While stripping the hoses from my 4.6, a couple of the metal tubes came away with the hoses attached - one from the top of the rocker cover, and another from the throttle body. The tubes slide back into their respective holes and fit well, but presumably were set with some kind of paste/ sealant. Anyone care to recommend/ suggest what i could use to lock the tubes back in place? Epoxy?

Loctite 2700. It even stops the oil filler neck from unscrewing from the rocker cover when you try to take the filler cap off.

I use loctite on the oil filler neck too, but do you think it is going to retain a tube in a smooth bore? I have some, so easy enough to try, but isn't epoxy safer ? ie not designed to loosen at high temp...

Gilbertd wrote:

Loctite 2700. It even stops the oil filler neck from unscrewing from the rocker cover when you try to take the filler cap off.

Due to serious lack of time, I had mine serviced last week (instead of doing it myself as usually). It took two youngsters and finally one a bit closer to my age to take the cap off without the filler neck...

th.

I use Loctite 603, the old green high strength bearing fit, mostly because I've got it in stock. It is said to be designed as a retainer for cylindrical components rather than thread locker so it ought to be better at the pipe retaining job.

Trying to extract meaningful data about the actual real world strength of the umpty-six breeds of Loctite makes a two bottle of whiskey hangover seem like pleasant relaxation. I've never really gottten a handle on it but usually manage to choose something that works.

603 claims 22.3 Newtons/sq mm, 3,250 psi shear strength under iSO 10123 test conditions. Which is pretty strong. The data sheet gives explicit cure / strength curves for aluminium substrates too. I doubt if it gets up to much over 80 % of its strength in steel but it does cure properly.

Loctite 2700 is a thread locker claiming around 35 - 40 Nm / 25 - 30 ft lb breakaway torque and 20 N/sq mm, 2900 psi shear strength so its pretty similar strength to 603 in steel. Being a threadlocker it really doesn't like being used in thicker layers or being used with an activator. Strength with activator is about 1/4 of that without. The really worrying thing about 2700 is that it's very sensitive to substrate. According to the dat sheet it gets to full strength on steel and zinc, half strength on brass and one third on stainless steel and zinc dichromate. No curves for aluminium which is worrying. Given the low strength on stainless steel I suspect that oxide layers inhibit cure and seriously degrade performance.

2700 is a modern formulation claimed to be health and safety friendly. The sort of thing that generally means the new improved doesn't actually work as well out in the real world as the old stuff. Getting the best out of it probably needs much more careful preparation too.

Clive

I only suggested 2700 as I got some off the shelf at my local factors and it is claimed to be high strength rather than the other stuff they had on the shelf that was medium strength. I've used a couple of bottles of it on various things and nothing has come loose yet although they used to do some that was described as stud and bearing fix, but no idea what number that was. As Clive says, something intended for holding bearings might be better.

Totally agree that the best loctite to use is almost certainly the one you already have on the shelf. I have about 6! All old style stud fix, bearing fit, screw fix et-al labels.

If you start seriously perusing the data sheets it's very easy to end up wondering "what the heck is the difference between various grades". Way back an overly cynical co-worker reckoned it was all the same stuff with different colour dyes! Which may be taking things a teeny bit far.

However when I see a new to me grade mentioned I tend to have quick look at the data sheet just in case there is something special about it. No cure time / strength curve for aluminium and a low peak strength with stainless steel on the 2700 data sheet rang a few alarm bells as, way back, I've seen reports of cyanoacrylate joints being weak due to unsuitable substrates inhibiting proper cure. Loctite is basically a cyanoacrylate. I've certainly undone a few loctited bolts where the loctite apparently did next door to nothing beyond gum up the threads a bit. Where I'd done the assembly in the first place I couldn't blame the other guy. But it did hammer home the act that the stuff is not infallible.

But in a practical world how much strength to you need for loctite to be effective. Even not gone right off is probably more than enough. The oil filler spout joint is a respectable area so even something as weak as sellotape stickum would probably hold.

Clive

I keep it simple, I have 3 loctites blue, red,and green :) I went with epoxy in the end... I'll let you know if it fails. Tnx for the detailed analysis Clive!!

I just realised...Clive 603...are you such a loctite fan that you named yourself after a bottle of loctite?

romanrob

Nah.

Not loctite.

Comes from Bristol 603.

Had one stuck out front under a cover for about 30 years waiting for there ight combination of energy, funds and time to arrive so I can finally sort it out. Got scammed into it in the first place and trying to find folk to do the bit of fixing thats beyond me has proven impossible. Not helped by redundancy and carer thing putting a huge crimp in things over a decade or so from 2004.

I really need to get it moved on as I'm 70 in four days I'm unlikely to sort it. Lovely though the "gentleman's sporting carriage" is the P38 suits me better.

Was tempted to change handle to CliveP53 just to confuse the living daylights out of everyone! (Hint. Think Bike!)

Clive

Thanks for the explanation :) Sounds like one of your kids should be writing to the car show where they fix up dads old car :)