what you need is a new screw and ballnut/piston, and a day or so fiddling to replace.
this kinda thing.. i don't know if this fits your box... but now you know what the part looks like
NOS Mopar 1959-66 Chrysler Plymouth Dodge power steering worm & piston 1822736 | eBay
the spline on the end of the worm screw when new is a full compliment spline
the spline on the coupler is not. It has 1 spline that is double the width of the rest
they don't fit togther at first, work must be done...
when first installed i.e when new, the steering box is centerd and then the double width spline on the end of the worm screw is manually cut in the appripriate place to match with centred steering wheel and coupler. so it ends up, no longer a full compliment spline, there is 1 section where there is 1 double width spline, a double width valley, as it were that you cut yourself with a small grinder , to cater for the double "peak" in the coupler...
if somone has mashed the coupler on, any which way they can, and have not taken into account this "master" spline set up, i'd expect the coupler or joint to be damaged before the slightly harder splined end of the worm screw (bearings run directly on this part through its length it has to be harder)
if you are having coupler issues i'd speak to Bergman-auto (sponsor here, mopar focused) before speaking to borgeson (universaly useful stuff for all brands so not as mopar focused).
Borgeson will sell you a splined joint that would work ok on a race car with reinforced chassis/cage tied into the chassis up front, but that ridgid steel joint set-up is not necessarily the best, for a street car, that had a sliding pot coupler or rag joint orginally, installed to protect the top bearings in the steering box from chassis and k frame flex.
i.e no cage, no rigid front chassis/K, means flex, and therefore you are better off with the orginal slip joint/ pot coupler or rubber disk and pin, set up. So you don't smash up the top/head bearing cage on the steering box. the top bearing is a caged ball bearing much like those on the peddle crank of a raleigh pushbike... there is no deep bearing outer track to keep the balls in place its just a cup and profile on the worm screw keeping those balls in place
great for preloaded rotation, not so good in shear situations where a cone and roller setup would be preferable
both types of steering joint/coupler work but for longevity i.e 10,000s of miles on highway and crappy pot-holed city street, orginal set up is best
there are as you have found two spline sizes, has the wrong coupler been used in the past...?
did you have the correct one for the box in the first place? 1/16 of a difference i.e 1.5mm or 0.75 mm gap all round between small and big
I can't remeber which size is manual size and which size in power steering size.
Dave
