Series one aprilia radiator drain tap

[welleyes]

The drain tap on the water pump on our car is extremely worn and, as I am unable to locate another, I will have to make a new one. Most of the work, I can copy from what I have, but it has been butchered and frigged by a previous owner. I do not understand how the spring which holds the male part tight into the taper is located. The drawing in the Italian parts list is not informative. Does anyone have a photo or can remember the tap well enough to do a sketch? I seem to remember a suggestion that the same part or similar was fitted on early Fulvias; is that likely?

I can obviously work out an arrangement that will work satisfactorily, but it would be nice to do it exactly how Lancia did it eighty five years ago.

Stuart Tallack

[simonandjuliet]

Great idea to remake - I have a couple of them in bits so will take pictures later - they are quite different to Fulvia and as know, you need to take care not to foul the radiator support

[simonandjuliet]

2 different types .....

[simonandjuliet]

From my S2

[welleyes]

Good heavens! Those photos are just what we want. Still one question, though; does the non-angled one clear everything on the Series One? If it does, it is a lot easier to make than the one with the screw thread into the pump at an angle to the taper. Once again, thank you very much for your invaluable help.

Stuart

[welleyes]

Having looked at parts drawings for what I believe are earlier S1 and later S1, the long drain tap appears to be early S1, while the short tap with an angle between the planes of the screw thread and the taper is late S1. It also looks as though late S1 and the S2 taps are the same. Does that seem correct? The mangled pump on our 1937 S1 would appear not to be correct. That would make me quite happy as it is easier to  machine (or rather easier to hold when machining.) As we need the car in a weeks time, I will put a plug in place of the tap until I have made another tap of the long early S1 variety. I have a horrible feeling that we will not know if it fits and clears everything until we try.

The car has a great advantage over its owners as it is not a sentient being and does not know that it is old. We do know we are old and less capable than we were. Never mind!

Stuart

[welleyes]

We are not out of the woods with water pump and radiator and we are soliciting your patience and advice again. First, the gradual but significant loss of coolant left traces to suggest a leak at the water heated manifold and at the drain tap. The first we have solved and the second “cured” with a suitable M14 x 1.5 screw and washers. I will make a new tap when other more urgent problems have been solved. The way ahead looked clear, but a new problem has emerged.

There is water running out of the hole into which one of the bottom securing bolts for the radiator screws and it is not clear what stopped the water coming out before. The non leaking one appears to have something white in it perhaps to hold the water in; the other hole, I think, had something similar but now there is nothing there. We have the following questions….

1.   What is supposed to be in there? Is it meant to be a blind hole? I assume that it should be.

2.   Is it possible that the bolts that hold the rad on are intended to seal the holes? That seems unlikely and would obviously need a sealant on the threads.

3.    If a previous owner damaged the tank by using bolts that were too long and screwing in very hard, you would expect to see some evidence of damage as in a ragged piece where the bolt broke through. I have looked at a spare (unuseable) radiator and that clearly has blind holes; quite shallow, perhaps four threads deep.  They are M10 whereas ours are M12.

4.   I am assuming that the bolts screw into machined or stamped out parts which were brazed (?) to the bottom of the radiator. Surely the end of the blind hole could not have been so fragile that the bolt could push through. When the radiator was removed, there was some evidence of a cobbled together seal held in place by the top thimble which locates the rubbers under the radiator. It evidently did something but it fell apart when removed. As a bodge it had been quite effective, but it would have failed sooner or later.

5.   What should be at the bottom of the rad? I fear that we either need a rebuild of it by someone sensible or else another radiator; any ‘repair’ by us would be another bodge. We do not want to take it to a specialist who does not know Aprilias until we understand what should be there.

Any advice or information will be gratefully read before we have to make a decision.

Stuart

[welleyes]

Now I can answer part of my own question after closely examining the unusable radiator. The steel sides of the radiator are continued round the bottom corners for about fifty millimetres. Soldered on to them are the parts into which the radiator securing bolts are screwed and against which the cups on top of the rubber buffers bear. At the end of the threaded holes is the base of the bottom tank of the radiator. There is no connection between the steel parts and the base of the bottom tank other than close proximity. Some previous owner evidently lost the original bolts and has screwed in a too long replacement until each bolt punched a hole in the bottom tank. The subsequent leak was “repaired” by putting some form of hard setting cement up there backed up by a home made seal held in place by the top cup. It bears all the marks of a dealer doing a bodge sufficient to sell the car on. In fairness, it did hold water until the rad was removed, other than a gentle leak from one of the bolt holes, but it was nevertheless a shabby trick.

The long and the short is that we will need to have the radiator repaired. If my description of the way the bottom of the tank is constructed is wrong, perhaps someone will let me know. We would prefer to be able to tell a repairer what he is likely to find.

If anyone has a spare radiator, of course, we would love to hear of it. The one at present on eBay appears to have many problems of its own.
 

Stuart

[simonandjuliet]

I think that your description is correct - here are a couple of photos of a spare that I have. This one has been "rebuilt" but has a number of issues , so take care when you get yours done

The metric fine mounting holes have been replaced by coarse threaded studs and re-tapping the holes will be difficult without puncturing the brass frame as per yours

I have seen and tried studs on the rad/pump but I prefer the original set up - for me fitting is easier

[welleyes]

Simon,

We are very grateful for your help so far and for so much valuable information. We have decided, I think, not to bodge the radiator any further but to consult Vintage Car Radiators at Bicester about a rebuild. I will make a copy of the correct drain tap, but first need to drop the damaged rad back in the car for a final check that the earlier type of tap clears everything that is there. It would be nice to think that this is the last major job on the car, but it is never wise to tempt fate.

Andy and Stuart Tallack