It lives! ......... and the water pump leaks - boo.

[Bumpa]

My 1850HL hasn't been used since 1992 and although my brother-in-law started the engine occasionally in the early years, it hasn't run for at least 20 years. I have repaired and repainted the body and have rebuilt the engine, which was in great condition, so it has just had new shells, rings, timing chain, valve lapping, clutch etc.

Today for the first time for two decades it burst into life and it ran pretty well considering it will need timing properly and the carbs (SUs) need tuning.

But the ruddy water pump is leaking and all the while the engine is running it drips steadily from the hole beneath it. I am really annoyed about this as I spent a lot of time and care rebuilding the damn thing with all new parts. What is likely to be the problem? How can I overcome it?

What a cr*p design the pump is. It reminds me of the horrible affair fitted to the Lotus Twin-Cam engine. Why didn't Triumph fit a modular pump behind the fan like everyone else?

[yorkshire_spam]

Engine running is a great step forward!
Is it the pump that's the problem or the link pipe or something else?

[Reg]

If you keep it running for a while, it might re-seal itself..it happened to my old brown Sprint.

Yes, I agree with you..the pump is a crap design!

[Bumpa]

Engine running is a great step forward!
Is it the pump that's the problem or the link pipe or something else?

Hmm, I don't know. It's very hard to see while the engine is running. The water certainly seems to come from the area of the drain hole. I'll need to try and get a look with a hand mirror.

[Mahesh]

My car had the same problem after its 20 year odd slumber in the garage.

Having rebuilt the water pump 4 times, the problem came down to the thermostat
housing having a limescale type of block to the expansion tank.

The waterpump was the only outlet for the pressure to vent.

Might be worth checking if once warmed up is the hose to the expansion tank
hot or cold.

[xvivalve]

Did you machine the underside of the impellar?

[Bumpa]

Did you machine the underside of the impellar?

No Alun I didn't. I don't have facilities for doing such a thing.

[xvivalve]

Unfortunately, in all probability there lies your problem. The seal forms on the underside of the impellar which both scores in long term use, and corrodes and pits whilst standing long term, to the point where a new seal simply won't have a good mating face to work with.

I have some impellars here that I've had machined, a couple of 12s and a later 6 that I'll sell on an exchange basis, but unfortunately it probably means another rebuild of the pump for you.

Do check Mahesh's suggestion though, as I cleaned out a thermostat housing with that very same issue myself last week.

[Bumpa]

Oh dear. Thanks for your suggestion Alun. I expect you are right. I will check the thermostat and pipe but I'm 99% certain it is ok. I will buy an exchange impeller from you, mine is a six blade type. How much will it be? Who would you buy a new pump rebuild kit from?

[mahony]

Oh dear. Thanks for your suggestion Alun. I expect you are right. I will check the thermostat and pipe but I'm 99% certain it is ok. I will buy an exchange impeller from you, mine is a six blade type. How much will it be? Who would you buy a new pump rebuild kit from?

The spare pump I had was refurbished by Tony Hart for about £72 and he machined the underside of the impeller

[xvivalve]

Tony Hart is where I get my seal kits from; he sells them on ebay for about £25. His refurbed pumps are now about £100 exchange I think, but yes, he does either machine the underside or fits a ceramic insert. Ebay handle is 'HRS' something or other (Hart Racing Services).

Exchange impellar would be £25 inc postage

[xvivalve]

I tell a lie; they are £175 now!!

https://www.ebay.co.uk/itm/Triumph-Stag ... SwcUBYIGWg

Here's a link to the seal kits:

https://www.ebay.co.uk/itm/Triumph-Stag ... Sw~y9ZJAuG

[Bumpa]

Thanks. I've bitten the bullet and ordered one from Tony Hart. It is £175, but you get £50 back when you return your old pump. It's worth it to get something that works.

[mahony]

Wow that is a jump in price from when mine was refurbed ( must have been longer than I remember ).

[Bumpa]

Well the new pump from Tony Hart is installed and the car started again. It starts amazingly easily. First turn of the key. All seems to be well this time with no water escaping, and the heater gets nice and hot. I've had the rear wheels lifted off the floor and tried the clutch and transmission and it all seems good.

There is a strange noise coming from the region of the large silencer under the floor so I must investigate that, and oddly the clock isn't working, even though it was before I took the engine and gearbox out. The dashboard hasn't been dismantled so quite why the clock has given up is a mystery.

What's left to do? Properly tune the engine. refit the gearbox cover, and the interior carpets. Refit the seats. Buy some new tyres to replace the 30 year old ones on the car at the moment. Build up the brakes. I have all new discs and calipers, together with master cylinder and recon servo. Also the rear brakes have new cylinders and shoes. Once all that is done it will be just about ready for an MoT!