Marston OP Rebuild

[Swordfish]

Hi all

I would like to pick up from my earlier post here and rename it to something more applicable:

viewtopic.php?t=7269

Over the past few weeks I have been soaking all nuts and bolts in penetrating fluid, and having applied lots of heat I am happy to report that so far all fasteners have undone with surprising ease.
I am now trying to seperate the gearbox from the upper unit, but even with all bolts undone from the top of the drive shaft tube right down to the gearbox housing undone I am unable to seperate it. I would have expected it to come apart either at the water pump/gearbox join, or at the crankcase/driveshaft tube junction?
Is there something else that I have missed? Has the driveshaft simply corroded onto the couplings at both ends, preventing separation?

[Swordfish]

I have successfully separated the power head from the driveshaft. These early Marston motors have a round drive shaft tube with keyway rather than the square drive tube. This means that they are more prone to seizing together. Thanks to advice from one of this forums resident members I took a piece of 4x2 timber and with a hole saw the same size as the driveshaft outer tube, made a slot so that I could hang the motor upside down by resting on the water pump housing clamp. With the timber clamped in a vice I then was able to persuade the shaft apart with a hammer and wooden drift tapping on the crank case around the outer driveshaft mounting flange. It didn’t give up without a struggle, though!

[Swordfish]

OP613

[Swordfish]

OP

[Journeyman]

Looks like a very worthwhile project that is coming along well, I'll be watching with interest.
Dave.