mrbudge Posted November 23, 2012 Share Posted November 23, 2012 Am I missing something or does this TSB tell you to way overpreload the pinion bearings. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted November 24, 2012 Share Posted November 24, 2012 Can't argue with an engineer, eh? Quote Link to comment Share on other sites More sharing options...
Aaron Posted November 24, 2012 Share Posted November 24, 2012 Soo... Not checking the contact pattern, preload before or after, not inspecting bearing condition since it's been used with the improper preload... I see no ill future effects. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted November 24, 2012 Share Posted November 24, 2012 What we don't know is if this is due to an improperly tightened pinion nut during manufacturing. Perhaps an improperly set tool or tool out of calibration. A pinion that causes a POP or a PING suggests the pinion nut is "tight" and some pre-load exists. If the nut were truly loose you would have different symptoms like vibration, fluid leaks, rumbling noise and axle failure. Now I agree with the points that there could be something wrong with the gears but to be honest, unless these things were left hanging loose it is unlikely there is any damage to the gear set. Secondly, I doubt Ford would have us load the bearings without good reason, like my opening statement. But since you just never know with the world of Ford Motor Company I guess we will find out won't we? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted November 24, 2012 Share Posted November 24, 2012 I agree the setup procedure in shop manuals sometimes overloads the pinion bearing on assembly. I've set up numerous diffs over the years and you learn to take the factory info and give it a twist of experience. I have no recollection of any of my diffs ever coming apart in normal service, but I believe one or two were murdered (heavy dumps stuck in the mud). On a RWD a few inch pounds of drag measured after breakaway always worked for me. I've flattened out and reused crush collars when the new one did not want to crush using reasonable force. Few shops have the zillion ton press used at the factory to crush collars. IMO, if you're not comfortable with the procedure and you're experienced in doing diffs, making a reasonable change to the procedure is acceptable. If we followed the WSM to an absolute "tee" in every exacting respect, the vehicles would never leave our bays. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted November 24, 2012 Share Posted November 24, 2012 Every time a crush collar in my shop has been subjected to re-use or an "adjustment" requiring backing off and re-tightening pinion bearing repairs followed. Ford gives us a specification range to shoot for and it is not hard to hit it. On these rears that are shimmed I see guys fail to pick up a torque wrench and just whack the pinion nuts with an impact gun. After all, it is shimmed right? What could go wrong? I am failing to make a distinction here. Again, in my opinion Ford knows what happened on the affected vehicles and has made a calculated repair. Since the majority of our fellow technicians choose to make flat-rate repairs it should be no surprise to us that Ford gives us flat-rate fixes and technical service bulletins. Quote Link to comment Share on other sites More sharing options...
Aaron Posted November 24, 2012 Share Posted November 24, 2012 I agree the setup procedure in shop manuals sometimes overloads the pinion bearing on assembly. I've set up numerous diffs over the years and you learn to take the factory info and give it a twist of experience. I have no recollection of any of my diffs ever coming apart in normal service, but I believe one or two were murdered (heavy dumps stuck in the mud). On a RWD a few inch pounds of drag measured after breakaway always worked for me. I've flattened out and reused crush collars when the new one did not want to crush using reasonable force. Few shops have the zillion ton press used at the factory to crush collars. IMO, if you're not comfortable with the procedure and you're experienced in doing diffs, making a reasonable change to the procedure is acceptable. If we followed the WSM to an absolute "tee" in every exacting respect, the vehicles would never leave our bays. Unfortunately... not for .4 - (Road test, verify, repair, re-road test, verify, do paperwork, park car) I miss fixing Fords sometimes, but then I see bullshit labor times like this... Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted November 24, 2012 Share Posted November 24, 2012 Unfortunately... not for .4 - (Road test, verify, repair, re-road test, verify, do paperwork, park car) I miss fixing Fords sometimes, but then I see bullshit labor times like this... Labor times for rears suck on a normal basis to begin with. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted November 25, 2012 Share Posted November 25, 2012 We have no idea as to why this is an acceptable repair in thew eyes of the engineers. All of us are assuming that pinion bearing preload is already in spec. Yes, at first I was skeptical of this TSB. Having said that, most of us here can attest to the efficacy of "bullshit repairs". Tighten this - add a container of friction modifier for that - shim the other thing up... We can repair something with the idea that we don't ever want to see it again - or we can repair something on a SWAG and a gamble. In the last 40 something years, there are times where I have rolled the dice for customers on fixed incomes that honestly cannot afford a "proper" repair. My batting average has been better than I ever imagined. As you should have been able to tell, disabling emissions controls is NOT part of my strategy for "affordable" repairs. Quote Link to comment Share on other sites More sharing options...
mrbudge Posted November 26, 2012 Author Share Posted November 26, 2012 All I can say is I guess we will now be stocking more pinion bearings. It is funny how when I get a vehicle with noisy pinion bearings there is always a pinion seal replacement in its history. Quote Link to comment Share on other sites More sharing options...
Aaron Posted November 26, 2012 Share Posted November 26, 2012 All I can say is I guess we will now be stocking more pinion bearings. It is funny how when I get a vehicle with noisy pinion bearings there is always a pinion seal replacement in its history. Ain`t that the truth! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.