So are tailpipe expanders pretty much garbage?

[BikeRider]

The cat was stolen from one of my cars recently and I finally got around to replacing it. I bought a universal aftermarket cat, by Walker, but because the input & output are a lot wider than the 2 tailpipe sections, I've had to use various pipe reducers and clamps to get everything connected properly, along with tailpipe expanders I got as loaners from local auto stores.

Of the 5 I got, 4 were either broken or broke under moderate use. In one case several of the wedge segments broke, at the weak point where the rubber ring goes, and in the others the threads stripped from the nut. I think they were all OEM brand. The only one that didn't break was the larger one.

Are these prone to failure by design, or only the cheaper ones you can get as loaners? I'm going to have to **** join one set of pipes because I couldn't get any of these expanders to work, so there will be leaks. Is the HF one any good or just like the others?

And yes, I know, I should get the replacement cat welded, and probably will at some point. But I need to pass inspection ASAP and thought this would do for now, plus I wanted to make sure that the new cat would pass inspection before welding it on.

 

[pvfjr]

I haven't seen anything affordable that works OK. I usually get my exhaust pipe from a local exhaust shop, and it's a decent wall thickness. Maybe that's my problem? Perhaps cheap Chinese pipe from the parts store would stretch easier?

I've broken them too. I dip them in oil before use. It seems to help, but it's still tough to adequately stretch a pipe without breaking the tool. I've welded **** joints with success too. Easier to do on the bench, of course.

Or, go to the parts store and get an ID coupler that fits your OD pipes, then weld it to each.

Or, get a good quality stainless band clamp (the ones that are about 2" wide and have multiple bolts). They work surprisingly well for a **** joint.

 

[2ndGearRubber]

My astro expander has done very well for me. It's NOT a hydraulic expander, but it gets the job done.

FYI - factory pipe will not expand. You can bump it a hair, but it will crack before you get any real expansion.

 

[BikeRider]

My astro expander has done very well for me. It's NOT a hydraulic expander, but it gets the job done.

FYI - factory pipe will not expand. You can bump it a hair, but it will crack before you get any real expansion.

I was actually hoping to expand the reducer adapters to get them to fit just right. I was actually able to for all but one, which will have to be **** joined. I hadn't intended to try to expand the factory pipes. I also figured that with years of heat cycling they've been heat treated to the point where they're super hard and brittle.

Btw is there a preferred way to lap join pipes, front to rear: smaller into bigger or bigger onto smaller? And what's the best way to minimize leaks, in terms of clamp types and heat-resistant compound?

 

[BikeRider]

I haven't seen anything affordable that works OK. I usually get my exhaust pipe from a local exhaust shop, and it's a decent wall thickness. Maybe that's my problem? Perhaps cheap Chinese pipe from the parts store would stretch easier?

I've broken them too. I dip them in oil before use. It seems to help, but it's still tough to adequately stretch a pipe without breaking the tool. I've welded **** joints with success too. Easier to do on the bench, of course.

Or, go to the parts store and get an ID coupler that fits your OD pipes, then weld it to each.

Or, get a good quality stainless band clamp (the ones that are about 2" wide and have multiple bolts). They work surprisingly well for a **** joint.

I'll look into this. Thanks.

I hope those cat thieves burn their hands off trying to steal them off of just driven cars.

 

[Bigblue&Goldie]

The best use for the common parts store "expander" is for re-forming tube. In other words, if you have a piece that's been mangled from a u-clamp, these are good for restoring the shape of the tube. If you look at an actual expanding tool you will see how these tools are woefully inadequate.

 

[2ndGearRubber]

I attributed the OE pipe metal composition, being a type of stainless, to the refusal to expand.

Ideally, you don't want to stuff a pipe into another, against the flow of exhaust. Water and junk will want to sit there on the lip and rot. So if you cut off a pipe, slip the repair section sleeve over the OE pipe. This makes for a smoother transition, going smaller into bigger. Usually aftermarket pipe is such junk it doesn't matter that much, it just rots out in 24 months. The weaker aftermarket pipe is what I prefer to clamp onto as well, as the stiff and inflexable OE pipe doesn't want to smush down and clamp properly to the pipe inside of it.

