Worm Drive Woes (picture heavy)

AA Ford Discussion Group relating to the repair and restoration of your AA Ford.
User avatar
spectria
Posts: 1874
Joined: May 15th, 2008, 9:53 pm
Body Type: Mail Truck, Stakebed
Model Year: 1931
Location: Quincy, Ca.

Re: Worm Drive Woes (picture heavy)

Post by spectria » September 9th, 2013, 12:46 am

The cracking suggests (along with the spun carrier bearing) that there was insufficient preload on the carrier bearings, which would have effectively pressed those two halves together and added support to the casting. Add in a little extra overloading back in the day (whaat, overloading an AA???) and you get the damage...
Dave in Quincy, Ca. I love Pics!!!! Post them All!!! :)
Join the Ford Model AA Truck Club - membership form at http://www.fmaatc.org

Stakebed
Posts: 1187
Joined: June 14th, 2007, 7:29 pm
Body Type: Grainbox
Model Year: 1929
Location: Illinois

Re: Worm Drive Woes (picture heavy)

Post by Stakebed » September 9th, 2013, 4:07 am

Ahh yea, i do know this truck was used hard over its 20 known years of service....and when i found it it had tirechains on the wheels still haha

is there no way to know the condition of the inside without actually splitting the cases? Meaning i dont want to buy another whole rearend and be in the same boat...

and ha ha communist Connecticut :lol:

User avatar
TruckMan
Posts: 132
Joined: March 10th, 2009, 10:36 am
Body Type: Garwood Dump
Model Year: 1928
Location: Wisconsin

Re: Worm Drive Woes (picture heavy)

Post by TruckMan » September 10th, 2013, 11:16 am

As for me, I think the worm drive is more classic and I prefer it. I do have the one stamped with "B" that is 5.17 reduction. I can do about 40 MPH on a level road.

Hang in there. You will find what you need.
TruckMan

Stakebed
Posts: 1187
Joined: June 14th, 2007, 7:29 pm
Body Type: Grainbox
Model Year: 1929
Location: Illinois

Re: Worm Drive Woes (picture heavy)

Post by Stakebed » September 10th, 2013, 7:07 pm

yea i too love the looks and function of the worm drive. I probably will rip the carrier apart and see what the spider gears and such look like if the carrier is cracked this bad. I see one axle has alot more wear than the other teeth wise... I know i have some brake parts that are worn so i may be better off on aquiring a new rearend for all sorts of parts. (i know at least one possibly 2 other lug studs that spin or want to spin in the drums too) Anyone have the external stamping letters and ratio code? This is in case the brakes are stuck on my potential new rearend and cant do the 2.5 turns of drive shaft to one turn of one axle for high speed test.

Also if i can only find a low speed rear what makes it the low speed? Is it the ring gear or the worm? or both? Like someone said earlier my ring gear looks to be worn but useable. Are the carriers the same? Housings identical? I know someone said they had 2 stamped low speeds that got converted to high speeds...

Sorry for 101 questions but dont need two 900 lb boat anchors around :P :lol:

User avatar
spectria
Posts: 1874
Joined: May 15th, 2008, 9:53 pm
Body Type: Mail Truck, Stakebed
Model Year: 1931
Location: Quincy, Ca.

Re: Worm Drive Woes (picture heavy)

Post by spectria » September 10th, 2013, 7:50 pm

Stakebed wrote:yea i too love the looks and function of the worm drive. I probably will rip the carrier apart and see what the spider gears and such look like if the carrier is cracked this bad. I see one axle has alot more wear than the other teeth wise... I know i have some brake parts that are worn so i may be better off on aquiring a new rearend for all sorts of parts. (i know at least one possibly 2 other lug studs that spin or want to spin in the drums too) Anyone have the external stamping letters and ratio code? This is in case the brakes are stuck on my potential new rearend and cant do the 2.5 turns of drive shaft to one turn of one axle for high speed test.

