Achieving spec axle bolt torque.

I've done a few MK5 axles over the years. I've never been able to get the 200nm +180 degree turn. I've stood my 250 lb 6'5" butt on my biggest 1/2" drive breaker bar and could never get it much past 90 degrees on the final torque. I always also thought that there's no way the bolt or threads will hold up to a torque like that if I could ever achieve it. But I'm no engineer and I've felt the torque let up on the final torque of smaller TYY bolts so I knew what that manual said is probably right. I've also seen others around here complain about the monster torque spec.

Well, today I replaced an axle on a '10 TDI after the inner joint had just totally ate itself alive. I trust VW engineers and decided today was the day I achieve the spec torque no matter what it takes.

Two purchases later and I have an easy way to achieve the torque spec for future VW work. I just needed a BIGGER breaker bar. 40" 3/4 drive breaker bar on a 15/16" 12 pt 3/4 drive socket both Klutch brand from Northern Tool. The bill for the 2 comes to a little under $70 but its a lifetime warranty and that bolt is pretty important to your family's safety. With this setup getting that torque felt right and wasn't too difficult. I'm a believer in what the manual says that torque is now.

Exactly. It only feels wrong if your tools aren't up to it.

banshee365 said:

I've done a few MK5 axles over the years. I've never been able to get the 200nm +180 degree turn.

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Are you using the old-style bolts or the newer 24mm 12 point bolts? I believe the torque value for the new ones is only 70 Nm (52 Ft*Lbs) plus 90 degrees... brand new bolt every time... (please double check this!!!)

Yuri

ymz said:

Are you using the old-style bolts or the newer 24mm 12 point bolts? I believe the torque value for the new ones is only 70 Nm (52 Ft*Lbs) plus 90 degrees... brand new bolt every time... (please double check this!!!)

Yuri

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I'm glad you brought this up. This may be a good learning experience for anyone searching this topic.

There have been 3 styles of axle bolt for the MK5. The first was a hex bolt with a separate washer. Then there are the 2 flange head 12 point bolts with or without ribs under the head. The torque depends on the style of bolt.



P/N WHT005437 is the current bolt and the one I used for this job and every other axle R&R I've done on MK5's in the past few years.



The 70nm + 90 is for the bolt with the ribs as the ribs bite into the hub assembly. The smooth faced flange head needs the higher spec.

VW may have changed this in some TSB somewhere but I downloaded this erWin manual less than a year ago and I would assume it would be updated if it were incorrect. With the right tool this torque didn't seem to be too much. It felt like any other TTY bolt that's much smaller on other components. After 30 degrees or so past 200nm the torque required for rotation leveled off and it just turned, which means the bolt was stretching as designed.

Good to know, although I'm a big fan of ribs...

Yuri

I've never ever seen one with the ribs. If you're talking about the type of ribs on the bone then yes, I like those too!

What about an Impact Wrench....

I know this for the Mark V's but the axle nut on the Mark IV calls for an initial 148 ft-lb tightening torque, followed by rolling the wheel and ending with a final tightening of 37 ft-lb + 60 degrees. The final 37 ft-lb is okay but that extra 60 degrees in really, really, really, tough.

What I usually do is hit the nut with an impact for a bit to give me some peace of mind.

Cleenlivin said:

the axle nut on the Mark IV calls for an initial 148 ft-lb tightening torque, followed by rolling the wheel and ending with a final tightening of 37 ft-lb + 60 degrees. The final 37 ft-lb is okay but that extra 60 degrees in really, really, really, tough.

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Just for those who may stumble into this message thread - and please note, this refers to the MK-IV - not the chassis referred in this message thread: some of the Bentley manuals leave out a step (that you also skipped) - after that initial 148 Ft*Lbs tightening, you must loosen the nut 1/2 turn, turn the wheel 180 degrees, and then proceed with the 37 Ft*Lbs plus 60 degrees...

That said, many shops (and dealerships) simply put the impact gun on it and call it a day...

Yuri

I'm just referring to the MKV platform which is why I posted it here. 37 ft-lbs + 60 degrees sounds like a pretty easy torque to reach. 147 ft-lbs + 180 degrees is very hard to reach. I just wanted to post my finding of a locally available breaker bar and SAE socket that get the job done as the book says.

Dang it. Now I need to get a new bolt. I replaced a wheel bearing a few weeks ago & used the lower torque spec on the non-ribbed 12 point bolt.
Thanks to banshee365 for posting this info.

