Frozen bobbins

[Bigbaldybloke]

Back to the original question of how to remove the original siezed bolts. A good soaking with penetrating fluid repeated over a period of days, combined with heating as you suggest with a large soldering iron may eventually loosen the bolts. It did for some of mine, but by the time I had actually fully unscrewed some of the bolts the thread remaining in the bobbin was so corroded away that it was useless for securing anything. I went for a mix of drilling them out and using a nut and bolt, tapping them oversize or replacing the bobbin completely depending on condition and function. As for using stainless bolts, they are not as strong as high tensile steel bolts and can cause galvanic corrosion. That said I have used them in certain places such as along the bottom of the sills as I have stainless steel sill members. In interior applications where the bolts are going to be dry and hence there is no electrolyte the stainless probably will give no problem.

[alan.barker]

"Back to the original question of how to remove the original siezed bolts. A good soaking with penetrating fluid repeated over a period of days, combined with heating as you suggest with a large soldering iron may eventually loosen the bolts. It did for some of mine, but by the time I had actually fully unscrewed some of the bolts the thread remaining in the bobbin was so corroded away that it was useless for securing anything. "
That's just it, the good thing about Helicoils. When original thread so corroded away the hole is almost the Tapping size for the Helicoil Tap. So the Helicoil puts it back to original dia and stronger.
No need for stainless Screws.
I find it quicker to drill out corroded Screws and fit Stainless Helicoils. Much less faffing about and no excessive strain on Bobbins
Alan

[MalcM]

Slight thread bump as it sounds like I have largely the same issue.

Managed to shear the head clean off the first seat retaining bolt I tried to undo, after a decent tap with the hammer & punch, the other 3 came out fine.

On the chassis-body mounting bobbins, roughly 1/2 so far are solid. They've been doused with penetrating oil umpteen times over a decent period of time [~6 months ], tapped on the head and tail using a hammer & punch. Whilst the hammer tapping worked with the seat bolts, its not having as much luck with some of the chassis bolts.

I don't have a heavy duty soldering iron to use to apply heat, not very keen on using naked flame, with the fire risk on fibreglass but also the risk of weakening the resin through excess heat transfer. Am I being overly cautious here?

I'm at the point where the body needs to get separated to get things moving. So its either try careful heat or let my impact gun have a shot and deal with whatever the consequences may be.

[nmauduit]

also the risk of weakening the resin through excess heat transfer. Am I being overly cautious here?

no you're right, the polymerized resin would suffer from excessive heat, a mechanical way out (punch, drill, etc.) would be my last resort when all penetrating lubricant options have been applied.

On a very sensitive part applying cold on the innner part rather than heat (e.g. freezing spray can) may be attempted, but is usually not very effective without heat on the other side.

[alan.barker]

Why not make up a Drilling plate/jig to keep hss twist drill central and drill them out.
The Screws i'm talking about are the horizontal ones in the Front Turrets and Rear Turrets.
The rest you can just unscrew and shear the Heads off. The horizontal screws prevent vertical lifting of Body.
Alan

[jono]

After 'feeding' all my chassis bolts repeatedly for a week or so with GT85 (which incidentally I have discovered is a wonderful penetrating fluid) they all came off using a (judiciously applied) 700nm Kielder impact gun. This was on a '67 car on the original chassis.

Less success with one of the seat bolts but it drilled out and restored with helicoils, the others 'cleaned up' with a tap.

Headlight pod pivots (a couple had been previously bodged thus causing the pods to be misaligned) were drilled out with a right angle drill then cleaned with a tap - most came good. Two others had to be reamed out with a die grinder - I then filled the hole with metal epoxy, found the centre and then drilled and helicoiled them. The pods are a great fit now

[MalcM]

Why not make up a Drilling plate/jig to keep hss twist drill central and drill them out.
The Screws i'm talking about are the horizontal ones in the Front Turrets and Rear Turrets.
The rest you can just unscrew and shear the Heads off. The horizontal screws prevent vertical lifting of Body.
Alan

The screws on the horizontal plane thankfully all played ball, its only vertical ones that are giving me grief.

