Driveshaft Shimming Q

[rayjay]

I am replacing the driveshaft seals and noticed that the driveshaft has about 15 or 20 thou of end float. The manual shows setting the end float with a special tool that helps determine the numder of shims used. No spec on end float. <br /><br />I was thinking of adding shims until the end play is less that .005". Does this sound like the right thing to do or should I leave it alone ? Rebuild is not in the cards right now. <br /><br />Also the propeller shaft has about 1/8" of end play and there is no mention of any shimming for the prop shaft and no end float spec. Does the 1/8" end play sound right ?

 

[seahorse5]

Re: Driveshaft Shimming Q

What is the make, model, and year?

 

[marinemech1]

Re: Driveshaft Shimming Q

do not add or remove any shims!!!<br />the drive shaft and pinion gear are shimmed as an assembly with the upper thurst bearings.<br />when the unit is running the gears tend to move apart therefore the shimming tool preloads the bearingd simulating the gears being thrown apart<br />at rest the driveshaft will have up and down movement.<br />if you look at your manual it should show shimming fixture and you can see what i mean

 

[Dhadley]

Re: Driveshaft Shimming Q

Lets start at the beginning. Seahorse has some good questions...

 

[rayjay]

Re: Driveshaft Shimming Q

Opps, and I used to be a parts man .<br /><br />1977 55 hp Evinrude.

 

[rodbolt]

Re: Driveshaft Shimming Q

I am with seahorse and Dhadley. but I will state that by adding shims you will lower the pinion and tighten up the backlash, by removing shims you will loosen the backlash. to much or to little places the load on the wrong portion of the gear tooth and will cause failure. the actual float is usually not specified on most OMC stuff but the shim procedure is. the shim procedure is not designed to control float but for placing the pinion gear in the proper relasionship to the fwd and reverse gears.

 

[rayjay]

Re: Driveshaft Shimming Q

I guess I am just used to dealing with automotive rearends. Sometimes you get one with high miles that has a little play in the pinion gear due to brg wear or the pinion nut loosening or whatever and I always tightened up the pinion nut just enough to take out the slack. Not ideal but better than the pinion gear rattling around on loose brgs IMO.<br /><br />In this OMC lower unit there is no brg preload so I am probably better just leaving it alone or maybe adding a .002 shim just for the age factor. It does shift and work fine, just had some water in the lube. No external leak so I replaced the driveshaft seals and oring on the seal holder.