As you will see from the Photo, the previous owner of my Car had a repair done on the Exhaust which looks a total 'Bodge Up!'

Ideally I would like to fit a new down pipe but it looks like a pig of a job that will take a long time, as I'm pretty sure the nuts will be rusted solid and so I am going to leave that till after the Summer.

It looks as though this join is now about to fall to pieces, so could anyone advise me of the best way to repair it, as I would like to do this myself.

Updated: with more photos


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How long are you willing to tolerate the car being "down"?

I think to do this properly the down pipe has to come off, and yes, the nuts will be rusted, but nothing that PB Blaster or some other penetrating solvent won't help you break free. The nuts to the exhaust manifold/down-pipe union are a PITA to get at, but it can be done with a long enough extension and patience. Trust me, having taken all the exhaust manifolds off my V12, I can tell you that only having to take the down-pipe off is a piece of cake.

Get it off, have an appropriate service shop weld the break, and put it back on. I'm not sure how to suggest a quick patch to whatever caused the PO to do this "repair" in the way that they did.

Do you have any idea what the issue was that the PO was trying to patch in this way?

Thanks,

John
1987 XJ-S V12
64,000 miles

 

What a mess. The downpipe must be replaced OB, nothing else will be a decent repair. If you have a lift, things are much easier.

If you want it to last the summer (brakes Ok now?) buy some exhaust bandage and wrap it up in a dreadful second bodge-on-bodge and hope for the best.

When the time comes, it might go easily and it might not. Worst case is that the manifold flange breaks off and you have to replace the manifold as well. There is, however a very good chance it will go OK. I suggest this procedure:

Get a jam jar and put in 50% acetone and 50% ATF. Shake it up and using a 1" paintbrush paint the mixture all over the downpipe/manifold flange nuts and studs protruding downwards from the nuts. repeat daily for about a week. Then get the long extensions ready and undo from below when the car is on the lift. The nuts (two per flange, diagonally) should come off reasonably easily. If a stud snaps, you can use the other two on the opposite diagonal when reinstalling.

Install new downpipe using factory crushable sealing washers, which are relatively expensive but much better than the aftermarket alternatives. Good idea to put on the full monte stainless (including downpipes) from Bell or similar, all things consdered!

Greg

 

I would get a downpipe, Ebay or any of the xjs suppliers, or call your local exhaust centre ie Kwickfit. Take it to them 10mins done. saves a lot of frustration and anger......Simples

 

I would love to get that down pipe off! There are only 4 seductively easy looking nuts to undo but I've been there before on other cars and have a pretty good (or should that be bad feeling) that the nuts will be rusted solid

If only there was something that could split the nuts without damaging the threads.

 

Hi Greg

I had some brake pipes made up by a 'so called professional firm' who did them while I watched, using the very same Sykes Pickavant Kit that you bought.

But the problem was the guy who was doing the job, wasn't in the mood to listen when I suggested he put some oil on the die to help form the profile.

I've made enough 'wrong ones' to know what I'm talking about!
The end result was the profile was all over the place, so I had to reject them.

On the second attempt, he had too much pipe poking out of the holder, so it didn't form the nice smooth shape that you needed to make the seal.

At which point I abandoned Ship and walked out!

Up until then, I thought you were 'Bonkers' spending over £100 on that Brake Pipe Making Tool.

But then I saw the light!

Because you can waste even more than that by paying so called 'experts' to '**** the whole thing up' or wind up with a house full of failed attempts at making them yourself, by using an inferior piece of kit.

But 20ft of Copper tubing later! I made a couple of good ones and put them on, so I've just got to hope that I can bleed the Air Out to-day.

I totally agree that I need a new down pipe but my ramp has the other car on it, which I can't get off at the moment and if I break the manifold, then I think I will 'top myself!'

I was thinking of trying to grind off the nuts with a 'dremmel' or maybe drill out the studs.

As always on cars like this access is the first problem that you have to overcome.

(I will keep you updated on the braking situation either way)

 

Hi Malc

It was one of those Exhaust Centres, that did this horrendous 'bodge up' in the first place, so I would rather do it myself, as soon as I figure out how to undo the down pipe nuts, which are almost certainly rusted solid.

I will try what Greg suggested.

Greg is right!

I need to go the full monty and put on a Stainless Steel System if only I could get access to my hydraulic car ramp, which is presently occupied with another XJS that is awaiting a Radiator Transplant.

I can't even tow it off, as there are trees in the way!

Where did I put that Chainsaw!

 

OB

It was, of course, a purchase the cost of which I did not feel the need to fully vouchsafe to the Finance Director! But the sheer joy of proper tools and the feeling of being able to sort any future brake pipe problems is wonderful, as I am sure you will agree.

The nuts on the downpipe/manifold studs should be brass ones. If so, they should come undone after the acetone/ATF treatment. Basically, there is no point in all the grinding of nuts, drilling of studs etc etc until after the downpipe is off, if it is needed. Mine came off after 12 years since fitting no bother at all, so I think you should, for once, be positive!