I was hoping someone would have a magic solution of olde which would avoid me resorting to impact gun carnage followed by a whole load of drilling and tapping. Sounds like a bit of collateral damage is inevitable.

[Bud English]

I was hoping someone would have a magic solution of olde which would avoid me resorting to impact gun carnage followed by a whole load of drilling and tapping. Sounds like a bit of collateral damage is inevitable.

You might be surprised by the impact method. When I sent my brand new aluminum zetec flywheel off to the machine shop to be machined and fitted with a 110 tooth ring gear they managed to strip out one of the six round head, hex drive, retaining screws on the ring gear and didn't want to continue. I got a call to come and pick it up, which I did. I was back in less that an hour with all six screws removed, including the "stripped" one. They were trying to remove them with a hex key and I removed them easily with a hex bit in a 1/4" impact driver. The effect of many light impact blows worked where the brute force method failed.

[jono]

I was hoping someone would have a magic solution of olde which would avoid me resorting to impact gun carnage followed by a whole load of drilling and tapping. Sounds like a bit of collateral damage is inevitable.

You might be surprised by the impact method. When I sent my brand new aluminum zetec flywheel off to the machine shop to be machined and fitted with a 110 tooth ring gear they managed to strip out one of the six round head, hex drive, retaining screws on the ring gear and didn't want to continue. I got a call to come and pick it up, which I did. I was back in less that an hour with all six screws removed, including the "stripped" one. They were trying to remove them with a hex key and I removed them easily with a hex bit in a 1/4" impact driver. The effect of many light impact blows worked where the brute force method failed.

100% agree - it worked for me on my chassis bolts and I've just, this afternoon, removed the pinch bolts from my son's suspension struts which would not budge with a 800mm breaker bar.

The multiple blows shock them off without significant risk of shearing. The best tool I've bought after a 2 post lift

[MalcM]

Update from the weekend;

3 & 4, 13 & 14 [suspension upright mounting points] - these had all loosened off easily earlier. Only issue was there must have been some twist in the shell at the rear, so the threads received some galling from the additional plate that runs behind the bulkhead and those screws will need replaced.

Going front to back on the other locations;
#1, loosened by hand [socket and wrench]
#2, refused by hand, refused with 1/4in impact driver, loosened with 1/2in impact gun
#5 & #6, removed the nuts inside the rollcage easily by hand, loosened screws with 1/4in impact driver [didn't bother trying them by hand]
#7 & #8, loosened by hand [spanner]
#9 & #10, loosened with 1/4in impact driver [didn't bother trying them by hand]
#11 was fun and games, with the Spyder half cage I actually had 3 bolts with nuts here, middle one of them through the bobbin. 1/2in driver with spanner took care of the 2 not going through the bobbins, the bobbin one sheared the nut off the bolt but the head and most of the thread came out so won't stop the frame coming off
#12 was also fun, 2 bolts only on this side, they played ball with 1/2in gun
#15 internal nut came off easily with socket and wrench, bolt laughed at the 1/4in driver but the 1/2in gun shifted it
#16 was a royal headache, the head of the screw was hard in the corner of the frame so it wasn't possible to get a socket on it, even a normal one rather than an impact socket. Double nutted the internal thread to try and drive it out a bit from the other side, this didn't really work, so in a moderate fit of rage I used the 1/2in gun to lock the nuts together and simultaneously managed to rip the threads out the bobbin so I was able to remove the nuts and chap it out from the top with a hammer

So in summary;
- 1/4in impact driver was helpful
- 1/2in impact gun was meaty enough to resolve most problems, or pulverise them, depending on your viewpoint
- All bobbins will be getting helicoiled based on what I've read on here

[jaman]

Toilet bowl cleaner has about 10% Hydrochloric acid Does a great job of removing aluminum corrosion.

Has worked every time for me on boats & cars