Also if i can only find a low speed rear what makes it the low speed? Is it the ring gear or the worm? or both? Like someone said earlier my ring gear looks to be worn but useable. Are the carriers the same? Housings identical? I know someone said they had 2 stamped low speeds that got converted to high speeds...

Sorry for 101 questions but I don't need two 900 lb boat anchors around :P :lol:
I personally think your worm and worm gear are bad, I wonder if you could get a seller to flush the diff to then get a camera up in the case to look at the worm and worm gear?
HF Digital inspection camera image_11494.jpg
HF Digital inspection camera image_11494.jpg (143.19 KiB) Viewed 2753 times
Dave in Quincy, Ca. I love Pics!!!! Post them All!!! :)
Join the Ford Model AA Truck Club - membership form at http://www.fmaatc.org

User avatar
1crosscut
Posts: 816
Joined: December 25th, 2010, 7:22 pm
Body Type: 82-A
Model Year: 1929
Location: Lincoln, NE

Re: Worm Drive Woes (picture heavy)

Post by 1crosscut » September 10th, 2013, 8:16 pm

Hey Spectria,
I just turned 50 a couple of days ago. Pretty soon I'm going to have to have a doctor use one of those things on me........
Dave
------------
Dave

Stakebed
Posts: 1187
Joined: June 14th, 2007, 7:29 pm
Body Type: Grainbox
Model Year: 1929
Location: Illinois

Re: Worm Drive Woes (picture heavy)

Post by Stakebed » September 10th, 2013, 8:16 pm

yea the places im thinking of i would have to drag em out of the piles haha. it isnt too much of a pain to just slide them apart i wouldn't think: remove axle nuts or one side. to transport it home i would have to remove the torque tube and drive shaft so the support beams would need to come off too. then from there its the dozen or so bolts holding the halves together...

would love to bring along one of them cameras to undo fill plug or such and see what we see...

EDIT: even if the brakes are stuck it SHOULD allow the axle to slide outa the drum right? i cant remember how stuck mine were...

EDIT EDIT: What would you guys pay for one insides unseen? What would one pay for known good insides?

User avatar
spectria
Posts: 1874
Joined: May 15th, 2008, 9:53 pm
Body Type: Mail Truck, Stakebed
Model Year: 1931
Location: Quincy, Ca.

Re: Worm Drive Woes (picture heavy)

Post by spectria » September 10th, 2013, 10:07 pm

Stakebed wrote:yea the places im thinking of i would have to drag em out of the piles haha. it isnt too much of a pain to just slide them apart i wouldn't think: remove axle nuts or one side. to transport it home i would have to remove the torque tube and drive shaft so the support beams would need to come off too. then from there its the dozen or so bolts holding the halves together...

would love to bring along one of them cameras to undo fill plug or such and see what we see...

EDIT: even if the brakes are stuck it SHOULD allow the axle to slide outa the drum right? i cant remember how stuck mine were...

EDIT EDIT: What would you guys pay for one insides unseen? What would one pay for known good insides?
one semi-good worm gear went for $700 plus on eBay recently.
Dave in Quincy, Ca. I love Pics!!!! Post them All!!! :)
Join the Ford Model AA Truck Club - membership form at http://www.fmaatc.org

User avatar
spectria
Posts: 1874
Joined: May 15th, 2008, 9:53 pm
Body Type: Mail Truck, Stakebed
Model Year: 1931
Location: Quincy, Ca.

Re: Worm Drive Woes (picture heavy)

Post by spectria » September 10th, 2013, 10:09 pm

1crosscut wrote:Hey Spectria,
I just turned 50 a couple of days ago. Pretty soon I'm going to have to have a doctor use one of those things on me........
Dave
lol, I'm 61, and they ain't got near me with one yet. Nowadays you just swallow a pill camera and retrieve it later!
Happy B-Day!
Dave Z
Dave in Quincy, Ca. I love Pics!!!! Post them All!!! :)
Join the Ford Model AA Truck Club - membership form at http://www.fmaatc.org

User avatar
elfox
Posts: 159
Joined: January 27th, 2011, 8:56 pm
Body Type: 88-A
Model Year: 1929
Location: Port Orchard, WA