To be honest it may be okay. I would almost doubt you will have a problem with it. With the lower torque did the yield portion take a lot of effort to achieve or was it fairly manageable. Many people torque the bolt as hard as they can with a 1/2" breaker bar, call it good, and don't have any problems after that. But if you're like me, I like to do it the way the book says.

Also, if you didn't really wrench on that bolt you may still be able to treat it as a new bolt with the proper torque. Just jack up the car, loosen the bolt, torque it to 148 ft-lb's, set it back down, and do the the final 180 if you're comfortable with that. The bolt is pretty cheap though...

banshee365 said:

To be honest it may be okay. I would almost doubt you will have a problem with it. With the lower torque did the yield portion take a lot of effort to achieve or was it fairly manageable. Many people torque the bolt as hard as they can with a 1/2" breaker bar, call it good, and don't have any problems after that. But if you're like me, I like to do it the way the book says.

Also, if you didn't really wrench on that bolt you may still be able to treat it as a new bolt with the proper torque. Just jack up the car, loosen the bolt, torque it to 148 ft-lb's, set it back down, and do the the final 180 if you're comfortable with that. The bolt is pretty cheap though...

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All great points & just what I was thinking except there will be no jacking. I bought myself a lift for Christmas.
I'm thinking that I'll get the car in the air this weekend & tighten the bolt. I'm going to see how torque is on the bolt with the 70nm + 90 deg before I do anything. That's really just for my curiosity. Then I'll torque it up with my 1/2" breaker bar. I'll be ordering parts in a week or so & I'll add a new bolt to the list.

The only way I could achieve the specified torque was with a 40" 3/4 breaker bar pictures in my first post. I've tried with a 1/2" breaker bar and I couldn't get anywhere even close to a 180 with it. Gotta have the right tools for the job.

banshee365 said:

The only way I could achieve the specified torque was with a 40" 3/4 breaker bar pictures in my first post. I've tried with a 1/2" breaker bar and I couldn't get anywhere even close to a 180 with it. Gotta have the right tools for the job.

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I've got a piece of pipe I slip over my 1/2" breaker bar & got the 180 no problem on my other car.

Windjammer said:

I've got a piece of pipe I slip over my 1/2" breaker bar & got the 180 no problem on my other car.

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I also tried a 1/2" breaker with a 3" section of pipe, could only get it about 80 degrees. Gave up at that point, figured I may have done something wrong! Can't see it causing a problem.

I had the same experience with 1/2" drive tools. The purpose of this thread was to show the proper tool for the job. It's a $70 investment from northern tool but they have a lifetime warranty and it's probably. It the last time you'll be removing an axle bolt.

And then we have this... How do we ever get a clear answer?

Hello again

To clarify - my earlier response was based on research I did when I was asked this same exact question a while back.

I went back and checked my up-to-date copy of eBahn. This information originates directly from VWoA and is updated periodically. As such, it appears that the source information may possibly have been updated since the last time I checked into this.

Under "Front Axle Tightening Specifications", the torque specification for drive axle to wheel hub is listed as 200 Nm (148 ft-lb) plus 180° (1/2 turn). I'm also not seeing any distinction currently in eBahn between hex or 12 point.

Here's where it gets a little confusing - under the procedure titled "Drive Axle Bolt, Loosening and Tightening", eBahn lists the torque specification as 180 Nm (133 ft-lb) plus 180° (1/2 turn).

However, I also checked against VWoA's erWin information system, and it lists the torque specification for the drive axle bolt exactly as it appears in our printed repair manual. i.e.:
1. 12 point bolt, 70Nm (52 ft lb) then 90°
2. Hex bolt, 200 Nm (148 ft lb) then 180°

That's the information as it comes from VWoA, and that's what I'm inclined to recommend.

Hope this helps,
Rick W
Bentley Publishers

I think that info is far from correct. For one you can't even buy the hex bolt anymore. I've done several 12 pt bolts without the ridges lately to the 200nm +90 spec and havn't had an issue.

I know where your coming from but it's straight from Bentley. How do we really know what the proper value is? A quick search will give either torque value. I just want to know for sure. It's a big variance.

His reference to erWin is wrong as I have posted the clip from erWin on page 1 of this thread. He didn't sound too sure. I doubt you were speaking with an actual tech or someone really in the know there.

Sorry for resurrecting old thread.

From the information provided, it seems that now the only available bolts are without ribs.
So this means 200 Nm + 180 degrees torque spec.

