1941 CAD WORN SPIDER GEAR REAR END HELP NEEDED URGENTLY

[nzcad]

HI Tony,

Just to make sure we are talking about the same thing can you email me a picture of what you have. I believe the complete diff head weighs about 70-80 lbs. In Jays earlier post he said diff was about 75lbs and was the size of a cube 24" square.

Is that about right for what you have there??

Thanks Steve

[nzcad]

HI ALL....UNFORTUNATELY TONY HAS SOLD HIS DIFF PARTS TO SOMEONE ELSE SO I AM STILL LOOKING FOR A DIFF HEAD SO I CAN GET MY NEWLY RESTORED CADDY ON TO THE ROAD FOR THE FIRST TIME. THERE MUST BE SEVERAL OF THESE AROUND THE PLACE IN THE USA SO PLEASE HELP OUT....THERE ARE HARDLY ANY DOWN IN NZ. IF YOU DON'T HAVE ONE MAYBE YOUR BUDDY DOES.  I CAN EITHER ARRANGE TO HAVE IT COLLECTED FROM YOUR PLACE OR GIVE YOU A USA SHIPPING ADDRESS TO SHIP TO SO IT WOULD BE A HASSLE FREE DEAL.
THANKS STEVE

[Bob Hoffmann CLC#96]

Steve,
I'm not sure that your gears are the problem. The axles are held in by the plate bolted to the flange on the housing. The spider gears don't hold the axles in. . Maybe you could explain the problem a little more clearly.
Advise.
Bob

[Steve Passmore]

I already asked that question earlier Bob, it appears the wear is sideways in the planetary gears, how that materializes its self at the wheels for the sake of road safety I'm not sure.

[nzcad]

Thanks for replies. My car car has new rear outer wheel bearings. If you grab the road wheel at 9 o'clock and 3 o'clock there is movement in and out. (not end float). There is 2-3 mm play or looseness where the planetary gears are attached to the diff head. My repairer says you can put a finger or two inside the planetary gear sleeve and can feel or create movement there. He feels that there is always a little movement in the centre of wheel bearing and over the length of the axle shaft this can easily magnify to 2-3 mm.
Here in NZ we have a very detailed inspection by a government agency before being able to register a car for road use after it has been through the restoration process. My car has passed all the tests except for the movement in the road wheel I have described above so I really need a solution or most likely a replacement diff head (pumpkin) if I am ever going to get it back on the road. There must be hundreds of "pumpkins" up there if they used the  same rear ends right thru to the mid fifties??

[Bob Hoffmann CLC#96]

Steve T.,
Please understand that I'm on your side. Unless I'm really wrong, the spider gears have nothing to do with the play you have.
There's only ONE thing that holds the axles in, that's the plates & bearings. I'm not sure where your inspectors have come up with the idea regarding that amount of play. I think they're nit-picking. You need to either find a like car to compare in NZ or get someone else to measure their car. I have a bad back so I can't do it at this time. If you want to prove this play thing to yourself, pull the "pumpkin" out & bolt an axle in. I'll bet you will have the same amount of play as if the "pumpkin" was in.
HTH, Bob

[harry s]

The outer wheel bearing is a press fit to the axle shaft and there would be no movement there. The bearing and seal should fill the space in the housing to eliminate most all movement, but it is possible to have a small amount. The splined end of the axle just slips into the differental with no attaching or bolting so there is nothing to prevent the movement you mention. Once the axle is in place the backing plate holds it together.  I agree with Bob, the inspecting person is comparing 1941 technology to modern specifications. Harry

[gary griffin]

Harry nailed it. The axle to differential connection is a floating spline similar to the spline on a drive shaft which allows the rear end to move and it allows longatudinal movement. Possibly some sort of shim at the backing plate would work? There must be some way to eliminate some of the movement but concentrate on the outboard attachments, even if you have to put in something temporary to pass the test and remove it later. I would even consider some sort of wooden shim??

