Jamesmulvihill
Junior Member
I am about to install a Mitchell overdrive in my 1931 model a. My question is when I drop the rear end would it be better to disconnect the springs from the axle or disconnect the springs from the frame?
Mitchell Overdrive
- Thread starter Jamesmulvihill
- Start date
BRENT in 10-uh-C
Well-known member
Easier IMO to use a spreader and remove the spring hangers (shackles) and leave the spring up in the crossmember.
Welcome to Fordbarn!
Welcome to Fordbarn!
Jamesmulvihill
Junior Member
Thank you Brent I really appreciate your response. I have a spreader, just wanted to make sure this was the best way to do it, since I have never done this before. Thanks again.
inex01
Senior Member
Yes I agree I have installed two Mitchells this past year and using the spring spreader and leaving the spring in the pocket is definitely the way to go, but if your spring needs service then not much choice and well worth dropping but what a pain in the butt it is to stick it back up into the pocket!
Marshall V. Daut
Well-known member
As "inex01" recommends, if the spring needs servicing, now is a good time to take care of that. Unless your car has been restored in the last few years and you know for a fact that the spring leave ends have been ground at a bevel on the bottom and that lubrication still exists between the leaves, there will be no better opportunity to perform these tasks than when you install the Mitchell overdrive. You can also spread a layer of chassis grease on the top leaf and along the sides of the ones below it
before re-installing. This will reduce squeaking and metal-to-metal rubbing.
Contrary to what you often read here, I have always dropped the rear end WITH the spring still attached - for the past 50 years. I know there will be howls of derision about how dangerous this is. But I always attach a large C-clamp over the spring in the center as soon as it clears the cross member. The clamp stays in place as a spring spreader does its job prior to removing the spring from the rear axle. Once the spring is relaxed by backing off the spreader and laid on its side, the center bolt removed and then the C-clamp comes off. Leave the spring clamps in place while doing this to reduce the tension between the springs. Remove the two clamps after the center bolt has been removed. The spring can then safely be disassembled and serviced. Use a new high quality center bolt, not something purchased at the hardware store! And ensure that the head is squared up so that it will fit into the square hole in the top of the rear cross member. Put the C-clamp back in place until the rear end assembly is about to be re-installed into the chassis. The clamp is then removed and the assembly is jacked up into place. Piece of cake!
Why do it this way? I have helped friends try to install a loose rear spring back into the rear cross member because they read that was the "way" to do it. I decided long ago after helping them that this was more painful, frustrating and potentially more dangerous than the way I have described. That spring is heavy and awkward. You need two people to install the spring this way, while installing the spring attached to the rear end requires only one person. I have done it dozens and dozens of times with no injury. The key is use that large C-clamp during removal and installation. Because you are dealing with an old center bolt during removal, that is the time when it is potentially more dangerous than when re-installing with a new hardened center spring bolt installed. But for safety's sake, use the C-clamp anyway.
Once you have done the procedure as I describe, you'll never want to fight a loose spring re-installation again.
Marshall
before re-installing. This will reduce squeaking and metal-to-metal rubbing.
Contrary to what you often read here, I have always dropped the rear end WITH the spring still attached - for the past 50 years. I know there will be howls of derision about how dangerous this is. But I always attach a large C-clamp over the spring in the center as soon as it clears the cross member. The clamp stays in place as a spring spreader does its job prior to removing the spring from the rear axle. Once the spring is relaxed by backing off the spreader and laid on its side, the center bolt removed and then the C-clamp comes off. Leave the spring clamps in place while doing this to reduce the tension between the springs. Remove the two clamps after the center bolt has been removed. The spring can then safely be disassembled and serviced. Use a new high quality center bolt, not something purchased at the hardware store! And ensure that the head is squared up so that it will fit into the square hole in the top of the rear cross member. Put the C-clamp back in place until the rear end assembly is about to be re-installed into the chassis. The clamp is then removed and the assembly is jacked up into place. Piece of cake!
Why do it this way? I have helped friends try to install a loose rear spring back into the rear cross member because they read that was the "way" to do it. I decided long ago after helping them that this was more painful, frustrating and potentially more dangerous than the way I have described. That spring is heavy and awkward. You need two people to install the spring this way, while installing the spring attached to the rear end requires only one person. I have done it dozens and dozens of times with no injury. The key is use that large C-clamp during removal and installation. Because you are dealing with an old center bolt during removal, that is the time when it is potentially more dangerous than when re-installing with a new hardened center spring bolt installed. But for safety's sake, use the C-clamp anyway.
Once you have done the procedure as I describe, you'll never want to fight a loose spring re-installation again.
Marshall
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Marshall V. Daut
Well-known member
OOPS!! I fear my previous post exceeded the allowable number of words on this website. How's this abbreviated description instead: "Drop rear end with spring attached. Service spring. Re-install with spring attached."
There! Now, wasn't that instructive? You could probably do this job in your sleep with this shortened description at your disposal.
"Words"??? We don't need no stinking words!!!
