Datsun Roadster Forum-311s.org

Guys:

With me being such a pain in the a** , you might be wondering when are you finally going to see this car of mine rolling with the rest.....I can assure you that the day is closer than my postings make it seem. I am going through the inevitable little things that pop up here and there after everything is put to work as a unit.

I am happy to inform to those of you who followed my month-long battle with the electrical gremlins (and specially those of you who walked me through the process of finding the source of trouble), that my electrical system is working the way it's supposed to work now....it seems like indeed I needed a new volt. regulator.

But my next issue is not that complicated.....There is a persistent leak on the following brake (metal) line:

......if go on to the passanger's side of the car, just about the point where the pssanger door ends and the rear fender begins, down under the car there is a spot on the frame where you clip and connect the line with the "spring" covering it (coming from the front of the car) and the line going to the rear brakes. This connection keeps leaking to the point of eventually emptying the reservoir for the rear brakes. I even removed both lines, inspected them meticulously, and found no bending, worn out metal, or crack on either end, but they still leak! AM I missing something here?

Jorge

Could be cross-threaded - very easy to do and it will never make a good seal.

Hook everything back up, fill it up and have someone pump the brake pedal. You should be able to see where the leak is.

Then you'll have to bend up a new line or replace the fittings and reflare the original.

If you get a can of brake cleaner, spray down the whole area and let it dry or blow it dry with air. It evaporates quickly. This way you start with a dry line. Then do what Leigh said, pump it up and look. If it's a pinhole in the line, it will just be a wet spot that spreads out. Most likley spots for a rust through or rub through of the metal line are where the clip touches the line or under the spiral spring around the line. I have also seen the flared part of the tube crack where the fittings seal. If you are replacing anything, make sure you have the right flaring tool, brakes usually require a double flare which is essential to seal correctly. Sometimes it's easier to buy a length of pre made tubing with the proper fittings and just rerun it. If you get the old one out, you can get the new one 90% pre bent off the car and fit it in place.

I assume you are talking about a steel brake line with a spiral spring around it, a clip holding it to the frame, a male fitting going into a female to female coupling, and another male fitting on a steel line going to the rear brakes.
I think I have some spare couplings if that's the problem.

Leigh, thanks for the reply....i didn't think about that possibility.....and makes perfect sense , so I'll go back and check that tomorrow then.....

And Dave, thanks to you also Bro...u always contribute very helpful stuff when I have issues. I actually was assuming that the leak was at the actual connection, and didn't bother to consider the possibilities you added...I have some of that brake cleaner, so I will do that before anything else to see if i need a whole line, or the ends redone. By the way, YES, the line u are refering to is the one at issue, and at the exact location u describe.....and if the couplings are the problem, I would appreciate (and pay whatever u find appropriate!) the spares if you happen to find some orphan ones around....I'll keep you posted.

Thanks again guys!

Jorge

You might want to save the time of diagnosing and just replace everything. These parts are cheap and readily available. I think I might have a spare stock connector or you can replace with an aftermarket coupling...Won't run you anything more than $20 to replace it all! TR

Further to Dave's suggestions for troubleshooting hydraulic lines.

Start with clean lines and connectors by washing with Isopropyl Alcohol (methyl hydrate). Be careful, it is flammable!

You can make a very inexpensive leak detecting tool by making a thin paste out of fine chalk powder and Isopropyl. Chalk powder can be found at most hobby shops and Isopropyl can be found at most big box hardware stores.

Apply the paste solution with a small paint brush to the lines, connections, cylinders, etc. I.e. what ever requires testing. The alcohol will evaporate in a minute leaving a chalk film on the suspect parts. With the correct fluid level, apply normal or above normal pressure. Any leak of fluid will appear as a stain. This technique works well even in detecting hard to locate porosity and hairline cracks in slave and wheel cylinders. It works well in other fluid seal applications too.

Hope this helps.

Jorge

If it is at the connections that you are describing I think the problem my be a follows. The two coonections are both female flares. When I took these same connections off my car there was a small brass compression fitting sitting between the two female ends. Hope this helps.

Vince

Vince:

THANKS!!!! It is funny that you mentioned this because about a year ago, when I was taking everything off the frame before sanding/recoating it, I found on the floor of my garage something exactly like what you describe...and it was on the floor near the area where these lines connect. Originally I thought it was part of the gasoline lines (which connect near that same area), but it didin't fit.....then I put it in a zip-lock and forgot about it until now! As soon as I get home I will find the bin where I put this thing, and check if it is indeed what I'm missing there.....I'll keep you posted.

Jorge

Heres a dumb question, but did you make sure they were tight? I had a leak and it was due to it no being very tight. Just wonderning .

Joaquin

Joaquin:

As a teacher that I am, I have to say this: there's no such thing as stupid or dumb questions...just stupid answers! But besides that point, you are not too far from the truth though....the leak was worse a couple of months ago, and a quick check and re-tightening cut the amount of fliud leaking in half! But the persistent leak now is with the thing tightened .......thanks for the input Bro....because many times before I have overlooked the simpler solutions and wasted a lot of valuable time and resources because of it!

Jorge

The cheap and easy leak detector is old fashioned aerosol antiperspirant/deodorant, the kind that dries white and leaves those annoying marks when you try to wear a black T shirt. Or spray on christmas snow. Used both for home plumbing leaks.

Really sounds like that compression thing missing is a likley cause.

Ok, here we go again..... I put in the little brass compression fitting, bled the rear reservoir on the master cylinder, and pumped the pedal....no leak comming from the connector now.....but after a few pumps, there is a fluid fountain gushing out from the master cyl.! I went and unscrewed the bleeding screw from the passanger's rear cylinder, and air came out with quite pressure, then clear liquid. So I bled the rear cylindrs, pumped again, and the gushing off the master continues!

So now I have no leaks, but a new symptom shows up. WHat can be causing this? My master cylinder is new, and other than having lost all the fluid from the rear brakes reservoir and remain like that for several weeks, it worked fine when the line was leaking......

jORGE

You may need to bleed the master cylinder. It may have trapped an air bubble that is causing it not to draw oil properly. Give that a try and let us know...

TR:

When something like this happens where the master cylinder loses the flu on only one of the two reservoirs (in my case the one supplying the rear brakes) am I supposed to bleed BOTH of them still (the two reservoirs)? The fluid level on the reservoir supplying the front brakes doesn't seem to ahve changed at all even when the other one was empty due to the leak.

I bled the reservoir that became empty, and did it until no more bubbles were coming out...so u think there might still be air trapped in the master?

I will check it and re-do it in the morning anyways, and I will let you know what happens


jorge

In a dual master the front brakes (reservior to the reae of the master cyl) provides fluid between the primary and secondary pistons to actuate the rear brakes. On my 69, the piston for the rear brakes was stuck in the bore in the forward (applied )position. When the brakes were pressed, front brakes worked, pedal was low, and fluid squirted up in the reservior for the rear brakes and the bleeder on the master for the rear brakes would only dribble fluid. I think Joquain had the same symptoms I did. I freed up the piston, bled the cylinder, and problem was solved.

A small squirt of fluid, 1/2 inch high or so is normal in the reservior.
Hope that helps