Technical Gearbox main shaft stuck in spigot bush. Ouch.

[1500500]

Hi

I can’t separate the engine from the gearbox. Clutch stopped working and seems I now have the gearbox main shaft stuck in the spigot bush on the crankshaft.

Any tips for dealing with this would be most welcome

Cheers

 

[bugsymike]

Hi

I can’t separate the engine from the gearbox. Clutch stopped working and seems I now have the gearbox main shaft stuck in the spigot bush on the crankshaft.

Any tips for dealing with this would be most welcome

Cheers

Not specific Fiat 500 knowledge , but until someone more familiar with that model ....
In general terms from long motor trade experience, I assume you mean the first motion shaft that the clutch centre plate splines engage with. On most older cars the spigot bearing was a bronze bush in the centre of the flywheel/crankshaft, in which case they are pushed / tapped into the centre hole and then the gearbox shaft rests in it, so if that is the case and the cause of your problem, I would squirt oil in through the clutch release arm/lever hole in the direction of the spigot bearing and then apply even pressure on opposite sides of the bell housing and wriggle the engine at the same time and hopefully either the shaft will come out of the bearing or the bearing and shaft will come out of the flywheel/crankshaft.
However make sure you support the engine on the same plane i.e. not higher,lower, to the left or right of the position it normally sits against the gearbox or it will strain the shaft in the gearbox etc.

 

[fiat500]

Hi

I can’t separate the engine from the gearbox. Clutch stopped working and seems I now have the gearbox main shaft stuck in the spigot bush on the crankshaft.

Any tips for dealing with this would be most welcome

Cheers

Are you certain that it's the spigot bushing? If it was some part of the clutch mechansm itself that was wedging things, my suggestion might cause more damage. Put simply, I think you need to either turn the engine with the gearbox completly locked or vice-versa, and with luck, that would break the "stiction".
If you can lock the flywheel of have a secure way of stopping the front pulley from turning, you could try to gently rock the car backwards and forwards in gear. Alternatively, get the car in gear and put on the handbrake and chock the wheels in both directions and then turn the engine over via the front pulley. You might risk using the starter, with the plugs removed and everything switched off, but there is a danger that if it's really stuck, you might damage something else.
Before doing anything, I would remove the flywheelcover under the car and havve a look to see all is as normal. That might even let you get a lever inside and you could try to force the engine away from the gearbox. Good luck, take things gently.

 

[bugsymike]

Are you certain that it's the spigot bushing? If it was some part of the clutch mechansm itself that was wedging things, my suggestion might cause more damage. Put simply, I think you need to either turn the engine with the gearbox completly locked or vice-versa, and with luck, that would break the "stiction".
If you can lock the flywheel of have a secure way of stopping the front pulley from turning, you could try to gently rock the car backwards and forwards in gear. Alternatively, get the car in gear and put on the handbrake and chock the wheels in both directions and then turn the engine over via the front pulley. You might risk using the starter, with the plugs removed and everything switched off, but there is a danger that if it's really stuck, you might damage something else.
Before doing anything, I would remove the flywheelcover under the car and havve a look to see all is as normal. That might even let you get a lever inside and you could try to force the engine away from the gearbox. Good luck, take things gently.

As Pete says if it isn't the spigot as you believe, if the car has been standing for some time the clutch centre plate could be seized on the splines, however I don't know how much access there is through the inspection plate but if it was possible to unbolt the pressure plate from the flywheel, if the clutch is the cause and not the spigot you may be able to release it that way.
At the end of the day try and do it with "love and kindness" it usually works out cheaper

 

[1500500]

Thanks for the replies.

With inspection plate off I Can can see that the pressure plate appears to be ok.

I currently have the engine and gearbox on one jack each. So they are both moving around. That was probably not helping me separate them on the same plane…

I will put a piece of wood between the top of the gearbox and the body of the car and apply jack peessure to hold it in place. I will also try spraying some wd40 and then come back later.

I did wonder if applying heat to the flywheel would transfer up to tue crankshaft enough to make a difference.

I was driving the car when the clutch stopped working. I was 90km from home and had done a very long freeway drive to get there. maybe the long drive spun whatever grease was left there out?? I drove the car home with no clutch., luckily only two sets of lights where I had to turn the car off and then stat again in first gear.

