I broke a hard brake line. Now what?

[Z-Luke]

I was putting in my new eibach springs and tokico blues and I broke the hard brake line at the top of the rear wheel well. To even get the threads to come out it required an oxy acetylene torch to heat to red hot hod, smoking and boiling brake fluid before it would come loose. When it cooled off it froze together again with rust, and broke the hard line when moving out of the rubber hose threads.

I can't disconnect the other end without breaking it. The oxy torch couldn't even loosen it, and the gas lines are so close to the valve at the rear that is not safe to torch.

Every single bolt on my car required an oxy torching to red hot before it would budge. The ones that I tried with just penetrating oil and a propane torch all broke.

So what now? I'd consider replacing all the brake lines, front to rear, but I need to get the car out of the shop tomorrow.

Edited April 26, 2010 by Z-Luke

[jmortensen]

You could hit the parts store, buy a hard line that is about the same length and bend it by hand. You could also buy a flaring tool, a 10 x 1mm double flare end and a tubing cutter and cut the fitting off, flare the end and be on your way. If you haven't flared brake lines before it's kind of a bitch to do, so my recommendation would be to buy a line and bend it. I had a friend do this and the lines were too long so he put a loop in. Not the prettiest, but it worked.

[Z-Luke]

I can't disconnect the other end of the line, I can already tell it's just going to break off, with the threads forever stick inside the proportioning valve under the rear of the car.

The only thing I could think of was drilling out the fitting, bending the old broken off tube into the fitting, and glueing it shut with JB weld. So right now the JB weld is drying.

[ZCurves]

It would seem to me that having to heat ALL of the bolts you encounter with an Oxy torch is pretty extreme. I am thinking that you need to let some of the bolts soak with some WD-40 for a while. There are several methods to freeing up bolts that have seized from age and rust.

There is the Penetrating Oil Soak, There is the Shock Method (not with electricity) -this involves striking the bolt with a drift (softer metal rod, i.e. Brass..) or Punch. There is the Freeze Method - whereby you Heat the Bolt/Nut slightly and then you apply Ice or other coolant to the Fastener to be removed. This works by expanding the Nut and contracting the bolt. A 'coolant' you could use is the compressed gas 'Dusters' from an Office Supply store. Heat as mentioned above and then spray the bolt with the Duster turned up-side-down. Finally, there is the Oxy-Actl, which you have been using - this is not so great because you are heating (and expanding both the Nut and Bolt).

When working with Brake Lines, you MUST have a set of Flared Wrenches to get these loose without destroying the fitting - BUT that sometimes does not even help. Working on brake lines sucks and sometimes you have to mangle you way out to a fitting that will break loose and then replace the crap that wouldn't budge.

I would suggest the Soak then the Shock methods with a good Flare Wrench. Shock by using a Flare Wrench that is one size too small. Snug it against the fitting and tap -you don't have to go ape, just tap. Now try to loosen with the correct Flare (I am thinking it is a 10mm).

Still no bueno? Then what I have done is get a good pair of Channel Locks and then grip the Sheot out of the fitting and then jerk real quick to loosen. This has usually been as medieval as I have had to go on a Z. I hope that some of my tips will help you out. Please let me know.

[Inf]

Wow, JB weld being an integral part of the brake system? I wouldn't feel comfortable doing that personally. The brakes are one part of my car that MacGyver tactics have absolutely NO PLACE.

Assuming it works for you to get it out of the shop, you should definitely make an effort to fix that the right way ASAP.

What penetrating oil were you using, just out of curiosity?

[Z-Luke]

Believe me curves, everything on this car has been extreme. I soaked all the bolts for 12 hours with 7 different kinds of penetrating oil/foam/lube. Each bolt was first attacked with the shock method of taking a center punch and whacking a hammer on. Believe me, everything without being heated to red hot (and sometimes melted a bit by accident) just snapped off. Luckily, no permanent damage had been done until the brake line just twisted in two with almost no effort.

The prop. valve under the rear of the car is extremely difficult to access and did not respond to heating. I think the only permanent solution is to buy a new prop valve and go right back to the engine compartment with new lines. Flaring the line and jamming it into a another line sounds like the only good temp solution. I'm wondering if I can connect two hard lines using some kind of flex line with hose clamps. I'm also wondering if brake lines respond to solder at all.

[oldhemi]

Z-luke, if it makes you feel any better, my car has had "the broken bolt blues" since new! I think it got much worse from driving it through a couple of Connecticut winters.

I need to start on my brakes system soon and I am putting it off until I can "handle" all of the broken bolts, nuts, fittings that are sure to happen.

NO amount of your favorite witches brew will release these fasteners.

Solder is not a good idea when new hard lines are not that expensive. Barrel type connectors are also available and acceptable to join two lines together if you can not find the right length and 2 other sizes will come close.

Double flares are a PITA and require some skill.

