Allis Chalmers 720 with ARC Loader
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Garden Tractors
Forum Description: A great place to discuss the Simplicity and Allis Chalmers Garden Models
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=142308
Printed Date: 23 Feb 2025 at 8:20pm Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Allis Chalmers 720 with ARC Loader
Posted By: rustydollar
Subject: Allis Chalmers 720 with ARC Loader
Date Posted: 09 Sep 2017 at 8:29pm
I'm greatly indebted to one of our forum members for giving me the
heads up on this Allis 720, the tractor has problems with the Sunstrand
hydro unit and possibly more trouble inside the transmission.
Previous
owner had the top of the transmission off and drained the oil, said it
was full of metallic particles. With the engine running put into
either forward or reverse just makes grinding noises.
From the jest of the conversation I think someone has tried towing the tractor. And that's the real reason the transmission and Hydro unit s lunched.
When I get
it home I'll probably swap the trans axle along with the Sunstrand hydro
as a complete unit from my Simplicity 9020 into the 720. Which is
probably just as
much work as changing the ARC loader from one to the other.
The loader bottom plate has to be replaced as it has rusted through in places.

|
Replies:
Posted By: Dusty MI
Date Posted: 10 Sep 2017 at 6:29am
I have one that looks just like that. It has been re-powered with a B&S engine. I'd like to find a back hoe for it.
Dusty
------------- 917 H, '48 G, '65 D-10 series III "Allis Express"
|
Posted By: rustydollar
Date Posted: 10 Sep 2017 at 10:18am
Dusty MI wrote:
I have one that looks just like that. It has been re-powered with a B&S engine. I'd like to find a back hoe for it.
Dusty |
Your probably looking for something like this, it's a Brantley Backhoe Model 603 A http://www.mytractorforum.com/attachment.php?attachmentid=362465&d=1373091174" rel="nofollow - http://www.mytractorforum.com/attachment.php?attachmentid=362465&d=1373091174

|
Posted By: Orange Blood
Date Posted: 10 Sep 2017 at 8:55pm
The axle stub shafts that connect the differential, to the drop boxes, are known weak points, and fail if the unit is used harshly forwards, and backwards. This could be your problem. The root of the problem is, there is very little splined area of the shaft that contacts the differential, and it tears them off easily if used for much more than a lawn and garden tractor!
------------- Still in use: HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060 Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7
|
Posted By: rustydollar
Date Posted: 10 Sep 2017 at 9:37pm
Orange Blood wrote:
The axle stub shafts that connect the differential, to the drop boxes, are known weak points, and fail if the unit is used harshly forwards, and backwards. This could be your problem. The root of the problem is, there is very little splined area of the shaft that contacts the differential, and it tears them off easily if used for much more than a lawn and garden tractor! |
Previous owner had the transmission top off, engine running with trans engaged nothing visible turns.
When I get it home will have a look inside but I'm not planing on putting any money into it, just need one tractor operational for snow duty.
I just thought it would be just as much work to swap the loader over to the Simplicity 9020 as it would to swap the differential form the 9020 into the Allis 720 which cosmetically looks much nicer.
Thanks for the heads up on the weak point to look for damage.
|
Posted By: rustydollar
Date Posted: 10 Sep 2017 at 11:57pm
That drive axle being a weak point must have something to do with item 21 in the diagram below seldom seen on auction.
Plenty of the drop case's and bull gears, so I gather the spline is prone to breaking off and leaving the internal spline on the bull gear untouched.

|
|