Water pump issue

[Gary Schulz]

I purchased a nicely rebuilt original cast iron water pump from one of the folks on this forum and I noticed that the threaded disk where the pulley bolts had a very small crack radiating from one of the holes to the outer surface. Not being satisfied with this I took a stab at a tack weld in order to close it up. Of course instead of closing up the crack this caused a chunk of the outer rim to fracture (while chasing the threads with a tap).

Do you guys think this can be left as-is if loc-tite is used or do I need to take this all apart and try and replace the disk? The bolt still threads in nicely and holds reasonably well but I hate leaving it this way...

I put a puller on the end of it just to quickly see how much effort it is to move that disk and it doesn't move readily.

Do I need to replace this and take apart the water pump?

20200126_095819.jpg

[Dearg1275]

I would not run with it as it is. There is too much of a chance the bolt will work loose, get ejected towards the rad core, get trapped between the fan and the rad and wreck the radiator. You will need rather more force than a bearing puller to remove and replace the mounting disc. If you have a spare why not visit a local workshop that has an hydraulic press and see if they will press things off and on. That or send it back to where you bought it as clearly they have the ability to do this.

D

[iain1967s]

If you want to try fixing it yourself, Dremmel a shallow V and use MIG/TIG on the back side and the circumference then grind it back. I’d be tempted to put a non-weldable [brass] threaded rod or bolt of the correct thread into the hole, then weld the piece back on in-situ, so you don’t have to stress it with a drill and tap again.

[Gary Schulz]

Thanks for the replies. I am not sure how I will address a fix for this. I have a 20ton press but I am not sure how to support the flange. I guess I would need to make something for that but it winds up being a little thin. I could also try welding it again but that is pretty small and I can't get things too hot without risking the seal.

I also don't have another disk handy to use as a replacement.

I will need to ponder this for a bit...

[Andrew1967]

You could email Paul at E P Services, which is where I get my cast iron pumps overhauled.

He is very helpful and considering you're across the pond, I'm sure he'd advise you how to go about this rather than sending to him to fix.

paul@ep-services.co.uk

[Spider]

You could have another go at welding it.

Set the pump body up in a tub of water to keep it cool. Get a section of copper bar (Switchboard builder will have an off cut) and bolt that up behind the flange, then weld from the front. You'll want to coat the front side in antispatter. The copper well let you put the heat in to it you need to without having it melt & run away and the weld won't take to the Copper. If you've got oxy, after finishing the weld, remove the copper bar and letting that cool, heat it again with the oxy to a dull red and let it cool naturally to reduce the weld being 'hard' and making it a bitch to drill and tap.

[Gary Schulz]

I could keep the pump in water and back it with Copper to see if I can get a decent repair. I have a TIG and a MIG but in this case I am thinking the TIG would be a bit more precise. It didn't take well when I tried to close-up the crack so I am wondering about the metallurgy involved here.

I may take another stab at pulling the thing off first if I can locate a suitable replacement part.

[Supersonic]

I've a Gold Seal one for the small bore engine that you could have but it is postage costs to the USA, that is the problem. I also would not use a pump with this damage, too much could go wrong

Alan

[1071bob]

Quickest fix would be to drill and tap four new holes in between the originals. I seem to remember seeing a lathe and mill in your shop to knock up a drill jig.

[Oneball]

I could keep the pump in water and back it with Copper to see if I can get a decent repair. I have a TIG and a MIG but in this case I am thinking the TIG would be a bit more precise. It didn't take well when I tried to close-up the crack so I am wondering about the metallurgy involved here.

I may take another stab at pulling the thing off first if I can locate a suitable replacement part.

I wouldn’t bother trying to be precise, weld both the the hole and the missing bit and drill and tap. Trying to repair the edge and the refinish the hole will be a struggle to keep it centred.

[Hipwell]

Quickest fix would be to drill and tap four new holes in between the originals. I seem to remember seeing a lathe and mill in your shop to knock up a drill jig.

Best fix available here!

[dklawson]

+1 for tapping a duplicate, new, pattern.

If you want to fix this rather than add the new taps, I would consider pressing the flange off, brazing the repair, then re-tapping the damaged hole. Braze will be plenty strong and won't add any brittleness like welding will.

[Gary Schulz]

Many thanks for the advice here. Sounds very logical to just come up with 4 new holes 45 degrees off the old pattern.

I was offered a spare flange from a forum member so I put the pump in my press and was able to insert two "V" notched plates of steel around the neck of the pump supporting the flange well. I found a steel bushing slightly smaller than the OD of the pump shaft and pressed the old flange off. It was on there firmly but it turned out to be a fairly simple operation using my small (20 T) press. As soon as I get the replacement I will try to press it on with support under the shaft, not the impeller!

A puller wouldn't budge this without heat but the press was ideal...

20200127_062019.jpg

[Dearg1275]

It might be worth cooling down the pump assembly and heating up the flange to make things easier when it come to pressing it on.

D

[Gary Schulz]

It might be worth cooling down the pump assembly and heating up the flange to make things easier when it come to pressing it on.

D

Yes, I think that makes a lot of sense...

[360gts]

Hi Gary
Your flange is on the way ...sent off early this morning.
Cheers
D