Category Archives: suspension

#37 Dozers: The M1 and M1A1 Dozer Blade Kit.

M4A3-Sherman-105mm-Dozer-latrun-1
This M4A3 105 tank has an M1 bulldozer blade installed.

  Dozers: Turn Your Tank Into A Bulldozer!

This dozer blade came in kit form and could be installed on any Sherman. They came two to a crate, an M1 and an M1A1 each per crate. The difference between a M1 and an M1A1 Dozer blade was pretty minor, and an M1A1 dozer blade was universal, but the M1 blade only worked on Shermans with VVSS. This is because the M1A1 blade was wider. Here is some data on the blades. The reason the wider blade worked on the narrower VVSS tanks was because the kit came with spacers to fill the gap left by the wider A1 blade when used on a VVSS tank.

 

Blade Data

Blade Height: —————————————————————————————-48 inches

Overall width M1:———————————————————————————124 inches

Overall width M1A1:——————————————————————————138 inches

Added weight to tank M1:————————————————————————-7100 lbs.

Added weight to tank M1A1:———————————————————————-7400 lbs.

Lift height of blade M1:———————————————————————18 to 30 inches

Lift height of blade M1A1:——————————————————————18 to 42 inches

Lift Load, M1:——————————————————————————————- 4000lbs

Lift Load M1A1:—————————————————————————————–5000lbs

The TM for the kit makes it sound like it was installed on tanks at the Depot Level and then the tank was issued to a unit with the blade kit installed and ready to go. After reading through the tech manual, it could be done by the tank crew without to much trouble, though a small crane would be nice for the installation of the hydraulic cylinder, but that seems like it would be a rare occurrence. If the kit had a drawback, it was that the blade blocked the bow Machine gun.

bulldozerpic from TM9-719 4 –bulldozerpic from TM9-719 5

The kit broke down into several major parts groups.

bulldozerpic from TM9-719 7

Hydraulic Group: Was made up from external and internal parts that were a part of the Hydraulic system including the pump, an oil reservoir, and all the brackets to install these parts. There were also hoses and fasteners of various types. It also included a special wide angle periscope for the driver. Once

bulldozerpic from TM9-719 2bulldozerpic from TM9-719 3bulldozerpic from TM9-719 10

To install these parts a few things had to be removed from the interior. As this pictures show, the pump and tank assembly was fairly large. Essentially the tray for the spare periscope head box and the box had to be removed. The several brackets and guards had to be removed, and then the generator itself and its mount had to be pulled. It also involves disconnecting the transmission side of the propeller shaft, and installing a new pulley on it to run the hydraulic pump from. Once everything was installed, it did not impede the crew any more than when it wasn’t there since nothing took up the space right above the transmission.

   A few parts from the hydraulic group did get installed outside the tank, the hydraulic hose, run through the left headlight mount. A guard for the hose and a cable running from a handle on the inside, used to jettison the blade in an emergency. All these parts are universal to all models of Sherman, though a few brackets could require a little modification for everything to fit right do to the way some hoses and belts were run.

The hydraulic jack and the framework attacking it to the tanks tow points on the front of the tank are also in the hydraulic group.  There were several bracket sets for use with the different kinds of differential housing the tanks could have.  There was a cover assembly/bracket to protect the mount, and hoses, and help position the jack

bulldozerpic from TM9-719 11 bulldozerpic from TM9-719 8bulldozerpic from TM9-719 10

Suspension Mounting Bracket Group: This group used already existing bolt holes in the suspension to make installation easier.  Each kit came with brackets to make it work with VVSS or HVSS. The VVSS bracket could be adapted to work with either the M1 or M1A1 blades, the HVSS Brackets could only be used with M1A1 blades, because the M1A1 blade was wider to accommodate the wider HVSS. This bracket and had the pivot points for the blade.

