Seized bolt advice needed

MikeT · Unread post by **MikeT** » 29 Oct 2009, 12:14

I don't normally have much difficulty freeing bolts like this, the impact driver normally wins but not this time.

It's a Torx30 bolt on the injection pump I'm currently dismantling.

I've left penetrating oil soaking overnight from the back of the thread though there's no sign of it being seized through corrosion. Normally I would perservere with the impact driver but it's deforming and destroying the biting points internally rounding it off.

Any other tricks I can try before I ruin it completely?

uncle buck · Unread post by **uncle buck** » 29 Oct 2009, 12:29

Have you tried to tighten it?..... this will save you damaging the loosening biting points & may just crack it off from its seized position.

Another way is to use your torx bit in a spanner & whilst holding pressure on the spanner in a loosening direction tap the base of the torx bit with a hammer....keep holding the pressure on whilst repeatedly tapping the torx bit...this sometimes works.

Good luck.

HDI · Unread post by **HDI** » 29 Oct 2009, 12:40

I would try the above too. In the workshop I would use an impact gun , not much resists that !!

Unread post by **CitroJim** » 29 Oct 2009, 12:44

Those can be frightfully (or should that be frighteningly?) tight Mike.

I use a Torx bit (good quality one) in a little 3/8" breaker bar to undo them and hear a satisfying crack as they let go.

MikeT · Unread post by **MikeT** » 29 Oct 2009, 13:05

Unfortunately, and the photo doesn't show it well, half the bolt head is flush against the housing leaving little room for options. Yes, I always smack the impact driver in both directions to both tighten and loosen but will try it again. Failing that it'll be a drill job I guess.

citronut · Unread post by **citronut** » 29 Oct 2009, 13:34

i would resist hitting it to hard as you migh fracture the caseing, its only cast alloy,

i do sometimes find with Torx bits you think its one size, but when it feels like its going to strip the splinse, you find it turns out to be the next size up,

otherwise can you get a small chizle at the side of the head to drift it loose,

regards malcolm

VertVega · Unread post by **VertVega** » 29 Oct 2009, 13:40

- Did you try Freezing Spray. It usually helps.
- If there is enough room for cutting tool (like Dremel) you can cut a line as seen in the picture for a large flat head screwdriver.
- Drilling would be fine as a last option

MikeT · Unread post by **MikeT** » 29 Oct 2009, 14:03

I remembered I have an electric impact driver

But all I got was smoke as the bolt is truly rounded now.

I didn't think of freezing but did try heat around the casing to no avail. I suppose I can stick it in the freezer?

There is a chance I can cut a slot.

VertVega · Unread post by **VertVega** » 29 Oct 2009, 14:11

MikeT wrote: I suppose I can stick it in the freezer?

That would not help, I guess, because the idea of the freezing spray is to cause a sudden temperature drop in screw while the larger body stays almost in the same temperature as before. Shrinking will loosen the grip.

MikeT · Unread post by **MikeT** » 29 Oct 2009, 16:11

Slot is now cut though not so well where the head is flush (unless I risk cutting into the body a mm or so)... I tried an impact bit in place and looks like it might work. I also removed the other bolt and tapped the housing so it swivelled back and forth slightly so at least I know it's free under the bolt shoulder then reinserted and retightened that bolt to take some of the levered pressure off.

I'll see if I can spray freeze the bolt head - should I also heat the surrounding body to amplify the temperature difference?

MikeT · Unread post by **MikeT** » 29 Oct 2009, 16:43

Thankfully, it's off now but what a fighter! It cost me a chisel and one impact driver flathead bit.

Thank you everyone for your suggestions and support. FCF wins the day again 8)

uncle buck · Unread post by **uncle buck** » 29 Oct 2009, 17:17

Glad you're sorted

...there's nowt worse than loosing hours trying to free off a seized fastener.

Cheers.

citronut · Unread post by **citronut** » 29 Oct 2009, 22:49

it seems you use one tool from your tool box you did not mention, loads of PERCY WHAT SIT

regards malcolm

Unread post by **CitroJim** » 29 Oct 2009, 22:50

citronut wrote:loads of PERCY WHAT SIT

One very valuable thing to have at all times Malcolm. I use it all the time

Chlorate · Unread post by **Chlorate** » 30 Oct 2009, 15:41

What I've done with a rounded off torx bit before is hammer a slightly bigger tool into it since the bolt heads are usually pretty soft. Triple square (12 pointed star) bits are pretty good for getting more torque through the little buggers.