Wow. I believe you about what the Benzes say. I would love to see it somewhere in their writings. Of course I can't find it in my 123 manuals.
If that's what they say, that's what they say. I am amazed. BTW. what size radial clearance are we talking about? What, if anything, do they say to do if the last reaming results in a radial clearance just a fuzz greater than the specification? Scrap the job and start over? There are much simpler and easier ways to attain the same end. And adjustable reamers are one of the poorest ways to attain an accurate, that is, equal to a specification, clearance. The much older ways of calling fits, i.e., slip, thumb push, palm push, light press, and so on, all represent clearances or interferences, as the case may be. In this case they are radial, between pin and bushing, and are not different in principle than (MSWord would say "from"; I say to hell with them.) the clearance between connecting rod big end and crankpin. These ways of calling fits were developed by the 19th century railroad shops, who wrote that part of the book on machining and machine work, and are still true today. Tom Hargrave <[EMAIL PROTECTED]> wrote > To: <[EMAIL PROTECTED]>; Mercedes Discussion List <mercedes@okiebenz.com> > Subject: RE: [MBZ] King pin installation > > Mercedes specs a adjustable reamer with instructions to ream the bushings > until you achieve the correct radial play in the king pin. > > This is far from a single ream job & involves stepping up the size until the > king pin just fits, then assembling the king pin, measure the radial play > with a dial indicator, disassembling and reaming slightly larger. Then you > re-assemble & re-measure the radial play. This cycle is repeated until the > radial play is correct. > > You are correct about lubrication. It's the key to long king pin life. > > Thanks, > Tom Hargrave > www.kegkits.com > 256-656-1924 > > Robert Bigham wrote > Sent: Friday, October 12, 2007 3:19 AM > Subject: Re: [MBZ] King pin installation > > Regarding fitting kin pin bushings, I earlier said "nuf sed" > > I lied. > > It is a misconception to think that king pin fit in bushings is > critical. It does need to be right, but it is not in the class > with piston fit in cylinders or bearing shell fit in big ends of > connecting rods. It is much more tolerant than those critical > 'fits. > > I now recall that 1949-54 Chevrolet passenger cars have > king pin bushings that are full floating in the spindle and full > floating on the pin. No press in fit for bushings, no ream or > hone to fit on pins. Just slip them in. Takes minutes. > > And they, too, will last forever if the owner will keep them > greased. > > Manufacturers, in my experience, specify a fixed reamer, that > is, a non adjustable reamer, for king pin (also called spindle bolt) > bushing sizing. Ford for an outstanding example. Ford used the > same fixed king pin reamer beginning with 1928 Model A cars > until the last 1953 Ford passenger cars with king pins. Ball joints > came in 1954 on Fords, except that pickups kept king pins for > many years in the Twin I Beam front end. > > An adjustable reamer is an old time mechanic's tool for opening > up bushings that won't accept the pin unless reamed a bit larger. > They are not intended for reaming to a precise size, and can't be > set to cut a precise size. > > To set one to a particular size fairly close would require a ground > ring gauge and lots of time spent setting. The way they are used > is to ream and try. Reset. Ream and try again. Once the pin fits > the way you want it, stop. > > You can fit king pin bushings this way, simply because the fit is > not critical, but it is not a very good way. It is better than some > makeshift alternatives I can conceive. _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
