Prop will not fit?

[RussLCV]

Hello again

1275 engine, gearbox and clutch in, the gearbox has been rebuilt (not by me) is now installed and finally tightened everything down today so I thought I would pop in the propshaft too..............Well that was an understatemant!! I have oiled the prop to gearbox joint and oiled the gearbox shaft. The prop engages and goes in to about 1.5 inches and sticks. I have tapped it and then it will not turn freeley just release a little and its ok. I have removed it again and the same applies whe I try to fit it. So currently after over an hour its still not in. Any ideas is it becase the gearbox has a new rear oil seal and its a tight fit and needs to be persuaded to fit or any other issues I need to be aware of

Thanks in advance

[mike.perry]

Can't remember having any problems fitting mine. Is there anything on thetailshaft that should not be there? Have you tried poking a screwdriver down the tailshaft to see how far it will go?

[RussLCV]

Hi Mike nope I have not done that..........how far shold it go as thre is an oil seal there

[rayofleamington]

I've heard of this before and it is usually an easy mistake in the rebuild This might mot be your problem but the symptoms match.

The gearbox tail assembly has a plain bush (steel sleeve with bronze or similar material coating). The bush needs to be reamed to size after fitting however unless the rebuilder has come across this before they wouldn't know.
Whenever I've had these machined (using an engine machinist with some old school tooling still around, e.g. adjustable reamers...) they have reamed the bush to suit the prop*.

The gearbox tail housing is fairly easy to remove and does not compromise the gearbox rebuild. The tail housing has a flat mating face which is used to sit on allowing the bush to be machined true/square to the tailshaft axis. To machine this, the new seal will have to come back off and if the seal housing is damaged it'll need replacing again. The seal housing tend to be far more fragile than they used to be so I'd be in doubt about removing and refitting, although 20 years ago when I made the same mistake myself it was ok.



* Generally that's fine but this worries me a lttle in case one time I have a prop which is worn a little undersize - in which case you get a matched pair but both are out of spec. It's known for a prop to have wear biassed to one side as they will naturally run out if there is any play. I'd rather have a proper size guide so the prop O/D can be checked before it is used to size the bush.

[RussLCV]

hi Ray

Thanks for the information, not what I wanted to hear and this work seems beyond me and I have no idea what I need to do. What I do find strange is that this process needs to be done. What happens if I need to change or replace the prop in 6 months time, it will fit or will it need to be reamed again?
It would appear I have waisted my time installing this engine and box as it will all need to come out or can I remove what is needed with the box in situ. Any advice on what I need to remove and how is very welcome too, I seemed to have taken 1 step forward and then 2 backward

Look forward to your advice Ray and from others

[mike.perry]

Have you got the old box that you can try the propshaft on?
Worst case you have to take the box out again, if you haven't connected everything and put the cover on it should only take half an hour, a little longer if you kick the hubcaps, swear at it and have a cup of tea. Then you can try the propshaft out of the car.
I have fitted a ball race thrust bearing which should mean that it does not wear out like the carbon thrusts. You should see the state of the carbon thrust in my Series MM

[RussLCV]

Hi Mike

I have just poked a screwdriver down the sahft and it goes in 6 inches or so?

Anyone know how I remove the end cap to expose the seal and bush Ray refers to

[bmcecosse]

It is undoubtedly the bush that is too tight, assuming no damage on the prop. Is there no room to remove the tail in situ? And ask the 'reconditioner' if they reamed the bush to the correct size after fitting!

[RobThomas]

I've a spare tail end for a gearbox here in Llantwit if you need one, Russ.

Rob Thomas
01446 795489
Llantwit

[RussLCV]

hi all and many thanks for the info. Ray was spot on it sure was that bush so a big thank you to him.

I managed to remove the tail with box in situ, I tried prop into my spare box and it fitted no problems. When I removed the tail from the new box the prop would not go in and you can see that the bush is stopping it. So I have fitted the old tail and the prop is now in is OK.

Thanks all I just need this tail reamed out.....can anyone help with that

Thanks again

H

Ps thanks Rob I have 3 gearboxes it was this one was a rebuilt one

[les]

If you do it yourself Russ you will need an adjustable reamer. I did one a while ago, but unfortunately the bronze material in the bush was so thin that by the time the diameter was correct for the prop to slide in, the steel backing of the bush was showing, which of course meant the bearing surface had disappeared, two bushes were like this. Hope you have better luck.
btw pressing the new bush in is not for the faint hearted! In fact I think they are made too big diameter wise. New old stock seems to be the answer again.

[Pikey]

Russ
Ive got some reamers here, but nothing big enough for a prop shaft, sorry. Reamers are quite expensive to buy new especially adjustable ones and its something you'll probably never use again.

Try Pogsons 029 2059 3598| Tunnel Yard, Port Rd, Wenvoe, Cardiff, South Glamorgan CF5 6AB, hes a engine reconditioner. Hes done some good work for me, brake drum skimming and hes rebored my engine.

Regards

Steve B

[bmcecosse]

Just take it back to the person who 'reconditioned' the gearbox! And tell them to get it sorted.

[katy]

Just take it back to the person who 'reconditioned' the gearbox! And tell them to get it sorted.

If that doesn't work you might try honing it out w/a brake cylinder hone, but be very careful to keep it true.

[rayofleamington]

In this case I would recommend NOT using a brake honer - the amount of material you need to remove needs to be machined to give any hope of doing it right.

New old stock seems to be the answer again.

I've heard of this same bush problem last year, so I guess it's fairly common now.
When I last did one 10 years ago it wasn't that hard to tap out the old or refit the new.

I'm glad you're sorted now Russ - sorry I wasn't aroud the computer earlier, but you already found out that it IS possible to remove the gearbox tail casting in situ.