Slant 4 water pump howto...

[Jon Tilson]

There is lots to go wrong with this jobie so here are a few caveats...

First is to make sure it is indeed the pump thats at fault...
This means you must see water coming out of the slot. Run car with air filter off and use a mirror to be sure...
Many is the leaky bypass tube thats caused a pump to be "fixed" before its due...

Remove inlet manifold...I use a 1/4 drive half inch socket on extension after cracking them loose with a long ring
cos they can be a tad inaccessible...but a lot better than a lot of moderns...! Also disconect the varions heater pipes and temp guage sender You dont need to take off the throttle and choke cables cos you can carefull sit the manifold away to the left and still get access to the pump cover...

Pump cover off...remove three bolts and yank off...Problem 1 is it wont budge...ha! gotcha...

What I do is loosen it by tapping it gently radially. A few degress back and forth will loosen it enough to get it off...

Now the impellor and left handed bolt are staring at you...

Big socket on nut...think its 3/4 AF and turn it as to tighten it up on a normal rh bolt...One of 2 things will happen...
The bolt will come out...or the whole pump will.

If the bolt comes out the pump is tight in the block so you need a slide hammer to get it out. Ive got one with a left handed bolt adaptor that screws in to the pump. You can use the M Mouse tools that Rimmers sell too. Avoid digging screwdrivers into the brass cage via the slot! All you do is damage the cage.

The pump may then all come out with cage and all or just the shaft, impellor and bearing bit leaving the cage in the block.
Wiggle the slide hammer under the cage...dont bash the drive cog...and bump it out...its only 2 O rings holding it in...

Okay now you need to recon the pump. To do this you will need a press or a decent vice at the best. Remove the impellor first, the old seal, thrower disc, oil seal and then you see the bearing and circlip. The impellor is sometimes tough to get off...the bearing and circlip will certainly be. I've used local firms to get these apart with a press. Be carefull as the impellor can shatter if too much hammering is used...Press is much kinder.

Okay now its all in bits...refit is part 2 which I'll add later...

Jonners

[Jon Tilson]

Now comes a few important points on reassembly...

You should now have a bare shaft, cage, impellor and LH bolt. Everything esle will be replaced...

Examine the cog on the shaft carefull for wear or chips. Any damge and I'm afraid its ebay time....find a new one.
Also you want the impellor to be a nice tight fit on the top end of the shaft. Ive had some that are so worn that they go round. The splines must grip the impellor.
Have a look at the bottom face of the impellor where the seal bears on it. That face needs to be nice and smooth so it may need refacing at your friendly local machine shop....or source a new impellor....which isnt easy these days.

There are a few different top seal designs in circulation. I'll cover the 3 main ones....
1st your original...if you do find a NOS original seal by all means use it. This has a graphite ring that is sprung loaded against the under side of the impellor. This also has a rubberised outer bit which is an easy push fit into the brass cage.

Then we have the current commoly available seal which is similar except that the outer body is metal and is an interference fit in the cage. These need a press to fit into the cage...more of that later.

Finally the other common type I've seen has 1 superior (in theory) feature...it doesnt seal directly against the impellor.
It just has a rubber bit that the impellor sits on and has its own internal seal. Its sprung loaded to get a good fit to the impellor Its also quite a tight fit in the cage but a big socket and gentle tap will get it in.

The weakness with all these seals is that if you assemble the pump completely and have to use some form of impact...no matter how gentle...when refitting to the block you WILL damage the seal. Ive shattered a graphite ring and rogered the internal seal type in my time and I was EXTREMELY careful to use the bare minimum of force to get the pump back in.

So Ive adopted a different technique...

Its basically very simple...Only partially reassemble the pump. leaving the impellor and LH bolt til last.

To do this, first fit the bearing and pack it with grease. Ive never been convinced that the bearing gets lubricated by oil thrown up those spiral slots somehow...
Refit the circlip and put the shaft and bearing in the cage and drift it down as far as it will go. Then fit the oil seal so it sits close to the bearing and is also a firm fit in the cage. Then comes the water thrower disc, a small O ring and the top seal. If you have the new metal seal this will need to be fitted to the cage with a press as already mentioned.
Now fit the new O rings to the cage....there are 2 and its obvious which goes in which slot as the diameters are slightly different and its ready to go back in the engine block.

