HPD30 pattern check?

In process of re-gearing my hpd30.

This was my pattern when I was using setup bearings, was pretty pumped as this was the first pattern I got after setting up the backlash:


With the real bearings and races pressed in I end up with .0035" of ring gear runout on the diameter (not sure what it was prior). Backlash measures .005-.007 (measured in like 10 different locations..) which looks to be in spec. However my pattern went to this:








Looks like I need to back the pinion off a hair , but its close, some spots look more passable than others. Only problem is I don't think I can get the inner pinion race out without mangling the baffle.. which I would need to order a replacement for.

Any thoughts?

Consider adding more shim thickness to one side when setting your final carrier bearing preload, this will force the carrier away from the pinion. .003 more maybe, that would loosen you up .001 maybe on backlash, and center up your Pattern alittle. I would say Depth would be close to perfect. Some would say run what you have, your choice.:us:

Sorry forgot to say, than you don't have to mess with your pinion shim thickness, but you probably already know that.

that always happens with final bearings. Ugh. its almost like starting over, but not quite. Shoot for a 3-5 thousandths BL and you will be very happy. I think the tighter pattern will help reduce deflection under the extreme conditions.



but this says decrease backlash, so I would say decrease BL and bring the pinion in a hair more to keep the BL tight since if you decrease it you will start to get our of spec, I don't think you are done with the pinion depth yet. This is what sent me spiraling on patterns before .

http://www.pirate4x4.com/articles/tech/billavista/Gear_Setup

Thanks guys, I would think that Thehowler is right that I want a tad more bl.

Looking at this pic, I have toe contact:


I've pressed carrier bearings on with pre-load shims so I think I'm going to try removing maybe .003 or .005 from the pinion spacer stack and see where that lands me. I think a tad less pinion depth will help pull the pattern out and gain me a touch of backlash?

HobHayward said:

Thanks guys, I would think that Thehowler is right that I want a tad more bl.

Looking at this pic, I have toe contact:

I've pressed carrier bearings on with pre-load shims so I think I'm going to try removing maybe .003 or .005 from the pinion spacer stack and see where that lands me. I think a tad less pinion depth will help pull the pattern out and gain me a touch of backlash?

Click to expand...

yep you are right . it was late and I misread. you want to increase BL. Sorry.