backlash. Good idea on checking it multiple times around the circumference of the gear, I'll add that to my list.

One last question, not about the gears: I haven't yet installed the new seal in the torque tube. Which way does it go? I would think it's meant to seal the oil in the rear end and keep it away from the grease on the U joint, but I'm not positive, and I haven't found a description.

Thanks again.
 
"One last question, not about the gears: I haven't yet installed the new seal in the torque tube. Which way does it go? I would think it's meant to seal the oil in the rear end and keep it away from the grease on the U joint, but I'm not positive, and I haven't found a description."

See page 266 of the Service Bulletins.

Bob
 
The original grease seals were made of leather and it was important which direction they were installed as the leather could fold over on itself. I don't think it matters which direction modern Neoprene grease seals are installed. They will snap around the shaft and form a grease seal.

Many supplier catalogs say that they should be installed with the taper facing the lubricant. This is confusing as there is a taper on both sides of the seal and they are not clear about what lubricant they are talking about, the differential oil, which is incorrect, of the bearing grease, which is correct.

the way I install the seals it to place the seal on my insertion tool such that the seam in the seal housing is up against the stop of the tool. It might not seen correct to some, but is has worked for me.

See attached article.

Tom Endy
 

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