early 28 worm drive

[chief5215]

My fire department has a early 28 (LATE FEBURARY} Fire truck . The rear has never been gone through and is starting to have a little bit of noise We also want to do a brake job on it. Is there any books on this particle rear. Haven't been able to find anything on this in my books. What information do I need to have to get you to help us through this project. Thanks Billy

[1wonton]

Be sure you don't use modern gear oil with EP additives. I destroyed my '29 AA rear end by using the wrong oil. Seems like Oil is Oil, right? NO! Use steam oil 600 wt or you might be shopping for a "new" rear end.

ron

[1crosscut]

Here is a link to a thread that I posted a while back that has some pictures of the inner workings of my January 29 worm drive.
http://forums.aa-fords.com/viewtopic.ph ... ive#p20582

Yours being an early 28 the bearings on your differential might be straight bearings instead of the tapered bearings. Other than that they are very similar and quite simple to pull apart for a look see.

[chief5215]

Are these parts still available. Is this a project we can handle. We are a bunch of fire fighters from a vol. fire dept. This is our original fire truck . We just last night pulled motor and transmission and converted it back to original transmission and multi disc clutch. Thanks For all your help WE NEED IT

[1crosscut]

Generally the parts can be found from other enthusiasts. Might take a bit of searching though. I do know that the tapered roller bearings can be had new but can be spendy. For the other bearings you will most likely have to find used ones. If your bronze ring gear and spiral drive gear are bad finding a replacement low speed set is going to be easier than finding a high speed set. Since the truck no longer has to race to fires the low speed will do just fine for parades and such. A gasket set is available from the vendors.
Don't worry too much about pulling it apart and taking a look at it. They are pretty straight forward. Keep track of how things come apart and take pictures as you go.

[1crosscut]

In reading your first post I assumed that you were referring to having a noise inside the rear end. Hopefully that is not the case and you won't have to split it apart. If you can pin point the source of the noise first and find it is not inside the rear end that would be a bonus.
Doing a brake job on these trucks is not hard. Yours will be simpler than most as you do not have emergency brakes to deal with. The hardest part of a rear brake job can be pulling the hubs off.

[KimVanOrder]

Noise? first thing is check the roller bearings on the front and back of the worm. That may be your noise. You hope.

KVO

[Stakebed]

i have some internal parts to the early 28 worm and a low speed gear set for it, these are for the early 28 without separate emergency brakes

[chief5215]

I think I read that you can tell which ratio rear I have by the rear backing plates, I posted 2 pictures and also a picture of what I think was a hot bearing

[1crosscut]

It looks as if there has been some damage and repairs made to the thrust bearing on your rear end. It doesn't look like any that I have seen. I am betting that is where your noise is originating from. Going to be interesting to see what it looks like when you open it up.
To check the ratio for sure you will need to:
Make sure the truck is turned off!
Jack one rear wheel off the ground leaving the other wheel in contact with the ground.
Mark the wheel that is off the ground with chalk or a piece of tape so you can count the revolutions of the tire.
Place the transmission into 3rd gear.
Use the hand crank and turn the engine over counting the number of turns of the crank to one turn of the wheel.
If you turn the crank just over 2 1/2 tuns to one rotation of the wheel you have high speed gears.
Any more turns than that it is a low speed.

[KimVanOrder]

Dave: When you say " 3 rd. gear" Do you mean High gear. (just in case it is a 4 speed). Just to be sure to get a one to one ratio going thru the trans and or under drive if so equipped.

BTW ? how many Revolutions for a low speed?

[chief5215]

If you look at the 1 picture It doesn't appear to be damaged, I believe it has been so hot that it burnt the paint. It wasn't like this in September when we pressure washed the under carriage for our annual fireman's Parade. but we were in 5 Christmas parades after that I will check the ratio in a hour or so, If I remove the 4 bolts in the end cap will this give me access to that bearing Again Thanks Billy

[1crosscut]

Billy the reason I thought that it was damaged was the cap on the end of the rear end is different than any I have experience with. If it got hot enough to burn the paint the thrust bearing may have seized to the shaft and spun in the housing. Not a good thing to have happen.

Kim, yes putting it into third so it is direct drive. I would suppose that would be the same with a 4 speed coupled to a worm drive. I'm not sure at the moment how many rotations for the low speed.

DSC05711.JPG (138.17 KiB) Viewed 8316 times

[Stakebed]

yea i was going to say that cap looks funny too...

[1wonton]

I have a complete '28 rear end (and front end) if you need one. This is the early high-speed axle with no seperate emergency brake lever. Located in Vallejo, ca.

ron