I've yet to find the bottle of Kroil or P'Blaster spray can.

1990 'lil red' Volvo 240 DL Wagon needs a new exhaust and new exhaust manifolds to had gasket (& studs & nickel anti-seize).

Stupidly, six years ago what was a used 240 cat back became one solid fully welded pipe at the Spokane Valley, WA Discount Muffler from header pipe to tail pipe. Ah, well.

So the used cat back is now very used. Before it falls off, I scoped 550$ of exhaust from new (no spin flange) header down pipe to the tail pipe with new cat there in.

Rust at the exhaust manifold studs and nuts. Rust has welded where the flange nut meet the manifold. Rust at the manifold to header pipe. And one hanger.

Recent research suggests the user of either muriatic acid (a dilution of hydrochloric acid to <9) or white vinegar. Eye dropper or toothbrush. Rather vinegar as it is far less reactive.

I understand with Kroil or Zep, as these have a rust dissolving action, it can take days, week, months. Cycle the heat by running the engine.

Have you folks use acid to free them rusty nuts and bolts like in the exhaust?

I understand Art won't perform exhaust repair anymore. I totally understand. Yet in an Uncle Old Duke-ism, an exhaust repair shop may be all shysters.

All flaky inside the rear muffler.

Thanks.

Dud-McDuffed












--
Beh.

Volvo OEM Cat back.

FCP has it, no, yes, no.

I'll Kroil and B'laster and tap and engine heat for the next 18 months or so, remove the cat back and then the manifold.
--
Beh.

On re-installation make sure you use grey never seize compound. You will not regret it when ever you take this system apart.

I realy want myself to be able to dis-connect the exaut system with minimum problem because it is all stainless except the down pipe and I realy want the under the axle pipe. It is so easy to pull out from under the car to work on it. The cat triangular flange has been drilled for 5/16" inox bolts to join the down pipe.

This down pipe is an original Volvo part that has had a couple electric welds on it. First to weld a new triangular flange in place and also plug some local pit corrosion that showed up at the support bracket and also where the sound froof metal shells touch the pipe.

A long time ago I removed these sound froof shells to prevent road salt from accumulating and bore the rather heavy wall OEM down pipe. This pipe last a long time when repaired.

Around 2001 I found some 2 inch o.d. used dairy farm milk inox pipeline and welded the angles the best I could. Needless to say I had to make many adjustments afterward. Of course I had the time since I was retired.

Since I have not purchased inox U bolts I need to replace these every 2 years due to galvanic coorrosion. We have road salt all winter in our area.

I dont think I will see the end of this exaust system ,it will never corrode.

Thank you. Got the Permetex 8-ounce Nickel anti seize.

Found the retainer that rubber ring hanger secure to to carry the front of the front resonator.

I'll apply this anti-seize to the unions and securing hardware.

My hope is to remove the cat back system, remove the exhaust manifold, clean and replace gaskets and stuff. New header pipe and cat.

Rather put the li'l red 1990 240 DL drive line into a clean 242, rebuild the engine, and well that'll never happen.

Well overdue to inspect, treat or replace, the exhaust union clamps on the 92 and 1991.
--
Beh.

I have cut apart several 700 exhaust systems using an inexpensive tailpipe cutter.

do a search for - Lisle tailpipe cutter - in the listing, you will find a cutter on eBay for around $25

You only have to swing the cutter about 90 degrees to cut a tailpipe.

I cut the pipe before and after the part that kicks over the rear axle and about 6 inches before any part if the system that will remain.

I leave 6 inches in order to manipulate the stub to remove it from the system.

As a plan B if the stub won't come out, I cut the pipe flush with the remainder of the system an insert an old screwdriver and then larger tools to collapse the stub.

To connect the new pipe into the remainder, you may need a tailpipe expander which you can rent or borrow for free from many parts stores. In my youth, we used to pound a Coke bottle into the pipe using a block of wood and a hammer.

Before you remove the old system, look it over carefully and take pictures. Many sections are parallel to the ground, or vertical. Lay the new system on the ground beside the old one to see if they are the same.

I mark each female pipe end at one inch and two inches from the end - that way I can assure that each pipe is inserted the same length. Put clamps on with just enough tightness to hold things but allow minor adjustments before full tightening.

