MTFCA Forum

Have a speedster build and tearing apart a rear axle I’ve got. Looking for input on whether new ring and pinion is warranted. Also I see some wear on axle, Babbitt thrust washer was broken when I tore apart so assuming it caused the wear?

That ring & pinion need replaced. All other parts need to be carefully checked. The gears have been shedding metal particles, and all metal debris needs to be cleaned out of the housings.

The wear on the axle doesnt bother me if the bearing surface is close to standard. 1.062". measure the gear & differential housing for wear. You should see 1.807" & 1.812" respectively if not worn.
I would also change the gears. Do it right one time.

speedytinc wrote: ↑

Sun Sep 18, 2022 10:39 pm

The wear on the axle doesnt bother me if the bearing surface is close to standard. 1.062". measure the gear & differential housing for wear. You should see 1.807" & 1.812" respectively if not worn.
I would also change the gears. Do it right one time.

Where am I measuring on the gear and differential housing to check those specs?

The wear in that crown wheel indicates that there was too much backlash, possibly contributed to by the failing thrust washer. The gears need TO BE replaced.

Allan from down under.

pedechad wrote: ↑

Sun Sep 18, 2022 11:25 pm

speedytinc wrote: ↑

Sun Sep 18, 2022 10:39 pm

The wear on the axle doesnt bother me if the bearing surface is close to standard. 1.062". measure the gear & differential housing for wear. You should see 1.807" & 1.812" respectively if not worn.
I would also change the gears. Do it right one time.

Where am I measuring on the gear and differential housing to check those specs?

Under The gears where they ride/rotate in the differential housing & the hole in the differential housing half where the gear rides, both sides.

Allan wrote: ↑

Mon Sep 19, 2022 6:54 am

The wear in that crown wheel indicates that there was too much backlash, possibly contributed to by the failing thrust washer. The gears need TO BE replaced.

Allan from down under.

Not sure how you're able to determine excessive backlash from that wear pattern. What I see, is evidence of a poorly aligned ring & pinion gear, regardless of what the backlash condition might have been. Honestly, if it were re-used, with a proper mesh adjustment, that gear would probably be fine. I say that however without seeing a picture of the pinion gear. That's only if you need to save some $$$ however. Since you've got everything apart right now, it would the right time to use new gears.

For a car you intend to drive, choose better gears. If it’s a parade car or goin in a museum and just needs to move under its own power, they’ll be fine

Here's pics of the pinion gear

The pinion gear looks too good. I wonder if someone replaced the pinion just to get the car mobile again. I'd replace the ring and pinion, and any other worn parts.

The case hardening is worn through. Also very rough surface, so the wear in the future will be excessive. Time to replace. While you are at it, go through the entire rear axle and rebuild it. If you don't have one, the booklet distributed by the club, and sold at many vendors, "Front and Rear Axles" or "Ruckstell Axle" are excellent step by step descriptions of how to do the work and adjustments.
Norm

I hate to pass judgement on a pinion gear that I dont have in hand for a close inspection. That being said, the gear looks good. If its ford script, you
could use it with a very good used ford script ring gear. I believe ford's gear manufacturing consistency was exceptional, so mixing used gears with minimal wear doesnt bother me.
But do not replace the ring gear only with a non ford gear of the period or new today. Chances are high that the gear teeth will be slightly to significantly different.

Jerry, if you can get hold of a copy of Ted Aschman's "Tinkerin Tips, volume two", there is a section on setting up the crownwheel and pinion mesh correctly. Part of the article shows a set of drawings indicating various wear patterns and how to make adjustments to achieve the correct rolling fit for straight cut gears. Excessive wear on the heel of the gear teeth, as shown in the photos, is due to too much backlash.

Hope this helps.
Allan from down under.

Thanks all for your insight. I’ve got a couple other rear axles I can tear into to see if I’ve got another gear set in better shape than this one.

Appreciate the help!

I'd install a new set of gears and any other needed parts in the axle you already have apart and make sure they are set up correctly. Be sure the housing isn't bent or otherwise damaged. The bearings that support the gears have to be in good condition for an adjustment to hold. Mixing used gears with other used gears or new and used gears is asking for problems.

Another approach that might save time and money would be to try using one of the other complete axles you have. Either one or both of them might be in good shape just as they are, with no need of being torn down. New seals and new lubricant might be all that's needed. If not, you wouldn't be out a lot, since you already have them, and all options would still be open.

Ok I tore apart the other two axles I had. One had bronze washers while other was still Babbitt. These might be in a little better shape. One of the diff housing is different, has studs rather than bolts.

Here’s the other one

Another shot

Replace worn parts.

Nothing you've shown is worthy of re-using...listen to Pat.

I wouldnt use either of your ring gears.
Do the job right once.

Thanks all. Where’s best place to buy a new ring and pinion set? I see Lang’s and Snyders has them. Is it worth trying to find a good used set now that I have an idea of what bad looks like?

If you had the time to find a real nice gear, yes. I dont think you do. Good original ring gears have gotten quite scarce. You could try a wanted ad here. Mark Chaffin has a good selection of good original parts.
Not sure what brand or makers gears the vendors sell today. "Mark" auto parts used to make the best gear sets. USA made. The gears are stamped with the mark name.
Ask the vendor.

I'd stay away from used parts in this case. It would be very difficult to get a used ring & pinion set up and adjusted exactly as they were set up when last run, and any other adjustment is likely to result in excess noise and rapid wear. Mixing used gears often results in problems, and replacing just one gear out of a used set with a new one is likley to cause problems. If you want good results that will last, obtain a new ring & pinion and make sure they are set up correctly with new thrust bearings, and any other worn parts in the assembly replaced.