[Jim Stamper]

     When the new axle bearings were installed was their width checked?  It sounds to me like the bearings are a bit narrower than the originals, allowing the axle in and out movement. The bearings do not fit tightly in their bearing pocket in the end of the axle tubes, so they can slide in and out if they are narrower than the originals. Also, were the bearings actually pressed onto the axles as indicated in an earlier post? This is necessary.

     It may even be in the interest of expediency in the past the wrong bearings were fitted to the axles and cardboard or cork shim was put in the pocket to take up that slack, and discarded during disassembly.

     Or, if no shim was used behind the bearings and the axles have been sliding in and out for years a wear pattern should be well established on the axle splines and installing the axles like that would be a no no.

     I am having a hard time believing the restorer had the differential out of the car and so was able to put his fingers into the spider set side gears where the axle splines mate into. If he did that and found all of this looseness, why did he even reassemble it that way? He obviously knows your countries safety requirements. It makes no sense to reassemble it.

     Maybe I have read this whole thread wrong, but as I understand it, my take on this is that the wrong bearings have been used.

                                          Jim Stamper CLC#13470

[nzcad]

Thanks for ideas. I purchased car partly restored.Was advised diff had been restored and checked and found new bearings and seals had been fitted and because there was no end float I didn't go any further. When car was put in for certification the play was discovered. We have since disassembled the rear axle to find cause of the problem and discovered it was not easily repaired. It is definitely not end float and there is minimal wear on the inner axle splines.
The wear or looseness is where the spider gears are attached to the rest of the diff head. If you put a couple of fingers inside the spider gear spline on one side you can feel a tiny amount of movement but on the other side there is approx 3mm of movement. It appears to be on whatever joins the spider gears to the rest of the diff unit.
It seems to me we either need to find the original factory tools used to dismantle repair and reassemble the unit or just find another pumpkin that doesn't have the play in it. It would be a big help if forum members could ask around their contacts...there must be a 3.36 pumpkin out there somewhere. In meantime I have a brand new restoration sitting in garage until I can find one so would really appreciate your help. Can be shipped to a USA address as we will be bringing a Packard car back to NZ in a container in a few weeks time. Thanks Steve

[Jim Stamper]

     Find another pumpkin. I believe, even after you get the spreader tool and have the ring gear/ spider gear assembly out you will then have to grind off the rivets holding on the ring gear on to service the spider gears. And where would the parts be to do any service to it? They were never mean to be serviced so there just aren't any parts, I believe. If you could fix it you would then have to
find some very precise bolts to bolt the ring gear back on.  This is something that has interested me for some time, but I have been convinced such endeavor is folly. There are plenty of 41s around, you will find one.  Check Ebay.

     Have you called John Gately in Boston? He is always listed in the Self Starter as a parts supplier. Cadillacs "rusting in peace". I spoke with him this fall and he had a 41 then. I have bought parts from him in the past.  617 445 3300  11AM-9PM I think, EST. It was still in the car when I spoke with him and he wanted me to help him remove it if I bought it so something would need to be worked out. Greyhound bus would probably serve to get it out to the Packard, or UPS.

     My reason for considering going into one of these was to try and adapt 37 spider gears to the 41 rear end so I could use a 41 pumpkin in my 37 coupe. The 41 is a much better rear end and fits the banjo, but the axle splines are different.

                                                  Jim Stamper CLC#13470

                                                   

[TonyZappone #2624]

John Gately is probably the most reasonable parts vendor for vintage Cadillac parts.  He is a compassionate hobbyist and very helpful.

[nzcad]

MANY THANKS TO JIM STAMPER WHO SPENT MANY HOURS LOOKING FOR A REAR END FOR ME WITH THE CORRECT 3.36 RATIO PUMPKIN AND THEN WENT AND COLLECTED IT, CRATED IT AND SHIPPED IT TO ME. THE SPIRIT OF FELLOWSHIP IN THE OLD CAR WORLD IS STILL ALIVE AND WELL.