Of cours, Volvo once sold very nice cat back systems with all parts needed and everything fit properly!

Starla cat back. I'll cut in front of the weld of that glass pack after the cat and before the final muffler.

Use an adapter for the split pipe into the front resonator with the cat pipe out.

Tasca Parts sells the Starla cat back kit here, PN 31372147
https://www.tascaparts.com/oem-parts/volvo-muffler-31372147



the cheaper FCP is out of stock.

iPd has it.

Apply Kroil for the long haul. I'll expect to revisit this next year.

Hopefully nothing falls off.

Thank you.
--
Beh.

Hello KGV! I only chime in when I think I actually can help. Even a good regular mechanic won't tackle mufflers and exhaust- best left to muffler shops. Let me recommend House Springs Discount Muffler shop.Located about 20 miles from us,right off Hwy 30. Got my 740's exhaust from Cat back last year for about 40% less than the shops here in town.They're really skilled too, and the one guy was even familiar with older Volvos. Might want to give them a call.-Tinkerbelle

Hi Tinkerbelle,

I've been following your thread on your 740.

Thank you. I'll check out the House Springs Discount Muffler.

Sort of sucks the people you knew in the 1980s, like Rich at Brentwood Volvo and the Parts Barn owner in Rock Hill are gone.

With all this website this and dot dot dot dubya dubya dubya click click it is hard to find parts.

I researched the use of weak acid to free rust welded hardware for my 1990 240 DL 'li'l red' wagon.

So a muffler shop may help.

Thank you!
--
Beh.

Yeah, my 740- that was a long way to go to get to 'crank position sensor'. But it's fixed.I put in new spark plugs and a blower motor last week. I'm waiting on the new resistor that I ordered from Parts Geek. Isn't Red still at Brentwood Volvo? He was always helpful but he couldn't come up with a blower motor resistor.Yep, parts are getting harder to find. Nothing in junkyards either.BTW, Big 3 auto salvage is walking distance from that muffler shop- could be an interesting trip! I was going to suggest naval jelly for the rust. But it's extremely caustic and from those pictures, I still think the muffler shop is your best bet.They fastened up my dragging muffler as a temp fix until they had the time to do the whole job,and they didn't even charge me! I like that kind of service. I'm sure you'll get it fixed one way or another.---Mary

Hi Mary,

Sure Happy it's Sat-Your-Day!

I got a Starla cat back system. I'll get Volvo hangers and clamps. And a exhaust pipe cutter as james_a_sousa recommends.

I'll keep your muffler shop contact info.

Glad your 740 Bendix Rex ignition / Regina injection is ever better!
--
Beh.

Yes, I saw your post- well that should do it! Nice cool weather coming up after Tuesday too. Good time to do that job. Happy Balloon Race Day!-- mary

I understand Art won't perform exhaust repair anymore.

If you're speaking of me, you're correct, but can't imagine where you heard it. I just replace everything, unless the damage is confined to one or two parts, like when Mrs. Art backed into a snowdrift and bent the rear muffler and S-pipe. But those two items had been recently replaced, so were not rust-welded to the axle pipe. All came apart easily.

It takes up a lot of space, but I've kept a complete kit on hand cat-back. It fits all the non-turbo cars we own. Getting the front muffler off of the cat's outlet pipe usually takes a dozen whacks with a 2# maul that leaves that front resonator less than pretty.

No use for rust dissolving fluids cat-back. Have soaked header nuts though.
--
Art Benstein near Baltimore

I'm so busy I don't know whether I found a rope or lost my horse.

Hiya Uncle Art!

Soaked header nuts with ... ?

Hope Mrs. Art is okay from the snowdrift impact!

Volvo Forums,I guess? Someone mentioned you don't deal with rusty Baltimore exhausts in Volvo 240 and give it up to the muffler shop.

It is the original header pipe and manifold. I'd like to replace all from the exhaust cylinder head back.

I've read articles and seen videos about people using muriatic acid (dilute HCl) and white vinegar, and other compounds. The acid reacts to the rust first, dissolving it and leaving steel behind freeing the rusted sized components. 10% strength used to adjust pool PH. Vinegar is safer as it is less reactive at the same PH and dilution.

There is a few articles here I found before that mention using acid on rusted exhaust components.

