Paranoid about stripping a thread what torque to use?

Post by **leyther8008** » Wed Oct 29, 2008 8:49 am

Are the torque setting for a Minor a national secret or something? every handbook I,ve trawled through only lists main engine componant torque values.
Not a mention of any in the suspension sections, and I want to replace a damper.
Now not wanting to turn an hours job into a weekend marathon by stripping a thread, I need to know the torque setting for the 4 front BSF fixing bolts, but can I find it? No.
Is anybody willing to divulge this setting to me? I will swear alegiance to the Minor if it helps.
Or point me towards a comprehensive list of settings for future reference.

Post by **mike.perry** » Wed Oct 29, 2008 9:32 am

The published torque settings are the only ones you need to know, apart from Series MM engine settings which are listed on the Series MM website.
Provided you use the correct length and jaw sized spanner and just tighten the nut or bolt up tight you should be alright. If you use a socket and wrench just note that it has more leverage than a spanner and use a little less force. The larger the bolt the more force it will take, anything larger than 1/2 A/F you are pretty safe with. With practice you can feel when a nut or bolt is reaching its stretch point.
The most likely time to strip a thread is if the nut or bolt is siezed when you should leave it to soak in Plus Gas or WD 40.
The problem you may encounter with the front dampers is if the captive nuts behind the cross member have come loose, it's a tricky job trying to get a spanner on them. Are you sure you want to change them? they are usually pretty reliable, Ive never had to change one on my cars.

Post by **leyther8008** » Wed Oct 29, 2008 9:49 am

Oh yes I need to change one, oils coming out of the main pivot nearly as fast I can pour it in, completely shot I,m afraid.
I,m fully aware of spanner leverage issues, I,m a bit of a monster and can put to much power into a breaker bar! so I would like a torque figure to use then I can put any failure down to something other than my own cackhandedness, when I have to explain another weekend of her seeing my backside as I,m bending over the engine to my beloved..

Post by **mike.perry** » Wed Oct 29, 2008 10:33 am

Torque = Force x Distance or something like that, so calculate your own figures to keep her happy.

Post by **Luxobarge** » Wed Oct 29, 2008 10:39 am

OK, so you're not interested in a torque figure that's been carefully calculated by the factory ('cos there isn't one!) but you want one that will help to prevent you stripping the bolt threads, yes?

Assuming that the dampers are still on the car, try tightening them with your torque wrench, increasing the setting gradually until the existing bolts JUST start to move as the wrench clicks. Then you have a setting which is a) slightly tighter than they are at the moment and b) is proven not to strip the threads.

This assumes that you're using the existing bolts for the new dampers....

Any good to you?

Cheers

Post by **leyther8008** » Wed Oct 29, 2008 10:57 am

Worth a try but dont they take a 'set' over time i.e. it takes more torque to move a fastened bolt than to tighten one? Somebody must know the setting?

Post by **Luxobarge** » Wed Oct 29, 2008 11:01 am

leyther8008 wrote:Worth a try but dont they take a 'set' over time i.e. it takes more torque to move a fastened bolt than to tighten one? Somebody must know the setting?

True, but you're still going to obtain a value which won't strip the threads eh? If the "setting" makes you nervous, then tighten them to 10% less.

I'm not sure you have any other real option, as mentioned above, an "official" setting for these bolts probably just wasn't ever published.

I know that's what I'd do!

Post by **bmcecosse** » Wed Oct 29, 2008 11:21 am

Just tighten them with a ring spanner no more than 8 " long and you will feel when they are tight enough! It's really not difficult.
But - here's a guide to the torque values you should be using - make sure the threads are clean on bolt (wire brush it) and captive nut (ideally run a tap through) and oil the threads well!

http://www.sizes.com/tools/bolts_SAEtork.htm

Of course -you don't know what standard these bolts were made to (unless some marking on the head ?) - but I think they are 3/8" diameter (only guessing - so please check and correct me if wrong) and so 25 ft lbf would seem a good figure from that table to use. Seems a bit low to me - but you take the chance if you go much higher - don't blame me!

Post by **mike.perry** » Wed Oct 29, 2008 12:46 pm

Just knock the lock tabs back, stick a socket on the bolts

and go for it.
I'de be more concerned about getting the damper arm off the top swivel tapered pivot arm.
Oil the threads replace the bolts and tighten without straining. Knock the lock tabs over (or replace them with new ones) and you will be fine.
If the bolts are too loose the suspension will knock over bumps.

Post by **alainmoran** » Wed Oct 29, 2008 3:44 pm

when I want to avoid stripping a thread, I just use one finger to push the spanner around, that way it is MUCH harder to push things to the point of stripping ;)

Post by **MarkyB** » Wed Oct 29, 2008 5:52 pm

As has been said it's better to use a spanner than a socket wrench especially on the front shocks.
Just use your arm muscles and not your body weight and they should be fine.
It's not like they'll fall off with no warning. Run it around a few days and see how they feel then.
I have managed to strip one of these and it was a pain to sort out. I think I drilled a hole somewhere and put a nut on the protruding thread. And I err on the side of caution when doing things up.
If memory serves the threaded part is the same as the one that holds the door hinges. I.e. about a quarter of an inch thick.

Post by **Zack** » Fri Oct 31, 2008 5:57 pm

Maybe cross reference some specs from a Mini or MGB? I'd think if the mounting hardware is the same size the torque spec would be similar...

Post by **bmcecosse** » Fri Oct 31, 2008 6:03 pm

Completely different damper types and mountings on both these cars! Only the rear dampers on an MGB are vaguely similar to Minor rear damper arrangements.

Post by **brixtonmorris** » Wed Nov 05, 2008 11:40 pm

i dont think the bolts go into captive nuts they are square plates in the cross member like on the inside of the door hinge pillars.

Post by **mike.perry** » Thu Nov 06, 2008 12:27 am

My damper nuts came loose on my Series MM, the bolt kept turning but I managed to get a spanner on the nut, so I assumed it was a captive nut. Could be wrong though -- again.

Post by **brixtonmorris** » Thu Nov 06, 2008 12:26 pm

They may have changed them on later cars, due to the captive nut not being reliable, and difficult to deal with if they rotate.

Post by **RogerRust** » Fri Nov 07, 2008 7:59 am

I only worry about the sensitive things like cylinder head.

But HERE IS A COMPLETE list for the MGB. Including rear shock absorber 55 - 60 foot pounds.

Torque about detail! I think its people getting up tight.

I was taught that the correct torque for a nut was go to the point where it strips then go back a bit!

Post by **MarkyB** » Fri Nov 07, 2008 9:07 am

Whoa!:o

55 - 60 foot pounds.

Sounds like too much to me That's more than the cylinder studs head which are meatier than the shock bolts.
The general torque values at the bottom should give a useful value.
I'm almost sure the captive part is the same as is the one in the door pillar and it's only about 1/4 inch thick.