$20 Exhaust Flange Repair

[Mr Bear]

1987 GMC Jimmy 350 Sierra Classic

The problem was a 30 year old exhaust flange doughnut on the passenger side.....puff, puff, puff, and stink in the cab with the windows down.

Before replacing the entire manifold, (yep, studs rusted to the point I knew they'd break off in the flange), try this.

Go ahead and break off the three studs close to the flange and take out the doughnut. Salvage and reuse the three hole flange connector.



I have 2.25" OD pipes, duals with no cats. There are two sizes of exhaust doughnuts, so bought both at $4 each.....after removing my old leaking doughnut, I noted I needed the smaller of the two.......old and small new one on the right. Ill take the big one, on the left, back.



For $5 each, I bought two of the 2.5" opening hand cuff clamps. Knowing the bolts would not be long enough I fished around in the parts bins at home and came up with two longer bolts, nuts, washers, spacers, etc. I selected the 2.5" opening size as its just barely big enough to go around the throat of the exhaust flange and still take a 3/8" bolt, coulda used a smaller id clamp on the down pipe, but at 2.5" opening it slides up and down freely, smashing the doughnut real good for a fine seal.



One new bolt goes through the handcuff clamp, down through one hole of the original three bolt flange and through the hole of the lower handcuff clamp. Slide in another bolt on the other side of the two hole handcuff clamp and squeeze the doughnut but good by tightening the nuts. You could also use all thread and eliminate spacers as you won't run out of thread if like me, you had short threaded bolts.



Test ride......no fumes in the cab, finally, I can put the windows down, just in time for spring.....and, no embarrassing noises, just the ever irritating rumble and drone of two magnaflow mufflers behind that good running 350......well, the mufflers may be too noisy for an old man but at least it no longer smells or sounds like a cockerspanial being squished every time I get on the gas pedal.

[andyh1956]

I've seen those at the parts house but didn't know how they worked.
Thanks!

[Mr Bear]

Never seem em before this. There's a bazillion styles. All generally called split flanges. They're cool!