Have a giant baking soda container handy and some in dilution to neutralize before the acid attacks the bare metal.

Sawzalls, angle grinders, MAAP or acetylene torches I do not have anymore or have access to. I'd have to rent. Rather not.

I'll see what Turbobricks has on the topoic.

Thank you!

Happy Monday!
--
Beh.

"Sawzalls, angle grinders, MAAP or acetylene torches I do not have anymore or have access to. I'd have to rent. Rather not."

you can get a new sawzall --- the kind you have to plug into a socket---rather cheaply these days as all the manufacturers move to Lithium battery powered tool lines.

check around.

Hi CeeBee!

Thank you.

I'll look these up. I forget about battery powered power tools.

I got a Starla cat back system on the way. I'll use a pipe cutter on the end of the cat pipe to length and an adapter so the two fit together.

Don't want to cut the exhaust studs!

I'll deal with the rest of it next year or so or sooner.

Thank you.
--
Beh.

Art, heard this yesterday, from a teenager.

He said:
"I ordered a chicken and an egg, Online.
I'll let you know."

cheers

CB good to know a teenager. When he lets you know, ask him to get fresh news about why chickens cross the road.
--
Art Benstein near Baltimore

"Smedley had become the Clint Eastwood of chicken crises." -Kenn Amdahl

My go-to rust buster is Mystery oil, and a long soak before you show up to remove
exhaust manifold bolts. I use Mapp gas to heat the bolts red before trying to remove. I'd prefer ox-acetylene but Mapp gas has worked OK. Regular muffler clamps come apart or break off with using heat first.

Taking out O2 sensors can require Oxy acetylene, I usually leave that job to pros.

BB

Angle Grinder with a metal cutting wheel.
Cut it into pieces.

That's what a muffler shop would do.

Yes, I now pretty much go straight to using an angle grinder with a thin metal cutting wheel. Of course do be careful to work safely with full protective gear and have an extinguisher at hand just in case.

Shadetree exhaust system repair is often one of the messier things to deal with that quickly ends up becoming a bigger problem than it first seemed. By the time you're ready to give up, you may have opened up the system and it would at the very least be rather noisy to drive to a properly equipped and experienced muffler shop where they'll make quick work of it and be able to fashion things like hangers, connector pipes and adapters as needed.

I'll share a few of my own shadetree tricks when a proper torch isn't available to get things apart and make things fit during installation.

I now skip going for my MAP torch when a few good blows won't move things and go straight to work with an angle grinder, starting with cutting the clamps off as a warmup. Unless things are braced, you can sometimes cause unnecessary damage forward and back when beating, prying and wrestling the whole system to open things up, so cutting nicely avoids that. A fragile old cat may needlessly collapse if you're not careful. Worst is to damage or open things up at the down pipe or (perish the thought) the header. The cut sections drop straight down with minimal mess to clean up and you can cut into more convenient lengths for removal and disposal.

Depending on which side of the joint I'm trying to salvage, if I want to preserve the inner section then I'll cut off just ahead of the joint and carefully nick a spiral channel that I can peel open with pliers, perhaps aided by a cold chisel. To preserve the outer sleeve, I'll leave a small stub protruding, cut up inside the slits (perhaps even make new slits if there aren't any), them use BF pliers to crush the inner pipe to be able to pull the remainder out, pehaps aided by driving a cold chisel or punch into the gap to crush it further ahead.

For installation, pre-mount the hanger clamps and tail pipe, possibly even pre-mount a connector pipe if you've got enough room to work. Don't pre-tighten unless you're sure things are going to end up aligned, experience helps there.

Here's another trick I now do during reassembly to minize wrestling and beating on the system that might damage things forward. It's especially helpful when you're not up on a hoist to have full leverage from all angles. Often times things don't fit well, especially when connecting different makes of exhaust components. I'll wrap the ends of a ratcheting tie-down (two if needed) just a little forward and back of the two sections, ratcheting it taught while wiggling up and down to further close the joint. If needed I'll also use the angle grinder to add or extend the slits a little.

I'm sure others have developed their own techniques to make do with what tools they have on hand.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

Fcp has an exhaust system cat back for $154 & header for $112,,& then bolts &nuts,,a few $ more

ATF mixed with acetone works pretty well. 2 x a day for a week or so.