Cutting my driveshaft!!! no option!

[Dotong]

Hi, after trying everything to get my lower unit off (ive definately got all the bolts), hung it upside down, even tried to pry it apart with two 4x4s my last option is to cut the driveshaft to get it off! has anyone done this, can you weld it back?

Cheers

 

[Moody Blue]

Re: Cutting my driveshaft!!! no option!

Are you able to drop the LU at all ?

Cutting is pretty drastic. Will have to replace the driveshaft, don't think it could be welded straight enough.

Once it is cut, you will need to pull the powerhead to TRY and get the driveshaft out of the crankshaft. You will also have to pull the lower unit apart to get the bottom half of the driveshaft out. Sounds like alot of work. If the shaft is seized, its a good bet that many of the fasteners you will need to remove will also be seized.

 

[blue90HP50]

Re: Cutting my driveshaft!!! no option!

I posted my suggestion last night. Did you try my method?
Blue

Polite PS: Continuing a thread is best, so everyone sees all info at once!

 

[4JawChuck]

Re: Cutting my driveshaft!!! no option!

In general if you require a cutting torch to disassemble any consumer product...your doing it wrong.

Have you consulted a factory manual?

 

[Dave1027]

Re: Cutting my driveshaft!!! no option!

Before doing something stupid that will end up costing you a bundle, why don't you take it to a recommended qualified and certified Mercury service center.

 

[Dotong]

Re: Cutting my driveshaft!!! no option!

hi blue,

yes tried your method it still didnt budge, almost rounded the nut by putting so much force in it, i drilled a small hole in the middle casing too enough to get heat to shaft near top and still nothing!!

Thanks

 

[DuckHunterJon]

Re: Cutting my driveshaft!!! no option!

Since you drilled a hole in the casing, hang it upside down and spray PB Blaster or Kroil onto the shaft, letting it run down towards the splines. Spray it a couple times a day, letting it sit and soak. I haven't found a bolt yet that didn't work free with PB. Have had to let them sit a week sometimes, but they come free eventually. Hate to see you cut it, then all that's involved with getting the parts out and replaced. Good luck.

 

[Chris1956]

Re: Cutting my driveshaft!!! no option!

Adding to Jon's suggestion, which is a good one, you might try to put some heat on the driveshaft along with the PB Blaster. Alternate heat and cooling, with the penetrating oil, may just help it loosen up.

 

[turtles11756]

Re: Cutting my driveshaft!!! no option!

are you sure it's not the shift shaft splines that are frozen ? i have a 1970' 50hp with the same problem .wait a while before you start cutting

 

[CharlieB]

Re: Cutting my driveshaft!!! no option!

Help get some of us up to speed here.

WHAT motor, how many bolts/nuts did you remove?

Before you start doing anything like cutting, give us ALL the information we need to better advise you.

 

[Bob_VT]

Re: Cutting my driveshaft!!! no option!

Is the trim tab removed????

 

[Dotong]

Re: Cutting my driveshaft!!! no option!

Hi, just to answer all the questions and keep everyone up to speed ill tell you what ive done so far. its a mercury 45hp classic fifty and i assumed that the lower unit would come apart like my blueband 650. ive undone the trim tab, removed the bolt from underneath, the nut above the prop and the two side nuts as far as they will go. it drops down about 5mm, if you lever the gap to try and pry it from one end the other end will close and the same if you switch ends, suggesting its the driveshaft holding it. if i try to move the shift shaft there is play in it, so it cant be that holding it. So ive turned the engine upside down spaying wd40 down shaft from hole i drilled in casing. ive tried wedges and still nothing it wont budge an inch!!!

Thanks guys for your input so far!

 

[Dave1027]

Re: Cutting my driveshaft!!! no option!

I'd use Liquid Wrench penetrating oil. I have had better luck with that. Let it soak a day and bang on the drive shaft with a hammer and screwdriver to vibrate it loose.

 

[dbrew]

Re: Cutting my driveshaft!!! no option!

if you have all the bolts off even the one under the rudder looking tab and it still aint comming out i would take it in to a dealer and just ask a mechanic for some advise it is always free to ask and they can look at it and inspect it i dont know how mutch they would charge but i will bet it will be cheaper than a new lower( they arent cheap) good luck

 

[Chris1956]

Re: Cutting my driveshaft!!! no option!

There is one more "just short of radical" approach. You can remove the bearing carrier of the gearcase, remove the propshaft, and remove the nut holding the pinon gear to the driveshaft. You may be able to pull the driveshaft up thru the waterpump cover (destroying it), and remove the gearcase, with the driveshaft still in the crank.

I would do some research to make sure this approach is valid. I think it will work on the larger il4/6 motors.

 

[Chinewalker]

Re: Cutting my driveshaft!!! no option!

Does the motor run? If so, an old trick to loosen up rusted crankshaft/driveshaft is to loosen all bolts and run the motor, shifting gears, and generally making the lower unit work around to help loosen it up. Do it in shallow water with the boat tied up so that if it works loose enough to fall free it will be retrievable...

 

[Dotong]

Re: Cutting my driveshaft!!! no option!

Hi Chinewalker,

i tried that too initialy but i cant run it for too long because impeller doesnt work untill i replace it!

Thanks

 

[milehighboater]

Re: Cutting my driveshaft!!! no option!

I would try lifting the powerhead off before cutting my driveshaft.

 

[Mi duckdown]

Re: Cutting my driveshaft!!! no option!

Do not cut the drive shaft. You will be hard pressed to find another one. They are not available.

 

[Mi duckdown]

Re: Cutting my driveshaft!!! no option!

DOTUNG. What works better than heat and oil, is heat and water, it makes the rust explode.
Ive done it many times on rusted brake lines. bolts etc.
Since you have a hole in the casing and have it upside down. squirt lots of Marvel Mystery oil on the shaft. That stuff Works. keep squirting for day or two tap the shaft with a bronze punch and hammer While rotating the shaft.
An Air hammer with The blunt end works wonders also.