Towed gang mowers

Edwin Robertsin Machinery & Mechanics

GangMowers.jpgEdwin Roberts of Classic Mowers looks at the towed gang mower and suggests that they still represent good value for smaller sports clubs if maintained correctly

Being ground driven, towed gang mowers are not too complicated and are, therefore, relatively easy to maintain.

When I first started repairing grass machinery, towed gangs played a big part in my work load. I remember working on Greens Rangers, Mitchells, Atcos, Shanks, Lloyds and, of course, the redoubtable Ransomes.

The Ransomes gangs have stood the test of time. They will put up with being left outside in all weathers, with no oil and no love and affection and, yet, still work (of sorts). However, if cared for correctly, clubs will have a set of mowers that will give years of trouble free mowing to a good standard.

In this article I will look at the Ransomes Mk 3 Aero Cutters, Mk 10 and Mk 10 Sports Cutters, Mk 12 Magnas and later Mk 11 and 13. The differences on the latter are the gear selector mechanism and the bottom blade adjuster bolts.Before.jpg

The construction is fairly basic. The front axle draw bar has ¼ inch steel side plates which mount the gear and pawl drive assembly. The cutting cylinder runs on two self aligning bearings, in two removable bearing housings, which slide into the side plates. The bottom blade pivots on two shoulder bolts which also supports the land roller assembly.

Stripping units for reconditioning is as follows: Start by removing the wheels, rear land roller and bottom blade assembly. To remove the cutting cylinder first remove the covers on top of the gear boxes and remove the bolts on the cutting cylinder bearing housing. Remove the cutting cylinder by pulling up out of the frames. Remove the gear case covers, check and clean gear box parts, idler gear and shaft. Remove the main gear and pawl assembly and gear selector parts.

Worn and cracked hole for roller & bottom block.jpgOn the Mk 10 and 12, the gear selector slides in and out and is retained in position by a spring and ball detent assembly. On the Mk 11 and 13, simply pull in and out and lock by turning the lever. It is best to remove both types to clean and oil. Remove the springs and balls and fit new ones. Clean the housing where the parts slide in and out. Clean out the spring hole with a good fitting drill to remove old grease and rust.

Check and clean the main gears and pawls and the gear hub bearings. Fit new if required.

Check the idler gear pivot shaft for wear, and also the hole in the side plate where the shaft fits into it. The shaft can become loose and wear the hole into a slot. This will allow the gear to move up and down in the side plate as the mower is driven. In time this will result in cutting cylinder bearing failure.

Also, check the hole in the side plate where the roller and bottom blade block pivot. The draw bar will also wear at the point where the frame fits. All the worn parts can be built up. This can be done with stick welder, then, cleaned up with an angle grinder. The holes can be cleaned up with a round file.

The cutting cylinder bearings are of the twin row, self aligning type. When I fit new, I use the sealed types as I find that greasing with a grease gun is often overlooked and, as the mower generally stands outside in all weathers, the sealed bearings help to keep the rain out.

Worn idle shaft which will result in bearing failure.jpg

There can be two types of oil seal fitted in the bearing housing. For the Mk 10 - 12 use the Dowty type seal which seals on the outside of the seal. For the Mk 11 and 13 use a seal which is on the inside. If you have problems getting Dowty seals try your local bearing supplier. Do not try and fit later types into Mk 10 and 12 bearing housing as the outside diameter is too large.

Check and clean gear covers if required. Remove the seals from the cover by drilling out the copper rivets. There are two types of seals fitted, rubber or leather. I find it best not to fit the rubber type. The leather seal is a superior part but it is not easy to fit. Now we get to the bit, where, on Blue Peter, they would say "don't do this at home".

Prior to fitting, the leather seal is softened by warming it up in a pan of oil on a stove. Do not over heat the oil. Remember this is a dangerous procedure so wear safety glasses and protective clothes. Also, have a means of putting out an oil fire. This may sound a bit dangerous, but it is the only way to fit the seal to the case.

When the seal is warm, remove from the oil and place in the case with the steel ring. Fit a rivet from the outside of the case. Fit the seal and ring. Place the rivet head on the vice and punch up from the inside. Now work around until all the rivets are fitted. To help in fitting rivets a tapered pin punch is used for lining up the holes for the rivets to go in.

I find it is best to fit the seals and cover assembly onto the gear hubs when still warm so that the leather seal will go over the hub without splitting. So, it is best to do this operation when the gear assemblies are refitted to side plates.

Next, look at the bottom blade block assembly. Regrind the bottom blade. If it is worn remove the bottom blade and fit new. I find it is best to grind the new blade on the block as this will make it easy to set up for cutting.Fully serviced and ready for work.jpg

The rear land roller assembly will require the bearing cleaned or a new one fitted. If the rollers are in poor condition you could fit new lightweight ones. These are not repairable but will do the job.

Check over the cutting cylinder for damaged blades and broken welds and repair if required. Repaint and regrind the cylinder.
All the sub units are now ready for fitting the machine together. This is the bit I like.

Starting with the cutting cylinder, fit it in to the frame, fitting the four bolts on each side plate. Place the adjusting tube assembly on bottom blade adjusting bolts.

Now, fit the bottom block assembly and rear land roller, greasing the pivot bushes and bolts. Fit new adjusting nuts and bolts to the bottom block, adjusting the pivot. Then fit the gear assembly and gear case to the side plates. Fill with oil. Fit to covers. Refit wheels. Adjust cutting cylinder. Refit to frames and test.
If you have completed all the work thus far you will end up with gang mowers that will give you another ten years of good service. Happy towing.

Edwin Roberts

Classic Mowers
27 Clinton Street

Telephone 07849709812

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Machinery & mechanics