Rebuilding a Model T Rear End

Topics Last Day Last Week Tree View    Getting Started Formatting Troubleshooting Program Credits    New Messages Keyword Search Contact Moderators Edit Profile Administration
Model T Ford Forum: Forum 2016: Rebuilding a Model T Rear End
Top of pagePrevious messageNext messageBottom of page Link to this message  By Jon Allen on Monday, August 15, 2016 - 04:22 pm:

Think long and hard before you decide to rebuild a Model T rear end. There is a good reason why Glen Chaffin and Stan Howe no longer rebuild rear ends. After doing my own (mainly because they wouldn't) I understand completely.
I did a Ruckstell which is the more complicated case. By-the-way, Glen's book was very helpful.

I am not a cheapskate engineer. Everything that could be new is new right down to the Ruckstell housing itself. (New parts are "part" of the problem). The only old parts are the two axle gears (obtained from Chaffins) and the spider gear assembly which was in good shape.

Here is an incomplete list of what was wrong (and consequent warning to those about to do this):

1) The drive shaft hole to pin the U-joint was too far to the rear by about 3/16".

2) John Regan's pinion gear lock-ring set screw rubbed on the torque tube (even though I smoothed the inside welds). Please don't get on here and blame something else. This problem is so bad that Chaffin's now grinds them down before shipping.

3) TWO ring gears in a row(!) (from Lang's) had bad threads for the ring gear bolts. I ruined a bolt trying to force it. Ruined a tap trying to tap it. Don and Steve Lang were absolutely wonderful about replacing these ring gears. The gears were from 2 different manufacturers and both had bad threads.

4) Setting backlash on the ring and pinion I found that the gears were too tight. A rare occurrence according to Glen Chaffin's book. It took four paper spool washers to correct the clearance. That is too many, so I had a metal shim made at a machine shop 0.030". Cost I won't even tell you. With that and 2 paper washers the backlash is good.

5) The next disaster was the axle bearings. They were too tight. (By-the-way they are the new solid roller bearings, not Hyatts, but Hyatts are also too tight) Even with straight housings and axles, there are 4 things (at least) that effect the fit: the axle housing diameter, the sleeves, the roller bearing, and the axle. If ANY of these are off, it won't fit right.
So mine are too tight. How to fix that?
After some discussion with Don Lang, we came to the conclusion that the best way was to find good Hyatt bearings that were worn down. Probably about 0.495" rollers would do it. (You get double the reduction or 0.010").
Don was willing to spend the time to measure Hyatts and send me the ones with that much wear. Thanks to him for being so helpful!

I think I am seeing light at the end of this long tunnel. I am in the "Final Assembly" stage in Glen Chaffin's book. The real test will be when this baby hits the road.

Pray for me...!

Regards,
Jon


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Semprez-Templeton, CA on Monday, August 15, 2016 - 04:50 pm:

Jon, Ditto everything you said, and I will add undersized NEW repop drive shafts to that list. Without the support of John Regan, I would be crouching in a corner assuming I had lost my mind.

My hobby is rebuilding Diesel fuel injection pumps but model T rear ends are too difficult!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Monday, August 15, 2016 - 05:54 pm:

I'm glad I'm not the only one - I also had to add shims between the carrier and driveshaft housings to bring the gear backlash within specs on my Ebay Ruckstell.

I also did some minor grinding on the head of the allen screw on the Fun Projects pinion bearing kit (after I applied Loctite and tightened it down securely).

My Ruckstell came to me with good, used axles and driveshaft, so I didn't have any issues with them or with the fit of the (original style) Hyatt bearings.

I had a spare, used transmission drive plate handy, so I used it to check the fit of the reproduction U-joint. Good thing I did, because I had to do some grinding on the faces and corners of the U-joint to get it to slide into the drive plate.

While it would be nice if everything fit perfectly on the first try, I considered the adjustments I had to make as something to be expected when assembling a mix of new reproduction and used parts. No big deal. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cliff Colee on Monday, August 15, 2016 - 07:29 pm:

I have to agree with Mark - it's part of the "experience". I am going through much the same process, blending new parts with old, as necessary. I tend to lean toward new parts if there is the slightest need, though.

Only problem I encountered was my own fault: I did not do a THOROUGH inspection of all original parts immediately following disassembly. So there have been several instances when I was at work stoppage because I needed a new part. Thank heaven for parts suppliers who ship orders the same day as received...

Next time, if there is a next time, I will disassemble, clean, inspect, and submit one parts order that covers all. If I have to return unused parts, so be it. Or, keep the extra parts for "the next time" - or sell to other local club members.

