300 Tdi Injector Clamp Nut Tension

[DeanoH]

According to the manual the correct tension for the injector clamp nut is 24 Nm. Mine failed at less than this whilst tightening. The others didn't feel good whilst doing up, so I guess I'll ditch the lot.

https://www.aulro.com/afvb/images/imported/2013/02/1177.jpg

Might ignore the manual and settle for 20 Nm on the replacements.

Any one had a similiar problem.

Deano :)

[manic]

Hey Deano , been there done it. When I snapped one of mine I almost had a heart attack, for a moment I thought I had snapped a molded part of my new c.head off!! :o

After a fair few bolt snapping incidents whilst changing my CH, I always try to use new bolts where possible and look at torque settings as a guideline.

For the clamps I stepped up through the torque settings 5,10,15 and when getting up to torque if the next click didn't come quick enough, I just left it!

One of mine made it 24Nm and others I only dared get close... I suppose they fatigue from all the heat exposure over the years. All new ones and you probably would get 24Nm on them all no probs.

Matt

[manic]

oh btw, I still have three of those studs in my old CH if you want me to post them... should be same part number 300tdi/200tdi?

[MR LR]

I stretched all of mine before I bothered looking up the torque setting!!
New ones were good for 24Nm

[DeanoH]

Thanks guys. New ones are pretty cheap and Roverlord is only 1 days post away.

Frightened the crap out of me too. I had visions of having to remove the head to extract the remnants. :eek:, and after all that bull**** 60 degrees plus 60 degrees plus 20 degrees and similiar crap with the rockers for heavens sake, talk about making a simple job difficult......................

Never been more thankful for my usual pedantic thread cleaning and using gallons of anti sieze, stud remnants came out easy with a gentle tap from the cold chisel. :D

Deano :)

[Spel1]

Or, if its Sunday and you just broke the stud and need to use your TDI for work on Monday. Go to the auto parts store that's open, buy a packet of high tensile M8 bolts with the same amount of thread as the stud. Cut the head off and clean up the edges, then use it as a stud. Fits fine with no issues. I think the narrow shoulder of the original stud might be a failsafe for over tightening in the alloy head, ie the stud will break before it pulls out of the alloy. Whatever the reason, the home made stud is still there after 100k kms. Simon

[DeanoH]

Binned my 3/8" drive torque wrench today, just doesn't feel right. If I torque up fairly quickly it 'breaks' cleanly and feels good. If I torque up slowly it 'hangs on' and doesn't 'break' till way over tension. I reckon this is what may have happened with the injector stud(s).

Deano :)

[Spel1]

Binned my 3/8" drive torque wrench today, just doesn't feel right. If I torque up fairly quickly it 'breaks' cleanly and feels good. If I torque up slowly it 'hangs on' and doesn't 'break' till way over tension. I reckon this is what may have happened with the injector stud(s).

Deano :)


Dry threads might have been binding up. Have you tried the torque wrench in different circumstances, or with some loctite on the threads? Its easy to reach apparent tension if the nut sticks in place too early.

[Blknight.aus]

Binned my 3/8" drive torque wrench today, just doesn't feel right. If I torque up fairly quickly it 'breaks' cleanly and feels good. If I torque up slowly it 'hangs on' and doesn't 'break' till way over tension. I reckon this is what may have happened with the injector stud(s).

Deano :)

Dig it out post it up and I'll service it for you.

Dont use high tensile bolts, the OEM studs are shanked so they do break before you overtighten them and kill the head. If they snap off before they hit 24NM then they have been over tensioned previously.

on a standard sidchrome 13mm ROE spanner I pull upto 40NM without too much effort so they are quite easy to over do, just like the bolt for the cran case ventilator, the rocker cover bolts and the dreaded centrifuge oil filter on the TD5.

Typically its not the butcher that does them up too tight the first time that has the problem but the guy trying to do the righty afterwards that does.

[DeanoH]

Thanks Dave. :) though I wonder if it's worth the effort.

It's a Kincrome which no 1 son bought home from work as it 'failed' its annual calibration test. Actually it 'passed' its annual calibration test because no accuracy requirements were given to the testers by the owners so it automatically 'passes' regardless of the results. :eek::eek:

Actually its calibration is only out in the 0 to 10 Nm range, above that it's OK (+ or - 5%) which I reckon is fair enough.

In the end he bought a new one, with calibration chart, which was cheaper than testing the 'old' one anyway.

PM me your address dave and I'll send it to you. :D

No problems with dry threads Spel1, I'm a real Nazi for for anti-sieze thread lube, especially steel into alloy.


Deano :)

[Blknight.aus]

most torque wrenches wont stay in calibration at the bottom 1/3rd of their scale anyway, normal torque wrenches have a tolerance of +/- 5%

[VonSwirl]

I've just sheered off my bolt! Can anyone give me some tips on how to remove the stud? It has sheeted off just below the bottom of the thread so there is no thread left but there is still a bit of stud protruding... Help!!

[Blknight.aus]

left hand drill bits and rigid stud extractors or easy outs.

use a flat face burr to level off the remainder of the stud, use a self centering center punch to locate the center and have at it.

if you need to drill it oversize and run a helicoil into it.

[uninformed]

a note on Torque wrenches, if you have the type where you rotate the handle to increase or decrease the force amount, you should always back it right off before putting it away in your tool box...

