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Hydraulic belt tensioner disaster

21K views 15 replies 7 participants last post by  rovert 
#1 ·
I'm in the home stretch of my epic struggle with my cooling system overhaul, which is now stretching into a second day. While I was trying to get the new belts on, I stripped the bolt in the hydraulic tensioner. The DIY said this bolt was T50, but as I have just learned from searching this lovely forum, some are 8mm hex. Most likely mine was 8mm hex, and not knowing that, I used a T50 which stripped it. :ben:

TL;DR: Is there another way to get the belt on, if the bolt in the hydraulic tensioner is stripped? I have a belt-less, coolant-less car at the moment so I can't run out and get an extractor kit right now.


:cry:
 

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#2 · (Edited)
It also helps to get some high quality hex bits and torx bits. Most of the ones sold at stores are too soft. I recommend these


http://www.ecstuning.com/BMW-E46-330Ci-M54_3.0L/Tools/Hand_Tools/ES11420/

I've used them several times and put over 50 ft-lbs of torque and they don't show any wear at all.

as far as your problem



Remove the top long bolt and try to get the bottom bolt that hold the bottom pivot of the hydraulic cylinder with a 13mm wrench if possible. just be carefull becuase it will snap.
Then take the tensioner assembly off and try to get the allen bolt off with a vice grip. or other methods.
 
#3 ·
I stripped mine and used a small prybar to reinstall the accessory belt. I think I put the accessory belt onto the tensioner pulley and onto everything except one pulley (either water pump or P/S pulley). Then I pushed the tensioner pulley down with a prybar and slipped the belt over the last pulley.

Later I removed the whole oil filter housing, drilled out the middle of the tensioner bolt, removed it with a broken bolt extractor, and put in a new one.
 
#5 ·
Well, i did just install a new aluminum water pump pulley, so i guess i'll try the prybar method and hope for the best, heh.

Off topic, but i just moved to dallas two weeks ago. Do you have any recommendations on a good shop indy shop to use?
 
#8 ·
Sorry to bring back an old thread. Mine is slowly being stripped so I left it off the car so I can replace it. I want to get the bolt tomorrow and I'm wondering if the dealership is the only place I can get this locally? Or is there a specific size that I can ask any car parts store to find?
 
#10 · (Edited)
Real OEM says it's an "M10X25"....but I fit an 8mm into it to get it out...I'm confused.



Here a pic of the bolt naked with my new pulley being modelled...LOL


I definitely want to get it replaced with something that's not slightly stripped for the future replacement of the pulley.
 
#11 ·
There is no reason I can think of for why you can't use a normal, high grade hex bolt. A socket head cap screw (what you have in the pics) is basically just a bolt with a different tool used to fasten it. There is no other difference in the function of the fastener. If it was inset into a counterbored hole, then it would be a different story (which is the primary reason why these types of fasteners are used).
Considering all of the problems I have read about dealing with these things, I may just replace all of mine with normal Grade 8.8 hex head bolts.

Also, the M10 x 25 description has nothing to do with the size of the hex bit used to remove it. The M10 means it is a Metric 10mm diameter fastener. The 25 means it is 25mm long.
 
#12 ·
I would think having the 8.8 hex head bolt would make it much easier since we're always using a bunch of hex sockets anyways to take our cars apart. You're on a roll getting everything apart then run into the hydraulic tensioner and realize you don't have any allen sockets...what a burn! That's exactly what happened to me a few months back...
 
#14 ·
Good choice! I am going to use grade 8.8 hex head bolts to replace as many Torx and socket head cap screws as possible, when I start my major overhaul/rejuvenation project. There are some areas where they are necessary, so I will leave those alone.
I think the manufacturers use them in some places (like the belt drive) to discourage people from doing the work themselves. One other reason they use them is that they work better with automated assembly equipment. And, there are some places where they are necessary. But they use them in a lot of places where they are not needed.
Even though I have all of the proper bits and tools, I still do not like trying to torque these types of fasteners.
I also remember some poor guy who stripped a Torx bolt when he tried to remove his Disa. It turned into a major time consuming mess. I don't remember if he ever got it out.
I'm glad this worked out for you!
 
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