98 corolla front flange bolts, exhaust doughnut?

[ziggy]

hi all. 98 corolla VE model. yesterday, i finished installing a new aftermarket evan fischer exhaust system. what a pita it was! Mainly too trying too get the middle pipe, 2 segemnts connected. and...installing the 3rd piece, catalytic converter and front pipe, one big unit, and a bosal doughnut gasket. New muffler too. I have new flangebolts, springs, the guide, i bought at autozone. doorman brand. they fit. oh got new 02 sensors too...
INstalling the new flange bolts, front exhaust pipe...i tightened the bolts till the sorings were smashed tight looking, not incoiled looking. Few hours earlier, i had left them 75% turned, so the springs appeared looser started car, and some smoke im assuming exhaust came from connection area thier. why i tightened them so tight.
i do know, the top of the bolts ride the bottom flange too allow felxibility. well after tightening so tight, small leak at mid pipe. use aluminum tape, and 2 inch connector. seems too have stoped it, as thier was air coming out a small seem of the connection. not after the tape and connector. muffler and gasket didnt leak.
did i over tighten the front pipe flange gasket bolts? tookfor a drive, and thier still a small leak somewhere. it rides pretty ok..but when going after stop, thiers a visible exhaust noise then it stops.
or...what would be the correc torque specs fro the front pipe exhaust doughnut flangle bolts?
imthinking of getting some liquid metal stuff i triedmonths ago on a small hole in old 18 year old resonator under the corolla it worked flawlessly.

 

[Ethan1]

Whaaaat? I'm confused. Are you just looking for a torque spec? Try listing only the relevant details, in chronological order...

 

[JC1]

I had a 98 Sienna and once I changed the OEM exhaust, every subsequent exhaust repair was a test in patience. Non OEM stuff doesn't line up nicely or you need to bend exhaust hangers to make it fit without banging into the frame etc.

You may need to make a few adjustments to get it working property.

 

[Donald]

Why install anything but a basic exhaust in a 1998 Corolla.

 

[kschachn]

It's a little hard to tell exactly what you're asking, but the flange bolts only completely pass through one half of the exhaust, one flange has larger holes than does the other side. When you tighten the nuts the torque is against a hard stop, not randomly compressing the spring.

Look at this picture. If the bolt you have is passing completely through both flanges then either it's the wrong bolt or something is amiss with the flanges. The correct torque for that bolt is for the bolt itself, it doesn't have anything to do with the spring per se.

As an aside, I've done quite a bit of Japanese exhaust work and I concur wholeheartedly with JC1. I've had nothing but bad experiences with Bosal. It never fits correctly and if you do struggle it into submission it won't last long.

 

[cjcride]

Like JC1 alluded to.
I did exhaust work on a 91 Corolla years ago. Similar trouble. I finally took one aftermarket bolt to the Toyota dealer and compared the bolts myself. The aftermarket bolt shoulders were too long by almost 10mm. Bought the pricey dealer bolts, problem solved.
The long shoulders cause the springs to compress completely defeating there purpose.
Dealer gasket also fit better.

 

[cjcride]

Originally Posted By: cjcride
Like JC1 alluded to.
I did exhaust work on a 91 Corolla years ago. Similar trouble. I finally took one aftermarket bolt to the Toyota dealer and compared the bolts myself. The aftermarket bolt shoulders were too long by almost 10mm. Bought the pricey dealer bolts, problem solved.
The long shoulders cause the springs to compress completely defeating their purpose.
Dealer gasket also fit better.


Fixed it.
The edit option times out TOO quickly.

 

[ziggy]

i see. ok..the bottom of the exhaust manifold, the flange, has built in nut on both sides. its not completely flat. the new exhasut, evan fischer, the flange is flat. The doorman bolts, were the same length as the old rusted dealer ones. but a tad different. I torqued the bolts, so the springs were touching eachother. I have a feeling it isnt torqued right, i cannot find the torque specs online anywhere, for the correct torque for the ,bolts. anyone know??/
It would seem too me, the springs on the bolts, should have some leeway room too move. I kept turning the bolts, with a long extension, 2 size fittings and a 3/8 drive, from under the car, till the bolts almost wouldnt turn anymore.
Did i do it right? i mean, torque them right? maybe i should loosen them?
And yes....i am very familiar with aftermarket exhaust stuff almost never fitting right. its a hit or miss, more often a miss.

 

[kschachn]

Originally Posted By: ziggy
i see. ok..the bottom of the exhaust manifold, the flange, has built in nut on both sides. its not completely flat. the new exhasut, evan fischer, the flange is flat. The doorman bolts, were the same length as the old rusted dealer ones. but a tad different. I torqued the bolts, so the springs were touching eachother. I have a feeling it isnt torqued right, i cannot find the torque specs online anywhere, for the correct torque for the ,bolts. anyone know??/
It would seem too me, the springs on the bolts, should have some leeway room too move. I kept turning the bolts, with a long extension, 2 size fittings and a 3/8 drive, from under the car, till the bolts almost wouldnt turn anymore.
Did i do it right? i mean, torque them right? maybe i should loosen them?
And yes....i am very familiar with aftermarket exhaust stuff almost never fitting right. its a hit or miss, more often a miss.


