In the industrial, aircraft, automotive and other worlds, cotter keys or safety wiring is often added to assumedly properly-torqued critical fasteners to assure continued clamping force. Even then, long-term, high-frequency vibration can dissolve safety wire and allow the fastener to come unfastened. It would appear some of the fasteners on OEM and aftermarket brake systems could use the belt and suspenders approach to avoid what is called amongst those that have experienced it “High-Speed Disassembly”. Chrysler famously even used LH threads on the LH wheel lugs and bolts for years to avoid this phenomenon. Remember to tell your tire guy before he tries to loosen the LH fasteners by turning them to the left. Disc brake rotors famously glow cherry red so one might assume nearby fasteners get quite hot, also. This will release a little clamping tension and perhaps break down an improperly-selected Loc-Tite. Thanks to all who have emphasized this important issue. May all your disassembly’s be slow and intentional. Rich Barber Brentwood, CA Just another 100 degree day here—looking forward to autumn Wednesday. From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of Anna F Noia sa-noia@xxxxxxxxxxx [Chrysler300]
Sent: Monday, September 21, 2015 1:41 PM
To: John Nowosacki <jsnowosacki@xxxxxxxxx>; John Grady <jkg@xxxxxxxxxxxxxxxxx>
Cc: Matt Allyn <allynentertainment@xxxxxxxxx>; Larry Jett <LarryWJett@xxxxxxxxx>; chrysler300@xxxxxxxxxxxxxxx
Subject: Re: [Chrysler300] CAUTION; disc brake conversions All these bolt loosening and falling out is from "NOT TORQUEING THEM DOWN". they require a set "Torque". This is usually in Foot pounds or is it pounds feet, either way, or even metric units! It must be looked up and used. Then the Bolt, nut or fastener will hold as designed. If not torqued, the vibration and heat cycles will loosen it faster that you can imagine. Every size bolt/nut/thread combination has a "Torque" range, or as designated by the manufacturer. Check your manual, there is a setting for every bolt in the car. IMHO. Good Luck. Best Regards,
Stephen A. Noia
1-408-210-4736 cell Had an unfortunate experience with a cast iron torqueflite I had rebuilt to fix lack of reverse. Bolts holding the tranny to the bell housing/converter cover came loose after a year or so, lunching both the front pump and converter and causing major front pump leak which left me stranded. On Sun, Sep 20, 2015 at 7:27 PM, John Grady jkg@xxxxxxxxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote: Really appreciate this Larry ; the warning aspect is super important ..maybe we need a section on website about known 300 failure modes like the throttle on ram cars sticking or JK boisters that have been messed with . That being said , the AAJ kit or any other important part of a car has to have the bolts torqued properly ( engineer hat on-- ) just like rod bolts . When torqued properly the bolt stretches slightly , like a thick rubber band and will not "back out" . I do not know if they spec a torque .. If not they should . I was victimized by a mopar steering falling off the frame in a restored Cuda ( Jamie H found the problem) all stock stuff assembled by a guy who did not torque the mount bolts. One was gone it was hanging loosely on 2 after 900 miles ; i was looking for steering linkage issue , all brand new . Almost got killed on 90 due to this , evolving poor control of car between two trucks 8" away . Had th is again on 4.0 jeep motor mounts after engine rebuild . Bolts got loose and then broke off , due to back and forth loading once they could move . Never happens to the factory jeep . So , broken tabs etc with only one bolt holding it may not be a design problem , it may be a loose bolt problem . Safety wiring on planes usually means the bolt has been torqued and provides indication of that ; it is not the same as say a castellated nut and cotterpin , which will positively stop any turning . Grade 8 or ARP bolts torqued correctly ought to be safe .. And loctite helps , but locktite is temp sensitive . Like lug nuts .. Same deal . GM bolt too ? Sometimes you see a dot of paint on critical car bolts when new . Same thing; they have been torqued to a spec . Torque converter and crankshaft bolts are another area where you see this issue . It can happen to anyone not usiing a torque wrench on critical bolts . I have 2 AAJ conversion on 2 of our 62's. I too had that problem with the Caliper Bolt Pins coming loose, and backing out. I now add lock tight to the threads to keep 'em from walking out of their home. Two recent troubles with AAJ conversions I have installed. One: my 66 300 rag. The upper caliper rod that holds the two halves of the GM caliper together, fell out. This left me with a curious "clunk" when leaving drive ways or over a speed bump. This must not have been too serious as I drove it months and miles in this condition before discovering that the 5 inch long piece was missing and NAPA has plenty of them called caliper somethings at little cost. PC photo of 76 Monte Carlo will show the part at the NAPA counter. Two: my son's 68 Charger. With my favorite grandson and Robert leaving soccer practice, he felt some thing wrong in the brakes and made two circles of the parking lot whereupon the entire caliper and pads broke off the AAJ part and lodged those parts high in the wheel well making steering impossible and zero brake pedal. (Why no pedal? neither pot lost any brake fluid but the rears didn't function either) Two hours wait for AAA but all are home safe. I have a photo of the busted AAJ part with one of the two bolt holes shattered. Guessing the other of the attaching bolts had fallen out leaving the remainder to support the entire brake system. It couldn't. Thank God it didn't happen last week when he made three passes at the 1/4 mile. Mid 14's at 100 mph Lesson learned: Probably these two main bolts must be safety wired or cotter pined. Certainly the two main bolts plus the two minor spacer bolts on the GM caliper should be i nspected routinely rather than just ignored. I will be inspecting my two remaining disc conversions today and insuring the two main bolts are to be permanent party 510 794 7911 I live in my own little world but it is OK: Everybody knows me here. ![]()
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Posted by: "Rich Barber" <c300@xxxxxxx>
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