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Loctite problem

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So I have a little problem with some cap screws on my TR6. There are 6 of them holding my CV joints to the diff.

When I put them in normally, they work loose.
When I use blue loctite they work loose.

When I upgraded them to longer, stronger cap screws, and blue loctited them in, they STILL worked loose.

Is red going to hold them?
Is there a stronger option?

Help...
 
First, sounds like a fitment problem.

You say they work loose, is that the cap screws(bolts) unthreading?. First I would make sure there is good thread match. Second, what is going through the head of the CV? Is it threads on the bolts, or is it shoulder of the bolt? I would look for bolts with a tight shoulder where they go through the CV flange.

Then with good solvent clean up the residue from the bolt holes, Red loctite has NEVER come undone on me, on any fastener I've applied it to over the years. Sometimes it may take more effort to unfasten, but it has always stayed tight.

Did you read about the brake caliper update in the last 6 mag? Just got mine. I was hoping there was an email address for the author as I would like to input one VERY important item that was not mentioned, or overlooked. could make the difference between breakage and crashing or not.
 
Clean both surfaces thoroughly with either Loctite's own Kleen N Prime, or use acetone. Oily residue will entirely defeat the properties of Loctite.
I've had properly prepared, red Loctited fasteners require heat for removal.
Jeff
 
Same here. Clean threads thoroughly, red ~sparingly~ and proper torque. Usually requires "dilligence" when it comes time for the next disassembly.
 
They're in with the red.
I'll let them set overnight and we'll see if that fixes it.
 
It's actually a "pressure adhesive" so should be ready to go after you torque 'em down.
 
I have used the red loctite and never had an issue. Like was said above, make sure the holes are clean. I like what Ron said above about having a shouldered bolt pass through the un-threaded section.
 
DrEntropy said:
It's actually a "pressure adhesive" so should be ready to go after you torque 'em down.
Click to expand...

Well if you want to be pedantic - and let's face it who doesn't - it needs a little while to set up. For steel a couple of hours according to the sheet. Allegedly it reaches full strength after 24h - which is why I was leaving it overnight.

Loctite 271 specs

Regardless, I'm taking it for a little trip round the 'hood to see if all the things I've swapped out are leaking, oozing - or in the case of these bolts - working loose.

Fingers crossed...
 
FYI for those who haven't seen it, Locktite comes in a handy stick form now. :thumbsup:
 

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Blue loctite does not harden as red does. Blue is for light duty as in waterpump pulleys and the like. Red will glue everything together, but there are different degrees of red. Green is a lighter loctite that does not get real hard.
 
Hmmm... If this were mine, I'd look beyond the Loctite, as your thread root/bolt composition is likely the issue. Spend 20 bucks and buy AN aircraft bolts/nuts with the exact grip length from Aircraft Spruce. www.aircraftspruce.com Loctite certainly can't hurt, but it is simply no substitute for really good hardware.

If you have a Caterpillar main dealer near you, they have outstanding hardware too in Grade 8/exact grip lengths. They'll sell you as many or as few bolts as you want, in zinc or black oxide.
 
I have 12.9 socket head cap screws from McMasterCarr - 91303A198. I'm not sure what I can get that's better than that...
 
Why metric?

They're plenty strong enough, but perhaps they are not wide enough and they're getting hammered in the drilling?

What are you torquing them to?
 
He has custom CV jointed halfshafts using modern components. That's why the metric. It's not a case of metric parts in a hole drilled for standard fittings.
 
swift6 said:
He has custom CV jointed halfshafts using modern components. That's why the metric. It's not a case of metric parts in a hole drilled for standard fittings.
Click to expand...

Well then something "custom" is not engineered properly or the cap screws are the wrong grip length.
Good hardware (which he has) cleaned and torqued properly with red threadlock will not loosen.
 
Rather than Loctite, I drill small holes, at the top of the bolt and then wire them all together. I am not sure if you can do it in your application. Works great, then when it's time to take them apart, just cut the wire and unscrew.
 
My suspicion would be that something is out of true or balance, creating vibration that loosens the fasteners.

Had a similar problem years ago on my TR3A driveshaft, and worked around it by upgrading to "distorted thread" type locknuts rather than the stock Nylocs.
https://www.mcmaster.com/#catalog/114/3139

Later I replaced the driveshaft, which probably solved the problem the right way, but I liked the locknuts so well that I still use them on all my Triumphs.
 
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