Centre section to CAT parts and sizes.

[guest7372]

Hi,

Apologies for starting another topic but I can't reply to older posts that cover the subject.

Having just replaced the rear box about a month ago with new rubber hangers and the proper spring and bolt set with gasket to attach to centre section..... My centre section has now dropped off (sheared) just behind the flange that joins it to the Rear section flange. I don't know how I missed it when I did the rear section! It looked fine to me. I'm wondering if it was generally weak anyway as previous owner had rear and centre joined with paste and bolts (no springs) so no flex.

Anyway, I have the worry of trying to get the centre section off and away from the CAT now with those infamous rusted Stud bolts and nuts.

I see TG and Jocko were discussing it a while back. I intend to attack it with some Irwin Bolt grip and nut removers. I haven't got a torch or a grinder. Nor a garage with spare parts and I don't have a drive. This will be done on the street with car jack and axel stands if its possible. I know it'll probably be a squeeze under there and I won't get the leverage. I'll see how it goes before I give in and take it to a garage.

But, the question is:

What size are the Stud bolts and nuts you used to replace the rusted ones connecting centre to CAT sections and what type of gasket did you use between the two. Is it a conical olive gasket made of wire similar to the one used between rear and centre or is it spherical.

I need to buy these car parts for Eurocarparts if possible as they are the only place near me.

Thanks for your help 

[guest1372]

Sounds like the back joint was stressed before, plus it seems to be the weakest point in these cheap exhausts.

Good luck with it, it might take a while but it should hopefully all come good, although if a garage will do it without changing the CAT you really should take them up on that.

I cut the worst cat flange bolt with a hacksaw blade wrapped in cloth, and removed one with a socket, and one with mole grips if I remember correctly; there's not much room for tools.  Lying on the floor cutting a bolt with about 2" of blade movement and not much pressure takes a long time and will make you reconsider whether this was a good idea.  You do need quite a bit of space to work so jack up in several stages and have the stands as high as you can do safely, maybe front & back on one side.   I probably used M10 bolts and washers from my stock, it's just a plate to plate joint (plus a lot of paste) bolted up tight.
--
TG

[guest7372]

Thanks TG.

I took it to a garage after work and they said it looks like they may be able to remove the bolts as they must have been replaced at some point.

But...... they said the metal is very thin on the CAT (i'm assuming the flange is all rusty), It was one of those garages where they don't like you to come in and have a look yourself so I don't really know what they meant.

Suffice to say, they said they wouldn't attempt the job of removal without supplying me a CAT as well, so it looks like unless I attempt this myself, I'm looking at a CAT, centre section and the labour..... big bucks

I have posted an image Honda sent me for posterity, to help anyone else out.

It looks like there is a gasket numbered 15 that is supposed to go between the CAT and centre section. And the stud bolts are labelled 4 and 28 possibly, from what I can see from the tiny drawing.

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[Jem]

It might be worth trying another garage. One that will let you have a look. I recently had my mid section replaced and I thought it was blowing near the front but it was at the back near the joint with the back box.

I said at the time I was worried it was the cat. The guy said that they have only ever replaced one or two cats on Jazz's.

They are not a common bit to fail. They put a new mid section in no problem.

I took my to a wilco fast fit that I have used for years and trust them.

[Jocko]

I replaced the cat and the centre section, when the centre section failed. Garage found it impossible to split them and save the cat. New cat cost me £85.15, complete with gaskets. I had to return old cat for that price.

[guest1372]

Here's a before & after picture - although you can't see it here, be careful of the O2 sensor and it's wiring nearby.  IIRC the cat flange was flat, so the gasket is to suit whatever centre section is used but I resorted to paste as the old surface was poor.  You might need to adjust the hangers if the centre box sits too close to the sill as it might knock when accelerating on left hand turns.

Only reason I did mine was because the garage wanted to sell me a CAT as well.  The flange on the cat looks terrible but the box itself is fine.  An original cat has a scrap value of about £40, an ECP replacement has a scrap value of zero....  that tells you there must be some difference in quality.
--
TG

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[guest7372]

Thanks for your input guys!

Took it to another garage. They seem confident that they can remove and replace the centre section and save the CAT..... For £126 parts and labour. Seems kind of expensive to me considering I can get the centre section and bits for about £50 off eurocarparts.

But such is life, it's constantly raining and I guess it's just too much of a stress to attempt this myself given my lack of tools. Guess I'll just have to bite the bullet!

[sparky Paul]

The rear joint on cats does seem to rot terribly, but there are ways to save them if they are very nasty. I've built flanges back up with the welder before, or cut them off and welded another flange on, cut from an old exhaust.

Took it to another garage. They seem confident that they can remove and replace the centre section and save the CAT..... For £126 parts and labour. Seems kind of expensive to me considering I can get the centre section and bits for about £50 off eurocarparts.

Bear in mind that £20-odd of that will be VAT, and that garages tend to stick to one motor factor for all their parts. If they are anything like my nearest factor, you can add 20-50% to ECPs prices with the usual discounts.

But such is life, it's constantly raining and I guess it's just too much of a stress to attempt this myself given my lack of tools. Guess I'll just have to bite the bullet!

It's no fun laying under cars at this time of year!