Some 15xx rolex info...

[automatico]

The 25/26 jewel 1520 used in the 5513 Sub, Air King etc is exactly the same as the 17 jewel model except for jewels in the reverser pivots and jewels in the movement plate for the intermediate wheel of the autowind assembly. The same balance assembly with flat hairspring is used in both.

The chronometer grade 1570 is a bit different besides the jewel count as it has a different pallet fork, escape wheel and balance assembly with Breguet type hairspring. Jewels can be installed in place of bushings in the reverser pivots of 17 jewel models but they will not accept the same jewels as used in the 25/26 jewel movements but must use special order jewels with a larger OD. If a watch is worn for a long time with worn reverser bushings, the reversers will run partly out of mesh and wear the red anodized finish and wheel teeth. The intermediate wheel can also run partly out of mesh if the intermediate wheel bushings wear and this will sometimes result in worn or broken teeth on the intermediate wheel. You can tell when the bushings on the intermediate wheel are going south by looking closely at the reverser for swirl marks caused by the wheel running out of true. Intermediate wheel bushings can also be replaced with jewels so it is a good idea to replace them all at once.

The bushings tend to wear out on the autowind reverser pivots if they run dry or get dirty and it is better to replace worn bushings with jewels, not new bushings. Intermediate wheel bushings will sometimes show a lot of wear if the mainspring bridle does not slip freely against the mainspring barrel wall when fully wound. When the MS grease dries out, the MS bridle (friction slip clutch) will not slip easily against the barrel wall under full wind and all the winding rotor power ends up at the intermediate wheel and can break teeth off and/or elongate the hole in the bushings, especially if worn during conditions where vigorous activities cause high rotor inertia. This sometimes causes balance "knock" as well as wear or damage on various autowinding parts.

(The intermediate wheel transfers power from the autowind assembly to the mainspring and has a relatively heavy load on it.)

Another problem with all 1530 base movements (1570 etc) is that the mainspring barrel runs in the bare plate on the dial side...no bushing or jewel, (I guess they were trying to save 50 cents) The lowly Eta 2824 even has a jewel at this location and Rolex finally put a bushing at this location on the 3035 when it came out because they had to...the faster beat movement makes more MS barrel revolutions per day. If the dial side MS arbor hole on any 1530 base movement runs dry long enough it will wear the hole in the plate out of round causing the MS barrel to drag on the plate. This gives the same symptoms as a dirty movement or weak MS...low running reserve etc. It looks like the plate is probably too thin to install a jewel at this location if the hole wears out but a bushing might work if you can locate the exact center of the original hole. An elongated hole can be closed up a bit with a punch but this is not good practice.

　

Auto weight axles wear out and usually the first sign is when you can hear the rotor rattling when you shake the watch up and down a couple inches with the dial pointing up or down. They all rattle a little bit but a loose axle knocks louder so listen to one known to have a good axle and gib (rotor clip) first for comparison. Another check for worn rotor axles and/or broken rotor axle jewels is to remove the caseback and examinine the movement plate for signs of the winding rotor rubbing the plate. They all probably have the rotor hit the top plate now and then but when the axle gets worn out or a jewel breaks the wear will be easy to spot. The fix is a new rotor axle and gib along with one or both jewels if needed. I will not get into proper rotor axle removal but if some hack simply drives it out of the weight without cutting the rivet down they can damage the hole in the weight and the new axle will not be a proper fit.