Replacing the Flange in an Exhaust System

a exhaust pipe
  • 2-4 hours
  • Intermediate
  • 25-75

Your exhaust system, if you keep the car long enough, is going to need a bit of fine tuning. It may be a hole that gets knocked in it by debris on the road, or hitting a low lying bump and knocking it loose from the rack. But here we are going to talk to you about one of the most common, replace the flange in an exhaust system. The flange can get damaged especially in states where you have salt on the roads. It will get eaten up by the salt and road wear and rust away at the manifold connection which is where the flange is at. Replacing this is much cheaper than replacing the entire system.

Tool You Will Need

Two flanges of the proper size for your car

Two nuts and bolts for the flanges


Drill with bits

Jack stands

Protective eye wear

WD 40

Ratchet set

Small vise grips

Step 1 - Getting Ready

Take the two flanges that you just bought for your car. Using the hack saw, cut the top off the curve of one of them. Then also using the hacksaw, do the same on the bottom part of the next one. So you will have when you put them together, one complete flange that will fit over the pipe for an easier installation. Next lay the two flanges one on top of the other and using the drill and the proper size drill bit for the bolt you are using, drill one hole above the opening on the right. Then drill a hole through both flanges under the hole on the left. These are for the nuts and bolts you have bought.

Step 2 - Removing the Damaged Flange

First you will want to make sure that the vehicle is cool enough to work on. Next put your car up on jack stands so you can get under it with some ease of movement. Getting underneath the car where the exhaust system and the manifold is. Make sure you have your eye wear on, it is dirty and rusty underneath there and you don't want any of that falling in your eyes. If you can, unbolt the old flange off the manifold, spraying it first with WD-40 or bolt remover. If you can't get it off by removing the bolts, then cut it off leaving all the other parts intact. be careful not to saw into the pipe going into the muffler or catalytic converter. After removing the damaged flange, take an old rag and clean all the remaining rust off with WD-40.

Step 3 - Installing the New Flange

Now that you have to old flange off, you are going to install the new one we have made. Slide 1/2 of the flange you have cut over the top of the pipe. Then slide the other part over the bottom of the flange. They should fit together nicely with the new holes we drilled lining up perfectly. Now take the new bolts and nuts and put them through the flange and tighten up as tightly as you can using your ratchet to fit the bolt and hold the nut with the vise grips. Check your work. You are done.