Replacing forward U shaped exhaust pipes

[Poptopcamper]

I need to replace my forward u shaped exhaust pipes on my 1978 VW Bus with the fuel injected 2000 cc engine. I’ve tried every size metric and standard wrench that I have, but none fit. 13 mm fits over the bolt and nut but it’s loose. 12 mm doesn’t fit. 1/2 inch is loose on the bolt and nut. 7/16 doesn’t fit??? Does anyone know the proper size wrench for these bolts and nuts? I don’t want to strip them with the wrong wrench. Thanks. Bill
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If you only have one tool in your tool box, and it's a hammer, pretty soon, everything looks like it needs to be whacked!
1978 VW Riviera
2021 Dodge Ram 3/4 ton
2020 VW Tiguan
2001 Harley Electraglide Classic
1986 BMW R 800cc motorcycle
2002 Chevy Camaro Z28
1999 Harley Sportster 1200 Custom

[SGKent]

mine are either 12mm or 13mm copper coated lock nuts. The bolt heads are 13mm on mine. The thread is 8mm x 1.25. Sometimes they are so seized that they have to be cut or snapped off.

They are called u-pipes or sometimes afterburner u-pipes. They were added by VW to give the exhaust gasses a longer burn time in the exhaust to lower emissions.
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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Poptopcamper]

Thanks. I’ll try to get them off with the 13 mm wrench after hitting them with some more penetration oil. Bill
_________________
If you only have one tool in your tool box, and it's a hammer, pretty soon, everything looks like it needs to be whacked!
1978 VW Riviera
2021 Dodge Ram 3/4 ton
2020 VW Tiguan
2001 Harley Electraglide Classic
1986 BMW R 800cc motorcycle
2002 Chevy Camaro Z28
1999 Harley Sportster 1200 Custom

[busdaddy]

Around here where it's damp and salty things like exhaust nuts grow smaller with time, sometimes a 13 loses enough metal to become a 12, but often it's a size between, 1/2" is a hair smaller than 13mm, but still bigger than 12mm. And two different brands of wrench can also be slightly different in how they fit the nut, especially the Chinese ones.

The cutoff wheel fits all size of fastener, metric or SAE.
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[SGKent]

might be time for an order of nuts and bolts, and a good pair of vise grips to grab the heads and snap them off. Cut off wheel works well too.
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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[lil-jinx]

hammer a 12 on and test your luck.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=620186
https://www.thesamba.com/vw/forum/viewtopic.php?t=668799
1974 Bay Westfalia. she likes to be called Ethel.
1968 Dune Buggy sold dec 2024

1974 parts bus
A smart man learns from his mistakes,a very smart man learns from other's mistakes.

[Poptopcamper]

Thanks for the feedback. I’ll get them off one way or another. Bill
_________________
If you only have one tool in your tool box, and it's a hammer, pretty soon, everything looks like it needs to be whacked!
1978 VW Riviera
2021 Dodge Ram 3/4 ton
2020 VW Tiguan
2001 Harley Electraglide Classic
1986 BMW R 800cc motorcycle
2002 Chevy Camaro Z28
1999 Harley Sportster 1200 Custom

[Wildthings]

Get the nuts red hot and quickly hammer a 6 point 12mm socket onto them and spin them off. One of the newer style sockets instead of the old style hex might work here as well but heat is going to be your friend.

[wrxnofx]

Mine were so cashed the easiest way to get them off was to twist them with a vice grips until the nut snapped off. The remaining bolt shaft was so rusted into the hole that I had to smash it with a punch as hard as I could to get it out. You'll want to replace the fasteners and nuts with new ones. I wouldn't even try to save them. Remember you'll need 4 new gaskets, too.
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1977 VW Type 2 Bay Window Westy FI

[jlrftype7]

You 'might ' look in using Whitworth wrenches. They're often 'in-between' Imperial and Metric sizes. If you can research a single wrench purchase, they're available on Amazon for fairly cheap money versus buying a whole Whitworth set that you'll never use, unless you fall in love with an old British Sports Car...

Other than that, if you can get a socket on any of the nuts, there are special sockets made for rounded off and rusted nuts, if you have room to use them with a ratchet. The wall of the socket, clearing an exhaust pipe next to the nut will be a factor as well. Here is an inexpensive extractor socket set from Amazon. Combined with heat, these type of sockets can pull off some amazing trashed hardware removal due to rust/salt, etc damaging the fastener.

https://www.amazon.com/Topec-Extractor-6mm-19mm-Ro...JEW34ELVT9
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'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto

[my59]

I started hitting rusty fasteners up with kroil a few days before getting into it, a shot per day for 3, 4 days, and try to tighten then loosen them before getting medieval. It has reduced the amount of broken hardware , especially studs.
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my59: Well son, my grandfather died before I got to drive it, so does that answer your question?
our79: sunroof bus w/camper interior and 2.0 FI
Other:'12 Jetta, '77 Benz 300D, and a 74 MG Midget.

[RLFD213]

Get a set of sockets for removing rounded off bolts and nuts. They’re normally 13mm but if they’re rusted they’re smaller then 13 but bigger then 12.