MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - &^%$!!!! Cat stud sheared... despite the use of cat saver nuts

Blast blast blast blast.

I decided to replace the exhaust today - a job that should have proven to be straightforward. Done it a few times now!

Soaked every thing in penetrating oil. I really wasn't expecting problems because since the MGW exhaust tests, I've had MS cat saver nuts fitted.

Blast!!!

I went to undo one of the cat-saver nuts, and the stud sheared off. Did I say blast? Blast!

So now I have the two fold problem of having a now u/s cat-saver nut and a cat sans a flange stud. Result: the job has escalated from an easy DIY job to one that I don't have the equipment to sort out. It'll now have to wait until such time as the car is serviced, I suspect.

This is why I love working on cars - even the easiest job nearly always seems to turn into a drama... >:o(
Rob Bell

I have a 'spare' cat if you want to borrow it Rob. Will need to find a spare cat saver nut though.

SF
Scarlet Fever

Would recommend SF option and then push out or drill out the studs from the old catalyst and replace with M10x30 bolts.
Stainless steel bolts, of course.
http://www.mgfcar.de/catalyst/DCP_0994.html
DK

Thanks Andy, I may have to take you up on that kind offer... but what really fills me with dread is the fact that the other side of the cat was never touched - so no 'protection' from the cat saver nuts... gulp!!!
Rob Bell

Oh oh! 8-0

My cat is ready for collection when you are (come and see my shiny new brake calipers...), but make it quick as the Treffen kicks off on the 31st! :-)

SF
Scarlet Fever

:-(((((((

Nooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo.
Hanah Kim

Cheers Andy, I'll pop over as soon as I can. I'll apply yet more WD40 to the remaining nuts - and then maybe we could get this done together? (Two brains better than one?)

Not sure how much longer poor old Hanah can hold out for 'his' exhaust! (I'm as frustrated as you mate!)

Cheers
Rob Bell

Hmm... Just had a thought. I wonder whether the repeated removal and tightening of these nuts during the exhaust tests weakened the studs???

Oh well - worth it in the end ;o)
Rob Bell



Hi Rob, DK´s suggestion is the only alternative
if one wants to either freqvently change between bypass tube and cat OR testing new systems ! By removing all 6 studs the cat easily just slides in place (with gaskets!) and the SS nut and bolts will stay shiny forever ... Giving each nut a blow with a hammer /punch will make the nut go on a bit tight. This will prevent any loosening by vibrations :)

BR, Carl.
Carl Blom

The cat runs extremely hot and this leads to all sorts of corrosion problems in the steel studs. Also stainless steel in never completely "stainless" so it is not surprising that the stud sheared. Copper grease may help in future.
Brian

Guys, thanks. I figured that the stud would need to be drilled out anyway.

Thanks for the bolt dimentions Dieter, much appreciated as usual :o) Not sure how much longer it will be serviceable? It's 6.5 years old with 63k miles under its belt. The outer casing is corroding too. Nice. Not. :o(

Dieter/Carl/Brian - can the existing studs be drifted out or do they need to be drilled? If they can be punched out - should this be done in a machine press or can it be drifted out with a hammer (I'm anxious that the shocks from the hammer blows will damage the catalyst matrix)

Brian - was thinking of copper grease for reassembly - but surely the heat from the exhaust will be too much for it?
Rob Bell

Rob, that's ok.. I definately understand how you feel. I replaced mine with cat saver nuts 2 years ago, but hopefully mine is not in a such bad condition!

Are you planning to do it yourself? Or leave it to a garage to do it for you?

Andy just might be a life saver here!

Anyway best of luck from me, please keep me posted.

Regards,
Hanah
Hanah Kim

The plan is to do as much as possible myself (and take photos) - so hopefully with Andy's help, this should be achievable.

Will need to drop MS a line for another cat-saver kit!!!

If all else fails, I'll ask Techspeed to sort out the damaged catalyst. If too far gone, I might be tempted to replace it with a sports cat... ;o)
Rob Bell

I bought a can when I changed my front discs which mentions 1500C. Presumably the grease goes and leaves the copper particles at this temp
Brian

re "Will need to drop MS a line for another cat-saver kit!!!"

Why, the last lot did not work!

Cheers

Patrick ;-)

Patrick Beet

Try Plus Gas instead of wd, gets through everything.
John

I knew someone was going to say that Patrick! LOL

John, is Plus Gas available from Halfords?

Cheers
Rob Bell

The thot plickens... :-)

Rob wrote:

>> Cheers Andy, I'll pop over as soon as I can. I'll apply yet more WD40 to the remaining nuts - and then maybe we could get this done together? (Two brains better than one?) <<

and

>> Hmm... Just had a thought. I wonder whether the repeated removal and tightening of these nuts during the exhaust tests weakened the studs??? <<


Free this weekend mate? I am available most evenings as well, but i suspect that this job may take a while. As you know i have a small vice and access to drills etc (cheers Dad!) so maybe it is best if you pop up to me. I'll also 'prime' my local garage in case we need access to an asceteline torch!!!!!!

Your theory about the exhaust tests could hold water, certainly the other demonstrator went back with only 5 studs on the catalyst...

SF
SF

Rob, the inner structure of the cat is rather fragile , so try either drilling or someone with a hydraulic press. In fabrication they are pressed into the flange. Probably all this so people wouldn´t be too keen on taking the cat away.... With all original 6 studs in place it is really a lot of fiddling before the cat can be removed !

BR, Carl.
Carl Blom

Andy, I'll drop you a line this evening when I get home.

Carl, thanks for confirming what I thought. I shall avoid using a large lump hammer then, despite the frustration! LOL
Rob Bell

I don't know where you can buy it, I use it at work and it's good stuff. Shouldn't be too hard to find it's pretty popular.
John

Thanks John - I'll look out for it :o)
Rob Bell

SF wrote:

>> As you know I have a small vice

Come on then Andy, don't be shy, tell us all about it... ;-)

Brian
2772MY
Brian

Over eating!!! :-)

SF
Scarlet Fever

Sweet... this weekend..
thanks Andy!

(why am I thanking you? Ask Rob :-D)

Hope it works!!!

If you need a cat.. my cat is sitting in the garage.. I am with a pipe.

(will I need a cat back on with a Trevor Rob?)
Hanah Kim

>>will I need a cat back on with a Trevor Rob?<<

If you value your hearing, then yes... ;o) LOL
Rob Bell

>> Sweet... this weekend..
thanks Andy!

(why am I thanking you? Ask Rob :-D) <<

Yep i know the destination of Rob's TT, who's picking up the bill for the carriage? ;-)

SF
SF

Haha.. Bill of course Dr. Bell...

(oh yeah.. good one)

:-D

(Rob will freak out if he reads this one!)
Hanah Kim

Rob,<>> Hmm... Just had a thought. I wonder whether the repeated removal and tightening of these nuts during the exhaust tests weakened the studs??? <<
Probably not but but this would have had a adverse effect on the stainless as it 'work hardens' especially if dry and then you will have a problem removing them.
For info.
Mike.
mike

Rob
You may well have drilled it out by now but I had this happen on a Rover 400 and went to Kwik FiT in desperation as everyone esle said a new cat would be necessary. They drilled it and charged me 50p for a new bolt. What a bargain.
David
david stonehouse

I think Rob will get it done this weekend. Seems pretty busy now not posting much last few days.

Hanah Kim

This thread was discussed between 18/08/2002 and 23/08/2002

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now