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Brake Line Nut very (very) stuck


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Hello again - after another long pause, its time for my annual postings requesting help.

Thanks to all those who replied in the past, with a specal mention for rcreweread who gave good advice about disassembling the pedal box. It does indeed all come apart, and is now painted and awaits re-assembly and fitment. This leads to .....

The continuing saga of my early TR4.

I need to install new master cylinders, but I could not undo the pipe union nut on the brake master. I had no option but to cut the pipe, alas. Never entirely defeated, I got the old master cylinder on the bench & despite serious heat I could not undo the nut. My current problem is I cant undo its twin either - the union nut at the 4-way junction. These are items 1, 2 & 28 in the diagram. Its hard to get at with the carbs & steering in the way, but I could get a spanner on the junction extender & a brake spanner plus an extension (another spanner, that old trick) on the nut, but no go. Its been doused with penetrating oil.

 

What to do? I suspect my only option is to buy a brake flaring tool, a mini-pipe cutter & a new nut. The sort of thing a garage can do in moments, but I have visions of it not working out. I vaguely toyed with the idea of making a heat shield and trying the heat trick, but disaster lies that way I think.

Suggestion please?

 

Thanks, Adrian + TR4

stuckbrakeline.jpg

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Hi Adrian,

good you drop in to our forum when you need us, always welcome.

Now as I read your post, You had to cut the pipe into the M/C, and the M/C is now off the car?

Your problem now is the same pipe into the junction on the chassis.

Well if its cut you can sacrifice it, and the nut, I would try, (and I see what you say about access,) alternate heat and cold to shock the threads, get a real good grip on the nut, a properly fitting 7/16 ring spanner, try tightening a fraction to crack it, if all fails then a good fitting set of mole grips on the nut while you hold the female part.

Persevere you will get it off, and when you do, be sure to blank teh pipe opening while you sort things, 5/16 bolt hand tight would do, but you do not want any **** in there.

I've also sent you a PM.

John.

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Be very careful with heat !, brake fluid is flammable.  In my experience it is usually the nut seized to the pipe rather than into the brass junction. On my 3a you can get at this part through the inner wing, but may be different on a 4, I don`t know, but as john says, the pipe is scrap now anyway, so cut it off above the nut so you can get a socket or ring spanner on the nut. Hardest thing being stopping the junction block from twisting and destroying the other pipes. If you have an electric paint stripper, these get very hot and have the advantage that it is a dry heat (no naked flame), and with a suitable shield you could warm up the junction block. ( I find a plumbers soldering mat very useful.}.

Brake pipe flaring tools, nuts, and copper or Kunifer pipe are all quite cheap and easily available on ebay, or take the remains of your old pipe to the garage and get them to make one for you, but they may not keep the unf nuts.

Ralph

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My thanks to all of you.

Reading my post I've spotted I didnt make myself clear: My apologies. I did get at the nut several times over a 2 week period, its drenched in penetrating oil. I got a proper brake spanner on the thing and the grip is good & I have another spanner on the brake extension. It too is secure.  I put some serious force on the thing.

Despite your collective excellent advice I'm reuctant to cut the pipe again & use a socket. I do get the reason why, but I'm nervous of getting into a bigger hole should I destroy the 4-way junction block. Currently the nut is very stuck, but at least I have total access to the free pipe at the master end. I think I'll have to go down the new nut, pipe cutter & flaring tool route - I dont have an electric paint stripper.  Good idea though.

 

My last question - whats the size of the nut to fit the brake master? 7/16 UNF 24 (??) tpi?

Again, many thanks -  its much appreciated.  All further suggestions welcomed.

cheers, Adrian + TR4

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I know it might be less-than ideal, but you might consider these plumbing type fittings to join sections of 3/16 brake pipe without the need to flare the ends: 

https://www.ebay.co.uk/itm/224281025948

They are a small version of what you would use on 15mm water pipe... The brake pipe locates inside and the ferrule seals the joint.

I never saw this done in UK, but it's very common in Asia.

This way you only need to replace a short length of pipe at the m/cyl.

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I have never seen that sort of fitting used on brake pipes. Totally different type of seal to the "flared end of pipe" usually used.

Would it REALLY take the pressure used in braking systems? (I know the advert says it is for use in brake systems, but…)

 

Charlie.

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It is basically a small compression fitting.

I can;t see any reason why it shouldn't work.   Compression fittings are used in industry with very high pressures.

 

However, getting back to the original issue.  Can all the other pipe connection be undone??

If so, undo them and replace the 4 way junction with a new one and fit a new ready made pipe to the M/C.

 

 

Roger

Edited by RogerH
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If the other pipes come off the junction, undo the other pipes. Cut the offending pipe off as near to the end as you can and make a new flare. They are easy to do with a hand held tool such as this inexpensive one

There may be enough length on the existing pipe, if not you can knock up a new one or get a local garage to knock you one up. A roll of Kunifer (copper alloy) pipe and pipe ends is a useful thing to have if you ever need to replace another pipe.

Once the junction is off you can sometimes use a vice and undo the pipe but the 4 way unions are inexpensive.

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15 hours ago, ctc77965o said:

I know it might be less-than ideal, but you might consider these plumbing type fittings to join sections of 3/16 brake pipe without the need to flare the ends: 

https://www.ebay.co.uk/itm/224281025948

They are a small version of what you would use on 15mm water pipe... The brake pipe locates inside and the ferrule seals the joint.

I never saw this done in UK, but it's very common in Asia.

This way you only need to replace a short length of pipe at the m/cyl.

Aren't they illegal in some countries?

Pete

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Going over this again, and whilst the M/C etc is being worked,

Sorry, this job needs done properly,

Plumbers pipe joints are not the way forward here, it needs a new pipe made and fitted properly,

and the four way connector also needs addressing, leaving it alone because its tight isn't the way to refurb the brakes.

Go back to it Adrian, get this pipe off, and then let us know what other than said pipe you need, we'll help sort.

John.

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Ok, many thanks.

Lets close this down for now. You comments are much appreciated, and interesting suggestion for pipe-joiners by ctc77965o

I plan to try & flare the free end of the pipe (ie: the MC end). If that fails I'll resort to - well I dont really know as I'm back at the beginning.  I think I'll then follow your collective wisdom of cutting the pipe at the 4-way junction end & applying a socket. I'll remove the carbs & the steering column for more access if needs be. Andy Moltu suggested undoing the other connections on the 4-way junction if possible, but they are firmly stuck too. 

regards, Adrian

 

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+1 For Andy's suggested tool, these are very good and work well with the Kunifer tubing, get a roll of said tubing, chop off all 4 tubes at the 4 way union and transfer it to the bench where you can safely apply some directed heat and maybe recover the the union, or get a new one, then, with the tool, make up new pipes maybe with new fittings, these are quite cheap, and you can carry on round the car replacing all the pipework for a relatively small outlay.

Cheers Rob    

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Hello

Success!  Channelling all those old episodes of Wheeler Dealers I used The Force and just - just - managed to crack the nut. I think the penetrating fluid helped, plus I swapped the spanner positions such that the bracing spanner was set against the the exhaust manifold and I could get both hands (or at least some combination of fingers) on the brake spanner and it microscopically yielded & then gave in. On the absolute upper limits of what effort I could apply. Whew. 

My thanks to all posters & a special mention to John Morrisons for the PMs.  

Parts en-route from Revingtons ....

regards, Adrian + TR4

 

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