Brake Line Question

I just notice this on my front brake line. (Circled)

is this brake line a metal line covered in rubber or is this actually a rubber hose?

i haven’t seen any leaks at all

Thanks for your help. It’s on a 1970 CJ5

 

There is metal braid under the outer rubber. Still, the outer layer is protective and I would replace any hose with that kind of damage.

 

thank you. I’ll find a replacement hose.

 

That is a flexible rubber hose with the threaded ends that are crimped on. Originals don’t have a metal braid, but are a nylon/fiber braid under the outer rubber casing. You can easily cut them with a knife that wouldn’t be possible with steel braid.
-Donny

 

What year did they stop using that "S" line? I have a set of 11" brakes all ready to install I want to put on my 66 axels. I thought I read here that I needed a hose that hooked up without the "S" line. I have the part # for Rock Auto brake lines. I want to have everything before I start the switch. Thanks for the help, Rick

 

I have installed 11" brakes on both styles of brake systems.

My CJ2A has the "S" lines with the brake line running on top of the axle. I used "Z" lines for an early CJ5 and non directional wheel cylinders (fitting straight not angled to the rear). My 67 CJ5 has the later brake line set up with the brake line running along the cross member under the radiator and the longer rubber lines from frame connecting directly to wheel cylinder ( no "Z" or "S" line). I used directional wheel cylinders with the fitting angled toward the rear. The fittings for the steel lines ("S" or "Z") are flared fittings and those for the hoses directly to the cylinders are larger and deeper than the fittings for the steel lines.

 

Like oldpappy wrote, you can eliminate the short S lines by using longer flex lines, just make sure they have the long threaded end to seat directly in the wheel cylinder. I used to use flex lines from the intermediate CJs (‘72-‘75).
-Donny

 

One thing to be aware of. If you convert from the "S" / "Z" line to the long flex line from the frame and remove the guard for the "S" line which is mounted to the king pin bolts use spacers the approximate thickness of the guard, or shorter bolts to prevent interference in the knuckle.

 

Curious - why would you eliminate the "S" tube? It looks quite purposeful to me. The factory did not add stuff like this for no reason.

Maybe the 10" or 11" brakes place the end of the flex hose higher wrt the knuckle. Then the factory could make the tube connect to the cylinder at more of an angle, and get the same geometry we see with the S tube.

 

There is nothing wrong with the "S" or "Z" tube arrangement, but the factory didn't go to the later arrangement for no reason either.

I don't convert one to the other. If the Jeep has the older setup with the "S" lines, and I am going to update to 11" brakes I simply use the "Z" line which was used for one year of CJ5 production. It is easier to fit to the wheel cylinder.

I do think the later design where the hard line is routed on top of the front cross member instead of being clamped to the axle gives a little better protection of that line, but it is a trade off because instead of a short hose with a guard on top of the knuckle you now have a long hose which could more easily get snagged in the brush.

 

I always replaced them with the later style hose. They were headaches. Years of people using the wrong tools to remove them left most rounded to the point of having to cut them to get them apart to change a wheel cylinder. Bending up a new one was challenging enough that it just wasn’t worth it. The radii were tighter than any tool could bend, so you’d pre-flare a guessed length of tubing, then add the bends with a 3/8” box wrench. Plus it’s an extra fitting to potentially leak. I wish I had the time back that I wasted on those things.

 

Interesting to me is that while the later design started with the CJ3B and, with at least two variation, carried into CJ5 production when at the same time the military version still had the short hoses and "Z" lines all through M38A1 production, or that is my assumption based on the M38A1 axles I have bought which were late M38A1 Marine contract axles, not sure about the earlier military contract M38A1s.

 

Thanks for everyone’s insight and suggestions. I’m hoping to get some time this weekend to work on it.

 

Thanks Donny, I wrote down the part # that Kenb posted, but it is good to know the years. I bought some "S" lines from the Jeep Docter, they looked like copper, I put a magnet on them and they were copper, Jeep Doctor made a re-call and told people not to use them. I got some new ones from a different source.

 

I think the military labeled the s-tube mount as a "rock guard." Sounds good to me.

 

With the older design there is a very short flex hose on top of the axle mounted to the guard, with the "S" tube going to the wheel cylinder, so less is exposed to damage. I suppose that is why the military specs on M38A1 differed from the civilian CJ5.

 

can someone point me to a correct part number and/or source for replacing these front brake hoses? None of the parts places carry them that I’ve found. My Jeep is a 1970 CJ5 with a 2.5 inch BDS suspension.

thanks in advance for your help.

 

take the old one in and have the counter guy get a replacement. he should easily be able to do that for you. the ends are standard sized, the length is easily measured.

 

Thank you.