Typically speaking, these are all "book learnin'" type rules. Make it fit. Sometimes you don't get to follow best practice for a variety of reasons.

https://www.amazon.com/dp/B000CQHVLI/?tag=atomicindus08-20

Mud is your friend, and will seal up slightly crooked interfaces. I'll just dab it on a shop rag and wipe it into a weeping joint. It'll hold well enough until a layer of rust forms and seals it shut.

 

[MJD1]

The lisle expanders are pretty good. As for which way to orient pipes. Think of them as funnels pointed towards the rear of vehicle. Front of muffler or first pipe gets expanded to go over the pipe in front of it. The pipe that's after the muffler or next pipe gets expanded to connect to muffler or first pipe.

 

[Jagmandave]

I rented one from the auto parts store yesterday - first thing I did was take it apart and put gear oil on the threads, then I greased all the internals and where the end pieces contact the segments. It worked, but was difficult to say the least.

 

[BikeRider]

The lisle expanders are pretty good. As for which way to orient pipes. Think of them as funnels pointed towards the rear of vehicle. Front of muffler or first pipe gets expanded to go over the pipe in front of it. The pipe that's after the muffler or next pipe gets expanded to connect to muffler or first pipe.

You mean going front of car to rear, each section goes into the next one, kind of like those articulating refuse disposal chutes used in building demolition, going top to bottom?

 

[BikeRider]

I rented one from the auto parts store yesterday - first thing I did was take it apart and put gear oil on the threads, then I greased all the internals and where the end pieces contact the segments. It worked, but was difficult to say the least.

I applied a generous amount of PB Blaster to everything but without taking it apart. But I think the nuts that come with these are junk, softer metal than the forcing bolt.

 

[Kscardsfan]

Don’t know if they’re all garbage, but I can tell you that if you’re in high school working on your first **** box car trying to install glass packs, and if you use an impact gun to open the expander up, it will blow up into lots of smaller pieces.

 

[BikeRider]

I used an impact, but in every case the nut threads stripped. They should sell these things with several replacement nuts, and make them with harder steel. They'll fail way before the extra rubber rings that come with them are needed.

 

[vssjim]

I have the Lisle and Astro kit and they both work good for me

 

[joel_400]

I actually have two of the Lisle kits. Bought one new and found another at the local flea market for ten percent of what I paid for the new one. So when somebody asks to borrow one that's the one that gets loaned. It is an amazing tool. I've expanded good 2 1/2 to over 3 inch with it. Just take it easy and keep rotating as you go and it work phenomenal! I did notice that Harbor frieght has a kit that's darn near the same thing for lot less. May be worth a shot. Or you could get the measurements and see if you could get a local muffler shop to make what you need.
Joel

 

[joel_400]

Exhaust Pipe Expander Kit

Amazing deals on this Exhaust Pipe Expander Kit at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[unslow1]

I've had good luck but I never use an impact on one. Slowly with a box-end wrench. They are great for straightening the bent ends you often get when the pipes are knocked around during shipping.

 

[tyyost]

There are two different tools being talked about here synonymously, the one I think the OP is talking about is a basic **** tool that is designed to maybe if your lucky pop a crimp or dent from a clamp out of exhaust pipe. These cost $15-$25 bucks at the parts stores.

The other tool, the actual expander, sold by Lisle, Astro, and now HF use an steel wedge tool designed to be used with an impact and a series of inner and outer sleeves to actually expand pipe. I have an Astro set that I have used for 3-4 exhausts and it works well. The o-rings that hold everything together are a little bit of a pain but it hasn’t failed to do what I needed. The exhaust I did before I bought the tool had me driving to 4 different local shops trying to get them to open up the new pipe for me.