The VVSS mounts used a replacement suspension cap built onto the blade mounting bracket, and another replacement cap with bolt holes. Another part of the vertical suspension mounting bracket bolted to the unused return roller holes on the middle boggie assembly, the same one that used the built in replacement caps. The replacement cap with extra bolt holes replaced the cap in the front boggie assembly.

bulldozerpic from TM9-719 12

The HVSS mounts were simpler. You just removed four bolts in the first and second suspension arm supports and install the horizontal suspension mounting bracket with longer bolts and lock washers. This is a much easier install than the VVSS mounts, but neither seems overly hard.

bulldozerpic from TM9-719 13

Once you have the mounting brackets on, you get to move onto the…

bulldozerpic from TM9-719 bulldozerpic from TM9-719 14

Bulldozer Blade Group: This group is basically the blade and it arms that mount to the pivot points on the suspension brackets.  This part of the job is where you could really lose fingers or toes. You need a nice flat area, the area you stated in hopefully, and then you drive the tank up to the blade, careful to keep it centered. The tank stops to feet from contact with the blade, and the driver raises the jack piston to the same as the connecting pin on the Blade group.

This is a multi-person Job, since the co-driver has to hold the quick release cable, in the release position, while the tank is driven into the Jack arms pivot points, and then let the pin close on the eye on the Jack head. The co-driver, while doing this is also guiding the tank into place on the blade arms. At this point the latches on the pivot points can be locked down, a large hammer may be needed and the quick disconnect cable fed into place and loosely connected in the interior of the tank. When it’s pulled the whole assemble will come lose and can be backed out of.  You can see some of this in a video in the Shermans in motion section.

bulldozerpic from TM9-719 16

The final step would be installing the M14 periscope in the drivers position, filling the system with fluids and testing it out. The system was easy to use, and had dual controls, so the co-driver could operate the blade if the driver really needed both hands. The controls were a simple lever used to raise and lower the blade, raising it by hydraulic pressure, lowering it by cutting the hydro pressure and letting the weight of the blade bring it down. Removing the blade was as simple as pulling the quick release cable. If you planted the blade in the ground just right before release, so it wouldn’t move, you could drive the tank right back up to it, hammer the pivot point latches in place, put the pin in the jack and go.

I have to say this is a very impressive kit. It did make the tank a bit front heavy and probably shortened the life of the front springs, it was not a problem in any real way or the Army would have had modifications made to solve these problems. This kit saw prolific use with the US Army and Marines, and since it worked on any Sherman model, probably everyone else who used Shermans and could get their hands on it. This dozer kit was the most effective way of punching through hedgerows as well, working much better than the dedicated hedge row cutters. A tank company would get one dozer blade equipped tank into the HQ platoon, if there were enough kits to go around. There might be another one in the Battalion HQ platoon.

bulldozerpic from TM9-719 15

The Lone Sentry has published a report from Shortly after WWII called the Armored Special Equipment report.

This report covers all the armored funnies, or specialty vehicles from Hedgerow cutters, DD tanks, and Crab modifications. Our interest from this article is the feedback on the Dozer blade setup.

This was the feedback on its combat use:

The tank dozer was employed extensively for numerous purposes commencing immediately after D-Day. Some of the missions for which the tank dozer was employed in the European Theater are outlined below:

(1) Shortly after D-Day a platoon of four tank dozers of the 741st Tank Battalion operating on the beaches under intense fire, removed beach obstacles, opened roads and pushed off beached landing vehicles.4

(2) The tank dozer was used to break through hedgerows, broaden existing gaps and gaps blown with explosive charges; and thereby facilitated the use of other than normal entrances through hedgerows.5

(3) Tank and gun emplacements were prepared.

(4) Roadblocks were cleared; and in addition, rubble, wrecked vehicles, and snow were removed, and craters filled. It was found necessary in many instances to provide a tank dozer for these purposes to work in conjunction with the roller type mine exploders in sweeping roads and shoulders.

(5) In connection with the Roer and Rhine River operations, bridge approaches were built, launching sites for LCM’s and LCVP’s and crane sites were prepared, and cuts dozed in the river dikes.

The Tank Dozer has the following merits and deficiencies:

(1) Merits:

(a) The tank dozer provides armored units with a standard vehicle that can be readily employed to reduce obstacles and assist in the advance of units or to assist in the preparation of defensive positions.