Re: Worm Drive Woes (picture heavy)

Post by elfox » September 11th, 2013, 7:10 am

Stakebed -

If I am incorrect, someone please chime in and correct me. But as far as I know, the carriers are the same for the high-speed and the low speed. The worm and the ring gears are whats different when comparing one ratio to the other. The high speed has 31 teeth on the ring and 6 on the worm (31/6 = 5.17). The low speed has 29 on the ring gear, and 4 on the worm (29/4 = 7.25). This is what determines the ratios of 5.17:1 or 7.25:1. The low speed rear end has an "A" stamped on the back of the differential, and the high speed has a "B" stamped on the back. However, I wouldn't trust those stamps without spinning a wheel or the driveshaft, as the gears may have been swapped out at some time in the past. I have both the "A" and "B" stamped rear ends, and the photos below show where they are stamped. The pictures are both taken from the behind the rear differential, and on driver's side. (Sorry the "B" is a little hard to see).

Image

Image
Dave
Port Orchard, WA

Stakebed
Posts: 1187
Joined: June 14th, 2007, 7:29 pm
Body Type: Grainbox
Model Year: 1929
Location: Illinois

Re: Worm Drive Woes (picture heavy)

Post by Stakebed » September 11th, 2013, 3:44 pm

i would imagine they would be the same, would be expensive to make 2 castings for carriers when one design that would fit both gears be sufficent. are all the bearing sizes identical between the two? (once again i would imagine in a cost perspective)

User avatar
Brady
Posts: 361
Joined: October 21st, 2003, 1:38 pm
Body Type: None
Model Year: 1930
Location: Norwich, NY 13815

Re: Worm Drive Woes (picture heavy)

Post by Brady » September 11th, 2013, 4:30 pm

part numbers indicate all same - if there were differences, there'd be no need to stamp A or B. Early ones had a 'TT' embossed in the casting, and used the TT ratio, which was the higher gear. The "A" ratio came out later (many thanks to Neil for this information). I like the worm drive application for doodlebugs due to the weight and clearance issues -

Stakebed
Posts: 1187
Joined: June 14th, 2007, 7:29 pm
Body Type: Grainbox
Model Year: 1929
Location: Illinois

Re: Worm Drive Woes (picture heavy)

Post by Stakebed » September 11th, 2013, 4:37 pm

Very good info Brady! thanks! Now the hunt is on...

EDIT: made some calls found a localish one for $150, been stored inside a barn on blocks outa the dirt for 25 years and came from a rolling chassis. unsure if its a low or high but easy enough to tell if the drums are free which he doesnt remember. id say that aint too bad. that entire rearend from torque tube/radius rods to drums and brake hardware.

User avatar
spectria
Posts: 1874
Joined: May 15th, 2008, 9:53 pm
Body Type: Mail Truck, Stakebed
Model Year: 1931
Location: Quincy, Ca.

Re: Worm Drive Woes (picture heavy)

Post by spectria » September 11th, 2013, 6:51 pm

Stakebed wrote:Very good info Brady! thanks! Now the hunt is on...

EDIT: made some calls found a localish one for $150, been stored inside a barn on blocks outa the dirt for 25 years and came from a rolling chassis. unsure if its a low or high but easy enough to tell if the drums are free which he doesnt remember. id say that aint too bad. that entire rearend from torque tube/radius rods to drums and brake hardware.
Buy it! You could recover your costs just selling the brake parts!
Dave in Quincy, Ca. I love Pics!!!! Post them All!!! :)
Join the Ford Model AA Truck Club - membership form at http://www.fmaatc.org

Stakebed
Posts: 1187
Joined: June 14th, 2007, 7:29 pm
Body Type: Grainbox
Model Year: 1929
Location: Illinois

Re: Worm Drive Woes (picture heavy)

Post by Stakebed » September 11th, 2013, 8:00 pm

i prolly will - guy is going to be outa town for a week tho so next weekend haha.

Post Reply