Thermostat bolt extraction

[piran]

Ok, so trying to change the thermostat and the bolts holding the thermostat housing have sheared. I've just got a bolt extraction kit but they're not showing any sign of budging. A quick look and a new housing is around £140 any suggestions ?

[Puglet1]

There are several methods.

1. Saturate the bolts with a good penetrating oil, tap the bolt several times to shock the threads / assist with oil penetration. Leave for a while then try using a good set of mole grips or your extraction tool again.

2. Apply heat to the base of the bolt using a flame , I use Oxy acetylene but you may be able to do it with a butane torch? I usually get the bolt cherry red before applying grips again.

3. I have also managed to remove a broken stud by mig welding an oversized nut to the broken bolt. This has a dual purpose of transferring heat into the bolt / housing and also allowing a socket to be used for removal.

4. If all else fails, as a last result you can drill down through the centre of the bolt and re- tap a new thread.

 

If you were closer, I’d offer to help but did it to Worcestershire area is a bit far.

[johny]

One of the bolts goes right through the housing so does a corroded section protrude out of the bottom?

[Colin Lindsay]

Herald 13/60? Firstly, no panic, we've got lots of those second-hand if needed.

You've got enough of the bolt stub sticking up to get a grip on. A good set of stud removers - the grip type rather than the reverse-screw-in type should grip those, but give them some help by either heating the housing round about with a gas torch, or applying a good penetrating oil (NOT WD40!) and allow time for the treatment to work. If you have a smaller hammer (you don't want to break them or the housing) then tapping the top of the bolts in a light repetitive rhythm, or hitting the outside of the housing adjacent to the bolts might shock them free.

Even a basic move like hacksawing a slot in the top of those and using a screwdriver might work once they loosen up a bit. You can drill down into them using a very small drill bit then getting progressively bigger until the metal is paper thin but try not to damage the threads in the housing. 

[piran]

39 minutes ago, johny said:

One of the bolts goes right through the housing so does a corroded section protrude out of the bottom?

No, I can feel the hole but the bolt doesn't go all the way through

 

[piran]

31 minutes ago, Colin Lindsay said:

Herald 13/60? Firstly, no panic, we've got lots of those second-hand if needed.

You've got enough of the bolt stub sticking up to get a grip on. A good set of stud removers - the grip type rather than the reverse-screw-in type should grip those, but give them some help by either heating the housing round about with a gas torch, or applying a good penetrating oil (NOT WD40!) and allow time for the treatment to work. If you have a smaller hammer (you don't want to break them or the housing) then tapping the top of the bolts in a light repetitive rhythm, or hitting the outside of the housing adjacent to the bolts might shock them free.

Even a basic move like hacksawing a slot in the top of those and using a screwdriver might work once they loosen up a bit. You can drill down into them using a very small drill bit then getting progressively bigger until the metal is paper thin but try not to damage the threads in the housing. 

I've been soaking in WD40 for the last week with no effect - is there an alternative that you recommend?

I've just bought a set of extractors - but they're the reverse thread sort and aren't budging

I went to try heat and I'm out of gas and nowhere nearby stocks the bottle I have

so it's all rather frustrating

[foshi]

do you have a welder , if so weld a nut on the heat alone works wonders .

Edited October 20, 2023 by foshi

[trigolf]

I've used Plus Gas pentrating fluid for years. Get's my vote. Halfords used to sell it.

[piran]

Just now, foshi said:

do you have a welder , if so weld a bolt on the heat alone works wonders .

nope

[foshi]

1 minute ago, piran said:

nope

ok with out heat your going to struggle , have successfully drilled them out .

[trigolf]

There looks like enough bolt shank to get a Stilson wrench on, if you don't have stud extractor.

[piran]

Have ordered some Plus Gas and a blowtorch - will pick them up tomorrow and see where we go from there

[JohnD]

Penetrating oil - Innotec Deblock.   Works every time for me.

Heat - try to get the bolt stub RED hot. allow to cool, add Deblock!

Welding a nut on the stub -  The thermostat housing is part of the water pump housing.  Take off the water pump and you have something easier to carry and take to a garage or body shop.  Ask them to weld a nut on for you, or else find a prper machine shop and get them to remove the stubs.   If necessary the last will have no problem in putting in Helicoils to deal with damaged threads.

John

[Chris Longhurst]

I used Plus Gas for years & changed to WD40 thinking it was a penetrating oil - it is a poor penetrating fluid but very good for displacing  water, protecting from rust. cleaning painted metal, removing sticky labels from glass & pottery, etc., etc!!

