Concrete mixer repair. Breakage that I did not expect

There is an old concrete mixer in use, which has mixed at least 25 m3 of concrete. But when loading four buckets of ASG, the gear began to slip. By all indications, the bearings began to collapse. There was an idea to buy a new one:

But why buy when it can be repaired! Found a video on how to repair a concrete mixer in case of bearing failure:

This made it easier to understand the problem and I began to disassemble the mount.

From the outside, in the last batch of concrete, it flowed from the outer cover. This also indicated that the tightness of the lid connection inside the drum was broken (second slide).

He knocked out the bushings with a bolt and removed the drum from the "arc". The axle came out easily.

It was useless to unscrew the bolts, because shortly I tried to tighten them, tried to improve the tightness. I cut it off with a grinder. Inside I was waiting for a "surprise":

Under the cover of the bearing assembly, it turned out to be clean - no concrete got there through the loosened bolted joints. And the axle in the hands did not stagger. So it's not about bearings and bolt holes. There was no concrete under the inner lid either. There was only rust.

Looking closely, I saw a crack in a circle that connected all the bolt holes. Hit - the central part of the drum fell inward. The drum was held only by the fact that it was sandwiched between two covers.

I cut the bearing assembly in half. Everything was clean there too, even without traces of corrosion. The bearings were found to be free of play and turned easily. There was even grease inside one. Later I filled them with fresh grease and left them, did not change.

What to do with the drum and concrete mixer in general? I decided to brew it in a car service - scald it on both sides with a semiautomatic welding machine.

I cleaned the welding spots on both sides with a wire attachment for a grinder and took them to the city. What happened - in the second and third photos. I smoothed the irregularities with a thick circle for the grinder, but did not grind the weld seam to the end.

From a piece of rubber from a car camera I cut a gasket for the inner cover and gaskets for new M8 bolts.

I screwed the lids to the drum. I used the nuts with a plastic sleeve - so as not to unscrew. These were installed before the repair. During assembly, the axle had to be sunk into the bushing a little lower so that there was better contact between the gear and rack. Because due to the welded seam, the rail was raised by a few millimeters.

Of course, the view of my concrete mixer is unsatisfactory. This is due to the fact that you mix the concrete during the whole working day and the concrete sets on the body during this time. Ideally, it should be cleaned and repainted. But for me the main thing is efficiency.

Issue price 1600 RUB If you had your own welding machine, the restoration would cost the price of new fasteners (10 bolts, nuts and washers each).

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Photos of the author (c)

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