My rear end has a very slow leak / seep, so I decided to take a look at the fluid level. I removed the plug and stuck my pinky in the hole. I could reach fluid with my pinky, but it was below the fill plug. I hear that is a reasonable amount of fluid as the fill plug was lower on the later axles.
Anyway, as I was sticking my pinky in and out of the fill plug, I could feel something move a little, so I got the flashlight out. There was a loose nut that I think holds the cage together. I spun the rear wheel and at least two of the nuts that are accessible right at the fill plug were finger loose. I tightened them up as best I could pushing on the castled ends with a screw driver.
It seems that two of the bolts are too long for the nut. When the nut is tight, the hole in the bolt for the safety wire is well above the nut. The wire is there, but it is just keeping the nut from falling all the way off as the nut will turn several rotations before the wire touches the castle portion. At least one nut fits the safety wire properly.
I assume I will have to take the rear end out, split it and repair this issue, and anything else that might need attention. Everyone says to "get the book" for the rear end rebuild. I looked on the langs website and found a book for the Ruckstell, but not the standard rear end. Does anyone have the title?
Are there "pros" out there that are recommended if I wanted to outsource the job?
Right now, everything is quiet and I don't want to take the car down for the summer, so I am leaning towards relying on the nut that is tight until the winter. Is that crazy talk?
Joe...if my awful memory serves me right, those nuts need to be safety wired together. I'd not recommend driving the car another foot until you pull the rear end and open it up. That said, the book you're referencing is "The Model T Ford Front and Rear Axles" by Glen Chaffin. It's available through the MTFCA website.
That is what I fear. The bolts have safety wire running through all of them, but two of the bolts are too long or the nuts are too short such that the safety wire isn't doing anything and they loosened up.
This site has some info, along with a link to the book.
study the safety wiring closely, a properly wired assembly cannot loosen up. If it does, it is wired incorrectly. Bolt length or nut thickness does not matter, the wiring twist,tightness of the twist, direction of twist, and location of the wire anchor point affects the safety wire effectiveness.
FWIW-- Here is what I would do. Pull the left hand wheel and drum. Pull the two bolts that hold the radius rod on. Pull the large nut that holds the spring hanger in. Pull the 7 bolts that hold the housings together. Pull the 3 spool bolts on the left side and loosen the other 3 a turn or two. Now you can slide the left side housing off. If you want, you can pull the right side axle nut and pull the unit. Or just do it under the car. Wipe it off and look it over, tighten those three center carrier bolts and wire -- not cotter pin -- them. If the drive side thrust washer is brass the off side probably is too. If they are brass, put it all back together and drive it for the rest of the summer. Couple hour job.
They are safety wired.
If the holes the bolts are in are THREADED it might just be OK until the winter. The safety wire is preventing the bolt from rotating and the bolt is generating a clamp load because it is in a threaded hole.
I assumed the holes were through holes and the nuts were providing the clamp load, but I couldn't understand how the rear end was so quiet. If the nuts are just jam nuts that would explain how 2 could be so loose and the assembly is still tight.
Even if the bolts are in threaded holes, I will pull the axle this winter. If the holes aren't threaded I will have to pull it next week...
Pull the rear axle apart and rebuild it. If you have this problem you have many others.
The club manual says to put cotter pins in the 3 carrier housing nuts. Using safety wire on nuts does not have the same effectiveness as when used on the head of bolts.
...I'm sure others will disagree.
There are two different types of differential carriers. The earlier ones have studs and nuts that hold the two halves together. Later ones have nuts and bolts. The earlier differentials must have the nuts wired so that the studs cannot come out. Later ones can have either wire or cotter pins.
This safety wire is on the shaft of the bolt, which is solidly attached to the head of the bolt. I would think it would be equally effective on the shaft or the head of the bolt, but am always willing to learn.
A cotter on the bolt through the castle of the nut prevents the nut from turning relative to the bolt.
Safety wire on the bolt prevents the bolt from turning even if the nut loosens. Assuming the bolt is in a threaded hole, which I am hopeful someone will confirm, if the bolt doesn't turn the joint remains tight even if the nut loosens relative to the bolt.
I ordered the rear-end manual here:
Joe, just to clarify Steven's response. If the diff centre has studs threaded into one half, then the nuts need to be wired to prevent the studs turning, just like the studs on the ball cap on the front radius rod.
If the centre is held together with bolts, these are not threaded into the carrier. The nuts do the clamping. In this case, a cotter pin will hold the nut in place, thus preventing the bolt from coming out.
Hope this helps.
Allan from down under.
I would order the CD from this club and watch it three times taking notes about clearances and torques before attempting to dive into a rear end for the first time. I would also ensure that you have a good 0-1" range micrometer, a good digital caliper and a dial indicator with magnetic base. These can be bought at Harbor Freight very reasonably and are absolutely essential to evaluate the condition of the parts and make the necessary adjustments. I think a lathe is a handy tool as well for trimming the bronze thrust washers but you can use sand paper mounted on a good flat surface.
