Why isn't there a flex joint in the 3B exhaust? (1 Viewer)

[MarkBC]

I found the exhaust leak from my 3B, it is right under the flange between the exhaust manifold and header pipe. If you zoom in you can actually see it behind the bolt on the right. I put my finger there with the engine running and it's blowing hard through it.

Since the pipe is still in good shape, I'll probably just take it out (not sure how I'm going to access the bolt in the back ) and weld that hole up. But I'm wondering, why is there no flex joint in this system? The 3B shakes something fierce when idling so isn't that going to put stress on a rigid pipe going all the way to the back? Should I put one in?

And is it stainless? Can I weld to stainless? It looks like the flange isn't and maybe that's why it broke in the first place, combined with engine vibration.

 

[georgebj60]

Not sure if the 3B is the same as the 2H, but on my 2H the downpipe is bolted to a bracket off the bellhousing. Any shaking and they all move together. It's not until later down the line that the rubber mounts are in place to absorb the movement.

 

[mudgudgeon]

If you have it out of the vehicle, it's the perfect time to add a flex joint.
I built an exhaust system for a HDJ80 and had some really tight tolerances to the frame.
The flex joint I ordered took a while to arrive so I ran it without for a couple of weeks.

Without it, I had some clanging at shut down, and a hanger tore out of the pipe within the first couple of weeks. with the flex joint, no rattles, and no issues at all

 

[gerg]

Flex joints are so helpful. I get the rear bolt with a 3/8 universal and a long extension. It doesn't look it but there is barely enough room to get to it. Penetratin oil is key. You can weld to stainless with regular mig wire but your weld will rust like crazy so paint it up with high heat paint. You can get stainless mig wire though.

 

[MarkBC]

Not sure if the 3B is the same as the 2H, but on my 2H the downpipe is bolted to a bracket off the bellhousing. Any shaking and they all move together. It's not until later down the line that the rubber mounts are in place to absorb the movement.

Doesn't seem to be. It seems to go straight down then across and bolts to the body / frame.

Exhaust pipe for Toyota Land Cruiser 60, 7 generation 08.1980 - 10.1984 - Toyota Car and Auto Spare Parts - Genuine Online Car Parts Catalogue - Amayama

Exhaust pipe for Toyota Land Cruiser 60, 7 generation 08.1980 - 10.1984. Buy OEM spare parts online. Low prices, proven reliability, fast shipping from Japan

www.amayama.com

 

[gerg]

Bolts to frame I think is why it cracked at the weld. Normally downpipe is braced to engine then hung by exhaust brackets which allow movement. If you put a flex in and leave it bolted to frame I think it will eventually damage the flex section. This Stuff moves a lot. Bolting to frame will allow transmit lots of vibration/ noise to cab too I think.

 

[MarkBC]

But the picture in the Amayama link shows it going away from the engine, over to the right side of the vehicle with a big bracket there which must go onto the frame or body. Mine has been worked on so it doesn't have that bracket. There is a good amount of flex in the whole system from the exhaust manifold all the way to the rear bracket on the frame by the bumper.

 

[gerg]

ahh k

 

[georgebj60]

Bracket 1 should be bolted to the bell housing, I've attached a picture of the one on my 2H. Bracket 2 has big rubber bushings to catch the hangers that are welded to the exhaust.

Nowhere should the exhaust be hard-bolted to the body or frame. Only with rubber bushings. An exhaust can lengthen a lot once heated up, and moves a lot with the drivetrain. It should basically be hanging by the rubber mounts, guess that's why they call 'em exhaust hangers.

 

[georgebj60]

I have an extra one of those #2 brackets I removed from my FJ60, but it doesn't have the rubber bushings. I might be able to find them though.

 

[brownbear]

Is the exhaust there stainless? It could the aluminized steel. Where they put a coating of aluminum to keep it from rusting.

I'd put an expansion joint in there. I have one. But it's off my turbo...

 

[Freewheel]

I put one in my straight pipe exhaust out of the 2H turbo, i couldn't figure out how it wouldn't tear itself to pieces without one.

 

[roalco]

I think that you will find that the original Toyota exhaust systems, as designed, worked and lasted perfectly well without a stainless steel bellows type flex joint (which is a weak link as it is very prone to work hardening and circumferential cracking). It's all in how the exhaust system is hung and supported. Toyota or reputable professional custom made (ie. In my case, Midas) they are all hung with adequate flex hangers.
That said, I find that most older cruisers I see now have cobbled together exhaust systems made more with good intentions than actual design experience.

 

[MarkBC]

Mine has a couple diy rubber mounts at the muffler, and the final factory rubber mount on the frame by the rear bumper. When replacing the muffler etc they didn't put things back the way they were so I'll need to start pulling together those brackets.

 

[FJBen]

I have the full OEM exhaust (and OEM) muffler still on my BJ74. I still need to put that bracket piece you are showing back on.

 

[DEADSALT]

reason for no in line oem flex joint;

just in case the PO cranks on your oil filter, gives you more room to work.

 

[MarkBC]

So the exhaust pipe was sheared right off under the weld at the manifold flange. I'll weld that back up but I'm concerned that it will just break again. Steve at EBI says to get a flex joint so that's what I'll do, I'll put it in the horizontal part. It will work for now.

I have the bracket on the vertical part right after the manifold which bolts to the bell housing and it was tight so I'm not sure why the pipe broke. Just old, and a bad design I guess.

 

[-MaTTi-]

Is the exhaust there stainless? It could the aluminized steel.

Aluminized steel it is, not stainless. If repaired, spray some zink/galvanized paint on it, it holds well.

 

[-MaTTi-]

I added flex joint (2” SS) in the pipe, also original support is mounted with better clamp.