MrFusion

Hey guys, I was wondering what the best approach to removing exhaust manifold bolts is. Truck has 200k on it and the manifold seems appropriately rusty. I has been sitting for 5 or 6 years. My goal is to spin them out with out snapping any off in the head.

I've been soaking them with 50/50 ATF/Acetone, PB Blaster, and or Freeall off and on for several months now.

My plan was to let the truck idle for 15-20 mins and try to loosen the bolts while they're hot or at least pretty warm.
Any thoughts, tricks, or suggestions are appreciated.

I'm replacing the stock manifold and bolts with an ATS 3 piece manifold and grade 12.9 studs. Also installing my upgraded HX35 and 4 inch exhaust too.

deere country

I would use heat on them if your afraid they may break in removal, just use only what's needed to get them loose.

thrashingcows

Seems like you have been doing everything I would have suggested. I might have been throwing heat cycles at the bolts with a small Oxy/Map gas torch between penetrating fluid schedules.

I use one of these....



The running it and loosening them while warm is a good idea as well.

NJTman

Yup, I've got 3 of them.

one for the shop, and two for the work truck. They make the stubby bottles now, so they're not as tall, and can get into tighter spaces.

NJTman

BTW,

Don't google stuff that you don't want to find.

Oh, my..... read this DEFECT


or this: https://www.smokstak.com/forum/showthread.php?t=81169

bannerd

Take the truck for a ride and get the EGT's up a little. When you get back from a nice drive, hit the bolts with a impact gun.

Always remember, tighten, loosen, tighten , loosen. You don't want to twist the bolt off or you'll have some issues

oliver foster

I have taken off dozens and dozens of original manifolds with the rustiest looking bolt before.
They don't usually give you as much of a problem as you would expect.
I use my cordless impact on them after soaking them with PB Blaster. You can spray them from the back side of the head as well.
If they seem to be not be moving after a few blips of the impact, I add some heat.

I have never tried to run the motor first to heat them up, but I like that idea.
I am usually working on a motor that is out of the truck already and sitting on my shop floor when I pull those.

mknittle

while soaking with PB tap the bolt heads with a smallish hammer. Not too hard all you want to do iss setup a little vibration. It helps to break up the rust.

thrashingcows

Wow....that is some serious stuff! Thanks for posting that up T-man!

I have been using those bottles for years, and never knew they were a time bomb. Will be double checking them from now on, and might put a small flame resistant cover over the crack prone area to be a little safer.

MrFusion

Wish I could! Truck is far from road legal and not really road worthy. I move it around my yard and occasionally the road in front of my house. I figured I'd let it idle for 30mins and maybe run it up and down the road a few times before I try to loosen the bolts. I definitely DON'T want to have to drill broken bolts out.

MrFusion

That's terrible. Thanks for the heads up on it. Fortunately I have a Victor OxyFuel set up if I need the heat wrench! I'm trying to avoid that though.

MrFusion

Does driving the truck around the yard and up and down the street between dousings of penetrant count as heat cycles??? Been doing that a bit.

NJTman

After looking at the photos of the dudes who got blowed up, I'll never look at one of those containers again. I have to remember to get them OUT of my truck tomorrow.

james1

When using heat to assist the removal process, where should the heat be applied? That is, should the flame be directed at the bolt head, the manifold, or the cylinder head? How exactly does heat help rusted parts began to separate?

TIA

MrFusion

Heat tends to cause the metal to expand a bit and creates a bit more space between the threads so they are looser and slide past each other easier. Rust expands between the threads making them tighter than they should be and binding them together.


Another benefit of heating and cooling cycles is that the associated expansion and contraction of the metal can sort of break the rust bond between pieces.


Where to apply kind of depends on what you can get to. For example: When I had to get frozen bolts out of a turbine housing on the bench I heated the housing around the bolt to expand it. That worked on 2 out of 3.