53 Mercury steering box question

Need help in tracking down the culprit for a distinct clunk right when the steering wheel is centered (wheels going straight). Does anyone know of which bearing set that would probably cause this? I would think the worm bearing would turn more than once and the clunk would be repeated. I am guessing the sector bearings, but then I found out that there is a spring in the upper part of the box.

 

The adjustment screw may be a tad tight.

 

The only bearing adjustment is the end play on the worm shaft. the sector shaft rides in bushings. The screw and locknut in the cap at the end of the sector shaft is for adjusting the lash between the worm and sector.

 

thanks for the reply, perhaps this might help narrow it down. The clunk feels like the wheel wants to stay in a groove or detent. It only happens when the wheel is straight WITH THE FRONT WHEELS STRAIGHT. If I turn the wheel around one turn it is NOT THERE, either way. It feels strongly like a bearing missing a roller or ball. I can get the repair parts, but would like to narrow the cause down.

 

Check your idler arm. they wear funky, so you have to do it with the car on the ground.

 

good idea, but weird why does it only do it with the steering wheel straight and the front wheels straight. I will check it for sure.

 

Sounds like it might be in the box, a few years ago my steering wheel came up while driving, no steering, and had to push it back down. Found that the shaft came out of the worm gear, fix it but it really needed a new shaft, it did make a clunking noise too. On a 53 Merc 2DR SD.

 

Yeah, that sounds possible, guess I will have to tear it down, really has no play whatsoever, weird. thanks