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Thanks Chris..I was not trying to say anything about lubing wheel bearings , as no brass out there , but very good point. I knew of the dual seals, but to be frank never thought about why, other than “wow. Cool! additional protection against brake contamination”. Kind of an odd design, compared to rest of industry . I think eventually all with open axle bearings ended up sharing wheel lube with diff lube, to my knowledge, or else sealed ball bearings. I like very much the shimmed Timken design from an engineering perspective, much better than GM pressed ball bearings on Chevs ; there is a reason RR freight cars have Timken…not ball bearings , but perhaps the (?.013) side to side motion possible with Chrysler / Timken design makes seals unhappy. Do you know you can insert the nail shaped thrust bearings in thrust block without opening axle? Drill a hole in new one, maybe 1/8, put on end of two welding rods welded together end to end that fit in that drilled hole , heavy grease , get very bright flashlight, you can do it from wheel opening. Often when pulling axles, these “brass nails” stick to axle ends as you draw out axle, pull out of their hole, then drop to bottom of pumpkin, then you cannot shim it…big gap. People take out all the shims , still loose ,and unbelievably button it up . If you drive it like that, back brakes burn up due to touching drum, brake drum and axle now ride off center . How I learned all this pain , was back in 69. F by side of road in Chicago, in snow, on way to Boston. Just bought it from a guy who “did brakes “and “had to change wheel bearing seals”. Right. Smoke pouring off brakes 50 miles away. If you pull an axle , look in there…… a big “OH NO” often awaits if you see a hole and no nail.. I also remember “bought new” 60 Dodge getting grease on brakes at 80k, locking up, very common failure in these axles when relatively new, but bearing OK—brakes sure were not. ; whether it was grease or axle fluid I do not know; I believe this was quite an old design, maybe back to first Mopar axles. I wondered that first time “why didn’t they just put a drain slot or hole at backing plate to let any seepage out, instead of forced onto brakes? One wonders if they really need repacking every 25, (why would that be? No technical reason..really) or if that was a service revenue move. They do not now(fronts w same design, dual Timkens are common, as is “greased bearing sealed for life” ) ; Given you might pull out the thrust bearings, leading to pulling pumpkin for a reward to your good intentions, I’d tend to wait for sign of trouble, brake or bearing, leave well enough alone---you can do more harm than good rather easily, if you pull axle . my .02. your mileage may vary, no issues with that here . Question authority, and all that. John From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of kmaniak@xxxxxxx [Chrysler300] John, thanks for the heads up on this. Having said that, the wording of your notice could lead the reader to believe that the rear axle bearings, located at each wheel end of the differential housing, are lubricated with the same gear lube as the differential assembly. For 1964 and older Chryslers, including letter cars, this is not true. On these cars, the rear axle bearings are packed in axle grease, the same as the front wheel bearings. The greased axle bearings are contained and sealed with two grease seals, the inner grease seal that prevents the impingement of gear lube from the inside, and the outer grease seal mounted in the backing plate that prevents grease from contaminating the brake linings. Chrysler recommends repacking the rear axle bearings every 25,000 miles or at the same interval as the front axle bearings. This requires pulling each axle shaft and replacing both seals on each side. Any leakage of gear lube into the brake drum indicates that BOTH seals have failed. Many letter cars owners are aware of this design and required maintenance. But you would be surprised how many Chrysler owners I have met over the years who were completely unaware. So I thought I would mention this for clarity. Chris the KMANIAC -----Original Message----- Found out some interesting ,-- could be important ---stuff. In Auto Restorer; GL-5 gear lube has sulphur and other additives that attack brass, so not for use on manual transmissions or rear axles with brass / bronze parts ; GL-4 OK ; I know 300F has brass thrust bearings in Axle center (Timken style rear wheel bearings) , many cars of our vintage had brass transmission syncros , brass bushings in diff, etc . I have been using synthetic 75W Mobil 1, not sure now if GL-5 or 4; GL-5 made for all 100% steel bearings, like ball bearings etc typical of new cars , EP additives help those, are in GL-5 Heads up! John Grady, PE __._,_.___ Posted by: "John Grady" <jkg@xxxxxxxxxxxxxxxxx> To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to bob@xxxxxxxxxxxxx or go to http://autos.groups.yahoo.com/group/Chrysler300/join and select the "Leave Group" button For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang __,_._,___ |
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