(b) Armor protection is provided for the crew.

(c) The tank dozer can also be employed as a fighter tank.

(d) The tank dozer installation is simple, reliable, and its maintenance demands are negligible. 

(2) Deficiencies:

(a) The tank dozer installation overloads the front of the tank suspension system and increases bogie tire failures and suspension maintenance demands.

(b) The tank dozer installation materially limits the driver’s field of vision.

(c) There is insufficient clearance between the track and dozer blade arm to ensure safe operation with the addition of the standard 3-5/8 inch track extended end connectors.

(d) Sufficient dozer blade accessories were not available so that dozer blades salvaged from burned tanks could be readily reinstalled on other tanks.

 

I found this very interesting, please check out the Lone Sentry Web site, it’s a very informative place.

The source for this post was almost exclusively Tech Manual 9-719 Tank Mounting Bulldozer (M1 and M1A1). The TM can be found in our download section and the report on the lone Sentry.

Here’s a video from the army on how to install this dozer blade kit.

https://drive.google.com/open?id=0B5k30qNybbcZbm1HLTkwU1FUOWs

#35 Shermans In Motion

Sherman Related Videos 

This is the Post I’m going to put interesting video content I find on the Internet.

The Motors: All The Sherman Production Motors Being Run

Video of all the major tank motors running. I’ll add more videos as I find them.

R975 running.

https://youtu.be/NIJPzCOQZKM

GM 6046 running.

A57 being run.

Ford GAA being run up.

 

Tanks in motion: Sherman Tanks on Film, Either Modern Restorations or Period Videos. 

Here is an older video of an M4A1 that was restored and had new tracks installed.  They really put this tank through the paces and it’s worth it even if the music is a bit dated.

 

Here’s a short video of an M4A4 driving around.

The M4 105 Dozer, a video dedicated to just it! bonus includes Sherman drifting! They look like they are having so much fun in this video! Well until they bust it! This video is a BLAST!!!!

Shermans and a M31 ARV gutted and made to look like a M3 Lee again.

This was a Normandy Memorial day in 2013 I think. In this video, we see an M4A1 75 start up and then drive off, almost stalling.  Then later we get to see an M4A1 76w driving around.  Interesting how close they let people get to moving tanks.  Parked nextr to it is an M10 tank destroyer.

This is another Normandy D-Day Memorial, 2014. The Video starts off with an mid production small hatch M4A1 75, with a later production M10 behind it and then an M18.  After that an small hatch M4a2, and then the Fury M4A2 76 HVSS tank.

Ontario Regiments Museum’s M4A2 76 W HVSS tank driving around!

A video of a restored M4A1 driving in circles firing off its main gun, I’m sure modified to fire on propane as a noise maker.

A very long video, POV from the co drivers spot, on a restored, small hatch M4A1.

Restoration Videos

Here is a video of a restored Firefly Vc, a Sherman M4A4, with the a working A57 multibank motor, getting new tracks.  This may not look tricky, but these men are all risking losing fingers or toes, or worse, if someone messes up.

Video of a Very nice looking M4 105, with dozer blade being used to recover a M4A4 in very bad shape.

A start to finish ‘flower pot’ restoration on an M4A1.

A resto mod on a M4A1, with more footage of that nice M4 105 dozer.

A restoration going on in Texas.

 

#13 The Suspensions And Tracks: A Smooth And Comfortable Ride Was The Goal, And It Was Achieved, Somewhat

Suspensions and Tracks: It Suspends, and gets laid! 

UPDATE! See the new Suspension and Track pages found here this post will no longer be updated, all the latest info I have will be put on these pages to make it easier to find. 

M4 tanks came with three types of suspension the early VVSS, VVSS and HVSS. The early VVSS suspension system used 16 inch wide tracks. In the link above about Sherman details you can see all the changes the basic VVSS system went through. The VVSS suspension went from the basic two road wheel one return roller with no support module as seen on the Lee, to the later production VVSS bogies that had a bolt on return rollers, that could be bolted to either side of the suspension unit, and sheet steel track supports and much beefier structures that were still usable on either side of the hull. The suspension was one of the parts of the tank that went through so many minor changes, keeping track of them is out of the scope of what this document is meant to do. The Sherman Minutia site does a great job of covering these changes. These changes had little effect on the performance of the tank; think of them more of fine tuning of the basic design for strength, longevity, and ease of manufacture.

