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Discovery clutch change


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#1 white90

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Posted 12 July 2006 - 07:15 AM

Same engine, but far harder to do in a Disco in comparison to a Defender. No floor to take out, and slight difference in the crossmember arrangement means this job is quite awkward.
Vehicle is a 1996 300TDi Discovery owned by Freeagent of this forum.

There's more than one way to remove the upper bellhousing bolts, and I opt for removing the gearstick panel. You can use a multitude of extension bars, but the average DIY-er is unlikely to have enough to do it from underneath. You would however need a pop-rivet gun and 4.5 - 5mm pop-rivets.

Because the floor can't be removed, most of the work is done from under the vehicle, but start inside while your hands are still clean.
Centre console has to come out - carefully lever the gear and transfer knobs shrouds out of the main console and unscrew both anti-clockwise. Remove mat, and then the window switch cover.

Should look like this:-

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The switch plate is held to the main console by 4 x counter sunk self-tappers. Remove them and unplug the panel.

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Now the console itself - 2 screws inside the cubby box:-

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Two right at the front in front of the transfer lever.

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Next you need to disconnect the handbrake cable. Release the handbrake, remove the clip and withdraw the pin that connects the cable to the lever. The handbrake will now pull up almost vertical and allow the centre console to be removed. Once the console is a few inches away from it's place - unplug the cigarrette lighter socket (2-pin plug and the light for it). Unscrew the 13mm pinch bolt that holds the gearstick in place, and remove it. Lift the console clear and put it to one side. Now reconnect the handbrake and pull it on tight, the reason for this is explained shortyly.
There's two heater pipes that run either side of the transmission tunnel - pull each one backwards a few mm and they can then be left attached at the rear, but out of the way at the front.

In front of the transfer lever there's a mounting plate for securing the console, remove the 2 cross head screws and remove it.

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There's a steel ring around the base of the gearstick, and this has to be removed by undoing the 4 x self-tapping screws.

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There's a rubber cover that acts as a seal between the gearbox and inside the cab, There's a steel retainer that clamps it in place by rivets that go through the transmission tunnel.

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The rivets are alloy, and a 5mm drill is needed to remove them. The retainer is very thin, so take care not to bend it.

Once the seal is removed, the whole top of the gearbox is exposed.

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From under the bonnet - remove the fan shroud top section - the engine is going to tilt down as much as possible at the back and the fan blades will press on the shroud.

Now to get underneath. Jack-up the drivers side front and rear and support on axle stands or similar. Remove front and rear props completely.
At the rear of the transfer case undo the exhaust clamp (after-market system), remove the exhaust mount (one 13mm bolt), then undo the three 15mm nuts that hold the downpipe to the exhaust/turbo manifold, then unhook the remaining exhaust mount at the side of the gearbox. The front section of pipe is now free, and although you can't remove it without further work - it at least can be moved out of the way.
No need to disconnect any of the cables/wires/breather pipes, as the gearbox is only going to move back around 7-inches, and there's enough slack in these items to allow this.

Gearbox mounts next - 4 x 19mm bolts and 1 x 15mm nut hold each of these on. Undo them all - if the 15mm nuts come off with the studs, then this makes it so much easier to remove the mounts.

Drivers side:-

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And Passenger:-

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Tut! - look at all that dirt - someones a slacker! :P

Now place a jack under the handbrake drum, if the handbrake was off - there's a risk that the gearbox will roll off the jack - this is why the handbrake has to be re-applied once the console is off.

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Jack the gearbox up as high as it will go and the two mounts will then lift out.

Drivers side:-

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And passenger:-

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Clutch slave now. This can be left connected to all the pipework, and just tucked-up out of the way on the adjacent chassis rail. Two 10mm bolts hold it to the flywheel housing:-

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The connecting pipes are quite rigid, so it requires a little bit of pressure to get the slave out of the way up on the rail. Take care not to bend or fracture the clutch pipe.

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The gearbox can now be lowered until it rests on the crossmember.

Now for the bell housing bolts. The top ones are really difficult to get at, and this is why I removed the centre console etc - for the sake of two 15mm nuts.

The front of the engine needs to be kept in place in anticipation of gearbox removal - if you don't do this, the engine will level-out once the weight of the gearbox is off it. The angle is fairly crucial to re-fitting the gearbox - there isn't a lot of room beteen the top of the flywheel housing and the beginning of the transmission tunnel. Now remove all the nuts (15mm) and the lower bolts (13mm).

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There are two pairs of 13mm bolts you can see in the last two pictures that don't need to be removed. They brace the engine block and flywheel housing.
The engine and gearbox are now ready to part company, raise the jack on the handbrake drum until you see a small gap appear between the two, and raise just a fraction more. Get in a confortable position, grasp the flywheel housing either side and lever/wiggle/kick it free of the engine. Keep the weight on your arms and push it backwards - making sure the jack on the brake drum goes with it.
In this fashion the gearbox should go back around 7-inches, and let it rest on the crossmember and jack. There's now enough room to remove the thrust bearing, operating fork, and clutch cover/plate.
The fork just moves inwards and the clip that holds it to the pivot will clear and allow the fork and thrust bearing to be removed. The clutch cover/plate is held to the flywheel by 6 x 13mm bolts, and once they are undone it can be lifted off the centering pins. The cover is quite heavy - so be carefult it doesn't drop on you.

You should be looking at something like this now:-

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The operating fork has a bad habit of wearing where it pivots on the ball inside the bell housing. It's not only wise to replace this relatively cheap item (15), but to reinforce it as well. Welding a washer, or plate on top of the dome of the new one is a good idea. I chose the plate method, and the metal is now more than twice as thick as it was.

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The new clutch is Borg and Beck, I personally favour this make, and I always recommend them as a replacement. However - the manufacturers item is made by Valeo.

You really need an old input shaft to use as an alignment tool, but at a pinch you can fabricate something to do the same job. Alignment of the new clutch is critical - the gearbox may be resting on a jack and the crossmember, but you will have to take half the weight of it shortly, and it's so much better if the gearbox is going to slide straight on without all that ridiculous wiggling/levering.

New clutch fitted and spare input shaft still in place.
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Once fitted, remove the centering tool and fit the fork, thrust bearing, and slave pushrod.

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Putting the gearbox back on is heavy work, even though you are assisted by the jack under the handbrake drum. put the gearbox in gear and then take the weight of the bell housing and move it forwards so that the input shaft enters the centre of the clutch plate. If all is in line - turn the front output flange and as the splines line-up, the gearbox will slide on to within a few mm of the flywheel housing face. You can then use the nuts bolts to pull it on the rest of the way. Once bolted back on, remove the jack under the front of the engine and raise the gearbox as high as you can in order to re-fit the mounts. Nothing else to add - putting it back together is reverse of what you already did.

A few things to remember :-

This is the heaviest/most awkward of clutch changes - you have to take the weight of the box for a couple of minutes if you're lucky, and longer if you don't get the balance right when removing it. It might be easier if you could use another jack to support the gearbox as well, but then you'll be lying between two jacks whilst trying to move the gearbox and the two of them at the same time. Safer to use the one and sweat/curse a bit.

The rear doughnut split with use, and as you can see from these two pictures - it'll have to be replaced soon.

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Thanks to Freeagent - member of this website, for allowing me to post pictures of his Disco.
Les. :)
Tony


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