Overall, for a "shade tree mechanic" the process has gone well, albeit very slowly....

I am looking forward to taking Popeye out on his 'maiden cruise'....


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cliff Colee on Monday, August 15, 2016 - 07:31 pm:

PS: I am also grateful to have found a machinist who gets as much enjoyment solving problems on a 94-year-old car as much as I do!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Whelihan Danbury, WI on Monday, August 15, 2016 - 08:16 pm:

I must have lucked out. I rebuilt my standard axle into a Ruckstell a couple years ago. Using a Chaffin's kit it was actually pleasurable and reasonably easy. If you take your time and use good components I would say its easier doing one of these than a street-rod's rear end...and getting it right. The key for me was the right tools (good dial gauge for run out, good accurate micrometers) and nice new CNC machined parts where possible. I've had it in the car running for two years now and no problems and not noisy.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stan Howe Helena, Montana on Monday, August 15, 2016 - 11:43 pm:

There are a few things that make the Ruckstell rear end rebuild much more likely to go together easily and with correct clearances.

1. Straight housings. The easy way to make sure they are straight is to cut four wooden disks from 3/4 plywood with a hole saw the diameter of the boss in the housing with the sleeves removed. Not smaller and not bigger. Find a wood lathe if you need to. Press fit. Insert the disks. if you can see light all the way through the center holes that the pilot of the hole saw left you are probably straight or straight enough.

2. Clean the boss the sleeves fit in with a good flap sander and make sure there are no bumps sticking up or ridges that are holding the sleeves away from the surface when you put them in. Then run a cylinder hone in the boss on an hand drill and smooth them up. Those holes were probably the roughest machine work on anything done to a T. Virtually every one I've ever seen needs to be worked on to get the sleeves to seat right.

3. When you put the sleeves in, do it right. TWO radiator hose clamps around it nice and tight. line up the bump that drops in the hole and tap them in. If you are using those oil retainer things, you probably will have to machine or grind 1/6 - 1/8 of an inch off the end of the sleeve to get it all in there and have the bump seat in the center of the hole.

4. When you get the sleeve in, hone it slightly with the cylinder hone. Just enough to make sure it is all in place and seated correctly.

5. Instead of screaming and moaning in anguish if the bearing are too tight, hone the sleeve a couple thousandths. They are designed to wear and a little honing will just smooth them up and make them fit.

6. All the modern drive shafts seem to have problems with the hole being in the wrong place. I have not seen the new ones John is making.

Make sure you are not bottoming against the bushing at the top of the drive shaft tube. There should be a couple thousandths clearance between the back of the U joint and the bushing surface.

There are 4 flat surfaces on the shaft. Put it all together, BOLT the bearing sleeve to the bottom end of the driveshaft so it holds it in place and centered, put the U joint on 1/4 turn from the hole that is in the shaft, mark it with a transfer punch and drill a new hole. It is inside the U joint, you can't twist it off, make it fit and put it together.

7. The problem with the pinion/ring gear being too tight is easily solved.

A. Remove the new bronze plate. Check to make sure you pressed the bearing on tight against the surface. That is what is wrong 90% of the time.

B. If it is tight. Remove the bearing. Chuck the plate in the lathe. Remove .010 to .015 thousandths off the surface that the bearing presses against. Reinstall the bearing and the bronze plate and assemble it in the housing. You will have all sorts of clearance.

C. The bronze plates all vary a little, even the new ones. .010 there will move the ring gear back .010 away from the pinion gear. Before you start cutting on the new bronze plate, chuck it on the bearing boss and see how much wobble there is at the surface that mates to the planetary outer gear. You might be surprised. Clean that up if you need to, then take some off the bearing pressure surface.

I've had to take as much as .020 off the bronze plate to get the backlash right. It's a 15 minute job. It beats the hell out of paper shims, brass shims, profanity, anguish, late night phone calls, irate emails and calls to suppliers, etc.

8. The problem that I saw with a lot of Ruckstell work that came my way for a re-do after somebody worked on it or gave up and brought or sent it to me was that they never took time to see how the thing actually works and how it needs to go together, etc. The number one thing I think you can do to make one go together easily is to understand that every other clearance, fit/no fit is in one way or the other controlled by the distance the bronze plate is being held away from the boss that bearing fits into. Get that right and the rest of it is pretty much a shoo in.