Marshall
There! Now, wasn't that instructive? You could probably do this job in your sleep with this shortened description at your disposal.
"Words"??? We don't need no stinking words!!!
Marshall
Big hammer
Well-known member
Don't worry about the word cops R&R of rear end with spring or with out, and the reason for each way! That's what the OP asked for!
R&R of rear end with spring or with out, and the reason for each way! That's what the OP asked for!Marshall V. Daut
Well-known member
Two weeks ago, I removed the rear axle assembly from a 1911 Model T using the method described in my previous post. By the way, this is the incorrect rear end for the year Model T. See the attached photo of the procedure. Note that the rear spring is still attached and that a large C-clamp is in place - just in case.
Marshall
Marshall
Attachments
Marshall V. Daut
Well-known member
Thanks, "TerryH". Hopefully the description and photo will help someone safely perform this task. 'Not brain surgery. But a few (or many!) well-chosen words and a photo or two go a long way in helping a person envision what must be done.
Marshall
Marshall
oldredford
Senior Member
Very nice over-drive but the price is going thru the roof.
Tom Endy
Well-known member
The 3\8" center bolt on a Model A rear spring was never designed to contain the energy packed into the spring when it is spread. I believe it was only meant to hold the spring pack together until it was safely installed into the contour of the frame and clamped into place.
When the rear axle assembly is removed from the car with the spring still attached it no longer has the safety protection of the frame contour and all the energy of the spring is now being contained by a 3\8" bolt that may be 85 years old and rusted and with the head of the bolt ready to pop off.
Should that happen the upper leaves will fly 20 feet in the air and take your head with it if it happens when you are leaning over it attempting to wrap chains around it or apply C-clamps, or when removing them.
The safe way to go about it is to use a proper spring spreader and remove the rear axle assembly from the car with the spring and the spreader left safely attached to the car.
A lot of people will tell you they have removed the rear axle assembly many times from a Model A Ford with the spring attached to it over the years and have never had a problem. I don't doubt they have.
Tom Endy
When the rear axle assembly is removed from the car with the spring still attached it no longer has the safety protection of the frame contour and all the energy of the spring is now being contained by a 3\8" bolt that may be 85 years old and rusted and with the head of the bolt ready to pop off.
Should that happen the upper leaves will fly 20 feet in the air and take your head with it if it happens when you are leaning over it attempting to wrap chains around it or apply C-clamps, or when removing them.
The safe way to go about it is to use a proper spring spreader and remove the rear axle assembly from the car with the spring and the spreader left safely attached to the car.
A lot of people will tell you they have removed the rear axle assembly many times from a Model A Ford with the spring attached to it over the years and have never had a problem. I don't doubt they have.
Tom Endy
Big hammer
Well-known member
If you do it like Mark says, removing the wheels, lowering backing plates on dollies, you won't have to raise the car up in the sky to get the rear end out. Hope that makes sense, it getting late for me
Jamesmulvihill
Junior Member
Thank you all for your advice. Very helpful! I decided to use the spreader and took it apart today. I attached a picture. Now I have to figure out how to pull the drive shaft out of the banjo. Again I want to thank you all for your comments. This was my first time using the Ford Barn and I am really impressed with all of the responses.
Attachments
Mike V. Florida
Well-known member
Tom Endy
Well-known member
You are going to need a special puller tool. The Mitchell company can supply you with one. They sell them and they loan\rent them to customers that purchase an overdrive from them. Do not take the two large nuts loose at the back end of the pinion assembly as it will destroy the pre-load setting on the two pinion bearings.
Once you have the torque tube off clamp the puller tube to the drive shaft. It will press against the banjo flange to press the drive shaft and pinion assembly out of the banjo.
Next you will have to remove the drive shaft from the pinion assembly. Do not remove the 15\16" nut from the end of the drive shaft and try to drive the shaft out with a hammer. Doing this may cause the end of the shaft to mushroom inside the pinion sleeve and it will be very difficult to get it off.
You will need a couple tools to remove the drive shaft from the pinion assembly. Go to the web site of the Santa Anita A's of Arcadia, California at www.santaanitaas.org. On the home page put your cursor on "Technical Reference", my name will drop down below, click on it. It will bring up a menu of technical articles. Scroll down to either differential overhaul or Mitchell installation. Either article will show and describe how to go about it.
Good luck with your project,
Tom Endy
Hoogah
Well-known member
James, you might get some value out of the thread I started after undertaking the same installation on my '28 Phaeton a couple of years ago. Search for "The Mitchell is IN!" As a thread title.
I also found Tom Endy's advice to be invaluable (even though he added one of my photos to his Rear Spring Hall of Shame collection!).
I also found Tom Endy's advice to be invaluable (even though he added one of my photos to his Rear Spring Hall of Shame collection!).
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Jamesmulvihill
Junior Member
Thank you Mike and Tom. Guess I had better get a puller tool. Thanks for the installation instructions, that will really help.
Jamesmulvihill
Junior Member
Thanks Hoogah. I'll look up that thread title. Like the name "Hoogah"