When I first got the car on the road after engine rebuild with new crankshaft I had the same direct drive issue and at the time reamed the spigot bush a bit. It has lasted about 3 years but maybe it was still a bit to close a fit.

Cheers

 

[bugsymike]

At least you got home .
I wouldn't try heat as it will be hard to get to the right place without damage to other things.
Obviously nothing can be ruled out, but generally if the bronze spigot bearing was failing and seizing every time you completely disengaged the clutch you would have heard an awful screaming noise (it was common on early Vauxhall HA Vivas)
Note, I say completely disengaged, if happened when light pressure on clutch pedal then more likely the release bearing as the only time the spigot bearing and gearbox first motion shaft move independantly of one another is when clutch completely disengaged.
I see you mention the new crank and a tight spigot bearing, it maybe inspite of you reaming the bearing/bush it was still a bit snug.
In my experience the bush only acted as a support for the first motion shaft so a certain amount of "wiggle" was normal, they were never meant to be a snug fit (modern cars often don't even have them) also the original spigot bearing was made of bronze I believe and self lubricating to a certain extent, though when fitting clutches it was common practice to put a little dab of copper slip grease or similar via a finger into the spigot bush.
I only ever had one Fiat 500 a 1966 model I think and that was in 1978, I paid £60 for it and apart from push rod tube oil leak and a new clutch it went fine though not a clean as your model looks . I drove it flat out 250 odd miles fully laden for a canal barge holiday 55mph and 55 mpg quite impressed though deafened

 

[the hobbler]

As Pete says if it isn't the spigot as you believe, if the car has been standing for some time the clutch centre plate could be seized on the splines, however I don't know how much access there is through the inspection plate but if it was possible to unbolt the pressure plate from the flywheel, if the clutch is the cause and not the spigot you may be able to release it that way.
At the end of the day try and do it with "love and kindness" it usually works out cheaper

The clutch pressure plate can be unbolted on the 500 from underneath, very easily. Remove the flywheel under-tray (3 x 10mm headed screws) and then in turn undo the small bolts that hold the pressure plate onto the flywheel---6 x 10mm heads screws.

 

[the hobbler]

The clutch pressure plate can be unbolted on the 500 from underneath, very easily. Remove the flywheel under-tray (3 x 10mm headed screws) and then in turn undo the small bolts that hold the pressure plate onto the flywheel---6 x 10mm heads screws.

Silly question---have you made sure that you have removed ALL the nuts/bolts that hold the engine and gearbox together.I can't remember how many there are on the 500,but on the 126 bell housing there are 7, and 3 of them are around the starter---2 for the starter and 1 immediately beneath the starter for the bell housing.

 

[bugsymike]

Silly question---have you made sure that you have removed ALL the nuts/bolts that hold the engine and gearbox together.I can't remember how many there are on the 500,but on the 126 bell housing there are 7, and 3 of them are around the starter---2 for the starter and 1 immediately beneath the starter for the bell housing.

It may sound silly, but a few years ago doing a clutch on a 308 Peugeot having thought I had removed all bolts and could only feel what felt like a dowel sticking out towards the gearbox turned out to be an extra bolt hidden behind the oil cooler, a bit embarrassing after then about 48 years in the trade

 

[1500500]

Silly question---have you made sure that you have removed ALL the nuts/bolts that hold the engine and gearbox together.I can't remember how many there are on the 500,but on the 126 bell housing there are 7, and 3 of them are around the starter---2 for the starter and 1 immediately beneath the starter for the bell housing.

Yes but thanks as that can always be an issue. I have managed to get about a 2mm gap between bell housing and crank case.

 

[1500500]

The clutch pressure plate can be unbolted on the 500 from underneath, very easily. Remove the flywheel under-tray (3 x 10mm headed screws) and then in turn undo the small bolts that hold the pressure plate onto the flywheel---6 x 10mm heads screws.

I will try that tomorrow. At the very least it will allow a bit more wiggle room. Cheers

 

[1500500]

I will try that tomorrow. At the very least it will allow a bit more wiggle room. Cheers

I have undone the pressure plate and had just enough room to spray some wd40. I will have to sacrifice the friction plate in the hope of getting this sorted out.

Leaving it overnight to see what happens.

 

[bugsymike]

I have undone the pressure plate and had just enough room to spray some wd40. I will have to sacrifice the friction plate in the hope of getting this sorted out.

