Exhaust Flex Pipe Repair and Replacement

How do you repair flex pipe on exhaust?

This is a question that is often asked, however before I explain how to repair a Flexi pipe it is important to understand what the Flexi pipe does and its functionality.

A Flexible pipe, also known as Flexi, Flexy Flex, Braid, interlock etc. it is a crucial component fitted to a vehicles exhaust system.

Mainly fitted to vehicles which have a transverse engine, there needs to be a section of the exhaust which can move with the engine, if the exhaust is too rigid then the system will crack and break especially near the expensive manifold, where the pipes that carry the waste gasses start, therefore to reduce the chance of this happening a flexible tube is fitted, normally after the downpipe, this will significantly reduce noise and vibration and prevent damage. Exhaust pipes get extremely hot from the gases passing through the system and out the tailpipe. Due to this, when an exhaust system needs to bend, shift, expand or be flexible, the manufacturer cannot use traditional materials like rubber. The flex pipe is made of metal, strips woven into a lattice or braid, and thus can withstand exhaust gas heat. Cheaper Flexi pipes are made from mild steel but do not last long, stainless steel is the preferred choice which is built to last longer.

The flexi pipe is a great solution but also created another problem and that is, it does not last forever, eventually this constant movement causes the flex pipe to fracture and break, furthermore it is not just wear and tear that will cause the damage, it’s also knocks, bumps and grazes, if the vehicle was to hit, maybe a speed bump and any other anomaly on the driving surface, this can also cause the damage.

Manufacturers install the flexi pipe as, non-removable which is welded in place, great for the manufacturers because they can sell you a complete downpipe which can cost hundreds and even thousands of pounds, not so good for the vehicle owner because this certainly means a huge bill.

The solution

Here at Profusion Customs we manufacture a huge range of stainless steel flexi pipes in all sizes; there are 3 main types of Flexi pipe, Some of the first designs of flexi pipe consisted of an inner bellow and an outer Braid this was great for light use.

The next development consisted of an inner braid, bellows in the middle and an outer braid; this provided better flexibility and longer life and was suitable for medium use.

The latest technology and which is by far the best method consists on a interlock tube with bellows in the middle and cased in outer braid, the key is the interlock pipe, this has proved to reduce vibration and noise and lasts the longest, do not confuse with pipes that just mention ilock, it must mention Interlock and have a interlocked pipe visible when you look through the middle. This is manufactured for heavy use.

As UK’s number one stainless steel exhaust manufacturers and suppliers we hold a vast range of exhaust flexi pipes, there are 2 variants available in differing sizes, please note we will only supply you the more superior and latest Interlock technology flexi pipes.

Weld On

Clamp On

How to measure and fit a new Flexible pipe

Firstly it is important to measure the outside diameter of the exhaust pipe near to where the damaged flexi pipe is fitted, this can be done in a number of ways, the best method is to use a Vernier gauge, if you do not have a Vernier gauge then simply wrap a piece of string around the tube and measure the length on a ruler, you can use the guide below:

This is a guide only.eg your string measures 164mm then the chances are your tube size is 2 inch diameter tube

Tube Diameter in MM Inches Circumference in MM
45 13/4 141
50.8 2 160
57 21/4 180
63 2.54 198
76 3 239

The second measurement you need to find is the overall distance of the Flexi pipe, see Image below

Weld on Flexi pipes are available in the following lengths and you can cut the distance nearest to an available size.

Inlet / Outlet ID Length Inlet / Outlet ID Length Inlet / Outlet ID Length Inlet / Outlet ID Length Inlet / Outlet ID Length
45mm x 100mm
(1.75” x 4”)
50mm x100mm
(2” x 4”)
57mm x 100mm
(2.25” x 4”)
63mm x 100mm
(2.5” x 4”)
76mm x 100mm
(3” x 4”)
45mm x 150mm
(1.75” x 6”)
50mm x 150mm
(2” x 6”)
57mm x 150mm
(2.25” x 6”)
63mm x 150mm
(2.5” x 6”)
76mm x 150mm
(3” x 6”)
45mm x 200mm
(1.75” x 8”)
50mm x 200mm
(2” x 8”)
57mm x 200mm
(2.25” x 8”)
63mm x 200mm
(2.5” x 8”)
76mm x 200mm
(3” x 8”)
45mm x 250mm
(1.75” x 10”)
50mm x 250mm
(2” x 10”)
57mm x 250mm
(2.25” x 10”)
63mm x 250mm
(2.5” x 10”)
76mm x 250mm
(3” x 10”)

If you are installing a clamp on flexi pipe then add 2 inches either side to allow for overlap and clamps.

Inlet / Outlet ID Length Inlet / Outlet ID Length Inlet / Outlet ID Length Inlet / Outlet ID Length
45mm x 200mm
(1.75” x 8”)
50mm x200mm
(2” x 8”)
57mm x 200mm
(2.25” x 8”)
63mm x 200mm
(2.5” x 8”)
45mm x 250mm
(1.75” x 10”)
50mm x 250mm
(2” x 10”)
57mm x 250mm
(2.25” x 10”)
63mm x 250mm
(2.5” x 12”)
45mm x 300mm
(1.75” x 12”)
50mm x 300mm
(2” x 12”)
57mm x 300mm
(2.25” x 12”)
63mm x 300mm
(2.5” x 12”)
45mm x 350mm
(1.75” x 14”)
50mm x 350mm
(2” x 14”)
57mm x 350mm
(2.25” x 14”)
63mm x 350mm
(2.5” x 14”)

Our clamp on flexi pipes come with the correct size clamps and in retail packaging, the clamp on flexi pipe can be fitted by a any handyman, please read the warning below:

Warning: When working on, under, or around any vehicle you must exercise caution. Please allow the vehicle’s exhaust system to cool before attempting to remove, as exhaust system temperatures may cause severe burns. If working without a lift, always consult vehicle manual for correct lifting specifications. Always wear safety glasses and ensure a safe work area. Serious injury or death could occur if safety measures are not followed.

Best thing is to leave this to a mechanic who will happily do the work for you for a reasonable cost, we do recommend a professional install the flexible pipe for you.

All our flexible pipes are made of Stainless steel with aluminized ends and come with a 12 month manufactures warranty against workmanship and defects.

Trade discounts may be given on bulk orders. If you require further advice please call us on 01753 686878.

We do offer a complete supply and install flex repair service, all you need to do is bring the vehicle into us we can then measure it and fit the most appropriate flex pipe for you, unfortunately we are unable to make any quotations over the phone for the service as we need to identify the exact position where the flex pipe has broken from and where the pipe would need to be cut to enable enough space for welding, on some vehicles the complete downpipe may need to be removed to gain access, please call to make an appointment for a free quote.