Fix My Lamborghini
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WATER PUMP REBUILD

Time to get onto the water pump rebuild. I had coolant leaking from the small hole at the back of the water pump that is there to stop the coolant from getting into the oil. I ordered the bearings, seals and gaskets from lambostuff.com and got it all for under $100US. Here is how I got it apart after removing from the engine.
Picture 1 - The removal of the outlet pipe once the circlip had been removed. I used a set of pointy nose pliers as my circlip pliers were not large enough to get it out. The pipe came out easily after the clip was removed. Once the pipe is removed, you need to remove the two nuts that are located on the drive cog at the other end as in Picture 2. Depending on which nut lets go first, you may need to use an impact socket and rattle gun to get it off (as I did).
Next remove the three nuts that mount the distributor and then remove the distributor drive shaft as in Picture 3.
Next you need to remove the bolt on the side of the water pump that retains the shaft. It is labeled in Picture 4.
Picture 5 - The shaft coming out, as long as you have removed the two nuts at the other end, it should slide out easily. I have marked the key for the bolt on the side and also the two orings that will be replaced. It did appear as if coolant had been getting passed the first oring.

​WATER PUMP BEARING

Trying to get to the second bearing inside the aluminium housing on the end of the shaft was a bit challenging, until you know how. My initial thoughts was to try and press it off as I could see the circlip on the under side of the unit but that didn't work. As you can see from the first picture, there is no obvious way to get the steel plate out. There may be a special tool you can use for there are three holes in the middle groove of the aluminum housing but I was unable to get any of the standard screw drivers to apply any force to push it out. So as in Picture 2 and the fact that I had new parts to replace all these, I used a screw driver to lever the edge up as I levered around, it eventually came loose. Probably not the best way but it did work. Under this there was another seal as in Picture 3. I used a hook to go in through the small side and pull the seal out. This seal came away easily and possibly the seal responsible for the leaking. As in Picture 4, I finally got down to the circlip that was holding everything together. I used a set of long nose circlip pliers to get it out. In Picture 5, I put it back in the press to push the shaft out.


WATER PUMP BEARING REMOVAL & SHAFT REPAIR

Picture 1 shows the removal of the circlip that retains the bearing. This is the one hidden by the distributor shaft drive cog. Picture 2 shows the parts once they have been separated. There are a couple more bearings not in this picture. The one that is the bearing for the bottom of the distributor shaft drive, I haven't got any pictures, but it is easy to get out and there are two washes on the bottom side to help with spacing. Picture 3 shows the socket I used to press the bearing out. It was a 1" sidchrome socket 1/2 inch drive with two extensions attached. The socket was 33.49mm external diameter it needs to be that size so that it presses on the outside edge of the bearing without interfering with the aluminum housing. Picture 4 shows the water pump in the press, ready to press the belt drive cog end bearing out. 
Picture 5 shows the shaft once I had got all the parts off. As you can see, the shaft was very pitted. If the seal re seats on the good section indicated by the green arrow, then I could probably get away with it as is, but if the seal mounts where the red arrow indicates, then it is unlikely it would seal. I have sent the shaft off to an engineering shop to have it repaired. They said they would either weld more metal onto the shaft and then machine it back down or they would manufacture a sleeve for it.

WATER PUMP SHAFT

I got the water pump shaft back from the engineering shop and this is what it looks like in Picture 1. They advised that they had "sleeved" the shaft rather than welding and machining down. I then put the aluminum housing back on and secured with the 16mm circlip. I forgot to take a picture of that. The next part to go on was the new seal in Picture 2. This is the one that would have been over the corroded part of the shaft. I used the drift gently to make sure it was seated correctly.
Picture 3 shows the press fit steel housing and the associated spring loaded seal being tapped back in using a 1 1/4 inch socket. Note, you can take the spring loaded seal out to just tap in the steel housing if needed. Mine went in pretty easy (Note this was the part that was removed with the screw driver earlier).
My picture records are NOT as good as I thought. I think I have one washer that needs to go in next but I can't identify the orientation of the washer. It has a recessed groove on one side. 

WATER PUMP REBUILD

Picture 1 shows the washer I am talking about. You can see the groove in the middle of the washer. Once I took the top of the pump off again, it became pretty clear where the part goes. This can be seen in Picture 2. The washer is turned upside down and it fits on top of the seal. Picture 3 shows the washer in place. NOTE the seal is spring loaded and you need to press it down to get the washer down and then insert the key. Picture 4 shows the parts back together again. I need to source 2 orings for the top and bottom grooves, middle groove remains clear.

WATER PUMP REBUILD PARTS

​Continuing on, you need to make sure you order all the parts. I had initially ordered the parts making the assumption that all the water pump parts were on that page, as indicated on Picture 1. I ordered parts 20, 25, 26, 34, 44 and 45 and basically anything that had seal or bearing in its description. What I didn't realise was that there are two orings required for the two grooves in Picture 4, above, that come from the crankcase parts page. The picture only shows 1 oring but the description page advises that 2 need to be ordered, so I am currently waiting for these parts to arrive to complete the water pump.

WATER PUMP REBUILD CONTINUED

Finally got the orings I was talking about. As in Picture 1, you can see the first one in place and the second one about to go on. 
In Picture 2, you can see the bearing that I have just tapped in using a suitably sized socket. I then used a socket to tap in the seal.
Picture 3 shows the water pump shaft being inserted. This must be done before the distributor drive shaft goes in. Also it may be easier to put the woodruff key in before the shaft goes in. The seal that was put in Picture 2, makes it difficult to insert later (but probably not impossible). You also need to be careful when you push the shaft through the roller bearing. You can dislodge the roller bearings if you are not careful. Make sure the shaft is FULLY inserted. Look through the retaining bolt hole and make sure you can see the slot. These are marked in the picture. (The other little bolt in the picture is the retaning bolt for the lower distributor shaft bearing). I have included one of the dismantling pictures (Picture4) to show you the retaining bolt. 
Picture 5 shows the bottom distributor drive shaft bearing going in. It is a good idea to keep good records of how you dismantle things. It is not clear in this photo but the circlip that retains the bearing has a 2mm gap. The two washers in the picture are what take up the slack. This is how it was when it came out so that is how I am putting it back in.
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  • Urus
  • Huracan
  • Aventador
  • Gallardo
  • Murcielago
  • Diablo
  • LM002
  • Jalpa/Silh.
  • Countach
  • URRACO
  • JARAMA
  • ISLERO
  • Espada
  • MIURA
  • 350 400 GT