 

[VolvoRyan]

If it doesn't cost a couple hundred bucks, it's not going to expand a pipe much.

Honestly, the $30-50 Lisle expander I have isn't much more useful than the $5 HF one I bought in a pinch. Just had to nudge a new pre-formed stainless pipe open a smidgen.

-Ryan

 

[joel_400]

I've been doing exhaust for over 20 years for the first 15 I didn't have the Lisle tool. When I look back I think WHY!? Even though I have my own tubing bender with expander on it I still use and love that Lisle tool. It's a life saver for on the car expansions or just a quick bump that's needed from time to time. Or when Im at work with no pipe bender. Just hard to beat that guy. It will actually expand larger pipe than what I have tooling for with my bendet as well! Money well spent if you do even a small amount of exhaust repairs!
Joel

 

[jpaw]

You can lose the o-rings or sacrifice them and heat the pipe with a propane torch. It will help immensely along with some grease.

 

[pbon]

**** with band clamps could work

 

[vanapplebomb]

There are different “expanders” and they are for different things. Expanders that reform the pipe so it is round again, and expanders that stretch the pipe to a larger diameter so you can make slip fit joints, etc. Trying to use an expander made to reforming tailpipes will break it if you try to stretch/open up the diameter of the pipe larger than it originally was. The expanders made to stretch the pipe are a good bit more $$ than the reforming type expanders.

 

[CJM8515]

those cheap ones with the fingers and a o ring holding it together are not meant for much more than reforming damaged pipe. a real expander like an exhaust shop has thats hydraulic is 10x better

this is what you really need https://www.amazon.com/dp/B0B1W7KVTS/?tag=atomicindus08-20

me, id go down to the local exhaust shop and pay the dude 20 bucks to expand the pipe if all else fails

 

[lilredex]

Btw is there a preferred way to lap join pipes, front to rear: smaller into bigger or bigger onto smaller? And what's the best way to minimize leaks, in terms of clamp types and heat-resistant compound?

I have used three overlapping shells to seal **** joints that do not line up, sometimes they are permanent, especially when welding is awkward.

 

[signcrafter]

My astro expander has done very well for me. It's NOT a hydraulic expander, but it gets the job done.

FYI - factory pipe will not expand. You can bump it a hair, but it will crack before you get any real expansion.

It's not a hydraulic as it comes but if you happen to have a green lee knock out punch set it has the same threads and makes this expander so nice to use.

I love my astro expander. Makes exhaust repairs easy. I bought a few different size sticks of pipe from napa and can pretty much make whatever adapters I need.

Sounds like the op has one of those cheap finger spreaders. I have one or two of them also and they work good for making pipes round again after they have been clamped and crushed.

 

[plcguru]

It's not a hydraulic as it comes but if you happen to have a green lee knock out punch set it has the same threads and makes this expander so nice to use.

I love my astro expander. Makes exhaust repairs easy. I bought a few different size sticks of pipe from napa and can pretty much make whatever adapters I need.

Sounds like the op has one of those cheap finger spreaders. I have one or two of them also and they work good for making pipes round again after they have been clamped and crushed.

I made one like that with the cheap harbor freight hydraulic punch. It worked great for my complete header back system. I basically copied idea from here http://forums.pelicanparts.com/911-.../957077-diy-sort-hydraulic-pipe-expander.html

 

[SM Racing]

I bought this kit:

17350 Pipe Stretcher Kit

Stretches Pipe up to 4-1/4" Including Stainless Steel.

www.lislecorp.com

Then I added a hydraulic pull cylinder. Used it daily for the last couple of weeks, had to build several exhaust systems and wanted to build some slips into certain parts. The setup works great for me, just need to build a stand so I don't have to sit on the floor.

 

[BikeRider]

Using the tools I rented I was able to expand enough of the adapters to be able to lap join all but one of them together. For the lap joints I used lap joint clamps and a single u-clamp. For the one opening that I wasn't able to expand, I **** joined it using a **** joint clamp. For good measure I wrapped a cut-up soda can on the **** joint and also on the lap joint that I secured with a u-clamp, and also applied lots of exhaust joint compound.

