Rust has eaten my exhaust flanges

I recently installed a MBPR cat back system because the rust had chewed through my OEM system. Took some PB blaster and brute force but the old system came out and a shiny new one bolted right on. Now a month later, at the exit of the cat (before the Y) the flange has totally disappeared! Not sure if this is fixable with fab work or if I should just bandaid it and save my pennies for new cats. Advice?

 

Any exhaust shop should be able to take care of that for not too much.

 

That's crazy looking! Is that JB weld on there? Depending on your financial situation, you could get those two pipes welded together as @TacoTuesday603 mentioned. If you live in an area with lots of rust, get a stainless catback. 316SS is highly corrosion resistant. 409 is more common and cheaper, but less corrosion resistant than 316. 304SS would also be better than 409.

 

What’s that white stuff?

Getting it weld repaired would be ideal. Or you could do it yourself with an exhaust clamp and a grinder. There's also something called exhaust sealant or something. It’s just rtv but I guess for high temperatures, I got a tube buried in my toolbox somewhere.

$12 DecoHongDi 2.5"es Exhaust Clamps 2 Packs,2 1/2in Lap Joint Band Clamp 304 Stainless Steel for Muffler Pipe Repair,Catalytic Converters

https://www.amazon.com/Exhaust-Clam...932&sprefix=exhaust+clamp,aps,165&sr=8-5&th=1

 

exhaust shop.

if the metal is too far gone, then a good material Y pipe and catback, assuming the headers/downpipes are fine

 

I've got a stainless MBRP catback on it, what we are looking at is just passed the downpipe after the cat. Unfortunately I will probably need cats ASAP too but I am just trying to buy some time. The other stuff is like JB weld, I was having some hissing/leaking sounds so I was trying to cover all bases and seal up connection points and it's lasted a few years LOL. No real exhaust shops up here doing that kind of work in North Conway but plenty of garages who can do light fab work. I got some split flanges last night at AutoZone and will try my hand at band-aiding it this afternoon but right now it sounds like a dirtbike.

 

I believe the oem diameter is 2.25". You could probably get away with cutting off each end and using a band clamp.

$19 EVIL ENERGY 2.25" Exhaust Clamp,2 1/4" Butt Joint Band Clamp Sleeve Coupler Stainless Steel for Pipes,Mufflers,Catalytic Converters 2PCs

https://www.amazon.com/EVIL-ENERGY-...&sprefix=2.25+exhaust+band,aps,97&sr=8-3&th=1

 

Welding it together straight through would be a cheap and easy fix. But keeping some kind of bolt-able connection there would allow you to take the exhaust apart in the future.

 

Use a clamp like others suggested.

I would not suggest welding it because the OEM flange joint had a donut seal allowing for some movement. Otherwise you may get rattles or additional rasp.

 

True, if there was originally a donut and some spring-bolts there needs to be some flex there

 

My thoughts exactly and also why I am seeking professional fab help to put flanges on. I think I've tracked down a friend who welds and has a lift to help.

 

What about those flexible exhaust pieces at the auto zone? I have the exact same problem (not as severe. I can at least thread bolts through and tighten it *mostly*). Figured I could cut the exhaust before and after the flange and use an exhaust flex pipe there? How do flex pipes not leak? The bendy type I mean.

 

Flex pipes use heavy gauge corrugated tubing to flex. The 4.0 exhaust doesn't have any flex sections, so it shouldn't require one to be added. The donut type flange doesn't flex. It's a mechanical connection using spring loaded bolts. The only time the exhaust would need to flex is from deteriorating motor mounts. This is not true of all vehicles, but for the 4.0L Tacoma, there's no flex sections in the oem exhaust. My truck has 155k and still doesn't leak. I did build my own T304SS catback with a donut flange.

Adding a flex pipe is like adding a band-aid. If your pipes are rusted, it will eventually crumble apart. The ones at your local autoparts stores are likely aluminized mild steel. They will rust apart in a couple years if you live in areas with snow.

 

Thanks for the info. My trucks a 2.7 and honestly I’m just trying to fix it enough to pass inspection here in Maine. A few years sounds good to me lol. It’ll need a whole new muffler by then anyways as it’s got a small hole, and so if I still have the truck I’ll just replace both. Much more concerned about finding someone to un-seize my rusted camber bolts so I can finally get it aligned lmao.

regarding the not needing to flex, is the flange just there for easier assembly/disassembly then? I had been afraid to use straight tubing or clamps because I figured it was there for vibration control/designed to flex ever so slightly?

 

I mean 17yo me would have cut off the flanges and ground it up and slipped a pipe over the gap and cranked it down with a couple of the exhaust clamp bolts. and if its only a temp cheap fix you still could do that

 

https://www.tacomaworld.com/threads/best-way-to-chop-exhaust.760563/


Cut the sob

 

Yes. The flange is there to separate the cat back from the cat pipe. There's no way you could remove the exhaust from the heads back to the tail pipe as a single unit. At least for the 4.0. It also allows for the cats to be replaced without having to replace the entire exhaust system if necessary.

 

Gotcha. So chop it, patch it, and re-chop if I ever have to remove the whole system. I think I’ve found my solution. Thanks for the info! Like I said, I had assumed it was supposed to slightly flex so I was afraid to patch it with solid tubing

 

It’s more like chop it, reflange both pieces, unbolt if you need to remove it.

Another option is to use V bands. They sell all different sizes.

One issue you might have is if the existing pipes are severely worn as in thin as a soda can, welding can be difficult to impossible.

The example below, the weld on flanges are awful short. Even what summit is showing seem short but not as bad.

$45 EVIL ENERGY 2.25" V Band Clamp with Flange Male Female Stainless Steel 2PCS

https://www.amazon.com/EVIL-ENERGY-...74&mcid=87d383e64c05333b855a34fcfa565a7c&th=1

https://www.summitracing.com/parts/sum-694225

 

Somewhat common

https://www.tacomaworld.com/threads/excessive-rust-on-the-exhaust-connection.428642/page-3