Edited April 26, 2010 by oldhemi

[Z-Luke]

hmmm barrel connectors, I will have to look into this. It's amazing how small of a job the actual suspension work is compared to the bullshat around it. I bounced the struts out, compressed the springs, unthreaded the top nut, oxy-torched and pipe wrenched the insert lock and had the new components in within a fairly short time frame. About ten times the amount of time was spent struggling with the things needed to be taken off prior.

Oh, and in case you were wondering, the old shock absorbers were COMPLETELY DISINTEGRATED. They came out of the strut tube in pieces. First the top retainer fell out, then some rubber gaskets, then the shiny tube that runs through the entire shock body, then about a liter of shock oil, then the canister all that was supposed to be contained in. No wonder they didn't absorb any shock.

Edited April 26, 2010 by Z-Luke

[jmortensen]

Oh, and in case you were wondering, the old shock absorbers were COMPLETELY DISINTEGRATED. They came out of the strut tube in pieces. First the top retainer fell out, then some rubber gaskets, then the shiny tube that runs through the entire shock body, then about a liter of shock oil, then the canister all that was supposed to be contained in. No wonder they didn't absorb any shock.

Those were just original shocks, not disintegrated. They have a (leather?) piston seal which rides on the inside of the tube and that's about it. You can actually make those work pretty good supposedly by running different weights of oil. I haven't played with them other than just removing and installing a strut cartridge replacement, but I've read where others have.

Saskatchewan explains the rust issues... I think the stock prop valve is brass (been a while, but my vague memory of messing with the stock prop valve in my 70 maybe 7 or 8 years ago says so) and if that's the case I'm guessing that might be the easier solution.

[Z-Luke]

Okay, so the good new is the Eibach/blues ride AWESOME. Compliant, but noticably firm. They take big impacts with grace and protect your chassis and spine over railroad tracks, but their limit is curbs. On large drops the soft travel section gets eaten and the hard section shows it's fortitude.

Surprisingly, the rear ride height seems to have not changed, perhaps it sits slightly higher.

But what a difference the rear made alone...I glide over railroad tracks and deep ruts, and enjoy a supple ride on the street with the expense of some firm hits on uneven heaves and perpendicular breaks.

The bad news? The rear brake system doesn't work at all at the moment. It holds fluid with my JB weld job, and I put a bolt in where I can't get a bleeder screw to thread far enough, but I'm only working off front brakes at the moment - which isn't that big of a difference since the rear never worked before either, suspecting air in the lines previous.

So now I've got a conundrum. Do I flare and compression-fit the broken line, or replace the entire rear brake system right from the main valve? Since the rear brakes never worked, there is a possibility that the prop valve or other hydraulic function will never work. Is it financially plausible to replace all the lines?

[Walter Moore]

Okay, so the good new is the Eibach/blues ride AWESOME. ...The bad news? The rear brake system doesn't work at all at the moment. ...So now I've got a conundrum. Do I flare and compression-fit the broken line, or replace the entire rear brake system right from the main valve? Since the rear brakes never worked, there is a possibility that the prop valve or other hydraulic function will never work. Is it financially plausible to replace all the lines?

The rear proportioning valve is brass. The fitting will not be rusted in place, but from memory it seems like you just about have to take the differential down to get to it. The really BAD NEWS is that in my experience when you remove the old fitting it will auger out the prop. valve and a new line will not seal. If that happens, PM me because somewhere around here I have one or two spares. (Unless someone "straightened up" too much...) No guarantee that they won't leak as well, but I can start digging.

The prop valve is NLA. The standard recommendation seems to be to replace it with an after-market adjustable unit.

I personally had a horrible time getting the rear brakes to work. I ended up bending my own lines all the way from the master cylinder back to the rear wheels. I was only able to do that because I removed the entire drive line.

Even then I had to replace every single bit of the rear braking system with new parts, most of them OEM, before I got the rear brakes to work properly. I can see why Nissan switched to disk brakes in the early 80's because in my opinion their drum brakes were iffy at best.

(We had a mid 70's Datsun B210 and that thing wouldn't stop for love or money, no matter how often the brakes were "fixed".)

As far as the cost, the lines can be bought either pre-bent, or you can just go to a parts store, buy lots of 3/16" straight lines and start bending to suit. By the time you get done you will be a passable "bender" (Think Futurama.)

New lines are hard to flare, but the old lines will be impossible. The steel gets brittle and the ends will split every time you try. Good luck. This is a big job, but it can be done.

[Maples71240Z]

Is that valve in the back a residual pressure check valve insted of a proportioning valve? they do serve different functions.

A google search for "residual pressure check valve datsun" seems to support that it is a residual pressure check valve not a proportioning valve.

Either case the cost to run new lines is not all that much $$$ just takes a bunch of time.

On my 71 the valve in the back was plugged solid and the one for the brake warning light under the M/C was also. I was able to tear them apart and clean them out. I did replace some of the hard lines but it was a PITA! I did find that it's a bunch easier to make some nice bends if I wore some good gloves.

Dave