Snapped water pump bolt

S

skmattwell

Active member
 London
It can never just go to plan can it... Is it just my luck or does this happen to everyone?

While replacing the water pump one of the studs that hold the pump on snapped, leaving a small stub too small to use the two bolt method to remove it. Vice grips have also been fruitless.

Short of welding a bolt to the thread, do I have any other options? Does the but that the water pump bolts onto come out at all or is it part of the block?
 

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Bad luck (and, yes, it does happen to us all!) but not the end of the world. That will survive easily on the reamaining three studs without leaking, I reckon. The seal is an internal O-ring rather than a face gasket so won't care about the odd corner and the pulling force from the belt looks to be pulling against the opposite one so, if anything, the missing corner is under compression rather than tension.

Just don't do it again next time :wink:
 
smorris_12 said:
Bad luck (and, yes, it does happen to us all!) but not the end of the world. That will survive easily on the reamaining three studs without leaking, I reckon. The seal is an internal O-ring rather than a face gasket so won't care about the odd corner and the pulling force from the belt looks to be pulling against the opposite one so, if anything, the missing corner is under compression rather than tension.

Just don't do it again next time :wink:
Click to expand...

So you reckon I'm okay to leave it be and just tighten the other three bolts? I thought the pressure of the coolant would push its way through
 
If it was a face gasket then there's a chance the outside lip of the pump might distort and weep if it was particularly hot but the seal is the O-ring so as long as the pump is in the hole, it'll seal. You could slacken the nuts off three turns, pull the pump forward and it still wouldn't leak as long as the O-ring was still inside the chamber. If anything it's a bit over-engineered (no bad thing) as many pumps only have three bolts.
 
Mark Plant and I had the same on a thermostat housing

In the short term the seal held with 3 of the 4 bolts in place

We then popped it off and eventually drilled and tapped a new hole for the bolt to sit in
 
In my experience, five minutes of heat with a small hobby blow lamp has always shifted a rusted bolt. In this case, I am not sure about applying directly to the aluminum but you could certainly heat up the stud and then cool it rapidly to release it
 
Would welding the bolt to the thread work? Then using that bolt to ratched it out? That's what my local mechanic suggested and seems easier than drilling and tapping a new hole
 
skmattwell said:
Would welding the bolt to the thread work? Then using that bolt to ratched it out? That's what my local mechanic suggested and seems easier than drilling and tapping a new hole
Click to expand...
That works most of the time. The heat from the welding process will expand the metals at different rates and should allow you to back the stud out relatively easy.
 
BumpyZ4 said:
skmattwell said:
Would welding the bolt to the thread work? Then using that bolt to ratched it out? That's what my local mechanic suggested and seems easier than drilling and tapping a new hole
Click to expand...
That works most of the time. The heat from the welding process will expand the metals at different rates and should allow you to back the stud out relatively easy.
Click to expand...

Thanks 👍

My last question would be, to anyone who might know, where to source a replacement stud? Wouldn't even know where to look for a part number
 
If you go get it out, which I don't think will be easy, tidy up the thread with a tap and just find a bolt a little shorter than the overall depth with the pump in place.

Or cut a length of threaded rod to suit.
 
Heat and a stud extractor socket should get the broken one out looks like enough left to put an extractor on it. Old school method of welding a nut on the end and using a socket and ratchet would also work + squirts of penetrating oil once it starts moving, work it forwards and backwards small amounts to get it out
https://www.ebay.co.uk/itm/325278799764?hash=item4bbc209794:g:eqUAAOSwOLljNS1k
 
bigwinn said:
Mark Plant and I had the same on a thermostat housing

In the short term the seal held with 3 of the 4 bolts in place

We then popped it off and eventually drilled and tapped a new hole for the bolt to sit in
Click to expand...

That's was a day :tumbleweed:
 
Just to close out this thread, I solved the issue with this sleeve nut:
https://www.ebay.co.uk/itm/175354711364?var=474601415504

Fortunately the remaining thread was long enough for a sleeve nut to go through the mounting hole of the water pump and latch onto it. I did have to drill out the water pump mounting hole by 1mm to accommodate the sleeve nut, but it was dead easy.

If you need to do the same get the following:
Allen Key Size: 4mm
Mandrel x Length x Head: 8x11x13mm
Size: M6
 
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