Hard-plastic replacement seals win the day for Zimbabwean plant hirer

The original seal alongside the Vesconite replacement seal.

Zimbabwe-based earthmoving equipment hire business Replants Africa Investments says its Vesconite Hilube seals are performing well on the company’s bulldozer’s hydraulic shift transmission.

The company maintains and repairs its own equipment and even makes its own components in some cases. So, when the seals between the transmission housing and the rotating clutch housing on its bulldozer began to fail, Replants Africa Investments made its own Vesconite Hilube ones.

Co-owner Doug Bawden, who has vast experience in repairing equipment at different sites as well as a background as an apprentice fitter and turner, notes that the original equipment manufacturer (OEM) parts he replaced were made of bronze, although another OEM manufactures the same part from hard plastic .

Bawden was inspired by the hard-plastic design of the other OEM. He also appreciated the ease of manufacturing seals from Vesconite Hilube compared to brass or mild steel. He is also impressed by the fact that the common 90˚C temperatures in bulldozer transmissions fell within the polymer’s optimal temperature operating range.

Bawden made the seals on a 1m lathe. He turned the outside diameter to the same size as the inside diameter of the housing and bored the inside diameter out to 2mm larger than the outside diameter of the inside of the groove in which the seals fitted. He parted the seal off around 0,2mm narrower than the groove and, lastly, split the seal with a Stanley knife and a sharp blow.

“I installed the seals in May and so far they are working well,” says Bawden. “During the compressed air test to actuate each clutch to see if there are any leaks, they sealed better than the brand new OEM parts did.”

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