88' 140 drive shaft replacement

[huddled]

Ive been told by a mechanic my shaft is bent. the seal has been replaced but im still getting water in L.U.
Is this common? and is it something a novice mechanic can do at home?

 

[Dhadley]

Re: 88' 140 drive shaft replacement

A bent d/s is not common, I think I'd have to see it myself. As for the water getting in did he pressure and vacuume test it? How does he know the d/s is the root cause?

Yes, you can do it at home if you have all the special tools. The original d/s was a 1 piece. It's an easier replacement if it's a newer 2 piece, the lower unit doesn't have to come atart.

 

[R.Johnson]

Re: 88' 140 drive shaft replacement

Those driveshafts have a lot of spring to them, you would bust the gearcase, or the exhaust housing, before you could put a permanent set in one. I have over the years used old, damaged driveshafts as pry bars, you can spring one a long ways before you put in a permanent bend.

 

[Joe Reeves]

Re: 88' 140 drive shaft replacement

A bent driveshaft will shear (break), usually just below the water pump plate after a unknown length of running time.

A bent shaft can be detected easily when installing the lower unit. As the lower unit is slid up against the upper exhaust housing surface to which it bolts up to, one side of the lower unit will be further away from that surface than the other side.

Also easily detected when off by simply rolling it across a flat surface.

The upper driveshaft housing and seal assembly that exists just below the water pump plate....... if only the seal was replaced, therein most likely lies your problem. It is always necessary to replace the seal and bearing housing complete. The seal leaks due to the bearing being worn somewhat which in turn allows the seal to go oblong........ it is impossible for a egg shaped (oblong) seal to function properly.

The above is assuming that your propshaft surface at the seal area is not damaged in any manner (ridges, grooves, etc).

 

[R.Johnson]

Re: 88' 140 drive shaft replacement

Joe: The shaft is not bent, the gearcase is sprung out of alignment. You may be able to twist that shaft beyound it's elastic limit, you can not bend it without breaking the enclosed castings.