Rear end setup. Not easy is it?

Mart

Mart

Well-known member
Well anyone that regularly sets up rear ends - I take my hat off to you.

I was following Capn Kirk's thread http://www.fordbarn.com/forum/showthread.php?t=204079&page=12 and was taking interest because I am doing a similar job.

Well I did what was quite a simple job. I replaced the bearing surface with a bush. That came out well, I posted about it. I then decided to change out the gears. No probs, but I found one of the side bearings was shot so I got a new one locally. Fitted that today, bolted up the carrier and started the shimming process to get the preload right on the carrier bearings. That took ages. Probably about 10 rounds of gasket swapping. Luckily I had bought the gasket set. Ok, then the pinion was fitted and the preload set. It seems tight to me, but does about 1-1/4 turns doing the spin test so I think it is ok. If I had an inch pounds torque wrench I could have been a bit more scientific.

I got that so I was happy with it and test fitted it all back together. The backlash seemed a bit too much, so I made an adjustment, basically by swapping the gaskets from one side to the other (3 thou between the two). That got it feeling ok.

I just finished bolting the side bells on fully. It took me about 6 hours some of which was setting up the axle in a position to work on it.

Like I said, I respect people that do this job. This was my first time. I would probably do it again, but I just wanted to say it took a lot more trial and error and assembly and disassembly that I expected.

I read the procedure by Tom Endy and found it very helpful.

Mart.
 
Mart,
You are quick.........Once I get the pinion installed in the center section
I assemble the rest of the rear end vertically in a home made wooden fixture.
Charlie ny
 
Here is a simple holder I use.

John
 

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Yeah, a vertical setup is definitely a must. I used a large vise bolted to the flat plate of an engine stand. It wasn't quite vertical as it sagged but I found it all right. I guess I made it more difficult for myself by having the axle shafts in place. Lifting the axle bell over the shaft multiple times and lifting the diff and shaft assembly in and out many times has built my muscles up.

I have just been playing snooker - No wonder I was tending to hit the ball harder than I Intended!

Mart.
 
Good job Mart. Mine went a bit easier because I was reassembling with gears and bearings that have been in place since 1940. The gears looked like they were properly meshed and the bearings looked good. For me, it was just a matter of measuring the existing gaskets and replacing with the same.
 
One thing I found out was to place the gaskets on the axle housing rather than on the face of the banjo casting. If the lip on the axle housing doesn't hold them in place, a little thick grease will do it. Also, a couple of my gaskets wouldn't fit over the lip and I had to break out the scissors to trim a bit. Finally, I destroyed a couple of gaskets during the fitting and I was glad I had bought extras.
 
Re the gasket placement. I made a couple of alignment studs from bolts with the heads cut off. probably about 2-1/2" long. They helped a lot. The Model A guide i saw had 10 of these studs, personally, I found 2 to be adequate. If I were doing it again I'd probably do it a bit different, and would be sure to get an inch pounds torque wrench on hand before starting.

Mart.
 
Mart, for pinion preload, if you know the spec and don't have the Ford tool.
Fix a long piece of steel to the pinion. equal lengths out both sides so it is balanced. then hang a given weight to the bar, If say spec is 10 to 12 inch pounds, hang a pound weight 11 inches from the pinion centre. From above the horizontal plane set the bar in motion. Does it stop, speed up, or continue evenly?
Having holes in the bar helps with locating the weight. Better than guessing.
 
i spent hours on a model a rear. one sat i spent one hole day in the shop. i put it together and put it in the car, it was not right. i sat there trying not to blow my cool! then i turned on the air , and took the rear out, and apart. then turned off the lights and did not come back for a week! finely got it back together. all i can say is take it very slowly! this was my first rear i have ever worked on, and it is quite
 
Brendan said:
i spent hours on a model a rear. one sat i spent one hole day in the shop. i put it together and put it in the car, it was not right. i sat there trying not to blow my cool! then i turned on the air , and took the rear out, and apart. then turned off the lights and did not come back for a week! finely got it back together. all i can say is take it very slowly! this was my first rear i have ever worked on, and it is quite
Click to expand...

Right on Brendan!! You really do need to take your time and do the settings correctly. Some of the previous posts here on this same subject suggest cutting corners to do this job quickly without carefully checking every detail necessary to get these banjo rears done correctly. Sometimes a person might get lucky and they will not have any further problems, especially on trailer/garage Queens that see very little actual road time. Just sayin' unless a person enjoys doing things a second, or maybe a third time, it's always best to do it right the first time. Just ask me how I know.

