Replacing bolts and screws on a car resto

[marlinspike]

Forgive me if this is a stupid question. We are restoring an old Saab. The bolts are rusty to the point of having to drill them out, or at least having to spend hours trying to crack them. A lot of them are steel torx (star) fitting heads.

When we replace them, is there any reason why they should be torx? Could we just replace them with stainless steel ones? The torx ones just round off so easily. Hugely frustrating that so much time is spent trying, and often failing, to remove rusty bolts. Currently at an impasse with the bolts holding the pipes that go into the air con condenser. Tried Plusgas and others.

 

[rikrobson]

There is no reason to continue to use torx as long as you can get a spanner or socket on the end. I believe its to reduce costs or deter home mechanics fiddling with there "technology". Don't use Stainless steel, A2 nowhere near the tensile strength of 8.8. Use Bright Zinc Plated. I'm afraid rusty bolts is half the fun of restoring cars. If you don't like rust get another hobby.

I got some stuff from aldis I think, is an anti rest penetrating spray, or WD40 or 3 in 1 penetrating oil. The use Irwin grip sockets and long slow torque. a breaker bar and something on the end. if that dont work the 3" cut off grinder is produce and that usually scares the bolt out. freezer spray sometimes works as does a bit of heat. The temperature differential breaks the rust adhesion.

 

[RonA]

I agree whole heartedly with RikRobson, no need to use anything other than good quality high tensile nuts & bolts. It's always been a bit of an arms race between the manafacturers & the home mechanic. They change the fasteners, the mechanic buys the appropriate tools to undo them & just when your sorted they change the fasteners again to screw you up. Similar story with ECU readers.
RonA

 

[rikrobson]

Oh and of the cut off disk doesnt work or get in the space the air chisel finishes the job off.

 

[rtbcomp]

I think Torx was invented to make it easier for robots to handle fasteners.

 

[Robotstar5]

I think Torx was invented to make it easier for robots to handle fasteners.

Torx and Spline drive fasteners make it a lot easier for the powered drivers used on the assembly lines as the driver bits engage quicker with less chance of "cam out".
Most tools are monitored and if they don't achieve correct torque and angle the track will stop until the problem is sorted.

 

[Jim Davey]

Torx are lovely when new, but a pain in the bum once they corrode, especially if the torx socket part was very shallow to start with. A big improvement on Allen style fasteners though as there is more engagement area on the bit. I do like 12 point bolt heads like you find on decent con rods.

 

[Robotstar5]

I've noticed Getrag gearboxes have bolts with an odd number of flats on (7 sided) holding the casings together

 

[piman]

Hello Marlinspike,

I've used copperslip when I assemble my old cars (and other things) and find they will unscrew years later, even on suspension systems etc.

Alec

 

[colnerov]

Hi, As said Torx is for assembly line effiency there's no need to replace like for like unless you're doing concourse or are anal about the restoration.

 

[marlinspike]

Thanks guys. I will take all that advice on board. Interesting what has been said, about torx making the assembly line easier, I wondered if there was a reason.

 

[Keith 66]

I feel your pain, my ford focus has just blown its exhaust, right at the front so its a new manifold as well as the rest. Poxy manifold bolts are seized tight. Its booked in tuesday to be fixed & i have been giving it lots of plus gas, If the mechanic breaks any studs its a head of job & then i might as well scrap it as fix costs will run to more than its value.
When working on the moggie all bolts get done up with copperslip. I also have used Stockholm tar on mooring shackles, this ancient remedy will keep a steel bolt from seizing even if its buried in the mud for years. Smells nice too!

 

[MattF]

Isn't Stockholm tar pine tar/pitch?

 

[Keith 66]

Yes Stockholm tar is also known as Pine tar, its basically distilled from pine roots. Used on horses hooves & in traditional boats. I put some on a set of iron mooring shackles & after four years on a half tide mooring they came apart & the threads were as shiny as the day i had done them up.

 

[marlinspike]

We were struggling to remove the air con condenser bolts and ended up breaking one of the pipes today. Annoying but there was no way it was coming undone. Pipe cracked so we cut through it and got the other bolt undone. So much time spent on struggling with rusty bolts.

 

[MattF]

Yes Stockholm tar is also known as Pine tar, its basically distilled from pine roots. Used on horses hooves & in traditional boats. I put some on a set of iron mooring shackles & after four years on a half tide mooring they came apart & the threads were as shiny as the day i had done them up.

Thought the name sounded familiar. Does that stuff harden after awhile, or does it remain sticky, (when exposed to air, not concealed)? Is it readily available over here? Seem to recall searching for some awhile ago and drawing a blank.

 

[Keith 66]

Thought the name sounded familiar. Does that stuff harden after awhile, or does it remain sticky, (when exposed to air, not concealed)? Is it readily available over here? Seem to recall searching for some awhile ago and drawing a blank.

It stays sticky for ages but hardens eventually.

 

[Coffinswell]

Thought the name sounded familiar. Does that stuff harden after awhile, or does it remain sticky, (when exposed to air, not concealed)? Is it readily available over here? Seem to recall searching for some awhile ago and drawing a blank.

Yes it should be. Try an agricultural suppliers; Mole Valley Farmers down here in the West Country; up your way I see Greens Country Store of Thirsk stock it, "Battles Stockholm Tar", six odd pounds sterling for approx one lb [450 grammes].