Broken tensioner bolt in block

Hi everyone,

I’m in the middle of swapping my timing belt. One of the bolts that holds the serpentine tensioner broke off inside the block. There’s not a lot of space and the angle is pretty tough so I’m unsure if drilling out is an option. Does anyone have any experience with this?

Picture of my timing belt included for your entertainment.

 

Ouch! I'm always afraid of something like that happening to mine. I still have the original tensioner in there as well.

 

Penetrant is your friend. Is this piece of bolt stopping you from removing the tensioner?


If memory serves, that piece of bolt starts to thread into the block behind the tensioner. Once you have the remaining bolts out, you should be able to remove the tensioner.

Once that's removed, get some wd-40 or Kroil or penetrant of your choice. Spray the bolt and let it sit. For added effect, tap it with a hammer LIGHTLY, BUT FIRMLY. This will help shock the threads.

After you've let the penetrant work, I'd get a set of locking vise grips, or just regular vise grips to grab the stud, and try to twist it out.

These are excellent. The teeth on these are "directional." They grip best one way versus the other. Exceptional tool.
IRWIN Tools VISE-GRIP Tools GrooveLock Pliers, V-Jaw, 6-inch (4935351)

$16 IRWIN VISE-GRIP Tools GrooveLock Pliers, V Jaw, 6" (4935351), Black, Blue Yellow, Silver, 6"

https://www.amazon.com/dp/B0030XMFJI

 

Also using a butane hand held torch can help if it’s not near anything fragile or important

also don’t panic

better to deal with a bad bolt

than a broken timing belt

 

Thanks for the advice. I’ve already tried pulling the tensioner and it didn’t budge. Maybe I forgot to loosen another bolt. I’ll see tomorrow and give an update.

 

Thanks for your reply. I’ll heat it up with the torch tomorrow and see what happens. I feel like I’m drowning in work to do on this truck, so it’s hard not to panic sometimes. But, it’ll just be that much more satisfying when I have everything fixed!

 

That’s a tough one. Take your time and many breaks so that you don’t get frustrated. As others have said, penetrating oil, heat, and a good pair of directional pliers. If needed, get a rental so that you can take your time. If you proceed meticulously, you will succeed. If you act like me, you can just make it worse. Good luck.

 

Hi everyone,

I managed to get the tensioner off. Not in one piece…

It put up a couple hours worth of fighting with a hammer, torch, pry bar, and penetrating spray. So, I hit it with the air hammer. Maybe I got a little bit too aggressive. Oh well. I’ll get a new one.

After I pulled the tensioner off, the bolt easily turned out with the torch and vice grips.

Now, I’ve taken off my harmonic balancer, timing belt cover #1, and the timing belt. My harmonic balancer also was a bit of a mini-project because I had to drill out and tap new threads in the holes of my harmonic balancer.

All I have left to remove now are the water pump and both pulleys. I tried to loosen a few of the bolts on the water pump but they were feeling pretty tight so I soaked them in penetrating spray for tomorrow. I never put much faith in penetrating spray in the past, but it seems like I tend to break a lot of bolts so I’ve been trying to use it more often.

Before I put my timing belt on, how do I go about resetting my timing? I know this is an interference motor so I want to be careful. I followed service information and rotated my crankshaft (when belt was still on) to the 0 indicator. Then, after I took the belt off, I turned the crankshaft about 50 degrees clockwise as per service information to “avoid valves contacting pistons.” Additionally, I moved my left side (when viewed from front) camshaft sprocket slightly clockwise to aid in removing the belt as per service information. Everything seems a little out of whack right now so I just want to make sure I get it right.

 

I’ve never done a Tundra timing belt but I’ve done tons of Hondas and Audis. There should be index marks on the crank, harmonic balancer, cams etc..just make sure those are all lined up right before you put the belt on, and make sure they don’t move while you’re installing the belt. Some cams have key holes in them to lock them in place with a center punch or something like that while you install the belt. Good luck my friend, and make sure and turn it over by hand at the crank several times and re-verify the timing marks are still aligned.

 

Hopefully this helps you in some way

Links to SHOP MANUALS

http://web.archive.org/web/20110102225436/http://www.ncttora.com/FSM/

 

How should I turn the sprockets so that they are on the timing marks? All my sprockets are clockwise of where the timing marks right now. Is it okay to turn them slowly counterclockwise so that they are on the marks or am I only able to rotate clockwise?

 

It’s never a good idea to rotate the “rotating assembly” in any other direction than specified. That being said, the belt isn’t on so…it would still be putting pressure on the valves and cam lobes in a manner that it’s not used to. I would only rotate it clockwise as the manual states. You’ll find spots with lots of resistance then it’ll just roll over, and hopefully not past your marks. If it barely goes past, like less than 5 degrees, I’d think it would be fine to back it up counterclockwise a bit. Everything just must be where it belongs when you turn the key. Verify it 10 times.

 

Do I have to slowly rotate all clockwise or can I do both cams if my crankshaft is in the right spot?

 

The belt is not on, so moving the cams won’t affect the crank. Just line each shaft up with the index marks rotating clockwise and verify everything, both before and after you put on the belt. Then rotate it over several times by hand. Verifying index marks and piston 1 being at TDC.

 

And if you haven’t already, pull the plugs. Makes things rotate easier.

 

Be careful. Since this is an interference engine, rotating any one part through almost a complete revolution all by itself to bring it back to the mark is a recipe for a bent valve. Especially don’t keep cranking on anything that feels like it’s binding. If one of the cams is a tooth too advanced, I think your best move is to back it up to where it needs to be. That’s what I do anyway.

 

@Tundra2
I seem to remember you had some issues with this part recently. Maybe you have some advice.

 

Which direction did they rotate to begin with? Just undo that motion - that is the safest and most logical thing to do. If they turned clockwise a bit just turn them back counterclockwise. If you start making full revolutions I believe you run the risk of pressing a valve against a piston.

If you haven't watched any videos of anyone doing this job yet I would suggest watching at least a few parts of a few of the videos in this playlist, if not all of them in their entirety.

 

^^^This

 

they make a special sprocket tool that fits into and holds the cams. it also is used to turn them. one can use carpentry clamps in lieu for holding the cams in place if you don’t like them moving around. i’d not sweat it an just leave the cams rotated until its time to line them back up and then use the spock it tool or carp clamp. line up the belt points with your tensioner loosely in place so you don’t get hung up there trying to lip it over. get belt all lined up and in place and then tighten down your tensioner last. it will make sense once you get into it.

 

Any updates? Is she running?

 

This is a pretty good lesson to research before you tear into something, and keep up with proper maintenance. That belt is just a few miles from snapping.

There is no reason to rotate anything when doing a timing belt on these, line up the marks and it puts the cams in a neutral position. You don’t want the valves to contact the piston in any way or they can bend.

 

i thing the question was if their was damage if the cams turned?. answer is no speaking from experience having done a tb job the cams seem to want easily trigger spring off to one side or the other unless held in place. the bolt on the tensioner breaking was a unforseen situwasion. sometimes things happen which make the next steps seem harder but as long as you keep working through it you prevail. -J.P.

 

I bought the truck about a month ago. If I hadn’t done any research, I probably wouldn’t have even thought to change the belt. Also, I was following service information during my repair which told me to turn the sprockets so that the valves didn’t contact the pistons.

 

I’d say you caught that belt just in time.