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Manifold studs

Post by Landie_Man » Sat Mar 07, 2020 2:28 pm
Joined: Sat Feb 15, 2020 5:01 pm
Posts: 19
Good afternoon all.

Upon changing my exhaust, I found one of the manifold to down pipe studs is sheered, and the other sheered upon removal... of course it did.

Engine is a 2.3 petrol, can anyone suggest a tool to remove the remains, like an easy out drill set. What is the thread?
Fleet:

1982 Bedford CF230 Dropside
1988 Volvo 240 GLT Saloon (Daily Driver)
1983 Triumph Acclaim CD
1978 Land Rover Series III 88"
1990 Carbodies Fairway Taxi

Re: Manifold studs

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Post by Phil Bradshaw » Club admin » Sat Mar 07, 2020 4:24 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 4550
If there's enough of a broken stud showing then it may come out after application of lots of heat (oxy-acetylene), or by welding on a nut. Manifold is best removed from the engine for this.

Otherwise the old studs may have to be drilled out for through bolts but there isn't much room for bolt head or nut on the side closer to the engine.

Studs original thread is 3/8" UNC both ends; original nuts are brass double length but standard brass nuts locked together tend to stay on longer.
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  • What is real is not the appearance but the idea, the essence of things. Constantin Brâncuși

Re: Manifold studs

Post by Landie_Man » Sat Mar 07, 2020 4:56 pm
Joined: Sat Feb 15, 2020 5:01 pm
Posts: 19
Thanks Phil, ever the saviour! One of them was sticking out an inch but I bloody sheered it and they’re now both flush!

I was thinking of drilling it, there’s more than enough room underneath. What size is the bolt head? 13mm is too small, 14mm is too big and even 1/2 inch won’t fit.
Fleet:

1982 Bedford CF230 Dropside
1988 Volvo 240 GLT Saloon (Daily Driver)
1983 Triumph Acclaim CD
1978 Land Rover Series III 88"
1990 Carbodies Fairway Taxi

Re: Manifold studs

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Post by Phil Bradshaw » Club admin » Sat Mar 07, 2020 6:35 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 4550
Which bolt?

Nearest size head between 1/2" and 14mm usually is 1/4" Whitworth (which can be mistakenly used in place of 5/16" UNC into the engine, until the threads bind or strip).
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  • What is real is not the appearance but the idea, the essence of things. Constantin Brâncuși

Re: Manifold studs

Post by Landie_Man » Sat Mar 07, 2020 7:08 pm
Joined: Sat Feb 15, 2020 5:01 pm
Posts: 19
Manifold to block. Luckily those are all
Ok, I just can’t get on them. It’s the down pipe
Ones which have sheered. They were bolts that someone had used. I can try and drill they
Out from underneath or through from the cab.
Fleet:

1982 Bedford CF230 Dropside
1988 Volvo 240 GLT Saloon (Daily Driver)
1983 Triumph Acclaim CD
1978 Land Rover Series III 88"
1990 Carbodies Fairway Taxi

Re: Manifold studs

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Post by Phil Bradshaw » Club admin » Sat Mar 07, 2020 7:26 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 4550
Heads on the manifold to block bolts should be 1/2" AF but usually waste away to under-size. Normal removal method is to use what will fit (often a cold chisel in the end...).

Manifold studs already replaced by bolts has a default answer to cover whatever thread (or not) is left in the manifold flange: drill out and replace.

5/16" high tensile or M8 class 10.9 bolts are easier to fit and usually will hold the exhaust on if the nuts are kept tight and the rest of the system is free to move with the engine (i.e. silencer hung on original suspension straps or similar).
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  • What is real is not the appearance but the idea, the essence of things. Constantin Brâncuși

Re: Manifold studs

Post by Landie_Man » Sat Mar 07, 2020 7:37 pm
Joined: Sat Feb 15, 2020 5:01 pm
Posts: 19
Thank you. I’ll try and drill them in situ. You think one of those screw extractors from screw fix might do it?
Fleet:

1982 Bedford CF230 Dropside
1988 Volvo 240 GLT Saloon (Daily Driver)
1983 Triumph Acclaim CD
1978 Land Rover Series III 88"
1990 Carbodies Fairway Taxi

Re: Manifold studs

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Post by Phil Bradshaw » Club admin » Sat Mar 07, 2020 8:56 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 4550
Left hand taper thread extractors usually are too brittle to shift rusted studs without breaking (and then leaving a remnant in the stud that's harder than a drill bit...).

Sykes-Pickavant type of fluted extractor and nut can work with being able to turn a stud both ways to break up rust in the threads but won't like being heated as well.
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  • What is real is not the appearance but the idea, the essence of things. Constantin Brâncuși

Re: Manifold studs

Post by Landie_Man » Sat Mar 07, 2020 9:28 pm
Joined: Sat Feb 15, 2020 5:01 pm
Posts: 19
Great! Maybe I’ll make use of a post ramp.
Fleet:

1982 Bedford CF230 Dropside
1988 Volvo 240 GLT Saloon (Daily Driver)
1983 Triumph Acclaim CD
1978 Land Rover Series III 88"
1990 Carbodies Fairway Taxi

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