Sunday, 1 August 2010

Changing the DHC’s water pump

With the Alpine Tour only a few days away there was no time hanging around, which meant an early start this morning. First I had to collect all my tools which were scattered over a few different locations. But before I started on that round I soaked all the nuts and bolts, that needed undoing on the engine, with penetrating oil.
After having collected all the tools I started with draining the coolant system and disconnecting the carburettors, in preparation of the removal of the complete manifold/carburettor assembly;

As I had already filled up the fuel tank in preparation for the scheduled trip to the Alps, I had to make sure the fuel hose coming from the pump was closed of properly. So I clamped the hose using a small ViceGrip and plugged the end;

With everything disconnected it was time to remove the manifolds mounting bolts. All could be removed without a problem. Only wondering what Muppet at Leyland designed the manifold, as the front bolt is pretty much inaccessible for a half decent socket set. Luckily I do have various spanners, but due to the limited space it was rather time consuming to remove this bolt;

But with all bolts removed and the heater pipe disconnected (nearly forgot that one) the manifold together with the carburettors could be lifted of the engine;

Giving me chance to look inside the engine for the first time in 17 years, doesn’t look to bad I think;

And after a minor break to make a brew, I tackled the water pump itself. Removing the cover was very easy, two taps with a rubber mallet and it was out. Was amazed to see that the gasket was blown out at the back of cover. But there were no signs of any leaks from there;

The pump itself did put up something resembling a fight, but it lost out against a sturdy washer, screwed to the pump’s shaft, and two hefty tyre levers. The impeller gave the game away why the pump failed. There is a fair amount of rust on it, almost certainly caused by being in contact with air for nearly 18 months;

Of course the brass cage remained behind in the block;

... but with this little tool it was a piece of cake;

After removing the old gasket and cleaning the inside of the pump cover, it was time to refit the pump. It did take a few attempts to get the jackshaft gears to engage with the gears on the pump shaft. But ones I got that right, the pump could be gently tapped in place;

Left me with checking the clearance of the pump cover;

Choose a gasket with the correct thickness (measured gap + (0.30÷0.50) mm) for the 12 vane impeller;

And tighten the water pump cover;

Only have to refit the manifold etc. but I ran out of gaskets and O-rings. Will get that sorted tomorrow morning, so hopefully the car will be ready by evening.


Un descendant du Poéte d'Arenella said...

Hello Beans ,
thank's very much to take time for pics of your work on water pump it's very fair for the other Tr7 drivers
If you have air problem and rubber becoming week with your tkc 1338. A kit find in Usa very clever built with aircraft aluminium I bought it and put it on my Tr7 in 2008 result top for all the function a tkc 1338 must done. The link with the item and seller If ypu want pics about my wotk to put them on my TR7 send me a mail to
Have a good holidays in Alps
regards from France Patrick

Patrick said...

During last July I have renew the water pump of my TR7 spider.
All your pics were a strong help to do a right work without mistakes .I m not a specialist at all in mecanic works but have good tools ....
Now and after 1850 km all is perfect and dry.
Thank you very much for your blog help.
best regards
Patrick France

Jose Paz said...

Great! Blogger lost all my previous message...I'll try to write the same info :((

Hi Beans! First of all, thanks for such a great blog with quality pics and information. You are a referral for lot of us, TR7 owners! :)

I've read your posts (this one and others) regarding the water pump. I'm trying now to remove mine, but it's sooo hard to do I've started to be afraid of breaking something.
I've removed the LH Bolt, andafter that, all I have read in manual is to pull out the pump from the block, that's all.
In fact, looking at thes DIY tool from Rimmer ( I conclude it's a LH bolt welded to a ring to pull out and lift the pump, isn't it?
But it's so strong attached to the block I'ma afraid to break something.
The cover itself was very hard to remove, I think all it's due 31 years without opening, and rust, and so on...
I just wanted to ask you if all I have to do now is lift the pump up, pulling from it, may be half mounting the LH Bolt to pull from it...
I don't know why it's so hard to lift it up, if its not attached to anything.
Maybe if I construct some tool similar the one you used for the brass housing...but attached to the pump in the place the LH should be?
Thanks for your blog again and all the shared experience. And great cars those you have in such a perfect condition.
If you can help me with this, thanks in advance! I'll ask for you later regarding the dismantling of the pump...because I've read here ( I can´t do it without a press or I can damage the impeller...
Keep in touch, bye!!:)

Beans said...