What would be the final VVSS, with the return roller that could be swapped to either side, was developed for the M3A4, with the A57 multibank motor. The combo of heavier hull and engine was putting the basic VVSS suspension with the built in return roller under to much stress and causing premature failures. The heavy duty unit was developed to solve this problem was later standardized as the M4 suspension type, though, the bolt on roller and skids would still receive improvements, a beefier skid, and a spacer to lift the return roller, and later a new assembly that raised the return roller higher, the core remained the same. The M3A4 would be the only version of the Lee to receive the heavy duty VVSS suspension units from the factory.

Early VVSS: Using 16 Wide Tracks

vvss early dia

Mid VVSS: Still Using 16 inch Wide Tracks

suspension unit late

vvss suspension broken down
vvss brakedown key
HVSS: The Improved 23 inch wide Track and Suspension System

sherman_bogie_hvss2

 

late VVSS diagram
Late VVSS diagram the whole suspension

The VVSS was later replaced by the HVSS system that had twenty three inch wide tracks, but the suspension was still a bolt on module. It was very well received and used on many late production Sherman models and a few of the variants. It solved the floatation problem of the narrow tracks with few drawbacks.  Thousands of 75mm Shermans received this suspension coupled to large hatch wet hulls. This would become the preferred suspension type for US Army Shermans, and many 75mm hulls either lost the suspension or had its 75mm turret removed and replaced with a T23 turret and 76mm M1A2 gun after the war

Sherman Idler diagram
Sherman Idler wheel parts

This type of system, that could be unbolted, was much easier to work on or fix when damaged than an internal torsion bar suspension or Christie suspensions found on other tanks. Changing the one bogey setup, or even two and putting the track back together was a lot easier than trying to get the stub of a broken torsion bar out of the hull so a new one could go in.

An experimental Sherman with torsion bar suspension was produced and found to be little better than the basic VVSS tanks, and no better than the HVSS tanks and production was never considered. The HVSS suspension made it onto a lot of things built on the Sherman chassis.  HVSS was also retrofitted onto hulls used in Israel’s M51 Super Sherman program.

Tracks:  They are a weapon too you know

 

Click any of the track images for a much larger version.

The Sherman VVSS had at least 14 different types of track, and there was another 4 types for the HVSS. I will cover them in more detail later. Most of the track types were ways to minimize the amount of rubber used in the tracks or to produce an all steel track, as good as the basic rubber and steel T41 track.

endlinks2

The narrow VVSS tracks limited the Shermans mobility in soft mud, sand, boggy terrain. The Tiger and Panther tanks were better off road than the VVSS Shermans. It’s a good thing they were so rare, and there was a limit to how much mud they could deal with. The mud also accelerated the maintenance problems both these tanks faced and eventually mud got so deep in late 44 no take could go off road much until the ground froze.

 

end connector wear tracktool tracktooluseThe Army came up with a field expedient solution called a “duck bill” end connector. The was an end connector with a sheet steel foot welded to it, when bolted in place on the track it added several inches to the tracks width in soft terrain. The only drawback was they broke off fairly easy, but were easy enough to replace.  This was a very popular and widespread modification, and many little local factories in France were contracted to produce them. They were also factory produced and installed on production Shermans.

Factory Duckbills
Factory Duckbills (image from the Sherman Minutia site.)

 

Sources: TM9-1750K Tracks-Suspension-Turret and Hull Mods M4 series,TM9-731B M4A2, TM9-731G M10A1, TM9-745 GMC M36B2, TM9-748 GMC M36B1, TM9-750M3, TM9-752 M4A3, TM9-754 M4A4, Sherman by Hunnicutt, The Sherman Minutia Site, Son of a Sherman by Stansell and Laughlin