PS... Brendan, will be looking for you at TROG. Will you be driving your pickup?
 
This thread leads me to a question that's been milling around in my head since my axle broke and after doing a lot of reading.
When new, these diffs had to be pumped out of the factory by the 100's (a guess) a day. Did those factory workers go through all of the same stuff that we have to to get these rears all set up? Assembly, disassembly, swapping gaskets, reassembly...etc. Or, did they just slap them together all the same and hope for the best?
 
There are ways to measure preload requirements in a production situation. Rest assured they were not just slapped together hoping for the best. Returns are not cheap for a company or a dealer? Remember these people did the same job over and over. Have you seen the video of the engine assembly line? Do you think you can put an engine together that quickly without a hitch? There is a little bit of different between us doing these jobs in our driveways or garage and someone working in an environment set up specifically for the task, including all new parts and specialized tools. An old time dirt track racer, hot rudder, fabrication shop operator helped me set up my V8 QC in his shop. I would guess the whole setup time (setting pre-load, backlash, etc) took less than a hour or so. It is amazing how quickly you can get the units apart and back together when you have right working environment.
 
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Capt Kirk said:
This thread leads me to a question that's been milling around in my head since my axle broke and after doing a lot of reading.
When new, these diffs had to be pumped out of the factory by the 100's (a guess) a day. Did those factory workers go through all of the same stuff that we have to to get these rears all set up? Assembly, disassembly, swapping gaskets, reassembly...etc. Or, did they just slap them together all the same and hope for the best?
Click to expand...


Ford worked at keeping very close tolerances on the parts, it was just "put together", years of wear and abuse along with modern parts tolerances make fitting different now, everything needs to be checked
 
I haven`t heard much about pinion depth. I mean.. If you set up your preload then backlash, run a pattern and it is off.. Did they start over or were the housing and pinion gears so close they all fit? I assume the new gears we get now come with shims for the pinion?
 
37 Cab said:
I haven`t heard much about pinion depth. I mean.. If you set up your preload then backlash, run a pattern and it is off.. Did they start over or were the housing and pinion gears so close they all fit? I assume the new gears we get now come with shims for the pinion?
Click to expand...

On the '35 rear I rebuilt for my Avatar fordor last May, after carefully setting all bearing preloads and getting gear backlash set to the middle of the spec, the very last thing I did was coat the gears with White Lithium Grease to check the mesh pattern. The pinion gear teeth were contacting the ring gear teeth in nearly dead center and the deepth of contact was right on the money.
As previously mentioned, Ford did a good job of keeping their machining tolerances tight enough so that shimming of the pinion gear to adjust its contact position with the ring gear was usually not necessary.
It would be very interesting to see original filmed footage of Fords assembly techniques for their early V-8 banjo rears. They had to have assembly tooling and gauging that was good enough to assemble these rears quickly without requiring all the BS that we have to do today in a small garage operation or under a shade tree.
 
When you build something up often enough, you get a feel for exactly how to set things and just how many gaskets to start out with, etc.. They had the advantage of all new parts and any tooling that could be made to speed up the process. You see films of them building engines but I've never seen one of them where they were assembling rear axles.
 
Thought I'd give you an update.

Ok, I know I'm not doing this in the correct way, but I wanted to do a sanity check on the pinion. I borrowed a good quality inch pounds torque wrench from work. The axle is in a stand, almost vertical, and is still all torqued up. I got the torque wrench onto the pinion using a socket and some adaptors to get from 1/4" drive to 1/2".

Now, this is a good quality torque wrench (calibrated even) but it's a click type. Not exactly ideal because the pinion is tight to start turning but then has a constant drag. I believe the constant drag is what I was trying to measure. Anyhoo.. I gradually increased the setting until I could maintain motion without it clicking. I used my other hand to start it turning then took up the slack with the wrench and continued the rotation. If I suddenly tried to turn it faster it would click.

I looked at the scale and it was reading about 16 lbs in. Now this is the pinion plus the axle, so allowing for the extra drag of having to turn the diff carrier, to me a total of 16 is ok. Without measuring it, just by feel and judgement I would have said it was a bit tight, but now having measured it, I think it will be ok. This is with used pinion bearings but one new bearing on one side of the diff carrier.

I know the correct way to do it is with the pinion not driving the axle, and the axle should be measured separately. But it is all buttoned up now. So I was happy with a sanity check being better than always wondering.

Mart.
 
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