My plan for today of fitting a new cambelt to my TD100 fell at the first hurdle because I can't get the bolt undone on the crankshaft pulley!!!

I've tried making up a tool from 2mm steel as-per the manual to hold the pulley and stop it turning but I've then put so much force in (via a very long extension bar made from a scaffold pole...) that I have stretched and ultimately snapped the tool, twice!

So I tried an impact wrench, albeit only 1/2" square drive, and that made no dent on this problem either. I have a 3/4" impact wrench too, but need a reducer for the socket before I can try that.

Meanwhile I got a 1/2" diameter right-angle steel socket-bar, fitted that with a 19mm impact socket, and slotted that onto the crankshaft pulley bolt. I then let the starter-motor and flywheel do their thing and swung that through 1/4 turn until it hit something solid. The result, after a dozen attempts, was that the socket-bar snapped!

So this crankshaft pulley bolt really is firmly stuck, possibly due to excessive thread-lock when I last fitted it 3 years ago.

Please tell me I'm correct in saying that it's a right-hand thread and undoes in the normal direction, i.e. anti-clockwise? If not, I've spent all day tightening it!!!

Does anybody have any ideas as to how I can get this bolt out, please?

i dont know the car at all but can you not put the car in gear, and get someone to sit on the brakes to lock the engine?

That was the first thing I tried, before I made up a tool. Most interesting from this was just how far I could wind things (in the opposite direction to the engine's normal rotation) before it was finally tight enough that I was really putting in serious effort.

The problem is not holding the pulley still, it's getting the bolt that secures it to turn relative to it. If I didn't know better, I'd assume that they are one solid unitary component!

Thanks for the idea though.

I have just ordered a 3/4" female to 1/2" male impact reducer, so I can fit my 19mm socket on my 3/4" wrench. We shall see what its (alleged) 720 lb ft torque can manage: hopefully the bolt will turn before something snaps!

I imagine you already have some penetrating oil on it? I no longer use WD40 which is not a penetrating oil but a water dispersant, in fact the 40th formulation they tried. 3 in 1 spray works well. The other trick is heat from a little butane torch, Although tricky in the space available and with the heavy pulley there soaking up the heat. I'm sure you know this but you heat the bolt head for a couple of minutes, then let it cool.

when this bolt comes out, will it cause the timing to lost. if not, jam an extension bar against the ground and use the starter to loosen it.

Renegade_8 said:

The other trick is heat from a little butane torch, Although tricky in the space available and with the heavy pulley there soaking up the heat.

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Thanks for the idea.

I did consider this last weekend but worried about doing so because the crankshaft pulley itself contains an inbuilt rubber damper, and I suspect that the heat required to shift the thread-lock (170 C I think) will destroy the damper long before I get the bolt out.

Quite apart from the £100 for a replacement pulley (I changed it 2 or 3 years ago when the rubber broke down) the car will be rendered undriveable until I can replace it.

arc said:

jam an extension bar against the ground and use the starter to loosen it.

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Nice idea, and in fact I thought of it myself too, see my original post:

Meanwhile I got a 1/2" diameter right-angle steel socket-bar, fitted that with a 19mm impact socket, and slotted that onto the crankshaft pulley bolt. I then let the starter-motor and flywheel do their thing and swung that through 1/4 turn until it hit something solid. The result, after a dozen attempts, was that the socket-bar snapped!

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And that was a good quality bar too, that has previously had a scaffold pole used on the end of it!

I'm amazed that this is as stuck as it is, and utterly bewildered as to how I'll shift it!

Thanks for the thought though.

hi oil burner,

i am not sure is your TD100 is similar to my JTD105. when i changed the timing belt, i don't have to remove the big bolt of the crackshaft. the crackpulley with damper has 4 littel torx screws holding it. buy just removing the 4 little torx screw, i can remove the rest of the components like belt covers, tensioner, idler n of course the belt.

i can change a t/belt kit set within 2hr max.. is that what u trying to do?

