Broken bolt in crank sprocket

Joined
Dec 13, 2018
Location
GA
TDI
2006 Jetta BRM
So I was stupid and re-used the bolts on the harmonic balancer when doing the timing belt on my 06 Jetta. One of the bolt heads broke off flush with the crank sprocket. I've never had to remove a bolt like this before. I guess I should drill a hole through it and use an extractor?

It seems the timing belt kit did have new bolts for this. I missed it at first since they are different, but they thread in just fine. They are shorter and have an allen head. The torque spec for the original ones is 7 ft-lbs + 1/4 turn. Would it be the same for the newer ones? I would be afraid of stripping the head.

Also, what is your method for tightening these bolts without moving the crankshaft? When the bolt broke I was using a ratchet with 19mm on the crank bolt and the handle against the drive axle to counter any rotation.

Thanks for any help or insight you might have!
 

Growler

Got Soot Vendor
Joined
Nov 24, 2003
Location
Millersport, Ohio
TDI
Schmutz, 2015 Golf Sportwagen DSG & Schnurren, 2001 Golf GL 2 door 5M
18 ft-bs. that is the torque spec for harmonic balancer bolts. using my trusty Kobalt 3/8" torque wrench this turns out to be just about the same amount of torque required to rotate the engine with an 18" long 3/8 ratchet with the car in neutral.

basically I didn't worry about counter holding the engine on such a small torque value.

always worked for me and never had a problem.


to get the old bolt out, take the rest of the bolts out of the balancer and remove it, there should be a short nub sticking out of the crank gear. most likely this is just loose in there now and you might be able to get a grip on it with a pair of needle nose or vise grips. if not, you could always try slotting the bolt with a dremel and turning it out with a screwdriver.
 
Joined
Dec 13, 2018
Location
GA
TDI
2006 Jetta BRM
It seems the ALH engine is 18 ft-lbs for the harmonic balancer and the BRM is 7ft-lbs +1/4 turn. However, ID parts sent me 6mm allen head bolts instead of 10mm triple-square bolts that were originally on it. I called them and he said he had never seen triple-square bolts on the BRM harmonic balancer and that it's always the allen head. I'm not entirely sure which torque spec to use with the allen head bolts.

There was nothing sticking out to grab on to, but I got it out with some left hand drill bits. It came out with the second bit.
 
Joined
Dec 13, 2018
Location
GA
TDI
2006 Jetta BRM
I got it out with some left hand drill bits. I'm just not sure what torque spec to use on the new 6mm allen bolts when mine had 10mm triple square bolts.

I think I'll just do 7ft-lbs +1/4 turn. It's probably the same as 18ft-lbs. I just see both values stated for the allen head bolts.
 

Growler

Got Soot Vendor
Joined
Nov 24, 2003
Location
Millersport, Ohio
TDI
Schmutz, 2015 Golf Sportwagen DSG & Schnurren, 2001 Golf GL 2 door 5M
every BRM I have ever worked on has the short 10mm triple square bolts holding on the serpentine pulley/balancer. the standard ALH/BRM thicker pulley will bolt on and work just fine if you are in a pinch and need an easy to find replacement for it.

I always just used 18 ft-lbs when I did all the TDI timing belts.
 
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