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gaz-mondey

Cat Removal Need Help

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Hi, I am trying to decat my mk3 tdci but having trouble, I have located all the bolts and SOAKED them in wd40 but they will not budge I even had my torque wrench on it and still nothing just rounding them off.

Anyone with some ideas to helo me please (am using snap-on tools so there not the problem as some people say they cheap ones are s***)

Sent from my GT-I9300 using Ford OC mobile app

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are you using 6 or 12 point sockets? try a 6, i always find they dont slip as much (i said i find - i dont want some physics person coming stating why it makes no difference!) hahaa

have you got an impact gun or anything like that?

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are you using 6 or 12 point sockets? try a 6, i always find they dont slip as much (i said i find - i dont want some physics person coming stating why it makes no difference!) hahaa

have you got an impact gun or anything like that?

Your absolutely right, a 6 point hex can apply much more torque without rounding the corners off. I never use 12 point sockets unless it's for a 12 point bi hex nut or bolt. Absolutely useless for rusted or seized bolts.

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blow lamp will work, just get it really hot before attempting to undo, may need reheating a few times as the threads corrode so they might start to undo then sieze again.

the heat inductors are superb for this type of job, as they only heat the bolt and do so in seconds, so no danger of distorting any metal surrounding it...well worth hiring/borrowing if you can...unless you want to fork out £500 give or take, to buy one ;)

would agree re the 6pt sockets...but if that starts slipping then try a imperiel socket of similar size, ideally looking for something that is a tight fit, even better if you have to tap it home with a hammer.

wouldnt use a power gun, too easy to snap the head off unless that bolt is freed off, just creates more work in the end...use ratchets/spanners so you can 'feel' any problem, reheat if necessary..before it shears

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by the way, are you talking about removing the manifold nuts, or the cat to centre section bolts...

reason i ask, if your removing the cat and dont need the studs your trying to remove, then just cut them off.

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ok, so the bolts your struggling with, are they nut and bolts..in which case just cut them off and replace...if they are studs/nuts, depending if the studs go through the joint rather than being threaded in exhaust, easier if you can get them undone, but worse case, cut them, drill the studs out and replace with nut/bolts..

dont know the cat set up off the top of my head, but if your talking about the manifold/downpipe studs then pays to spend extra time getting them undone, as if they shear, can be a right pain getting them drilled out and rethreaded or replaced..

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ok, so the bolts your struggling with, are they nut and bolts..in which case just cut them off and replace...if they are studs/nuts, depending if the studs go through the joint rather than being threaded in exhaust, easier if you can get them undone, but worse case, cut them, drill the studs out and replace with nut/bolts..

dont know the cat set up off the top of my head, but if your talking about the manifold/downpipe studs then pays to spend extra time getting them undone, as if they shear, can be a right pain getting them drilled out and rethreaded or replaced..

I do, (Mk3 Mondeo expert) the cat has captive nuts, (nuts fixed/ welded onto the cat itself) the cat sits vertically and is held on with 4 bolts that go through a plate that is part of the exhaust manifold from the top - there is also a bracket underneath that also has 2 captive nuts+ bolts - the only other fixings are 2 bolts holding the downpipe flange on, the car will need to be raised up (little ramps or axle stands may be enough) to drop the cat/ exhaust down - the threads on the bolts as they come out of the captive nuts underneath are the bits you should be appliing the wd-40

Technically, a decat works better than a gutted cat, as the gasses don't need to expand with a decat + a S/H cat is worth more than a decat, (you could even make a profit) most decats have boltholes that you just use new nuts/ bolts on, that means if you are fitting a deacat you could shear, grind or drill your old bolts off, no problem you don't need to touch the exhaust manifold nuts/ studs to get the decat off a mk3 diesel

A little bird tells me that you can MOT a diesel car no problem (especially a mk3 as it has covers, top and bottom) with a decat even now - Me, i could not possibly comment on that one :)

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PS - the cat is not the most restrictive part of the exhaust system - the back-box is, + if its performance/ economy you are after, a premium tuning box or remap would make a much bigger difference, anyway - if the car is smoking it is probably a burst boost hose (needs replaced) or the EGR valve - (needs a solid blanking plate fitted)

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Im not sure will check tomorrow I think tge 12 point would you recommend 6 then?

definatly yes. I have the set of halfords professional impact sockets - 6 point and great quality. I was changing an exhaust on an 05 punto the other month and slipped the sockrt , I thought it was already too late, but the 6 point socket got it straight off!

Sent from my Nexus 7 using Ford OC mobile app

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