Shouldn't the 180 degreee final turn be done with the wheel installed and vehicle fully on the ground?

Yes, that's how I do it. You should apply the 200 Nm value to the bolt first before selling weight on the wheel bearing though. Then, with the wheel on the ground, perform the half turn for final torque.

Great, thanks for confirmation.

Some background of the car. Around 8k miles ago there was an oil leak from transmission (manual). Turned out to be the shaft seal on the passenger side. So the drive axle needed to be removed to service the seal. Meanwhile, it was decided to replace front brake rotors (and pads) too. The very same passenger rotor was stuck to the hub and lots of hammering was required to free it.

After the service has been performed, the axle bolt was reused and tightened by hand (I mean without achieving any specific torque, just tight enough using breaker bar).

7k miles later, the very same bearing starts making a noise. Coincidence? 70k miles on the clock.

I'm not sure which bolt is originally installed in the car - the ribbed one or not. Will confirm that in about 2 weeks if anyone's interested.
For now I have prepared two new bolts - flat and ribbed versions (as well as new bearing holddown bolts)

banshee365 said:

that bolt is pretty important to your family's safety.

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I'm not exactly doubting what you are saying but what are the consequences of that bolt backing out or failing? The wheel is held on to the car via the hub and the steering knuckle. If the axle becomes unbolted to the hub then there is still substantial pressure keeping the axle splines seated inside the hub. Now the hub being unloaded by the lack of a bolt may damage or destroy the hub either slowly or quickly, I don't know. But I am very certain that if that center bolt fails you aren't going to lose a wheel.

For what it's worth I just did both of my front hubs and my new hubs came with the 12 point bolts that require 52 ft lbs Plus 90 degrees. That was pretty easy to achieve.

There is something VASTLY Different between 52 Ft-Lbs plus 90 degrees and the other bolts at 133 Ft-Lbs plus 180. It is night and day, to me as an engineer, and leads me to question the manual. I would guess that the 180 degree supplemental stretch would add triple the amount of yield in the bolt (about .75 mm or 0.030-0.040 inch). It would also be far more difficult to reach without that 3/4 inch socket and a loooong pipe.

bobthefarmer said:

There is something VASTLY Different between 52 Ft-Lbs plus 90 degrees and the other bolts at 133 Ft-Lbs plus 180. It is night and day, to me as an engineer, and leads me to question the manual. I would guess that the 180 degree supplemental stretch would add triple the amount of yield in the bolt (about .75 mm or 0.030-0.040 inch). It would also be far more difficult to reach without that 3/4 inch socket and a loooong pipe.

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Yes, I wondered the same thing. But I found those specs in several different resources, not just the erWin manuals that I have. The difference is obviously the ribs under the bolt head. That style bolt can 'bite' into the wheel hub and hold it's torque better than a smooth bolt. I've never actually seen the style with the ribs. I've only seen the OE bolt's which are the 6-point with washer and the new 12-point smooth flange head bolt.

I have bolts of all three styles right on my table.
First one is the one with hexagon head and non-detachable washer.
Second one is is the one with ribs.
Last one is the new style with flat shoulder and no washer.

All of them have "8.8" markings on them. To me it looks not that hard but I'm not an expert in bolts.

Tomorrow I will be installing the flat shouldered one and trying to achieve the 200 Nm + 180 deg torque. We'll see how it goes.

Replaced the bearing this morning.
The old bearing had the bolt with ribbed neck.
Installed the bearing. Tightened to 200 Nm. Installed the wheel.
Lowered the car to fully rest on its weight.
Marked the positions where to tighten.
Using breaker bar and an extension, tightened +90 degrees. My God, that's tight. At some time we thought the bolt is going to break. Added 90 more degrees, so 180 in total..

It's really pretty tight there. Wonder how those bearings survive...

One thing I'm thinking about now:
When I removed the axle bolt, the threads were covered in grease. I suppose this is the CV joint grease.
Before installing the new bolt I didn't clean then inner threads at the CV joint (the new bolt was dry, though).
Tightened it to 200 Nm, then + 180*.

Having in mind that there might have been some grease on the innter threads at CV joint, I'm getting paranoid...

Did I overtighten that axle bolt?
Should the grease from inner threads be somehow cleaned before installing a new bolt?

Threads should be lubricated before going through with the fitting and torquing. Grease is coming from the CV Joint and that is a good lubricant. If you got 180 degrees after 133 Ft-Lbs, you must be of great strength! I believe the Grade 9 Bolts (8.8) will handle the torque (once).