TC Bolts

paulheger · 10 April 2018, 08:00

I'm having trouble finding the TC bolts in Belgium.

When taking the engine out, my TC was only fixed with 3 of the 4 bolts. I really have no idea how long this car has been driving with only 3 bolts fitted.
Now almost ready to put the engine back in I can't find a fourth bolt in Belgium. Tried to order from the USA, but $52 shipping is crazy.

What specs should I use for any replacements?
Metric bolts class 8.8 ok?

sb001 · 11 April 2018, 02:11

Hi again,
well I cannot attest to whether class 8.8 will work or not, I have never known the strength of the original German ones. I guess if that's all you can find over there it will probably work but I would try to find some way to strength-test it first, like tighten it down into a threaded hole that it fits (NOT the flex plate

) and see if it will take at least 15-16 ft/lbs.

I did look a bit earlier today over on a few of the European VW aircooled sites I know and you are right, I can't find these bolts anywhere! Even German ebay doesn't have them. I'll be happy to search around here and see if I can locate some company selling them that would be willing to ship over there for cheaper.

paulheger · 11 April 2018, 14:56

Thx very much for the offer!
I will have them shipped to Family in the US and they will send them over in a normal bubble envelope, I guess that will do in stead of UPS.

For now I'm putting the last things in and will be ready to put the "new" engine in, so I don't think I can wait...

Will go to a local hardware shop and ask for the best bolts, whats the worst that can happen; a snapped of bolt

sb001 · 11 April 2018, 15:44

Paul, I just posted this down in the Parts forum, but you might want your family to order a set of these from Mofoco:

http://www.mofoco.com/item/VW_Torque_Converter_Bolts_Used_All_Autostick_T2_T3_Fully_Auto/2970

Seems to be a very good price.

68autobug · 12 April 2018, 05:55

Yes, they are really inexpensive for sure....
and were made for the job... so have to be good...

LEE

sb001 · 16 April 2018, 23:38

I just got my new torque converter bolts in from mofoco today, I ordered both 6-point and 12-point sets:

I am intrigued by the 12-point style, never seen those before nor do I know what year models they were used on, but I might try those on reinstallation. They certainly have a lot less slippage on my 8mm star socket and are probably virtually impossible to round out.

paulheger · 17 April 2018, 08:23

For used bolts they are in great shape by the looks of it. Treasure them!

The 12 point bolts were originally in my '72 gearbox. I kind of like 'm, they have more ribbing in the spacer and the bottom of the bolt head. Would think of it as an extra help to hold them in place.

I was lucky as well. Only 15km from my house with BBT4VW. A know company here for high quality vw sheeting reproduction and also a great stock of original vw's.
From the mofoco website I had the original ppart number and while the guy first said that it would be impossible to find he found a little bag of 12 NOS TC bolts!! Exactly the same as the 6 point bolts in your picture, brand new. The brand of the bolts is Verabus and the strenght is 8.8 metric (Heat treated medium carbon steel), which equals US Grade 5.

Be carefull: the max torque advised for m8 grade 8.8 bolts varies between 22-25nm (just some differtent websites I was able to find.)

Did you already do a stress test?

68autobug · 17 April 2018, 09:12

Good news.... I wonder why VW changed from standard HEX bolt head to the multi splined head bolts... Hopefully they are all 8.8 grade DIN..
as there are no markings from memory on the bolts.... as I said before I have used hex headed bolts cut off [grade 8.8] and Allen headed hi tensile bolts.....

Lee in Australia

paulheger · 17 April 2018, 11:16

If the 6 point bolts are indeed NOS, then the grading is indcated on the bolts:

Picture is not very clear on it, but 8.8 is indicated

tmea · 17 April 2018, 15:55

Definitely look NOS to me. Nose taper on the threads.. All of the aftermarket ones I have seen have no taper and are very difficult to get started unless you grind a slight taper in yourself. I still have a difficult time with the 22 ft.lb spec in the manual. My references are not uniform either. My Haynes i believe says either 20 or 22 yet my Chilton's says 18. Both seem high to me. If you have any of the old ones I'd experiment first by getting a hardened nut in a vise and try getting 20 ft.lbs without stripping.