Leaving it overnight to see what happens.

Sounds a bit of a nightmare, steady even leverage at the bell housing and a bit of wiggling may still save the clutch.
From what you said before the spigot bearing does sound like the culprit.

 

[Goldnrust]

Doesn’t looks like a fun problem, I don’t envy you.

Just thinking aloud, as you previously had an issues with the spigot bush, something that by what other members have posted sounds like an unusual problem, is there a different underlying problem here? A bent gearbox input shaft maybe? Or something causing a misalignment between engine and gearbox and so side loading the spigot bush?

 

[bugsymike]

Doesn’t looks like a fun problem, I don’t envy you.

Just thinking aloud, as you previously had an issues with the spigot bush, something that by what other members have posted sounds like an unusual problem, is there a different underlying problem here? A bent gearbox input shaft maybe? Or something causing a misalignment between engine and gearbox and so side loading the spigot bush?

Always possible , but from what you mentioned previously about a snug spigot bearing maybe just not as generous on the tolerances as original.
Bush obviously need to be a tight fit in the flywheel/crankshaft, however the gearbox shaft hole needs to be a little more generous when making a copy. From a engineering perspective it doesn't need to be anything like an "interference" fit, more so a shaft can waggle a little, this also helps when fitting the gearbox in the first place. Also was the bush made from the same type of bronze material which is slightly self lubricating. I mentioned earlier we used to have Vauxhall HA Vivas that the bearing "sung" when holding the clutch down for too long at traffic lights etc. even with the factory fitted spigot bearing, but a little copperslip grease usually did the job.
Mind you until you separate the gearbox and engine we are only guessing.

 

[Toshi 975]

Original spigot bushes on the 500 were of the bronze type but the later 126 ones are plain steel and I believe they are the only ones now available.

 

[fiat500]

Original spigot bushes on the 500 were of the bronze type but the later 126 ones are plain steel and I believe they are the only ones now available.

i'm sure that I read that it was "sintered" steel, which I think, implies that it has micropores. I think the recipe with these is to soak the, at least overnight, in engine oil.

 

[bugsymike]

Sorry , re read your threads, so you reamed the original bush , for some reason I thought you had turned one up on a lathe.
I am not a Fiat 500 expert, last one of those I had was around 1978, but from an engineering point of view why would any one put a steel bush in place of a bronze one, I know it only turns when clutch is depressed, but given once fitted there is no way to lubricate it surely that is asking for trouble.
Modern cars don't use it at all the shaft only reaches the clutch centre plate but the bearing supporting it is made to suit that design.
Still when the box and engine come apart all will be revealed

 

[1500500]

Finally separated the engine from the gearbox.

Detaching the clutch pressure plate made all the difference. Thanks again.

The spigot bush does not look very happy and the gearbox shaft has a bronze tinge to it…

 

[bugsymike]

Finally separated the engine from the gearbox.

Detaching the clutch pressure plate made all the difference. Thanks again.

The spigot bush does not look very happy and the gearbox shaft has a bronze tinge to it…

Well done, wouldn't want to pay the hourly rate at the Fiat Dealers eh!
Your suspicions about the bush were correct then.
Was it a pattern part, non genuine?
If you haven't got the bush out yet from the flywheel/crankshaft and don't have a special tool, we used to do it by packing the spigot bush with thick grease and then using a snug fit clutch alignment tool in the hole or similar , then giving it a smart bang with a copper mallet, hydraulic force would push the bearing out. You may have to add more grease as it's displaced, it works really well and we did it all the time.
As Goldnrust mentioned a close inspection of the gearbox shaft after all the struggle may be advisable.
When you have the new spigot bush ready to fit, ideally it should have a slight lead in taper to encourage fitting, also if you offer the new bush to the gear box first motion shaft, make sure it will easily slide down the shaft, so you can wobble it around, so you know there is no future issue. Then it also should be a nice firm press (hammer in) fit in the flywheel/crankshaft as you don't want it spinning. Soaking in oil prior as has been mentioned may help also, though to be honest we just put a finger of copperslip or similar high temperature grease in the hole (not too much as to get on clutch plate though!).
Finally a very light bit of grease on the clutch splines and check the plate slides easily on the shaft and wipe off any excess, before aligning and fitting the clutch assembly.