It all ended up working out and the car's very quiet now, as it was before the cat was stolen. It also just passed inspection, so I'm good. It looks kind of funny with 3 lap joint clamps, 1 **** joint clamp, a u-clamp, cut-up soda cans, exhaust joint compound and some craft wire holding things up where the hangers that the cat thieves broke were (I'll eventually get those welded back on as the wire will eventually fail). But it's solid and it works and no one ever looks under a car.

Thanks to all for the great advice. Now I know that if I have to actually expand pipe in the future, either buy or rent the right tool, or take it to a shop. I was frankly amazed and delighted to see so many chime in with good advice and suggestions.

I do wonder though if there's a much simpler way to expand pipe in certain situations, using a cone made of hard metal, that you fit into the pipe and hit with a hammer?

 

[Beelzeboss]

I bought one of the threaded rod/o-ring things, stripped the thread first time using it on some thin aluminium tubing - useless.

So I lathed up a tapered plug and used a press to force it into the tube, worked flawlessly.



Then I welded these expanded bits to the rest of the tube

 

[toolenthusiast]

The best use for the common parts store "expander" is for re-forming tube. In other words, if you have a piece that's been mangled from a u-clamp, these are good for restoring the shape of the tube. If you look at an actual expanding tool you will see how these tools are woefully inadequate.

Yup. We use them in the collision industry to straighten the ends of pipes, mainly on cars that have been rear-ended.

 

[Ricky Joe]

I was actually hoping to expand the reducer adapters to get them to fit just right. I was actually able to for all but one, which will have to be **** joined. I hadn't intended to try to expand the factory pipes. I also figured that with years of heat cycling they've been heat treated to the point where they're super hard and brittle.

Btw is there a preferred way to lap join pipes, front to rear: smaller into bigger or bigger onto smaller? And what's the best way to minimize leaks, in terms of clamp types and heat-resistant compound?

I might would consider working a piece over the seam, creating a kind of sleeve that you can weld each end. Heat and bend as you weld. Might work.

 

[BikeRider]

I bought one of the threaded rod/o-ring things, stripped the thread first time using it on some thin aluminium tubing - useless.

So I lathed up a tapered plug and used a press to force it into the tube, worked flawlessly.



Then I welded these expanded bits to the rest of the tube

I wonder why these "expanders" don't use beefier forcing bolts and nuts like bearing press kits do. My Astro Pneumatic kit uses a 5/8" bolt and heavy duty nut and it's never stripped despite dealing with much stronger forces, and it wasn't THAT much more expensive. Just make the top wedge longer to accommodate a longer nut.

Btw what's a tapered plug? Rings a bell but I can't bring anything to mind. Although above I did ask whether one could use a steel cone and just hammer it in to expand a pipe, although a press would distribute the force more evenly.

 

[Beelzeboss]

I wonder why these "expanders" don't use beefier forcing bolts and nuts like bearing press kits do. My Astro Pneumatic kit uses a 5/8" bolt and heavy duty nut and it's never stripped despite dealing with much stronger forces, and it wasn't THAT much more expensive. Just make the top wedge longer to accommodate a longer nut.

Btw what's a tapered plug? Rings a bell but I can't bring anything to mind. Although above I did ask whether one could use a steel cone and just hammer it in to expand a pipe, although a press would distribute the force more evenly.

The bit on the left is what I referred to as a tapered plug, no idea if that's the actual name of it, it's just a piece of steel lathed into a cone shape

 

[BikeRider]

The bit on the left is what I referred to as a tapered plug, no idea if that's the actual name of it, it's just a piece of steel lathed into a cone shape

Ah, I see. Like my cone idea but with a truncated tip. A trapecone (trapezoid cone)? Although, an actual cone or something closer to one would prove useful in more situations. There's got to be actual tools like that you can buy.