Toyota Nation Forum banner

1 - 17 of 17 Posts

·
Registered
1996 Toyota Corolla DX
Joined
·
5 Posts
Discussion Starter #1
I was trying to replace a cracked exhaust manifold on my 1996 Toyota Corolla with a kit from O'Reilly, and my Dad and I successfully got the old one off. However, while we were installing the new exhaust manifold, one of the bolts snapped right off inside the head. It wasn't even that tight. It was less than 25 ft-lbs. We tried a bolt extraction kit, but we didn't have any luck. Here's a pic:
290574

It was like the two bolts to the left of it. They are just threads that screw in, but this one broke. Any advice on how to get it out or what I should instead?
 

·
Registered
1996 Toyota Corolla DX
Joined
·
5 Posts
Discussion Starter #3
The bolt was already stuck inside the head and we only took the off the nut that was holding the old exhaust manifold on. The nut was on there pretty tight, and the broken off part seems to be really stuck inside the head. Most of the other exhaust bolts were tight enough that only the nut came off. We were having a hard time with the bolt extraction kit because we would need a 90 degree drill to reach the bolt. Any ideas?
 

·
Registered
1997 Corolla
Joined
·
5,167 Posts
Ugh, perhaps the worst scenario when working on a car. Borrow an angle drill.
 

·
Registered
1996 Toyota Corolla DX
Joined
·
5 Posts
Discussion Starter #5
Do you think it would be fine if we put the new exhaust manifold on without that bolt?
 

·
Registered
1997 Corolla
Joined
·
3,706 Posts
Let's get the terminology straight. The parts with just threads are called "studs". They thread into the head, then the nut goes onto them. If you ever need to remove one that's not broken you can use the trick where you put 2 nuts on it and tighten them against each other, then use a wrench to turn the stud out. Look up a video on how to do this if needed.

For your problem you'd need enough room to drill it out then (hopefully) clean up the threads in the head with a tap. The threads would be easy to damage since it's aluminum. Removing the radiator might give you enough room to drill it out. I also recommend cleaning the threads on any studs and nuts you are reusing with a tap/die so you reduce the chance of breaking another stud if you have to remove them later.

If you need to drive the car now, then you could just put the exhaust manifold on with the intact studs and see if it doesn't leak too bad. There might be some sort of exhaust gasket sealant that might help seal it.

The exhasut manifold nuts have a spec of 25 foot-pounds...not very tight at all. This allows the exahust manifold to slide as it expands more than the cylinder head. If it's tightened on too much it can't expand and it's more likely to crack. Over-tightening will also risk stripping out the threads in the aluminum cylinder head.
 

·
Registered
2019 Corolla Hatchback SE - CVT
Joined
·
107 Posts
heh, welcome to the club. I had both take some of the threads with em. Cross threads is better than no threads in this situation my friend. Its a 94. send it.
 

·
Registered
1996 Toyota Corolla DX
Joined
·
5 Posts
Discussion Starter #8
Here's an update on the situation: My dad JB Welded the stud back in, and we decided to tighten it just barely more than finger tight. However, when I was torquing one of the other four nuts, ANOTHER stud came out, except this one didn't break. It was also the stud right next to the broken one, so I don't think I can get away with JB weld on this one too. Apparently when my exhaust manifold was changed by the previous owner (it has 291,000 miles) the shop broke a stud used a helicoil to get it in. It worked for about 140,000 miles, but half of it came out with the stud.
I also recommend cleaning the threads on any studs and nuts you are reusing with a tap/die so you reduce the chance of breaking another stud if you have to remove them later.
.
This was very helpful until I broke the tap and one of the nuts by cross threading it. I think I'm going to try and get this stud back in there somehow. It looked like the hole might still have threads in it, but I could use some advice.
 

·
Registered
1997 Corolla
Joined
·
3,706 Posts
Here's an update on the situation: My dad JB Welded the stud back in, and we decided to tighten it just barely more than finger tight. However, when I was torquing one of the other four nuts, ANOTHER stud came out, except this one didn't break. It was also the stud right next to the broken one, so I don't think I can get away with JB weld on this one too. Apparently when my exhaust manifold was changed by the previous owner (it has 291,000 miles) the shop broke a stud used a helicoil to get it in. It worked for about 140,000 miles, but half of it came out with the stud.
.
This was very helpful until I broke the tap and one of the nuts by cross threading it. I think I'm going to try and get this stud back in there somehow. It looked like the hole might still have threads in it, but I could use some advice.
I'm sorry if my suggestion of cleaning the threads led to more problems. You can get new studs and nuts at a Toyota dealer or online or you might be able to find something that works at a hardware store depending on how much down time you can afford.

I don't see anyway that JB Weld could be useful here. The JB Weld won't hold the stud in. The threads have to hold the stud in. And the extreme heat won't be kind to the JB Weld.

If you can get any broken studs out and the threads in the head are bad and can't be fixed, then I guess your only option would be to retap a slightly larger hole or try to use some sort of helicoil.
 

·
Registered
Joined
·
22 Posts
Alloy head expands about 1,0-1,2mm more than cast-iron exhaust-manifold. There's layer of graphite on gasket that helps them slide when expanding & contracting. DO NOT tighten more than torque-spec from manual. If you've got a leak, there's some unevenness on head or manifold that should be flattened out before re-assembly.

