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Glyn Harper

Gearbox removal advice

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Hi chaps. Just after a bit of general advice on removing the gearbox please?

I've actually done it once before, but it was about 15 years ago so I'm a little rusty!

So far I've unbolted the hubs, punched the roll pins out and popped both driveshafts out (boot floor is out of course). Taken the exhaust off, and the exhaust mounting cradle, as well as the selector mechanism.

It looks like I also need to remove both ends of the turbo oil return pipe, the wastegate and the turbo inlet hose (for clearance).. then the starter motor of course.

So, next comes the trickier bits! removing the clutch lever. Can't remember how to do that. any advice?

And for the actual gearbox.. I seem to remember unbolting the 4 M8 bolts that hold the gearbox mounts to the chassis, so they'll come out with the gearbox. Then I think I put a block of wood under the sump, and gently jacked the engine and box up enough to then slide the box back and off the input shaft before struggling to lift it out.

Does this sound right?

I think I'm about 70% there really, just the last 30% is a bit tricky! :)

While it's out.. I can't decide whether to change the clutch or not. It's probably been in about 15 years, but won't have done more than about 10,000 miles I reckon.

If I do.. do I go for a standard one from SJ Sportscars (£175), an uprated one from SJ Sportscars (£400) or an uprated clutch from PNM engineering (£234)

I don't know if anyone has any experience of any of these kits? I've not go money to burn, so may just have a look at the existing clutch to see how much life it's got left. Any ideas how to tell it's rough level of use?

I have ordered a new release bearing though. :)

Cheers.

Edited by Glyn Harper

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dont pull the driveshafts out the gearbox or the seals will leak - split the yokes and bag them up.

leave the turbo pipes alone they don’t need to come off.

drop the starter and the clutch slave off.

undo the gearbox mounts from the chassis - leave brackets attached to Box.

then the big bolts round the bell housing.

jack up and split.

clutch kits - I’d not believe much of the hype and smoke - they are all R25 turbo kits reboxed .......

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The gearbox is going away to Chris Cole, so the seals are getting changed anyway which is why I popped the driveshafts out. I've never actually tried splitting the yokes before.. should look into that for the next time really!

So does the clutch fork stay in place when I remove the box?

Good news about leaving the turbo pipe in place. I've ordered a new O ring for the sump end as it's a bit leaky down there, so I may swap it anyway while I've got a bit of time when the gearbox is away.

Cheers.

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The fork falls off when the Box is out ?

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Well, the gearbox is almost ready to come out! The only thing holding it in is the 8 bolts connecting the bell housing to the gearbox.

To get it out, I know I need to jack the engine up a touch, but looking at it, it's going to need to jack up a reasonable amount so the gearbox mounts clear the chassis. Will the engine mounts allow that much travel without being damaged?

I was tempted to remove the mounting brackets attached the the gearbox and engine mounts first, so they were out of the way. There's one bolt though which is a button headed bolt, shown on the parts diagram below circled in red. I had a brief go at moving it (as I knew if any bolt was going to be difficult, it would be that one).

Sure enough, it's fairly well seized. I didn't want to swing on it too much as it's an internal hex which will probably round out and then need grinding off.

I've actually ordered brand new bolts to replace all the mounting bolts for the gearbox, starter and clutch slave cylinder in stainless so it's not the end of the world if it does need grinding off. Just a real pain though to be honest.

I've put a load of WD40 on it and I'll try it again tomorrow. Or shall I just leave the brackets on? The gearbox is going away to Chris Cole so I don't want to burden him with having to get it off when he gets it. That's just a bit rude I reckon. :)

Cheers.

 

gearbox-mount.jpg

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There is absolutely no need to take those brackets off.  The box can be removed easily by just removing no. 45 (and the other side, obviously).

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Thanks. 45 is the one that is tricky to get to though as the bottom link is sort of in the way. I've removed 41 (the bolts holding the engine mount to the chassis) so I may try with those removed.

Having said that, I could probably jack the box up a bit now and get to the underside of 45 as it clears the chassis maybe? Not sure I've got the correct imperial sockets though!

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It’s only a nut and bolt - cut it off if you are having problems

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The button head is there because the bowden cables for the gear selector run right next to that dome head bolt, so I assume it's to stop it wearing the sheathing of the cable.

I've got another on order. I'll see if I can get the gearbox off with he brackets on, if not, I'll maybe chop it off and get mole grips on whatever left. :)

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I’d send the brackets to Chris. I did on both mine - they came back nice and clean

It should be a normal bolt

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I’ll try and get the gearbox out with the brackets on then. Did you leave the rubber mounts on when you removed it? I’ve got new mounts but they look easier to swap once the box is out due to the lower links being in the way. Although I gues I could take the lower links off. The other end is off already!

