differential assembly
 

As I add and subtract gaskets to adjust the preload I find that I am up- to 62 thousands worth of gaskets on the one side of the pumpkin and it still cannot be turned with my fingers on the ring gear. If I back off of the bolts to about 10 foot pounds it spins like a windmill. Should I be looking for a problem somewhere. Thanks in advance. Jack

Re: differential assembly
 

Sounding like your bearing(s) not fully seated? Or check that you have Timken 28156 (Rollers & cage) and Timken 28317 (cup) as some aftermarket bearings don't maintain the original bearing dimensions when assembled.

Also, there was a change in the housings. See page 382 of the Service Bulletins. You may have a "mix-match" situation.

More than likely you want to "split" the gaskets between the two sides. Once you establish the carrier pre-load THEN you move gaskets from one side to the other to change your pinion contact point - without affecting the target pre-load.

I suspect the 10 ft-lbs issue is simply reflecting the "compressibility" of the stacked gaskets, so try to get to the point where when fully torqued you have the "modest drag" according to what instructions you're following.



Joe K

Re: differential assembly
 

Joe K, No mismatch and I have double checked the races and bearings. The only thing I can figure is that the races are not fully seated but they seem to be and won't seat any further in. My main concern is ; will the system work with over 60 thousands worth of gasket?? Thanks for your thoughts on this, Jack

Re: differential assembly
 

I think it will, but there must be a reason for so much gasket. How do the spider gears fit between? Are they sorta loose (technical term) or more like you'd expect?

Also, check local pix of the differential carrier. The later Model B and running up into the V8 era was *similar* but generally different - and these will fit between Model A Trumpets - but not necessarily the same.

Model A Carrier - 9 bolts
http://www.model-a-ford.com/images/proj_2/Proj_2_20.jpg

V8 Flathead - 8 bolts
https://www.picclickimg.com/d/w1600/...and-Pinion.jpg

Re: differential assembly
 

I suspect the bearings are not driven on or are fully seated. This could be because they are not driven on fully, or because there is a burr on a carrier half ( or both). If you tried to use a chisel or other instrument to take them off that could easily happen. Take a feeler gauge like an .002 and see if you can insert it anywhere under the bearing seat. You should not be able to anywhere.... on either side.


Make sure the races are seated fully. Same thing.

You can use a small inspection mirror and light and ensure they look OK. Use an old race upside down if you need to give them a knock in. You can and will hear the ring when seated. Again, any burrs will do it.



Your base gasket will probably be about .010 to .015 or so per side. Variance plus or minus from there. Also ensure your housing gasket surfaces don't have issues. Take a flat file and run around the surface to ensure no high spots.. etc. Do the same to the banjo housing. Ensure all filings, shavings, etc are cleaned from everywhere!
after having done hundreds of flathead ford rear axles I know you will find the issue. Keep a keen eye on the details of the parts and be methodical and patient.

By the way, Joe's reference.... the "B" carriers are like the "A" except the have the B- part number stamped on them and are in fact 9 bolts like the "A". Shouldn't matter though.


Keep us posted please.

All the best!
Larry Shepard

Re: differential assembly
 

Again thanks Larry for the tips. I have to say that the mirror trick with a bright light needs better eyes than what this 85 year old has. I am in the process of taking everything apart again and look at all of the details again. No chisels were used or destroyed in this process. Again thanks for your support, it is what makes this hobby so much fun Jack

Re: differential assembly
 

I found that the bearings were not fully seated on the carrier. The space measured about 30+ thousands behind the bearings. After some persuasion I was able to close that up to less than 10 thousands. Now I have gaskets stacked at 30 thousands and the ring gear is still spinning freely. When I get a little umph, i'll start reducing gaskets until I get the drag that I am looking for. Thanks again for everyone's help. Jack

Re: differential assembly
 

The space behind the bearing needs to be “.000”.
.010 is not good enough. The bearings need to be pressed further onto the carrier. Make certain the cups are fully installed in the axle housings also. Use a mirror and flashlight to check.
Then make your preload and backlash adjustments.
Get help if you can’t make sure they are in the correct position.
You don’t want to have to problems and have to remove it again.

Re: differential assembly
 

Jack,
Glad you found the issue. As said above it needs to be fully seated . If you take and old race or driver that can safely be used drive the bearing all the way down . You should not be able to get even the thinnest of feeler gauge between the carrier and the bearing.

I know you guys don’t have access to them but I’m fortunate to have a Kr Wilson driver that ensures the bearings are fully seated.
Here’s a tip I use when putting in the pinion bearings .
I use an incandescent light bulb mounted in zsingle porcelain bulb fixture mounted in wood and warm the bearing in top of he light bulb . They pretty much slip on the pinion stub and it makes it easier for the 2nd bearing when ready.

Appreciate your responses back and hope it all gets resolved for you.
Larry shepard

Re: differential assembly
 

Thanks Larry, I wish I had thought of the light bulb method of heating the bearing, I had considered putting it in the wifes' oven but didn't. Now the problem is to remove the bearing where I have pushed in in nearly all the way. Jack

Re: differential assembly
 

No need to remove bearings. Just press them further onto the carrier.
You may ruin the bearing trying to remove it.

Re: differential assembly
 

Review Tom Endy’s procedure of axle rebuilding. It is on the Santa Anita As website. It will show you all the steps and tools needed to complete the task.

Re: differential assembly
 

I do the same as Larry. You should be able to use an old bearing and heavy hammer to drive the new bearing all the way down. Be sure to use a face shield, as bearings are hard and can chip when hit with a hammer. I know 2 guys that each lost an eye while hammering on a bearing.

Re: differential assembly
 

I just went through this. Used the old bearing over the new ones, piece of wood on top and a few blows of a heavy hammer. It will seat, just take your time.