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Broken intake manifold bolts question

6K views 14 replies 9 participants last post by  homesickalien 
#1 ·
Noticed a coolant leak. Turns out it was at the front driver's side corner of the intake. Started taking the thing apart. Both front corner bolts were rusted through. One rear one broke and one other came out but was in bad shape. The non-corner bolts were fine. Did some searching, looks like drilling out etc is in order. My question is, is the threaded part of the bolt entirely in the head or is part of the hole in the intake threaded too? If not, can I pry/force the intake up and off or is that a losing proposition? I'd like to get the intake off first then deal with the broken bolts but I don't want to spend time trying to force it off not knowing that it is still essentially bolted to the heads...If I should be able to get it off, what techniques should I use to get it off. I've tried shaking it with my hand and there isn't any movement at all. Penetrating oil is sitting in all the bolt holes during the work week. One bolt rusted out way far down. One broke way far down, and one broke pretty high up.

Thanks for any info.
 
#2 ·
Funny I'm in the same place you are tight now. After 2 days of trying to get the manifold off via prying and lifting with no luck other than breaking the front seal. I finally got a 90 degree adaptor for my drill and will be attempting to extract the bolt on Wednesday. If that doesn't work I've read that taking off the heads and trying from the other side works well. And if that doesn't work looks like I'll be getting my Gt40s soon. Good luck to you
 
#3 ·
why not take a dremel to the head? its only like grade 2 or 5, grind the head down, then snap the remain bolt head off... then it will leave a piece of the studd up that you might be able to grab with channel locks, if you try to snap it, then you are going to be looking a drilling and tapping the hole...
 
#4 ·
also for the op take a large flat tip screw driver/pry bar and pry up in the center of the heads/intake(i believe there is a slot there), might have to hit the scew driver with a hammmer to pop it loose. if the intake doesnt move then there is a bolt you miss or it hasent been removed in a while. also make sure the valve covers are removed as the overlap the intake
 
#5 ·
Im not sure about these small hockey but on all the diesels I've had apart that are v8s the intake bolts are angled so the go straight into the heads. If they are not drilled out/ broken off deeper than where the head starts your gonna **** something up trying to pry it off and they they are at an angle.
 
#6 ·
You have some of the bolts out, can't you get a flashlight and see if the intake is threaded (I don't think it is)? Everytime I mess with heads/intakes I end up breaking the bolts.....most people that are smart (not me of course) use heat on the bolts prior to taking them out. If I was doing your project, I'd go ahead and snap the corner bolts off as you already have some broken. I'd then pull the heads (probably breaking more bolts) and take them to a machine shop. Heads can always use rebuilds/upgrades and you don't have to worry about drilling and tapping (if you're concerned about doing it yourself). Both then again I'm lazy.....something about working smarter not harder?
 
#9 · (Edited)
I have all the bolts out (except for the broken parts...). The ones at the corner were so rusted there is not much to see in the hole regarding whether the intake part is threaded. I will look in the interior holes. I guess they are probably exactly the same. Just thought I'd ask as I assume a ton of people have done this before and I never have. I just wanted a confirmation before trying to get them out and having a facepalm moment.
 
#7 ·
You didn't say which engine you have, but assuming that it's a 302 or 351... yes, the bolts go straight up, and no, there is no threaded section in the intake itself. The manifold can be raided straight up off of the engine past the broken bolts, but you have to go up evenly- front to back and side to side- if there is more than one broken bolt. Otherwise it will jam against one bolt as you try to pry it off another.

Be careful if you jam a screwdriver or prybar between the block and manifold- the manifold is aluminum, and it can be damaged fairly easily.
 
#11 ·
PB Blaster should do the trick for soaking rusted bolts on a manifold, back in 08 I over tightened the temp guage sending unit and cracked it right in the threading and it was pissing out coolant, found 92 5.0 manifold in the JY but had to have the knock sensor hole drilled out so it was a $125.00 PITA mistake.

Take your time ~ :thumbup
 
#13 ·
Only one has anything sticking any amount out (in the back). I tried drilling and ez-out on the one where it at least broke flat above the cylinder head. I got nothing except the feeling I was about to break the ez-out so I stopped. There is nothing much left to the bolt but to drill it out at this point. Unfortunately I wasn't perfectly on center either so I'm not sure exactly how to correctly do this without going into the head on one side but only the remains of the bolt on the other.

This sucks. It's like the metal of the bolt just infused itself into the cylinder heads. There was absolutely no indication of that bolt coming out. Maybe I'll have better luck on #2.
 
#14 ·
in my experience removing broken studs is a pain. If the heads where off or you where doing a overall, I would say take the heads in and let your machine job handle. It will come out cheaper and they are better suit for removing studs.

Whatever you do, use some no-serizure paste on the corner intake bolts at minimum. Good luck, I don't want to be in your shoes and more so if it's the rear of the engine.
 
#15 ·
The heads are still in the car and I hope to leave them in there because, well mostly because I have not taken them out before and I'd have to take both out since I have broken bolts in both heads.

Let's just assume that I have to drill the entire bolt out. Is it a problem to just drill the hole out to the next size up which I guess would be 3/8? I would try to get it at 5/16 but since I was off center, I think I'm going to start drilling out the threads on one side and still have bolt material left on the other.
 
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