Alun would say at this point to replace the bush. Ive never needed to as mine have all been in good condition but its not a bad idea. Getting the old one out will need a quantity of grease and a dowel the same diameter as your water pump shaft.
Put the grease down the hole and drive the dowel in....the grease will then force the bush up and out...sweet.
Fit your new bush by gently drifing it in and clear up the old grease.
Now fit the pump minus impellor to the block. You will feel the end of the shaft go in to the bush and the teeth mesh with the gears and you should be able to push it down far enough so that the shaft wont turn by hand as the gears mesh. At this point the cage will be a tight fit and probably wont push down by hand. At this point you can use a big socket as a drift for the cage. I used an 1+7/8" one that fts nicely on the top lip of the cage and ensures even pressure as you drift the cage in to place. the lip on the cage will then be a tight fit against the block.

The last touch for the pump is to refit the impellor and bolt. You can use the bolt to pull the impellor down on the shaft without needing any impact and damage to the seal. You will see the impellor sitting nice and low and clearly bearing on the seal. Remember its an LH thread and do it up to the specified torque...which Ive forgotten.

Then its back to the old method of using feeler guages to check end float for the cover. You use gaskets of the right thickness to ensure your pump cover has clearance with the top bolt. There are 3 sizes of gasket in most kits and i seem to standardise around 1 thick and 1 medium on the last few ive done...dunno why. I refit these gaskets with a smear of grease so that the cover can be removed again and preserve the gaskets if need be...Clean the cover off and use copper ease to ensure it comes off easilly next time.

Tighten the cover evenly and then its refit the manifold and bypass tube, taking care with gaskets and O rings...especially the big one on the inlet manifold.

Ive taken to filling the system through the water pump cover before the manifold goes on as a check that the pump seal is working. This isnt full proof though as its not running and under pressure.

So manifold on and refill and and refit hoses and hopefully job is a good one...

Few extra details...If you drain the block from the drain plug in front of the starter, remember to refit it.

Make sure the hose clips are pointed so that you can give them all an extra tweak when the manifold is in place and its all wamed up and pressurised.
Well worth cleaning all the crud out of your hoses and rad while its all off...

Happy pumping...

Jonners

[finbar]

you could get an ohv engine instead and avoid all the trouble!

[1300dolly]

[David6214]

Its a very well written guide though, so thanks to Jonners for his effort....could someone make it a sticky in the tips for new owners section or something.

There have been a few of these guides written by various people recently, we should remember to get them added as 'sticky' so they are easy to find...

[Lewis]

Top stuff. Saved!

[Jon Tilson]

Thanks for the appreciation guys...
I knew an ohv wag wouldnt be able to resist the temptation...

Jonners

[SPRINTPARTS]

Hi Jonners,

Well explained rebuild method. I like your method of impellor fitting in the block, most times I use that myself. Just a quick plug here for our remanufactured 12 vane impellors. They have finally been casted and are currently sitting at the machine shop awaiting machining. It is hoped that we may have some available in the the next 7-10 days IF everything goes to plan. (Does it ever?)

Mark

[newguy]

Hi Jonners,

Well explained rebuild method. I like your method of impellor fitting in the block, most times I use that myself. Just a quick plug here for our remanufactured 12 vane impellors. They have finally been casted and are currently sitting at the machine shop awaiting machining. It is hoped that we may have some available in the the next 7-10 days IF everything goes to plan. (Does it ever?)

Mark

Will you be doing waterpump covers to?

[SPRINTPARTS]

The simple answer is no. Both 12 vane and 6 vane covers are still readily available through other sources. The tooling costs are too high for the anticipated demand. It is not our intention to compete with the other Dolomite parts suppliers but to provide parts they are no longer able to supply.
Philip

[newguy]

All good phillip

Where do you buy yours from?

[triple tango]

nice guide Jonners.
I like the tip about fitting impeller after fitting pump in block.

[Jon Tilson]

Yes it came to me in a flash last Saturday as I was redoing an "internal" type seal that I had just broken and looking in my parts box at the pieces of carbon ring that I'd removed from an earlier attempt of years ago. I thought the internal seal would take the gentlest of "persuaison" but I was wrong...
I mean why does it go? Most of the impact should just go down the impellor shaft to the bottom gear. Anything left you would think the spring would absorb......Anyway...there it is and it worked for me. If I save anyone else a sumpfull of mayo I'll be a happy man...

Jonners

[trackerjack]

you could get an ohv engine instead and avoid all the trouble!

Coo thats a good idea and spend life in the slooooow lane always looking for a complete engine to replace the knocking one you have got in the car
Pass the spanners old chap.

[finbar]

but think of the money you'll save on water pumps and head gaskets

good article by the way