[manic]

The protruding neck of the stud is ripe for a cut through the middle. I used a dremel with cutting disk and put a nice deep slit down the middle and then used a wide flat screw driver, tap it in with a hammer and screw it out. If its seized you can wedge a flat bit in there and use an impact driver.

https://www.aulro.com/afvb/images/imported/2013/02/1238.jpg

If that fails you can cut it flush and EZ-out

[Blknight.aus]

my bad, I thought the stud had snapped off below the block threads.

start out by cutting it with the dremel or a jewelers saw then have at it with the impact driver.

[roverrescue]

-steel stud into alloy housing I almost always reach for the old "nut + MIG" trick


-Just last night I was helping out a friend (who pulls the best coffee in town and NEEDS to be looked after).
-80 series cruiser held together with rust and spray paint
-Reversing down drive, started to accelerate and voila lost all drive.
-Calls me, I turn up with the works in the tray (and a roadie) expecting badness (her words on the phone were "the wheel has fallen off")
-turns out all 6 (yes 6) M8 drive flange studs plus the two dowels have failed, PS drive shaft has ejected and diff oil bleeding everywhere.
-So stuffed paper down the stub axle, cleaned up the oil so some poor unsuspecting landy wouldn't get blamed for it, locked the hubs engaged 4wd and drove to the shed.

-after strip down with the hub on the bench, all 6 studs have sheared off, real ugly, like below the flange height - ouch.
-Wheel bearings were appropriately adjusted (if anything a little tight).
-Axle housing eyeballs straight and no shaft issues revealed with the "eye-o-meter".
-My guess is the boofhead parts swappers who last serviced it, and are always in a rush rattled the nuts on a little over the recommended torque and 15 years of fatigue did the rest.

-Anyway, the "nut + MIG" trick worked for 5 of them, chased the threads, new studs from the "tojo scrapper bin" and happy days.

-the mongrel 6th was deep, probably shouldnt have, but tried a weld, and managed to weld the busted stud to the nut (good) but also the hub (bad) - and - well - for now my favourite barista is driving with diminished torque application. Will fix it or alternatively find a new hub...


:)

Steve

ps this is an unashamed red induced story that has little if any relevance to the current issue other than in a completely different situation my go-to technique has a 16.67% chance of failure.

[Blknight.aus]

biggest hassle with the nut and mig trick...

having the mig welder

for studs that are snapped in too deep for normal nut + mig and im not confident on drilling them out (usually only if its too angled off to get the drill or the flat head burr to get it started) I use this version

1. get a bit of pipe that fits in the stud hole, cut it to depth+1cmish
2. line it with some plastic straw at the end your going to insert into the hole to weld
3. coat the inside of the pipe with some spatter stop or tip dip.
4. remove the bit of straw and insert the tube dry end first into the stud hole
5. extend the wire out of the tip
6. cut a bit of heatshink to go over the wire and the tip of the mig, shrink it onto the tip, make sure it doesnt grab the wire
7. insert the heat shrunk wire into tube
8, touch it down, pull it back a little, make sure its centered and have at it,

It can help to shape the tube to the left over face of the stud by use of the knock ometer.

pull the tube gently with a pair of vice grips and if it holds turn it and it should come out.

I've only ever gone down to M8 size holes that have snapped less than 2cm down

[roverrescue]

Dave you sure know how to make a half cut guy seem incompetent!

"I've only ever gone down to M8 size holes that have snapped less than 2cm down"

These were M8x1.25 and the dud was maybe 8mm below deck height... sheared end was at 45 degree angle and after snapping off enough helicoils deep in some important part I really avoid them now.

I like your tube idea... what sucks is I have a heap of different diameter copper and bronze bundy pipe / bushing / etc which could have been used as a shield to the hub NOW THAT YOU MENTION THE IDEA... would not even need spatter spray with copper eh. cut a short 8mm length, drop it on the stud weld it in hot, drop nut over the top and finish the weld.

GRRRRRR I love that idea but hate it that it is 24 hours late!

When I get the desire or time or inclination or the job list is shorter Ill swing the rusty old POS back into the shed, strip the hub back down, weld it out, machine it flush, then template, drill and re-tap. Just didnt have the energy last night. Or Ill just be a parts-swapping-donkey and pick up a hub and fit that?????

S

[Blknight.aus]

if you do it with steel tube I usually get about a 30% weld onto the tube from the center of the stud.

if that holds the tube just unwinds the stud, if it doesnt I have a tower shaped weld that will perfectly hold the tube that I just pulled out that is now a conveniently lubed up drill guide that will let me start a 6mm drill bit(or a 1/4 inch centering drill) so I can get the left hand drill to go or the easy out in.

[DeanoH]

Back to Mr VonSwirl's problem, :)

Does your stud look a bit like this, but stuck in the head.

https://www.aulro.com/afvb/images/imported/2013/02/1177.jpg

I used a cold chisel on the edge of the base 'flange' to unwind the broken stud. :)

It helped that I had previously cleaned the thread (stud and hole) and had applied anti seize before screwing it in. :D

As the NEW studs also stretched (and 1 broke) before reaching their stated torque, next time (if there is one) I'll just use normal M8 studs and torque carefully.

Not impressed with this stud type.:(

Deano :)