I went back to Plus Gas for freeing nuts (I'm sure the one JohnD recommends is also good)

Chris

[Pete Lewis]

i love these type  of stud extractor  never fails 

available from many suppliers  check costs they vary a lot 

can use impact wrench or hand ratchet 

 

[ahebron]

3 hours ago, piran said:

Have ordered some Plus Gas and a blowtorch - will pick them up tomorrow and see where we go from there

Of the single bottle range the yellow gas (mapp replacement) bottles give the greatest heat, I have brazed with mine.

[68vitesse]

When you do get the broken remains to move l found it best to work it anticlockwise and clockwise moving it a little further anticlockwise each time until out.

Best of luck.

Regards

Paul.

[DanMi]

any second hand part dealer eg spitfire graveyard spitbitz etc will supply a used one often easier than getting the bolts out. spitfire herald etc are all the same

[Colin Lindsay]

12 hours ago, Pete Lewis said:

i love these type  of stud extractor  never fails 

available from many suppliers  check costs they vary a lot 

can use impact wrench or hand ratchet 

 

Never tried those; isn't there a danger they'll shear rusty studs?

[Josef]

12 hours ago, DanMi said:

any second hand part dealer eg spitfire graveyard spitbitz etc will supply a used one often easier than getting the bolts out. spitfire herald etc are all the same

I’d agree, there’s even one on eBay right now for £30 that’s already been cleaned up, slap some paint on and you’ll be done! https://www.ebay.co.uk/itm/285517415563?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=XSTcghsGTcO&sssrc=4429486&ssuid=en_MztWYTyu&var=&widget_ver=artemis&media=COPY

[Pete Lewis]

will those stud extractors shear a rusted bolt  well thats a risk all types of removal  wil face

last used mine on Dougs head stud which were gorilla fitted  and with two of us on a 3ft breaker bar worted without fail

yes any extracot cn damage threads if there are any but these with a chuck grip fully and allow high levels of torque

to be applied without any slippage 

they just work well 

Pete

[Wagger]

A good small set of Stilsons have always worked for me after a good soak with penetrating oil.

In the 'Old' days, somebody I knew had a drill that cut anti clockwise. It heated up about half way down and spun the remains out.

If it shears off flush, spot the centre with a centre punch and drill out using a 4mm drill to begin with and work up to the tapping size in stages. Take it easy as you do not want the drill to break off. Some stud extractors are brittle and break off, then you have a real problem.

At least Colin has spares.

[piran]

Well, went out and bought a blow torch and an extractor set, dirlled the first bolt ok, extractor wasn't up to the task, tried the next one up and it bit but wouldn't turn.

Tried drilling the next bolt and the bit snapped.

bought a new set of Sealey left thread bits.

Heated the first one a couple of times applied plus gas , heated more and eventually it cam out ! result.

got the new drill bits this morning and they didn't touch the second bolt, tried the original drill bits and the next one snapped inside the bolt. I've applied heat and plus gas etc. and it's not making a dent on it.

So I guess cut my losses and remove the housing... the bolts come out not too bad but it was still connected, spot the water rail at the back, and undo that - which snaps the pipe. Finally got the rest of the pipe off, have the engine in pieces and still need to separate the water pump from the housing. Need to get a new housing, water rail, gaskets and whatever else breaks .....

[Colin Lindsay]

If you bought those dreadful spiral reverse-thread extractors, join the club. I've broken two sets and never went back for more. 

With drill bolts, use a very very thin one to start, and get very gradually bigger. The thin bit will drill through the centre of the bolt, and very gradual increases in size widen the hole with less chance of it sticking or breaking, and the heat generated may even free it up. It's rare that I have to drill out as far as the threads. If that pipe snapped it was probably terminally rusty anyway; check the rest of the system for clogging and give it all a good flush. Stainless versions of the pipe are available, but in different qualities (some have a bracket welded on the end that's nowhere near where it's meant to fit)

[JohnD]

4 hours ago, piran said:

So I guess cut my losses and remove the housing... the bolts come out not too bad but it was still connected, spot the water rail at the back, and undo that - which snaps the pipe. Finally got the rest of the pipe off, have the engine in pieces and still need to separate the water pump from the housing. Need to get a new housing, water rail, gaskets and whatever else breaks .....

Welcome to classic car ownership, piran!   And well done, for having back plan! 

As Colin says, those "reverse thread extractors" (I can't remember their proper name, but it should be &(^%$&^)(*¬!!!!) are worse than useless, as the small ones are modelled on much larger design, and they break off, IN the snapped bolt.  Because they are made of vert highly tempered steel they are harder than any steel used, even specialist drill bits.   NOTHING can get the snapped end out!  There should be a sign at the top of this and every classic car website, "DO NOT USE THE ^%$&*)(*) REVERSE THREAD EXTRACTORS!!!!"

You can get sets of reverse threaded DRILLS, which are a much better option, especially when used as Colin describes, and may lead to the bolt undoing itself!

Hope things improve for you!

John

Edited October 22, 2023 by JohnD