Tom

sb001 · 17 April 2018, 17:48

Quote from: paulheger on 17 April 2018, 08:23
For used bolts they are in great shape by the looks of it. Treasure them!

The 12 point bolts were originally in my '72 gearbox. I kind of like 'm, they have more ribbing in the spacer and the bottom of the bolt head. Would think of it as an extra help to hold them in place.

I was lucky as well. Only 15km from my house with BBT4VW. A know company here for high quality vw sheeting reproduction and also a great stock of original vw's.
From the mofoco website I had the original ppart number and while the guy first said that it would be impossible to find he found a little bag of 12 NOS TC bolts!! Exactly the same as the 6 point bolts in your picture, brand new. The brand of the bolts is Verabus and the strenght is 8.8 metric (Heat treated medium carbon steel), which equals US Grade 5.

Be carefull: the max torque advised for m8 grade 8.8 bolts varies between 22-25nm (just some differtent websites I was able to find.)

Did you already do a stress test?

Hey Paul! That is great news that you found some NOS bolts!!!
I didn't realize the grade was imprinted on the 6 point bolts- if I look very closely at the ones I got from Mofoco though, it does appear it's on there (although almost unreadable.)
The 12 point ones don't seem to have any kind of grade indicator imprinted on them- but I still think I'm going to try them when I put everything back together.
I haven't tested these for strength yet, i think I'm just going to lower my expectations on them and go with around 10 ft/lbs which I know they will take.

tmea · 17 April 2018, 20:57

22nm equals 16 ft,lbs and that spec is for both fasteners (captive nut and bolt) being new. That Haynes torque spec... I don't know what the standard practice for re-torquing used fasteners is but I'm sure it has to be a lower number than new.

Tom

68autobug · 18 April 2018, 03:05

I didn't realise that there was any markings of any kind on the original hexagon head original bolts.... I have just done Mine up tight, as My only torque wrench is a Big one... I know that one of My son's has a small one now, so if I ever have to take the bolts out I would use a torque wrench.... with small bolts I just use a small spanner or ratchet socket and only use the short bar or spanner to do up small bolts where I can use a piece of pipe on larger bolts etc.....

Now, something I have thought about, is when bolts are tightened in a factory, if there is any oil or liquid or grease on the bolt threads, even a very slight amount, are the bolts tightened MUCH tighter than with a dry bolt thread.... using a torque wrench etc...

or wouldn't it make any difference as when the head of the bolt bottoms out and cannot go any further.. Does the torque stay the same?

? or change so slightly so it doesn't matter... Using a torque wrench with the same readings, Maybe .....!!! what are Your thoughts???

I should have started another post for this....

Lee in Australia....

why the color changes?? I have no idea.... I didn't change them..... Lee

sb001 · 18 April 2018, 04:17

LOL Lee I always like your Christmas-y posts

Well, I decided I wanted to drive the car, so I spent today reinstalling the newly rebuilt clutch canister, and then reinstalled the engine. I used those 12 point TC bolts, and torqued them down to 10 ft/lbs, and then decided to go around again and torque them to 14 ft/lbs, and left it at that. I can absolutely tell the difference in quality of these bolts vs those aftermarket ones- the tapered ends on these really help get them started threading nice and correct (no risk of cross-threading as I always am afraid of with those other bolts) and they seem to take tightening down much better.
Everything seems good, no problem getting into gear from neutral now, but I haven't really driven the car except up the street and back. I'll drive it to work tomorrow and see how it goes.

volkenstein · 18 April 2018, 09:47

All,
The supply changed from 12 point (original) to a replacement of Hex sometime in the late '70's - and mostly supplied as spares. A lot of OE was 12 point.

12 point while good, is harder to manufacture and I believe VW went to Hex as they would have found no real appreciable difference "in service" etc.

That's again shaky memory from years ago......if I ever manage to resuscitate my ETKA fiche I can check say - 69 vs 78 models.

Not much use........
Volkenstein