I couldn't find a picture of the attachment at the manifold, but the principle is the same. The shoulder on the bolt bottoms out on the manifold flange and limits the compression of the springs. It allows some movement but not a lot and sets the compressive force on the sealing donut. I've never seen one that has a nut on both sides of the manifold flange like you describe, are you sure it isn't just some thing rusted to the flange? That definitely would mess up the attachment IMO.

And if you don't have a torque value then it's just "tight" without breaking off the bolt. It's only enough to keep the bolt from backing out, since it is bottomed out on the flange (or in your case that "extra" nut), it shouldn't be critical to the force on the sealing donut. That should be determined by the spring compression - which is set by the bolt bottoming out. In other words the compressive force on the joint isn't determined by the torque on the bolt.

 

[ziggy]

Well yesterday took her driving. Thier is a small exhaust leak. I am burning more fuel than i should. Last time this happend was months ago, when the original front exhasut pipe completely rusted right in half lol. Car sounded like a lawn mower! it rusted where he heat shield half covering the pipe and the part wasnt heat shielded. What i did learn, car burned feul mad fast! yes i drove it a little. I got anew bosal front pipe form autozone, and a new clamp for it too converter from dealer. it worked fine. i must have torqued it right, the 2 spring flange bolts, doorman brand, non oem.
driving now, this is a 2 piece pipe sytem, meaning the front pipe and converter and resonator are one big piece. 2nd piece is the remaining length of pipe. it wouldnt fit right, even sprayed liquid wrench [censored] thing didnt wanna budge in. so after getting new hangers on and hanging it, i used my feet sitting too push it in, it mostly worked, except a tiny barely top section didnt wanna fit in 100%. to an extent, it did. turned car on, and thier was some air pressure coming out of that small imperfection fit. Used aluminum tape and a clamp, the air pressure was gone. driving last night though, the car sounds good idling, and driving. but when going over 30 MPH i hear a muffled exhaust leak. thiers no fumes coming in the car ( when the front pipe rusted, exhasut was coming in car). it appears too me, i just need too tighten the 2 spring bolts some more? its more prominent, the noise, on the passenger side than the driver side.
any ideas?

 

[ziggy]

im thinking of just going out, re loosen, and re tighten the bolts. But again, its over 30 MPH the muffled exhaust noise starts, hardish going up a hill, but on flat surface rides like a dream, and i burn a tad more gas.

 

[MDettling]

Take it to a good muffler shop that will take the time to listen and tell you where the issues are.

My 81 Corolla was the same way. Exhaust moaned mosta the time, more on curves.

Gutting the cat, new doughnut didn't help. It was a character thing..

Still blew cold a/c. Trans was in reverse as soon as selector was there. That was 185k in '02, till 210k in '06.

Aisin made great trannies.

The thing I couldnt get was, 325psi on a compression test for #4, the rest were 150-165.

A little lopey idle but raced a few civics head to head, had to turn the a/c off though.

Best $500 car ever.

3TC's rule. Better with a Weber I think.

Didn't mind 25mpg on a steady diet of MMO to every tank. Rich but sweet exhaust, mmmmm!

I'd pay 2k just to own another RWD 2door 1.8 DX with A/C. A bit less rust preferred though.

 

[ziggy]

thanks for the pic! this is what i have a gut feeling of. When i looked at the springs, from under the car, they were tight, like the springs touched eachother. I had a gut feeling i over tightened them. the aftermarket ones are different from dealer. OEM i unbolted, rusted, had no metal sleeve. It was jsut a bolt with spring and washer incorporated into the top of bolt. the doorman brand, was 3 pieces. bolts, a metal sleeve the bolt goes through, and the springs. As for the gasket, o ordered a bosal washer. Its different from the OEM one. OEM one appeared too be some kinda hard plastic , at least too me, but smooth all around, the bosal doughnut, was silver, but made of metal wires all wound and packed up together.
dealer wants $66 for a new OEM dougnut. I belive the spring bolts, were like $24 jesus is toyota pricey! my local toyota, few years ago, first time i ever sae a pair of windshield wiper blades, for $80. I asked the guy, how much was ONE wiper $39 i stood thier in awe with mouth open in awe

 

[ziggy]

so since im penny pinching. perhaps i should just loosen the spring bolts? next day off mondayif not raining, im gunna get back under car and loosen and carefully at a snails pace, use the doorman spring bolts, and see if i can sense the sleeve making contact with the base of the aftermarket flange.