I have a 1929 Fleet airplane that I wrecked in 1975 because the aircraft mechanic used cotter pins instead of safety wire between to studs. Early Kinner engines had the rocker stands held on by two studs. using cotter pins on the studs turned them with their nuts into bolts and they backed out.
Also; the safety wire diameter is determined by using a percentage of the hole diameter in the stud.
I have forgotten the formula. Royce should know the specifics. He is an aircraft inspector.
Thanks for the tip. If I understand correctly, in either case (bolt or stud) the nut is doing the clamping and if the nut is loose, there is no clamp load in the fastener. Can you confirm?
If the above is the case, it is time to park the car and pull the axle. I have the service manual, but any tips on pulling the axle would be appreciated.
There is no way to get them tight through that little hole. Fix it right.
Everything that is safety wired on a Model T uses.041" wire. It is the largest size commonly available.
I found out that finding bronze washers is no a guarantee of a sound rear axle assembly. A bad pinion bearing can kill you.
I am pretty sure there is no clamp load on the fasteners where the nuts came loose. That means I have been riding on one nut, which isn't ok. I still can not believe how silent the rear end was all things considered.
I contacted Kevin Prus and he said he could re-rebuild the axle with a pretty quick turn around, so I am going to pull it on Tuesday and drive it down to him on Wednesday. Kevin said to bring the entire assembly up to the U-joint to him.
It will be a shame to chip up all the beautiful paint to rebuild an axle that has almost no miles on it, but it appears necessary as something was not done properly and it isn't safe.
Any tips on rear axle removal will be appreciated.
Rear axle removal, courtesy of Steve Jelf:
From time 4:37 to time 4:56 Steve removes the two large nuts that are behind the brake shoes. I think these hold the shackle perches on. The next step shows him removing the shackle bolts.
I guess I will learn tomorrow when I take it out, but what was the reason for removing the large nuts if I am going to separate the shackle anyway?
Takes the tension off the rear spring and allows you to remove the shackles. When you go to put the rear end back put the nuts back on the perches, just started. Place a piece of 2X4 on the axle on each side under the spring ends. Jack up till you can install the shackles then use the nuts on the perches to pull them into place. This will also allow the perches to end up at the correct angle in relationship to the spring.
You shouldn't have to remove the perch nuts completely. Just loosen them enough to relieve the spring tension.
The rear axle is out!!! Following Steve's video made it an absolute piece of cake. Thanks Steve!!! I ended up having to take my muffler off to get the support bar in, and I did not need to loosen the spring perch nuts, I just adjusted the jack to have no load on the spring.
All I have to do now is load it in the truck and take it to Kevin Prus tomorrow. Hopefully the T is back on the road soon.
Thanks to all those that suggested not driving it as is, I think that was a disaster averted.
Thanks to all!
I dropped the axle off with Kevin Prus yesterday. I am looking forward to getting the T back on the road.
What a beautiful Ford!
Good on you with the axle removal. Nice way to lift the car. :-)
Like my Father In Law used to say to me; "Duey, I'm gonna ask you a question.": Joe,do you happen to have that steering wheel on upside-down? Prob'ly just a photographic illusion...
Thanks for the comment. It is a very pretty car, but the previous owner did not really drive it and I am finding I have a lot more bugs to work out than I anticipated. So far I have done
Coil rebuild by Ron Patterson
Carb rebuild by Stan Howe
Wheel rebuild from Stutzman
New NONSKID tires
Timer from TW
Take up a rod and center main to get rid of engine noise
Shim pitman arm and toe link
The steering wheel is upside down in the picture. While I wait for the rear axle I decided to take as much slop out of the steering as possible. I added shims to the pitman arm and tie rod ball cup to take up slop and I still had about an inch at the steering wheel that was all in the planetary steering gear. I was playing with different combinations if original and repo steering gear parts and checking the play. I had the wheel on and off several times as I checked and I guess I snapped the photo while it was upside down. It looks like I will use all repo steering gear stuff, but I have to turn the flange on the center gear down because the repo is larger and hitting the pins.
Joe : If you are getting into the steering system, you might want to consider changing over to the 5:1 ratio instead of the existing 4:1. No one will ever know the difference unless they drive the car, but the ratio change will make it much more pleasant to drive, especially with the small diameter steering wheel. My '25 coupe had a 4:1 gear set when I got it and I changed to the 5:1 and also found a short pitman arm. Together they provide much better,safer,and less direct steering feel, although I had to build and install a mechanical stop to prevent a possible over-centre condition with the shorter pitman. Bruce
I considered the 5:1 conversion, but after searchING and reading many old threads frim this forum, it sounds like it often doesn't work. The pin spacing for the pins that carry the three planet gears is different between the 4 and 5 to one ratios.
Joe : You have to change the main steering shaft as well as the gearset. A decent used 26-27 shaft is a direct replacement and you simply install the new gears . You still retain the steering gear box. It's an easy swap and well worth the effort, especially since your existing gears need replacement. Bruce
Kevin said the rear axle is done. Apparently he found several things he did not like and changed the carrier, both axle shafts, the ring gear, as well as seals etc. At least it had brass thrust washers in it...
I hope to pick it up Friday.