Fulcrum Pin - Eyebolt to Lower Arm

[Dean Moriarty]

Hello

I dismantled the N/S suspension on Sunday to fit the polybushes to match up with the ones done months ago on the O/S of the car.
Everything going fine and just had to attach the front lower arm and tie bar.
I should have been suspicious that all was going along too easily..........

On tightening the nut on the front of the fulcrum pin, its now just spinning. I can't tighten it properly or undo it now.
I assume the whole pin is just turning inside the eyebolt/lower arm. Should I be concerned about this? I didn't encounter this problem on the other side.

Any advice appreciated.

Cheers

[bmcecosse]

Usually it's held very tightly - is the nut spinning because it's stripped the thread - or is the whole pin turning? Is it still turning when you put the weight of the car on the suspension?

[chickenjohn]

Perhaps the cup is loose/worn inside the rear wishbone. It is the push fit from the rear wishbone that usually holds the pin while you tighten it up.

[Dean Moriarty]

It looks as if the whole pin is turning.
I was tightening up against some resistance as the front arm was compressing the front polybush. Then the resistance was suddenly lost. There is still some resistance which indicates that the pin is turning against something

I suppose I'll have to strip the whole lot down again and this time remove the arm from the torsion bar, (damn) but if the nut is turning with the pin then how will I be able to remove the front arm?

[chickenjohn]

You'll have to strip all the other nuts and bolts that hold the two halves of the wishbone together and apply some pressure with a pry bar to the front half of the wishbone, then you might be able to undo the nut.

Or try and tap the rear wishbone little further forward on the torsion bar splines and hope it gains some purchase on the cup.

[Dean Moriarty]

Cheers John.

That may have been the problem in the first place. I'll strip down.

[bmcecosse]

As above - the cup should be trapped inside the T bar open end - however the pin may be spinning inside the cup....... Get a pry bar in between the two halves of the lower arm - lever like mad while trying to unscrew the nut.

[chickenjohn]

Perhaps a few drops of loctite may be enough to stop the cup spinning inside the rear wishbone. Let it set for an hour or so before tightening the shackle pin nut. When you need to take it apart - many years later! - apply heat from a blowlamp to the area and this will loosen the bond of the loctite.

By the way- the eye-bolt shackle pin nut should only be tightened with the car back on its wheels and the suspension loaded. That loading on the suspension may also help avoid the shackle pin simply spinning when you try and do the nut up.

[Dean Moriarty]

Ok guys, I was wrong. I've stripped the front thread on the fulcrum pin, (damn)
Its my own stupid fault as I was using it to try to pull the rear arm forward.
I realise the pin is an interference fit into the lower arm and the manual states that the pin shouldn't be removed unless absolutely necessary.
So can I remove the pin from the lower arm and put a new one in or do they tend to come as an exchange item?
Either way, where is best to get the new parts or has anyone got a spare second hand one?

Many thanks

[Dean Moriarty]

Just looking at some MM commercial sites and it looks like the pin is available separately so I'm assuming its designed to be swapped over?

[bmcecosse]

The pin is absolutely NOT an 'interference fit' in the lower arm - it fits into the little cup - which sits inside the rear half of the lower arm. The poly bushes in the eyebolt then fit over the pin. It's the same pin as is used in the base of the lower trunnion on the king pin assembly. Get a couple of spares in stock !
Edit Correction! As pointed out below - that eyebolt pin is same as shackle pin, NOT the trunnion pin........ Still worth getting a couple of spares.....

[chickenjohn]

Ok guys, I was wrong. I've stripped the front thread on the fulcrum pin, (damn)
Its my own stupid fault as I was using it to try to pull the rear arm forward.
I realise the pin is an interference fit into the lower arm and the manual states that the pin shouldn't be removed unless absolutely necessary.
So can I remove the pin from the lower arm and put a new one in or do they tend to come as an exchange item?
Either way, where is best to get the new parts or has anyone got a spare second hand one?

Many thanks

You'll have to cut the nut/ stripped thread off with a grinder (tight spot though!) and replace the pin with a new one and new nuts. As BMC says, the pin fits to the cup and the cup is an interference fit inside the rear half of the wishbone. However, I think BMC is mistaken, as the pin is the same as a rear spring rear shackle pin- not a lower trunnion pin, which is a different item although it does look similar the lower trunnion pin is thicker between the threads- and more expensive.

Rear shackle/eye bolt pin:- sus719
http://morrisminorspares.co.uk/shop/pro ... 5176ef3b63


lower trunnion pin sus157
http://morrisminorspares.co.uk/shop/pro ... 5176ef3b63


You can tell that the eyebolt pin and rear shackle pins are the same as they both use the same size bushes!

[bmcecosse]

Oh yes ! Well spotted - I knew it was same as something and made a wee guess............

[Dean Moriarty]

Thanks

I got the nut off last night.
Does the pin come out of the cup easily?

[bmcecosse]

Yes - undo the nut!

[Dean Moriarty]

Pin removed. New ones ordered.

Thanks guys.