Exhaust nuts and bolts?

tricky1138 · March 3, 2020, 12:56

Or more specifically, the 3 amigos and the spring bolts from cat to back box.

My replacement manifold has some wrong sizes bolts in it and only one stud, but none of them work with the nuts that came off my old manifold - can i Just put 3 nuts and bolts through the 3 holes?

Also I snapped the spring bolt in back box end taking it out, so will have to drill the rest of it out, can you just put a nut and bolt through that one too?

Carolyn · March 3, 2020, 13:04

Yes, you can nut and bolt the manifold to cat. Not so much the cat to backbox, as the bolt you broke has a shoulder on it to set the spring tension. If you're careful and match the spring length to the other bolt - you'll get away with it.

If you're really stuck, I've got a spare bolt I could send you. PM me if you would like that. You could also by bolts and springs from Cats2U.(There's a cat fitting kit)

Edit: To use a correct replacement bolt, you'll need to drill the stub out carefully and run a tap through. Tap: M8 x 1.5

tricky1138 · March 3, 2020, 15:19

Quote from: Carolyn on March 3, 2020, 13:04Yes, you can nut and bolt the manifold to cat. Not so much the cat to backbox, as the bolt you broke has a shoulder on it to set the spring tension. If you're careful and match the spring length to the other bolt - you'll get away with it.

If you're really stuck, I've got a spare bolt I could send you. PM me if you would like that. You could also by bolts and springs from Cats2U.(There's a cat fitting kit)

Edit: To use a correct replacement bolt, you'll need to drill the stub out carefully and run a tap through. Tap: M8 x 1.5

Hi Carolyn - many thanks for that - I did presume that would be the case on both accounts, but always nice to get confirmation!

I was hoping to get away with a nut and bolt on the back box, as I dont have a tap set. Will see if anyone has one I can borrow. I have got spare bolts aquired from somewhere I cant remember, but thanks for the offer. At worst, would a long bolt with washers and the spring in between work?

Now just for some new gaskets too!

Carolyn · March 3, 2020, 16:19

Quote from: tricky1138 on March 3, 2020, 15:19
Quote from: Carolyn on March 3, 2020, 13:04Yes, you can nut and bolt the manifold to cat. Not so much the cat to backbox, as the bolt you broke has a shoulder on it to set the spring tension. If you're careful and match the spring length to the other bolt - you'll get away with it.

If you're really stuck, I've got a spare bolt I could send you. PM me if you would like that. You could also by bolts and springs from Cats2U.(There's a cat fitting kit)

Edit: To use a correct replacement bolt, you'll need to drill the stub out carefully and run a tap through. Tap: M8 x 1.5

Yes

Hi Carolyn - many thanks for that - I did presume that would be the case on both accounts, but always nice to get confirmation!

I was hoping to get away with a nut and bolt on the back box, as I dont have a tap set. Will see if anyone has one I can borrow. I have got spare bolts aquired from somewhere I cant remember, but thanks for the offer. At worst, would a long bolt with washers and the spring in between work?

Now just for some new gaskets too!

Call the midlife! · March 3, 2020, 18:24

Was just about to offer to send you mine but they're m8x1.25... booger.

tricky1138 · March 3, 2020, 18:50

Quote from: Call the midlife! on March 3, 2020, 18:24Was just about to offer to send you mine but they're m8x1.25... booger.

Cheers John.

Guessing I'm going to need smaller than M8 if I'm drilling it out.

Carolyn · March 3, 2020, 19:06

Quote from: tricky1138 on March 3, 2020, 18:50
Quote from: Call the midlife! on March 3, 2020, 18:24Was just about to offer to send you mine but they're m8x1.25... booger.

Cheers John.

Guessing I'm going to need smaller than M8 if I'm drilling it out.

Here's how we would do it: drill out with 6.4 mm bit. You won't have one of those, but 1/4" would be perfect. Start with,say a 3mm bit, then a 5mm one. That way you can get it well centred. You need to get back to good metal, otherwise you'll be tapping into rust,and the join won't hold up.

With the tools you have to hand, your suggestion of washer, springs and nut and bolt will probably serve you best.

Bossworld · March 3, 2020, 19:30

Quote from: Call the midlife! on March 3, 2020, 18:24Was just about to offer to send you mine but they're m8x1.25... booger.

I had a draft post for the same, Google'd it and found another bemused poster

https://www.practicalmachinist.com/vb/general/ever-hear-m8-x-1-5-thread-259023/

NeilGraham · January 27, 2023, 19:27

Exhaust system repairs can be a hassle, especially when it comes to replacing manifold and bolts. I suggest checking with the manufacturer to get the correct sizes and thread types, or you can use a screw finder tool to match the size and thread type. But if you can't find the right one, you can just put 3 nuts and bolts through the 3 holes. Also, if you snap a spring bolt in the back box end you can drill the rest of it out and use a nut and bolt through that one as well. And for the wall plugs, you can check with hardware stores, they have a wide variety of wall plugs that you can choose from to fit your needs. Good luck!

Joesson · January 27, 2023, 19:47

@NeilGraham
Hello and welcome.
We don't get many new members offering advice in their first post but that is a refreshing attitude.
Most post on here :
https://www.mr2roc.org/index.php?board=75.0
And introduce themselves and tell us what they have.
Looking forward to your story.