Hi Tazztham,

Yes, I have the same 4 torx screws (M6 threads from memory, I think) and have even removed & replaced two of them to hold the retaining tool that I broke (twice!). I was worried about removing all 4 screws in case it wouldn't go back in exactly the same place, and I upset the balance as a result ...but if you've done it, with no ill-effects, I'll give it a try.

Yes, I am trying to change the timing belt (& idler, water-pump etc.) and as far as I know the JTD105 engine is basically a 1910cc TD100 engine with more sophisticated (i.e. electronic) controls for injection & turbo. My understanding is that the 'metal bits' are pretty similar between the two, so if it works for you it should work for me too.

Many thanks for the idea and advice, it's much appreciated.

hi there,

don worry about running out of timing etc. the crackpulley has a key to it and it will not get wrong. just remove all that, and u will get into the rest. however, i do want to let let u know that changing the waterpump is not easy as u need to remove a camshaft sensor with tiny allenkey size but big bolt. guess what! i failled to remove that and leave the water pump..

also, u need to remove M18 bolt on the camshaft in order to take out the cam pulley. not easy also.

what t/belt kit set u using? ori or SKF? usually the belt will have 2 white line for u to gauge the timing...one for cam and one for crank.

so far i find it JTD105 engine is very easy to change t/belt. no sweat! compare to some jap where u must remove the big crackpulley bolt!

if u need help, do post here...cheers.

Hi there,

I think we have just found some of the differences between TD100 & JTD105

When I fitted the current cambelt 74,000 miles ago I had no problem whatever changing the waterpump, and have no recollection of a sensor on or even near it. Similarly, I don't remember removing the camshaft pulley: why did you have to do that?

The 'kit' I am using is a collection of parts supplied by Steve of Alternative Autos. I first spoke with him 3-4 years ago (when I didn't want to pay Fiat main-dealer parts prices last time) and he assembled all the necessary bits and couriered them to me. The belts in it are Dayco, although I have a suspicion that he sent me SKF a few years ago (I guess I'll see when I take it all apart!).

I kept the timing last time by putting a spot of paint on every pulley, and corresponding spots of paint on the engine block, before I removed the old cambelt. I then made very sure that all the spots lined up again once I had fitted the new tensioner.

I'm still pleased to know that I don't have to remove the big (and very stuck!) crank-pulley bolt...

hey mate,

IMPORTANT! yours is a TD100 and it is necessary to align your fuel pump, crank & cam shaft at the right spot. mine JTD does not need to align the fuel pump gear. so it makes much more easier when installing back the belt.

i bought a full SKF kit set with waterpump in it for about GBP90. All are SKF bearing but the belt is from Gates. i think it is a very good deal considering i am from Malaysia. if think u can get cheaper over there.

hope u can change them without fuss.

Are you really trying to remove the crankshaft sprocket to do a timing belt? Wouldnt you loosen the camshaft sprockets?

Anyway the crankshaft sprocket is a lefthanded thread and tightened to 360nm. You may well be tightening it.

OilBurner said:

Yes, I have the same 4 torx screws (M6 threads from memory, I think) and have even removed & replaced two of them to hold the retaining tool that I broke (twice!).

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From this post it sounds like you are using the timing tool to hold the crank sprocket while you undo it. That tool should not be used in that way, it will also be impossible. If its a tool you have made using the m6 bolts, those bolts wont take the force

I presume the gearbox is still on the engine. I used flywheel locking tools to take the cranksprocket off 3 engines. https://www.fiatforum.com/tech-talk/193721-tools-removing-flywheel-pulleys.html

just done the timing belt on a 1.6 weekend, the way I got it off was, top gear, footbrake on and use one of those electric impact wrenches for the wheels. really easy, and believe me no job ever goes easy for me, snapped bolts, lost screws, wrong size shape etc.