MS4A fault, AD41B Fairline Corniche

[Four0_4]

I’ve recently bought a 1991 corniche, she has been stood a long time 15 years ish at a guess. She runs really well but has the typical leaky mild steel fuel tanks so I’ve taken the engines out for access to replace them.
Whilst I’ve got them out I thought I’d go through them… first job, take gearbox’s off, unfortunately the bell housing was full of gearbox oil. On closer inspection the input shaft to the box is lose, very lose, in fact it moves vertically by around 10mm and in and out by about 10mm too. Clearly the bolt fixing it to the gear has come undone although I have no experience of these ms4’s as I’ve only ever had VP outdrives.
Im hoping I’ve been lucky and caught it in time before it totally fell apart inside and destroyed itself.
Has anyone had this issue before and if so did it cause any internal damage/adverse wear? Did it need any new internals?
Worst case I’ll put to new box’s on but that’s going to be expense, although has anyone replaced gearbox’s on a Fairline corniche? If so what were the old MS’s replaced with?
Thank you!

 

[QBhoy]

Hi there. Is this with oil in the box, it’s moving as described? Are there any tell tale running marks on the shaft that might indicate similar movements whilst in its normal state, as in aligned and coupled to the engine. Perhaps I’d also ask if it shows as much movement when you put it in gear.

 

[Four0_4]

Hi QBhoy, the oil has come out of the box past the oil seal into the bell housing.
There are no tell tail moving marks at all, I guess the Splines in the flywheel have been holding the shaft aligned. When I put it in gear there doesn’t feel any torsional play, other than the looseness of the actual shaft.

 

[fred247]

on shafts TAMD41,

 

[Four0_4]

Thank you Fred 247! So shaft ‘52’ from that diagram is lose and I’m guessing it’s because bolt ‘54’ has become lose….

 

[fred247]

I would guest that you have far more problems than a loose bolt, that would not allow for vertical movements, worn bearings and possibly worn input shaft is the culprit. spares are no longer available for these boxes, try volvopaul, he had some old spares. Best look at replacements. we snapped an input shaft on a n ms5b cost £1800 to repair ? and a couple of months to find spares that was 6yrs ago

 

[Four0_4]

I think your right, I am an optimist and was hoping it hadn’t gone to far!
If parts are that hard to find for yours then this will be more difficult given we 6 years down the line and yours was a newer unit. Plan b then. (Although I’ll take your advice and contact volvopaul)
Thanks again for your reply.

 

[Plum]

I think your right, I am an optimist and was hoping it hadn’t gone to far!
If parts are that hard to find for yours then this will be more difficult given we 6 years down the line and yours was a newer unit. Plan b then. (Although I’ll take your advice and contact volvopaul)
Thanks again for your reply.

If that were mine I would remove the whole inlut shaft assembly to investigate. If it is just bearings and seals then they will almost certainly be standard sizes obtainable from your local bearing shop. You said that before you removed the grarbox to investigate the oil leak "she runs really well" so unlikely to be too serious.

Www.solocoastalsailing.co.uk

 

[volvopaul]

I assume your at Farndon ? We met a few weeks back on the pontoon , I am Neils Engineer.

id say the input shaft bolt has come undone , you may find the box needs a gear set as the input shaft mates with the forward and reverse gears , I might have a set as I’ve many used MS4 parts .

 

[Four0_4]

Volvopaul, argh yes we did, well since we spoke briefly about my intentions all I’ve done is take things apart, I’m very good at that!! can you pm me your contacts?

 

[Four0_4]

If that were mine I would remove the whole inlut shaft assembly to investigate. If it is just bearings and seals then they will almost certainly be standard sizes obtainable from your local bearing shop. You said that before you removed the grarbox to investigate the oil leak "she runs really well" so unlikely to be too serious.

Www.solocoastalsailing.co.uk

Hi Plum, thanks for your response, with yours and Volvopaul’s suggestions I will strip down to investigate further before I give up on it!

 

[oldgit]

Hi Plum, thanks for your response, with yours and Volvopaul’s suggestions I will strip down to investigate further before I give up on it!

For anybody doing this job with engines in situ.
Not major job to get box out and on the bench for somebody to look at.
Boat can remain afloat and job can be done alone but box is heavy beast and a mate on hand is useful esp. on reinstallation.
Hopefully nobody has fitted a aftermarket deepsea seal and the shaft runs in the bog standard packed gland.This means you can push the propshaft right back out of the way to get the reverse gear box out.
Remove all flexible couplings .
Lots of photos does help.
Take great care disconnecting water cooling pipes they might be very fragile, corrosion on unions / copperpipes/ hose connections.
Keep in mind those MS4B came in three different ratios , make sure you find out which one you have , either from ID plate or once on bench checking input and output shaft rotations.
Princess 35 . 2.63 ratio.

Oops. Fairline Corniche Gearbox. 200HP 41B engines with 1.94 ratio..


Repair box if at all possible many new bits are still available from VP. A combination of new and old bits from our VP could get you underway again.
There are NO secondhand MS4 on the planet, thet last one was in USA at around $3.500 + shipping and 20% UK VAT. and replacing with a nearly the same but not quite ,hydraulic Hurth, is lot of money and faff.
They were available for around £2.500 new a few years ago , you end up with two different boxs.
Chum replaced both of his MS4 when one unit failed in his Princess 33.
Engine realigned/ moved etc and possible prop repitching.
If you do find a used unit buy it and hide it somewhere safe.
When box out ,pull back shaft inboard, should not weep any more than normal, any worries, a coat of grease on shaft will prevent water ingress.
Gearboxes.