Replaced prop shaft seals, how to set rolling torque properly?

[nathanj988]

97' VP 5.7 LK DP

I removed the outer drive shaft to replace the shaft seals and now during reassembly, I need to set the rolling torque. I have only had the boat for a couple months and haven't run it in the water yet. Before I disassembled it, the prop shafts had vertical play. Now that I have put the shaft back in and tightened the retaining ring, all the vertical play is gone. I tightened the ring enough to remove the prop shaft in/out play. My rolling torque value was only about 3 in. lbs to remove all the play.

The manual wants it set to 18-26 in lbs. To get to 20 in. pounds, I had to tighten the retaining ring quite tight. My concern is that I don't want to run it too tight and burn the bearings or gears up. I couldn't test the before rolling torque because I could tell it wasn't put together right and was too loose.

I'm not sure if the rolling torque values in the manual are only applicable for new gears or if I can use them during reassembly.

Thanks,
Nathan

 

[nathanj988]

Re: Replaced prop shaft seals, how to set rolling torque properly?

I was wrong, I just tightened the retaining nut more, and the rolling torque is only up to 15 in lbs. I had to take the lower unit off my stand and lay it on the ground so that I could step on the skeg to get tighten. I would estimate I have that retaining nut over 100 ft lbs.

How tight does that retaining nut usually have to tightened?

 

[muc]

Re: Replaced prop shaft seals, how to set rolling torque properly?

Shouldn’t have to tighten the retaining nut that tight.
The fact that you had play in the shafts before starting repairs is a red flag.
The manual rolling torque values are for new bearings that haven’t been spun under a load yet. Subtract 5-7 in lbs.
What is your gear backlash and tooth contact pattern look like?
I know you don’t normally need to check them when you just replace seals but fact that you had play before disassembly and that you have to tighten the retaining ring so much leads me to believe there are other problems ---- bad bearing or bad shimming.

 

[nathanj988]

Re: Replaced prop shaft seals, how to set rolling torque properly?

Muc, thanks for the help. The bearings look good and feel good, at least the ones that could see while replacing the prop seals. I checked the gear lash yesterday with a slightly ridiculous test setup and I was getting 0.008 lash on the outer shaft. I will probably make a better lash checking tool today that closely matches the Volvo tool, although I expect the results to be very similar.

I started with a loose retaining nut to see the impact on the gear lash and I noticed the following;
With the retaining nut loose, the outer prop shaft lash also moves the inner prop shaft in the same direction.
Retaining nut tightened to a reasonable amount, the outer prop shaft no longer wiggles the inner shaft.

I don't know, but I think the outer shaft shouldn't move the inner shaft.

I haven't checked the gear meshing, I will pick up some gear marking compound and check it.

How tight do you think the retaining nut normally is?