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You don’t need to take the lower links off.

the two small bolts 41 come off if you find that easier. Just jack the lot up at the bellhousing end of the engine. You can jack it up lots until the engine tilts and hits the bulkhead

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I've actually taken the lower links off anyway. It literally took about 1 minute per side, and the good thing is I can give them a good clean now as they are really filthy and covered in oil and dirt.

And I can now fit the new rubber mounts when the gearbox is away being serviced and get them oriented correctly. Got some nice titanium bolts in stock that I can use for the mountings! :)

Gearbox is pretty much ready to come out now apart from the 7 or 8 bolts. Need another pair of hands now, then We'll be there!

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21 hours ago, Glyn Harper said:

The button head is there because the bowden cables for the gear selector run right next to that dome head bolt, so I assume it's to stop it wearing the sheathing of the cable.

I've got another on order. I'll see if I can get the gearbox off with he brackets on, if not, I'll maybe chop it off and get mole grips on whatever left. :)

 

Unless I'm mistaken, the bracket shown is for the LHS of the gearbox, and there are no Bowden cables running next to it. The only cables I know of are the Morse gear-change cables, and they're on the RHS of the gearbox. I don't know why they originally used a button head bolt, but there must have been a reason otherwise it wouldn't be there.

After having seen that a replacement pair costs £424, I decided to remove my gearbox brackets prior to sending the gearbox away for rebuild.

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£424 ? oh my god......

All bolts on these brackets are standard hex head bolts

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My gearbox brackets are quite stuck on, but I'll have another go later at the button head bolt.

I've got the gearbox out now at least! 

There is definitely a button head on mine, and the bowden cables do run right next to it as mine is the early gear change, which I assume is why it's a smooth button head not a hex head.

I'll try and take the brackets off now the gearbox is out of the car. Just worried that if I do trash that button head one, it'll be a total pain. Although can't be that bad now it's out of the car.

You always find lots of other worrying stuff when you remove a large component. The clutch inspection cover isn't there. I'll have to either source one, or just bend a thin piece of aluminium and screw that to the casing or something.

When I took the gearbox out (quite carefully as well, there were two of us) the clutch shaft dropped out. That's meant to be held in with a pin, so that's not good.

Inside the bottom of the bell housing, there are loads of deep gouges in the housing. I can only assume at some point something has dropped into there and been ground around by the clutch. There is no damage to the clutch cover though and no swarf, so this is probably very old damage. I seem to remember seeing this last time the box was out about 16 years ago. :)

Also, it's a bit oily in the bell housing/sump area, so I guess the oil seal on the crank is probably leaking a bit. If that's an easy change I'm tempted to swap it now the gearbox is out. If not, then I'll just leave it. If it loses a bit of oil, I'll just keep topping it up! The car is 30 years old next year so it's never going to be perfect.

I've got a new clutch, clutch cover and release bearing to go on while the gearbox is out, as well as new gearbox mounting rubbers. I'll also do a load of cleaning before I do.

The gearbox itself is a bit mucky. Chris is going to cry when he sees what he's dealing with!!

image1.jpeg

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That gear mechanism is on the wrong side isn’t it ???

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The cap-head bolt is standard as well, as the cables run pretty tight against it.  The input shaft pin must be sheared, so that might mean damage to the guide tube depending on how it migrated.

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All will be revealed once Chris has it. I need to collect a small pallet tomorrow, get it ready to ship tomorrow evening, then collected and shipped Tuesday. Hopefully Chris will have it by the end of the week.

Just such a relief to have it out. Not that bad a job as it turns out really. Once you've got it jacked up you can do most of it from underneath with loads of room.

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See - told you it was easy

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Yeah it wasn't too bad. What's the crank seal like to do at that end if it is indeed leaking. Nightmare engine out job or easy? Just wondering if it's worth the hassle while the box is off.

The old clutch looks hardly worn either. Didn't think it would be that bad as it's probably done less than 10,000 miles. I'll swap it anyway though, as I've got another one for it and I really don't want to be removing the gearbox again for a while! :) 

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Took the old clutch off tonight. There is literally about 1/2 mil wear on either side of the disc, and the surface of the pressure plate still has the grooves showing from when it was machined!

Still, suppose it makes sense to change it anyway. Especially as I have a new one now!

So, next job is to remove the flywheel, but I don’t have a socket for the bolts. It’s a fraction bigger than a 17mm socket so I assume some imperial size. Any idea what actual size it is so I can get the right socket? I don’t have any imperial sockets  well, maybe a couple of the smaller sizes.

cheers.

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