Hi Jose,
For the DIY approach for removing the pump there are two options;
Use a spanner and try to undo the LH bolt. Sometimes the pump will come out (with or without brass cage).
If it doesn't I have a rather simple tool that can be bolted to the pump. It's nothing more than a short tube with a plate welded to the bottom. This is bolted to the pump (using the original bolt) and used to lever the pump out. Either by hand or by using tyre levers (take care not to damage the sealing surface of the engine block).
Good luck.

Jose Paz said...

Hi Beans! Thank you so much for you response ;)
Yes, I did know there are two options. Mine is of course the second one :(
My main doubt was about if the pump is somehow "attached", but I think it's just very hard to pull out, as you tell me your solution. Great approach, thank you so much! I didn't write to you again to tell I've made some kind of homemade slide hammer. Due to I haven't tested it yet, I did not tell you my experience with it.
It's basically a medium long pipe with threaded "tops", and a wider pipe around (the mass of the slide hammer). I have to attach the bolt to one of the tops and let's see what happens, but I think in my car, the pump is really really "glued" to the block. :)
Thanks, keep on that great blog!

George Weijer said...

Hi Beans,

Where do you buy the best parts for a waterpump?
I have to revise my 12-vane waterpump. It is leaking from the slot in the engineblock.
Thank you in advance.

George Weijer

Beans said...

Hi George,
Water pump repair kits are available through the usual TR7 specialists in the UK;
S&S Preparations;
Revington TR;
Links under TR7 & Sprint Parts section.
You can also try Nico Baas in the Netherlands.

Jose Paz said...

Hi again Beans!
Keep reading your blog, hehe.
I finally removed the water pump, and I was refitting it, by parts in the block, not as a whole, and a doubt arose, and I think you can help me with that.
The water seal, the graphite one I think...well, this one :)

it goes just right "over" the brass cage, isn't it? i mean, it does not goes "inside" the brass cage...

When I got the brass cage, the shaft with oil whaser, baring, etc, the last part is this sea l with an inner spring. I tried to stuck it into the brass, as I thought it was rubber, and flexible, but I can´t as there is metal inside. I think it goes just over ir, then the impeller with the LH bolt, and it fits well, but Im not sure as I did not assemble the pump before fitting, so I though you could help me with this.

Thanks again for all your work!! ;)

Beans said...

Hi José,
When you look at the post from the 9th of January 2008 you can see how the upper (water)seal should be fitted. The wider part should be facing down towards the brass cage. You have to press in the seal till the collar firmly touches the brass cage. After that fit the impellor.

ps. in the picture on the Rimmers site the seal is upside down.
And make sure that before all else the oil seal is pressed firmly into the brass cage.

Jose Paz said...

Hi Beans, thanks for your fast response. :)
Yes, I know the position it goes over the brass cage, a noted it down when disassembling the pump and thanks to your pictures and the water pump assembly diagram.
I was not sure about it goes over the brass, of course firmly pressed as you state, or inside it.
So thank you for your answer, it helps a lot. In fact, I was thinking about it, it should not go inside the brass cage, stuck into it, because it wont let the shaft spin rightly, it is not a bearing (which it does go put into the brass cage, but let the shaft spin, of course it's a bearing :) )

So thanks for your help. I'll just put the seal over the brass, against it, and done! :)

Thanks, have a great summer!! :D