Best bolt sizes for manifold bolts?

[LilHammer97]

I'm starting to replace my rear main seal today. It took me 3 GOSH DARN DAYS to remove the mini cat system.

So my general question of the day is what size bolts would yall replace the 4 at the manifold. And then the 2 where the muffler flange is. Mine were rusted all to hell and back so I dont really want to reuse them unless I absolutely have too. And like always thanks yall!

 

[Jerry Bransford]

All I could find for you is they're a Mopar 6505754AA bolt, the parts guide doesn't show the size. And the sites that sell them are all very careful to not give the thread size or pitch, I'd just take one of them to the local hardware store and use their thread-size board to figure it out. Or order them on one of the sites like Amazon, who does carry it.

 

[LilHammer97]

All I could find for you is they're a Mopar 6505754AA bolt, the parts guide doesn't show the size. And the sites that sell them are all very careful to not give the thread size or pitch, I'd just take one of them to the local hardware store and use their thread-size board to figure it out. Or order them on one of the sites like Amazon, who does carry it.

Thanks for trying to help sir. I'll be sure to post what the size/thread pitch is if I find one at the hardware house here in town.

 

[Steve Rodgers]

If you don't get MOPAR, be sure to get a high grade bolt, maybe grade 8?
not one the "no grade" junk bolts commonly found, they are pretty bad stuff.

 

[Apparition]

I’ve always reused mine, they don’t look pretty but they work.

 

[Goatman]

A grade 8 with the yellow zinc coating are by far the most rust resistant bolt I've ever come across. There are some I used to hold a fender on an old tractor that disintegrated decades ago and has sat outside in NY winters for better than 30 years, and they still look brand new. Like, completely brand new. Not a speck of rust.

 

[mrblaine]

Thanks for trying to help sir. I'll be sure to post what the size/thread pitch is if I find one at the hardware house here in town.

The bolt thread is M10 x 1.5 and they are about 45-50 mm long. The extruded U nuts that are clipped onto the exhaust manifold flanges are a locking type with an interference thread fit at the end of the threaded tube. The U nut is a dealer only item with no aftermarket equivalent that I have found.

 

[LilHammer97]

Thanks everyone for the great input but by the time I got done with replacing the rear main seal the store was closed so I just cleaned the threads up and reused them for now.

 

[jcw]

The bolt thread is M10 x 1.5 and they are about 45-50 mm long. The extruded U nuts that are clipped onto the exhaust manifold flanges are a locking type with an interference thread fit at the end of the threaded tube. The U nut is a dealer only item with no aftermarket equivalent that I have found.

I tried an m10 x 1.5 and was only able to get a half turn with the hand before it stuck. Is that normal for that kind of nut to do that. Would I just switch to a socket and blast past that?

 

[mrblaine]

I tried an m10 x 1.5 and was only able to get a half turn with the hand before it stuck. Is that normal for that kind of nut to do that. Would I just switch to a socket and blast past that?

I can't tell from here but they typically don't lock up and get hard to turn right away.

 

[TRevs]

I got an intermittent P1033 and since my O2 sensors are pretty new I wanted to look for other causes. A different thread advised checking the precat bolts; sure enough 3 were loose and one was missing.

The Mopar bolt appears discontinued so from this thread I got M10 x 1.5 x50 at the hardware store. They’re more difficult because there’s hardly room up there for the 17mm socket, but it can work.

 

[Spike Strip]

Just for more reference:

M10 x 1.5 x 45mm (from base of Hex head) with a 15mm Hex head that is 9.2 mm or 3/8 thick. Should get a 8.8 or higher grade steel bolt.

Very similar bolts available at McMaster Carr and would probably be easier with the 15 mm DIN Hex Head size.