At this point, fix it right once and for all. Previous owner didn't fix it correctly, which is why you've got these issues now. Helicoil sucks for thread-repair, they almost always come out when fastener is removed the next time. Use one-piece inserts such as Time-Certs or E-Z Lok.

To fix it permanently, remove radiator & hoses so you can aim drill in-line with studs. Use small masonry drill-bits to get pilot-hole started and go deep enough to use appropriate extractor that grips. First spray PB-blaster on threads and let sit overnight. Then use extractor to remove. Chase threads to clean and repair. Replace all studs with new ones. Toyota OEM Exhaust Stud 90116-10150

Also use copper nuts to hold manifold on. They are heat-resistant and won't corrode onto stud and get stuck like you've experienced. NCF10X1.25X14 - Copper Flange Nut Fine Thread Wide Flange [NCF10X1.25X14] - $1.53 : Bel-Metric, Metric Hardware, Metric Fasteners, Metric Bolts, Metric Nuts & Time-Sert Thread Repair

Remember... there's never enough time to do it right the first time... but there's always time to do it again...
 

·
Registered
1996 Toyota Corolla DX
Joined
·
5 Posts
Discussion Starter #11
I agree on the "never enough time to do it right the first time part," and the JB-Welded stud broke off (now really, who could have seen that coming?) ;) The exhaust manifold seems fine, so I will just leave it and hope it doesn't warp. Any chance of that happening?
 

·
Registered
Joined
·
22 Posts
The moral behind that saying is it always feels like you don't have enough resources to do proper fix. But, if you do quick hack-fixes as result, you WILL be forced to make time and spend way more money to do it correctly later. At some point, it'll break down on you at most inopportune time, such as when you're on family vacation or stuck out in boonies. Then you gotta pay for an expensive tow, lose out on vacation time, lost deposits at hotels, etc. Along WITH having to make more time (lost work) to fix it yet AGAIN... hopefully properly this time.
 

·
Registered
Joined
·
22 Posts
Toyota has good engineers and they design cars in minimalist smart way (they did own 33% of Lotus at one time). Don't try to second-guess them. There's nothing superfluous on car that isn't needed. What will happen without all bolts tightened down to proper torque is:
  • you'll end up with exhaust leak, depending upon your area, this will fail smog-test
  • at certain RPMs, leak will actually suck in cold air into exhaust
  • this will cause uneven heating of exhaust valves, leading to incomplete sealing
  • this uneven sealing will eventually crack your exhaust valve-seats and valves
  • head will need to be pulled for valve-job
Previous owner did hack job on repairs and is causing you bigger problems. At this point, you have choice to fix it properly and restore back to stock functionality with replacing missing studs. If not, next repair job will get even bigger and bigger.

So do proper fix, remove radiator and drill out those busted studs and replace them. Along with fixing mangled holes by previous owner's quick-fixes and use better one-piece inserts for permanent fix. I heard story of teenager taking quick-fix after snapping bolt in head for water-hose connector. Ended up costing over $1500 in repairs later when head had to be pulled.
 

·
Premium Member
1994 Corolla DX
Joined
·
4,175 Posts
A bit of a derail but @Haloruler64, @Pete Suhman, @Chris94 - I believe @JacRyann must either be @DannoXYZ reincarnated or his twin brother, right? It's literally like reading a Danno post, lol.

@JacRyann - read some of Danno's posts and I think you'll agree you have a kindred spirit! And a belated welcome to the forum! Looking forward to your continued contributions.
 

·
Registered
Joined
·
421 Posts
Left handed drill bits are really nice for extracting broken bolts and studs. I have also welded up a "handle" on the end of a broken stud and used vice grips to remove. The heat from welding really helps break them loose.

Helicoils aren't ideal but they will work if that's all you have the skills/ tools/ space to install.
 

·
Registered
1997 Corolla CE
Joined
·
2,661 Posts
A bit of a derail but @Haloruler64, @Pete Suhman, @Chris94 - I believe @JacRyann must either be @DannoXYZ reincarnated or his twin brother, right? It's literally like reading a Danno post, lol.

@JacRyann - read some of Danno's posts and I think you'll agree you have a kindred spirit! And a belated welcome to the forum! Looking forward to your continued contributions.
I agree!! Either way, it's great to have more people with this kind of knowledge around.
 

·
Registered
Joined
·
22 Posts
A bit of a derail but @Haloruler64, @Pete Suhman, @Chris94 - I believe @JacRyann must either be @DannoXYZ reincarnated or his twin brother, right? It's literally like reading a Danno post, lol.

@JacRyann - read some of Danno's posts and I think you'll agree you have a kindred spirit! And a belated welcome to the forum! Looking forward to your continued contributions.
Hmmmm, interesting character... We probably have similar backgrounds. I started messing with mechanics at 10-yrs old fixing my bicycles, skateboards and crossbows (parents wouldn't let me have gun! grr....). Started riding dirtbikes before I was old enough to get driver's license.

Having dealt with LOTS of broken stuff, I'm religious about following FSM. I've learned over decades that there are very few short-cuts. They always ends up costing way more time and money later. So I tend to follow manual and put things back to how they should be when they left factory. Once there, we can perhaps look into upgrading to better-than-stock with better materials or more modern designs.
 
1 - 17 of 17 Posts
Top