Auto Service World
Feature   July 1, 2003   by Jim Anderton

Save That Seal

Sleeving worn shafts give seals a new surface for leak-free performance


Leaky seals, especially at the engine front cover and at the differential pinion, are often caused by scoring on the shaft where the seal’s lip rides. Contaminants act like an abrasive, and with the seal’s garter spring acting like a sanding block, grooving can be severe enough to allow lube to work past the seal, and as importantly, rapidly destroys replacement seals. The answer is to replace the shaft’s contact area. One way is to use replacement seals designed to move the sealing element to an unworn area of the shaft, but a solution that allows the use of original-type seals is to sleeve the worn area of the shaft. Major bearing and seal manufacturers offer repair sleeves for shafts encountered in automotive work, and all perform basically the same way. Sleeves are thin-walled alloy shells that are provided with a removable flare at one end to facilitate installation. Installation can use the tool provided with some kits or with a piece of appropriately-sized tubing cut square and deburred.

Installation is straightforward:

1. Thoroughly clean and deburr the scored portion of the shaft surface.
2. Fill very deep grooves with a metallized epoxy filler, and install sleeve when the compound is still wet.
3. If flange must be removed from the sleeve, nick its edge with diagonal cutters to facilitate removal.
4. Place the sleeve, bellmouth out, into the installation tool or fabricated tube.
5. Tap the sleeve into place with the tool, positioning the sleeve to completely cover the worn area.
6. Remove tool.
7. If the flange must be removed, grab the precut notch with pliers and the flange will tear off along a precut groove, leaving a clean edge.
8. Install seal and housing/cover normally, using OE or normal aftermarket seals.

Removal of sleeves is rarely necessary in automotive applications, but if necessary, gentle heat or peening the surface in a line along the shaft’s length will loosen the sleeve for removal. Sleeving is a fast, low-cost alternative to replacing or repairing expensive assemblies like crankshafts, output shafts and differential pinions.