Pity about the lift being out of action, why not try the treatment, buy the downpipe and new nuts and special crushable sealing rings, then take the car to a decent garage and get them to go at it. In my case, because it is easier to reinstall the engine without the downpipes, I fitted them afterwards and did them up from underneath. It was actually very easy with the long extensions, and access quite decent (for an XJS).






Greg

 

Hi Greg

Those are amazing photo's, so I have put some better ones up to illustrate the bodge up that much more!

I'm losing all faith in Professionals, as they seem to know 'Jack All!'

But there is a problem! As some 'Clown' has used Steel Nuts, in order to join the down pipe to the manifold!

And they are rusted absolutely 'Solid!' and I also have a very long socket extension but this just keeps on flexing under the strain.

So I really think I am going to need my ramp!

What are your thoughts on using a Compressed Air Impact Wrench?

Which is on my shopping list along with a Sykes Brake Pipe Maker!

The DIY one I bought years ago cost nearly £40! which does seem to make the Sykes a bit of a bargain! and I think my fleet is big enough to justify the cost, so will be making lots of use of it.

As for the Brakes, I think the Air is almost out of the System, so I am keeping my fingers crossed as I have now run nearly 4litres of Dot4 right through it and I cannot see any dripping from the connections.

So there will be lots of test drives around the garden before She goes on the road.

 

Sorry OB I don't have anything useful to add, just a question. How did that make it past the MOT?

 

OB

Once you decide to go at it (in the autumn?) keep up the acetone/ATF treatment every day for a week and then try the extensions and a decently long ratchet. If no-go, do another week. I think that an impact wrench will just snap the studs. Once the rust has been penetrated they should turn.

I cannot see how you could easily get in there to cut the nuts, for the life of me; but just maybe infinite patience with a small cutting wheel in a dremel and plenty of spare wheels, and you might be able to make a vertical cut in the nuts to relieve the bind. If you think you can do that, worth a go if the treatment does not work. Worst case, the manifold can come off, but I do not suggest you start this until you have under cover workspace available, so that if it is a manifold off job, you are not rushed.

There are first class Jaguar specialists who never advertise and one looked after mine when I was working in the UK, but this is an expensive professional job if it goes wrong and the manifolds do have to be removed.

Greg

 

Now That's a very good Question!

At least it wasn't leaking, so maybe that was why!

 

Hi Greg

Excuse my ignorance but what is ATF? Its probably so obvious that I'll kick myself when you tell me.

With just the Air Cleaner Cover off and the filter out, I can get a dremel or a die grinder in there and maybe even a hacksaw blade in a pad saw handle and all from under the bonnet!

I used to have a gadget, which I've never used and cannot find, called a nut splitter, which as you probably know is a ring with a case hardened bolt that's formed into a chisel blade.

You are supposed to put the ring over the nut and then screw the bolt in, until it splits the nut.

Have you ever used one? (has anyone else ever used one? Please jump in if you have!)

If it works it might be well worth buying one.

The one thing I don't want to do is to mess up the Manifold, or as you say, that will be expensive to put right.

Clarke CHT246 Nut Splitter Set - Machine Mart

 

That method invites snapping the stud.

Instead, get plenty of penetrant on the joint, let sit, repeat.

Then, using a long steel bar hammer on the end of the stud, or using a suitable pipe, hammer on the nut. The vibration will help break the corrosion.

Finally, fit a deep well six point socket, extension and breaker bar securely. Then, don't use a steady pull, but rather smack or heave on the breaker bar handle. This acts much like an impact.

There is also the trick of tightening an eighth turn to break the corrosion before reversing. Heard of that one, but never resorted to it.

Of course, there is always the tried and true choice of professionals ... the blue wrench

 

Ok Plums I give up!

What the hell is a 'blue wrench!'?

One day someone will invent the perfect tool for this job, if only they had used brass nuts! but I can only dream!

 

"Blue Wrench" = Acetylene torch

A rusty locked up nut often becomes removable after being made good and hot, if it can be done safely. Be careful not to light anything else up though!

 

ATF = Automatic Transmission Fluid. Believe me, the mixture works, shake well before applying. Basically Plums' advice is 100%, and what I am trying to get at. Single hex socket very good advice.

Nutsplitters work, but I am not sure you will get one in there. Danger of bending/breaking stud if all not absolutely square and the nut splitter itself not counter- torqued (think levering the stud as you tighten the splitter).

If the dremel will get in there, then do that, easily the safest way. A vertical cut down the nut will be ideal.

Greg

 

And finally ...

why not just have a proper bodge done?

Remove the patch, save the flange and have some piping welded in using the salvaged flange.

If you take the dremel option, don't cut all the way through ... just most of the way and then finish with the socket .. six point of course. The dremel slit will relieve the pressure on the threads.

 

Ah Hah!

I should have guessed it would be that! A bit like Gregs 'Watchmaker' method which translates to a 'Blinking great hammer!'

 

related favourite saying:

"the difference between an amateur and a professional is the professional knows exactly how hard to hit it without breaking it"

another favourite technique ...

while applying torque with the breaker bar, strike the union of the breaker bar axially in line with the extension/socket with a hammer to vibrate the threaded joint