Back to the shop.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Tuesday, August 16, 2016 - 12:07 am:

Thanks Stan! I just printed that and it goes in my book of how to do stuff. Never thought about the honing the sleeves or housings. I have run in problems with the new bearings not sliding down the original axles and have ended up using the best originals I have. I now have a lathe with bed long enough to do a clean up cut between the 2 axle bearing surfaces. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By kep on Tuesday, August 16, 2016 - 03:11 am:

Weird. All the axles i have done were really straight forward.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Tuesday, August 16, 2016 - 08:06 am:

Thanks for the tutorial, Stan. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By john kuehn on Tuesday, August 16, 2016 - 10:22 am:

I rebuilt my axles in my 3 T's and they went together pretty well I thought. I had to grind here and there, realign things and do some fit up work but they work and run fine.
I used new sleeves with good hyatt bearings, used a John Reagan pinion bearing set up and ground down the head of the set screw to stop the minor rubbing. No big deal. I just did it and didn't worry about it.
I have to say this: If a person is a perfectionist by nature to begin with you'll find a Model T an imperfect piece of machinery. It was that way when they came off the assembly line.

I'm glad that folks are making reproduction parts so we can keep them going and enjoy them.
Even if we have to work at to do it every once and a while.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stan Howe Helena, Montana on Tuesday, August 16, 2016 - 02:08 pm:

My recommendation for Ruckstell work if you are unsure of doing it yourself is Ross Lilliker. He understands them very well and does excellent work. You can ship yours to him and back for a couple hundred each way.

The standard differential is much less complicated than a Ruckstell to get clearances correct and is much more forgiving.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jon Allen on Tuesday, August 16, 2016 - 02:55 pm:

Stan,
Ditto the thanks from Mark and Mark. The suggestion about honing the inside of the sleeves sounds like something worth doing.
I think that and good worn Hyatts will loosen things up so they will work Ok.
Regards,
Jon


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Tuesday, August 16, 2016 - 03:00 pm:

I may try pulling my Ebay Ruckstell apart again and having the machining done on its bronze plate, so that I can get the correct gear backlash without having to use shims between the main and driveshaft housings. Maybe a project for this winter? :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jon Allen on Tuesday, August 16, 2016 - 03:09 pm:

Stan,
Oh, sorry. I see on a second read that you were referring to the inside of the boss. Not the inside of the sleeve.
I will be sure to do that.
Jon


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stan Howe Helena, Montana on Tuesday, August 16, 2016 - 07:06 pm:

Both


Top of pagePrevious messageNext messageBottom of page Link to this message  By thomas elliott nw pa on Tuesday, August 16, 2016 - 09:30 pm:

If everything went perfect it would not be a model T, the only adjustment I had to make was one paper gasket, no it's not a Ruckstell but it was my first T rear, bad gears, threads and the driveshaft hole really should not happen. No complaints here----just the 90+ year old petrified grease


Top of pagePrevious messageNext messageBottom of page Link to this message  By Marty Bufalini - Grosse Pointe, MI on Wednesday, August 17, 2016 - 09:25 am:

I rebuilt the rearend on my 14 -- admittedly with some guidance and help -- and had no trouble and, believe be, I ain't no mechanic!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Wednesday, August 17, 2016 - 11:17 am:

Marty,

That must have been some real high quality help! :o)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Wednesday, August 17, 2016 - 11:37 am:

One thing Stan mentioned, that is very important is make sure the axle housings are not bent, and 90% of them are. The Tin Shed in Santa Fe Springs is the only place I know of who does this, but I'm sure there are others. The other thing I do is stay away from reproduction parts. And lastly I go by the Ford Service book, not these articles written by self proclaimed experts. As far as Ruckstell's go, they are very logical the way they go together. All you need to do is study all the parts you have and put them together. I use the correct style fiber thrust washer in my Ruckstells, because that is what is supposed to be used. Ruckstell designed them that way, and that is the way I believe they should be. Another thing that should be checked is the drive shaft. Make sure yours is straight before putting it together. As far as axle bearings, I use genuine Ford or Hyatt bearings. I don't have problems.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jon Allen on Friday, August 19, 2016 - 01:01 pm:

One final note. I was talking to an old high school hot-rodder buddy, John Farr. He has been building $50k -$100k hot rods with 500 - 600 horsepower for about 35 years now. Right now he is building 3 dragsters and about half a dozen hot rods in his shop, Farr's Racing and Rods.
I was bemoaning all of the after market parts for the Model T's that do not fit right.

He told me that in the hot rod world NOTHING fits right and it all has to be modified!

So we are not alone with this problem.

Thanks for your comments and helpful suggestions.

Regards,
Jon


Add a Message


This is a private posting area. Only registered users and moderators may post messages here.
Username:  
Password:

Topics Last Day Last Week Tree View    Getting Started Formatting Troubleshooting Program Credits    New Messages Keyword Search Contact Moderators Edit Profile Administration