Installing new brake lines, Do I put anything on the threads? Options

[rjames]

Not sure if I should leave them 'dry' or maybe put some brake grease on the threads? Thinking about all of them: soft lines to the calipers, and soft lines to the hard lines.
Haynes doesn't mention anything about it.

BTW, getting the rear brake hoses off were a giant PITA. But not impossible because I was able to cut the old lines off and get a socket on there.
That being said, I am still trying to figure out how I'll get the new new lines tightened enough. Any ideas? I'm about to hit the 914 search button hard, somebody must have posted a tip or two on this already.

[Mark Henry]

No

The hose should have a 17mm head on it...try a wrench instead of a socket (IMG:style_emoticons/default/smile.gif)

[rjames]

No

The hose should have a 17mm head on it...try a wrench instead of a socket (IMG:style_emoticons/default/smile.gif)

They do, but the rear ones are impossible to get a wrench on without removing some of the heating bits. I was hoping to avoid that. (IMG:style_emoticons/default/dry.gif) I better not have to take off the exchangers...

[ArtechnikA]

Haynes doesn't mention anything about it.

There is nothing to say. You don't need to put anything on the threads.

That being said, I am still trying to figure out how I'll get the new new lines tightened enough.

You 'must' use a flare nut wrench on these fittings.
(17mm? Really? I am remembering 15mm but it has been a while...)

The biggest problem is the concept of 'tightened enough.'

You must understand that brake hard lines DO NOT seal through torque applied to the threads(!).

They seal by compressive deformation of the bubble. The fittings need to be 'just tight.' If you (or a DAPO) really crank down on them you will flatten the bubble and it will not seal against the conical recess in the female portion of the fitting.

If this has already occurred you have few options, but I always address this by replacing the hard line. Available at the FLAPS in just about every size you could need. 10mm EUROPEAN BUBBLE FLARE. (Asian cars also use a 10mm fitting but the ends are different.)

[VaccaRabite]

And if you over torque, chances are good that you will round off the nut trying to crack them loose the next time something needs to be changed. And then you have to replace the entire hard line....

Zach

[rjames]

Haynes doesn't mention anything about it.

There is nothing to say. You don't need to put anything on the threads.

That being said, I am still trying to figure out how I'll get the new new lines tightened enough.

You 'must' use a flare nut wrench on these fittings.
(17mm? Really? I am remembering 15mm but it has been a while...)

The biggest problem is the concept of 'tightened enough.'

You must understand that brake hard lines DO NOT seal through torque applied to the threads(!).

They seal by compressive deformation of the bubble. The fittings need to be 'just tight.' If you (or a DAPO) really crank down on them you will flatten the bubble and it will not seal against the conical recess in the female portion of the fitting.

If this has already occurred you have few options, but I always address this by replacing the hard line. Available at the FLAPS in just about every size you could need. 10mm EUROPEAN BUBBLE FLARE. (Asian cars also use a 10mm fitting but the ends are different.)

Excellent info, thank you. I am hopeful that since their were no leaks prior to me removing the old lines (AFAIK) then the original metal lines are ok.

I knew a flared wrench would be required, but the wrench is too long to get on the nut without having to remove some of the heating bits, which I guess is a must. (IMG:style_emoticons/default/dry.gif) Or maybe I can get one of those 'flex' wrenches on there...

[ArtechnikA]

I knew a flared wrench would be required, but the wrench is too long to get on the nut without having to remove some of the heating bits, which I guess is a must.

I never did but probably we have different heating systems...

But you removed the springy retaining clips, yes?
That may be your problem...

Connect the fittings THEN clip the line back into place. You'll find you can move the lines around a lot to reposition your wrenches.

You'll never get them into place if you've clipped the flex hose in place first...

[rjames]

I knew a flared wrench would be required, but the wrench is too long to get on the nut without having to remove some of the heating bits, which I guess is a must.

I never did but probably we have different heating systems...

But you removed the springy retaining clips, yes?
That may be your problem...

Connect the fittings THEN clip the line back into place. You'll find you can move the lines around a lot to reposition your wrenches.

You'll never get them into place if you've clipped the flex hose in place first...

I have a '75, but have backdated the exhaust/heating stuff.

I got the retaining clips removed (my knuckles are still sore and I am still picking debris out of my eyes). Good idea about connecting the lines first before installing the clips. I haven't connected anything yet but will be jumping in to the fray again tonight.

[PeeGreen 914]

I have the wrenches you need if you don't have it finished already. You can borrow them or I can give you a hand (IMG:style_emoticons/default/aktion035.gif)

[Dave_Darling]

I have heard of people going through the engine tin holes to get a flare nut wrench on the rear brake line fitting.

--DD

[rjames]

I have the wrenches you need if you don't have it finished already. You can borrow them or I can give you a hand (IMG:style_emoticons/default/aktion035.gif)

Jon, you rock. Thank you for the offer!
Let me see if I can get it done myself, and if not I'll take you up on your offer. (IMG:style_emoticons/default/beer.gif)

[PeeGreen 914]

I have the wrenches you need if you don't have it finished already. You can borrow them or I can give you a hand (IMG:style_emoticons/default/aktion035.gif)

Jon, you rock. Thank you for the offer!
Let me see if I can get it done myself, and if not I'll take you up on your offer. (IMG:style_emoticons/default/beer.gif)

cool (IMG:style_emoticons/default/smile.gif)

[rjames]

Finally got the rear lines back on. I was able to go into contortionist mode and get it done without removing any heating parts or engine tin. I'm not moving very fast since this is my first time replacing the lines, brakes and rotors, but I've finished with the rears. Moving to the fronts tonight. (Notice that there were no pistion positioning clips installed in the front calipers)

Out with the old...


In with the new!


I know it's been said over and over again but a big thanks to Eric and the fantastic work he does on restoring calipers. They are the nicest thig on my car. Too bad the wheels all but cover them up! (pay no attention to the KYBs, they are next on the list to get replaced...)