More rear axle woes

[gmsclassics]

What with reading about Scott’s leaking axle and now mine again. These things are a real problem.<br>
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I thought it was just the seal I blew at Pukekohe and hadn’t had a chance to pull it apart until this morning. I had earlier cleaned the oil from the brakes (dismantled), from the wheel, tyre, wheel arch, shock and spring, body etc. First sign something else was amiss was when pulling half shaft out I saw swarf in the seal. Then there were the needle rollers lying in the oil just inside the casing. The added support bearing in the axle had destroyed itself. The sleeve on the half shaft that the bearing rollers were supposed to sit on had moved inward, the half shaft had flexed and the needle rollers came into contact with the shaft. Of the 19 rollers, we found 14 in the axle tube and 1 lodged in the diff housing. Drained the oil and that was obviously silver in colour! Have flushed out with brake cleaner fluid and the ‘magnet on a stick’ has been everywhere we can get it. Crown wheel and pinion faces look fine, as does LSD unit from the outside. Old bearing took over 2 hours to extract with a home made slide hammer. Bearing is a IKO RNA 49/28. Outer dia is 45mm and inner roller face/ outer dia of sleeve is 37mm. <br>
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Mark, If we look at thicker / stronger / less flexing shafts, will they entirely replace these bearings or will the diameter still be such that the bearing can be used?<br>
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I suppose the only good point in this is that a component failure led to the oil getting past the seal and not simply the system not coping. However, that is now instances both sides where these bearings have failed to remain properly located leading to flexing of the shaft and oil getting past the seal.<br>
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At this point we intend to:<br>
Renew the bearing – coming Monday – ‘sticking’ it to the sleeve in the axle casing with Loctite<br>
Reposition the sleeve on the halfshaft and weld it on (side nearest the wheel) to prevent further movement.<br>
Replace both seals and repack wheel bearing<br>
Clean the diff out again with brake cleaner. Put backplate on and refill with oil. We are assuming that the other needle rollers must have been ground to a pulp, contributing to the large volumes of silver bits in the old oil. Will probably run a couple of events and change this again. Using Castrol SAF-XA fully synthetic 75-140W. This is the one their Tech people recommended for use with LSD in racing conditions. The time and huge cost of dismantling the diff to ensure it is clean are putting me off doing this. I will also miss this Saturday’s meeting. Then only one more in May this season.<br>
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Any thoughts or comments?<br>
Geoff

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