removing stock cat with rust-welded bolts... ideas?!

[S3TH]

Hi guys, just in the process of removing my stock cat to replace with another at some point...

I just jacked up my 7 undid the bolts at the back tight but managed, moved towards the front of the car to undo those 2, they\'re damn near impossible! I\'ve tried everything, are these bolts supposed to come out?!

i was using a ratchet, no worky... went to halfords and bought a solid stainless steel one piece spanner in the right size... no worky...
i even fit the spanner over the nut and used a trolley jack to push spanner upwards in hope that it would loosen the nut, instead the whole exhuast was twisting around the damn nut...

any advise? is there a liquid that i could spray/brush on to hopefully loosen the nut up?

Thanks buddies. Seth.

[rx7veilside]

use wd40 overnight or use blow torch(carefully) or dremmel them off

[shaunwil]

Try undoing it on the side of the downpipe. Not sure if there are studs in the cat.

Looking at the parts manual the nut is on the downpipe side.

Shaun

[Timmy]

I recommend a proper penetraiting fluid over wd40.

[S3TH]

Have got a blow torch, how would you suggest i go about using it? lol
Just heat it up a bit then go smashing at the spanner again?
anyone got a link to penetraiting fluid? pref from the likes of halfords etc. which i can just go down and buy tomm morning!
it\'s quite a tight spot to dremmell!
Not sure what you mean by the nut on the downpipe side?

[Timmy]

should be able to get some from halfords i think mine came from there. was made by 3in1. wd40 will do if you can\'t get hold of it easy just may take longer.

[SiH]

Try penetrating fluid for a few days (PlusGas is good), then if that doesn\'t work, heat, and if THAT doesn\'t work, don some goggles, heat it up, and spray it with some pipe freeze spray. The thermal shock will make any corrosion run for cover. And any exposed body parts as well

[batman]

om my cat there were studs but all broke or so rusty no amount of wd40 was going to undo them so took it to my local tyre and exhaust center and two mins with the oxy torch had them melted off and new bolts done up in the de cat very quick

[RobbieRX-7]

Might be worth taking to your local exhaust shop. They should do it for a drink or 2 if they are friendly enough. From memory the cat has studs sticking out on both ends. Use some plus gas overnight

[leon]

Robbie is right the studs are on the cat, or at least they were on mine as we had to get 4 bolts after!, one of the studs on the rear had to be persuaded with an angle grinder :wave

[grinder]

i had the same prob with the FC

jsut couldnt shift them - took it to the local garage who heated them up and "broke" the nuts - so that i could remove them fully at home

got home and still struggled - where they had heated them - the nut came off taking all the threads with it

so i pulled the entire exhaust off , and then attacked it with drills , angle grinders etc..

once i got it all off - it went back with nuts and bolts - that way i can get them off in the future , or just a grinder and cut the nuts off - and you can then push the bolts out

Stu

[David Nock (RIP)]

If you can get at it, drill down the side of the nuts with a 1/16th drill or similar size,parallel to the threads, this breaks the grip of the nut when you spanner it again. If you can \'cut\' it open with the drill thats even better.

[S3TH]

Thanks buddies, I got the ****ers off ... was a combination of ample penetraiting fluid, hammer + flathead, a spanner and a jack, jacking up the spanner!! lol!!
ohhh today has been so long... the cats been changed... turned the car on to check, i completely forgot my alarm (or perhaps an rx7 feature?) autolocks the door once you turn the engine on!! i closed the door and examined the exhuast... when i realised what i had just done!!
took me over 2hours to break into my own damn car, the engine was running & died after the petrol ran out after about an hour!! arghh... my knuckles, fingers, limbs etc. are finished!! :flamed:rollin