pparaska Posted April 29, 2009 Share Posted April 29, 2009 I've searched and not seen mention of the problem and no solution. Having roughly 500 ft-lb of torque means that my diff cover bolts come loose quite often. I checked today and some were out 1 turn. The issue is that the flexing of the R200 case under that much torque loosens the cover bolts. Some of the US differentials have aftermarket cover/girdles available to help with this - they use longer bolts that go through the cover/girdle and down to the bearing caps. Has anyone ever designed a cover like this? What would be cool is a finned cover with a girdle integral to it. Any other options? I'm considering safety wiring the bolts but that won't help the flex. Quote Link to comment Share on other sites More sharing options...
DeleriousZ Posted April 29, 2009 Share Posted April 29, 2009 what about using belville washers to keep the bolts under const. torque? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 29, 2009 Share Posted April 29, 2009 The girdle covers prevent the main caps from flexing backwards under load, this flex allows the ring and pinion to move in relation to one another and chew each other up. Your problem is not the main caps flexing and causing a ring and pinion failure, your problem is that the diff is hung from the cover, so the cover itself takes the load (along with the front diff mount) that the 4 link or whatever suspension setup is used on the solid axle would handle. The cover in a solid axle takes relatively little load, and the girdle covers aren't there to strengthen the cover, they're there to strengthen the main caps. As for a solution, strengthening the cover will help, but might require some pretty serious trial and error. It's the elasticity of the mustache bar relative to the front diff mount that allows the cover to be flexed and pull the bolts loose. If the diff were rigidly mounted and the mustache bar redesigned so as not to flex, I think that would help too. Unfortunately that might be more of a race only setup as it would be loud inside. At least that's my theory after thinking on it for a couple minutes... Quote Link to comment Share on other sites More sharing options...
pparaska Posted April 29, 2009 Author Share Posted April 29, 2009 jim, as usual, a great arm chair engineering analysis. It all sounds correct to me. So a thick aluminum cover/girdle MIGHT be stiff enough, but a fabricated steel one might be a solution. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 29, 2009 Share Posted April 29, 2009 Pat, a steel cover might work but sounds like a lot of fabrication. I'd try adding a couple stiffening ribs horizontally across the aluminum cover. Just need to check for clearance with the mustache bar before having them welded on. Maybe a couple above and a couple below the bar itself. Quote Link to comment Share on other sites More sharing options...
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