M35A2 Brake line Size

[dropaduece]

Dear Fellow Members,

I have recently gutted all the brake lines on my M35A2. I am replacing all the lines and simplifying them where I can. The problem originally was that someone had a bunch of mutt lines and t's. All kinds of different diameter line was used and reduced or increased to other sizes.

I would like to know the optimum sizes to use when I install my new lines. So I will need to know what diamter line is needed to go from the master cylinder to airpack, from airpack along the frame, from frame to wheels, etc.

Could I get away with using 5/16" for the master cylinder to airpack and the frame lines, then drop it down to 3/16"? Or should I drop down to 1/4" at the wheels, or keep it all 5/16"

I just would like the best braking response a duece could give...


Thanks,
Seth

 

[Recovry4x4]

Factory was 5/16 all along the frame. 1/4 out to the wheels.

 

[dropaduece]

Thanks for the quick response. So would it be safe to say I should use 5/16" everywhere except the lines on the axles going to the wheel cylinders which would be 1/4"?



Seth

 

[doghead]

The items that the brake-line fittings go into, will dictate what size lines you need(only one size will fit that thread fitting). Go ahead and change out the rubber hoses while your at it, now's the time to do them.

 

[Barrman]

Yes, 5/16" on the frame, new hoses to the axles and then 1/4" on the axles themselves. Several vendors have new line sets. Well worth the price to get them all in a single box.

 

[Unforgiven]

Yes, 5/16" on the frame, new hoses to the axles and then 1/4" on the axles themselves. Several vendors have new line sets. Well worth the price to get them all in a single box.

Would you happen to have any hyperlinks for these complete kits?

 

[ddskehan]

I would like to second the request for the link. mine look fine , but at 40+ years old I would feel safer changing them out

 

[DirtMagnet]

In-line Tube.com did an outstanding job for me. I sent him rubber lines to replicate in the stainless steel braided flavor. He called me on a Saturday with some questions about them. You just don't see that kind of dedication very often. They are good.

 

[StoneMill]

Any other links for deuce specific brake line kits. I'd like to do mine while I have everything apart.

 

[JCKnife]

Bump for the same question again...

 

[MadHatter]

Steel brake lines loose their psi capabilities over a few short months, then drastically beyond that. I would recommend (and I'll be doing this on my M34 when I take delivery) you purchase cunifer line. It bends nicely without kinking and the 3/16" line will hold it's 16,000psi abilities for well over 20 yrs. I bought a roll of 1/4" by accident but decided to keep it and used the green coated stuff (which still oxidizes). Cunifer line is a copper/nickel alloy used in high end cars (subjective) such as Volvo's, Audi and Porche. The only place I know of is FedHill in Oxford, MA. Their website is http://www.fedhillusa.com/ They've got all kinds of brake line parts.

 

[JCKnife]

Steel brake lines loose their psi capabilities over a few short months, then drastically beyond that. I would recommend (and I'll be doing this on my M34 when I take delivery) you purchase cunifer line. It bends nicely without kinking and the 3/16" line will hold it's 16,000psi abilities for well over 20 yrs. I bought a roll of 1/4" by accident but decided to keep it and used the green coated stuff (which still oxidizes). Cunifer line is a copper/nickel alloy used in high end cars (subjective) such as Volvo's, Audi and Porche. The only place I know of is FedHill in Oxford, MA. Their website is http://www.fedhillusa.com/ They've got all kinds of brake line parts.

Quoted for visibility!

 

[markmontana]

Any other links for deuce specific brake line kits. I'd like to do mine while I have everything apart.

How about this:

OD Iron LLC Military Vehicle Parts and Accessories

 

[rmgill]

Ah, so the Cunifer is in fact a copper alloy HARD brake line tubing. It is more maliable and retains it's strength even when bent oddly.

Seamless copper-nickel 90/10 alloy brake line is strong as steel, completely corrosion proof and much easier to work with. Installed by high performance manufacturers such as Aston Martin, Porsche and Audi, Cunifertm brake lines maintain full strength for the life of the vehicle.

Its unique properties allow it to be snaked into positions that are impossible to do with steel brake line. Flares easier, minimum tube preparation required and no seam to split. Cunifertm brake line seals better, making it the best choice for your installation!

No other brake line compares for strength, reliability and ease of installation. It is the perfect replacement brake line for cars, trucks and buses.

Interesting.

 

[stumps]

Steel brake lines loose their psi capabilities over a few short months, then drastically beyond that.

That's quite a bold statement! Care to back it up?

The absolute maximum pressure you will ever see in a brake line is about 1200psi.... and that is stomping the pedal with a couple of hundred pounds of force, and a boost unit.

The steel lines are good for 10x that pressure when new. Even if they degraded to 1/2 their new strength, they are 5x overkill.

I would recommend (and I'll be doing this on my M34 when I take delivery) you purchase cunifer line. It bends nicely without kinking and the 3/16" line will hold it's 16,000psi abilities for well over 20 yrs. I bought a roll of 1/4" by accident but decided to keep it and used the green coated stuff (which still oxidizes). Cunifer line is a copper/nickel alloy used in high end cars (subjective) such as Volvo's, Audi and Porche. The only place I know of is FedHill in Oxford, MA. Their website is FedHill Brake Line - Where to buy brake line, fuel line, brake line flaring tools, brake line nuts and brake line fittings They've got all kinds of brake line parts.

No doubt the cunifer line is the cat's meow. And I am going to look into it for its corrosion resistance characteristic, but no way is its psi capability a big plus over DOT tempered steel lines... and your statement about steel lines losing their PSI capability after several months just doesn't ring true.

I have plenty of examples of factory installed tern plated steel lines that have exceeded their required specs for well more than 20 years. Most of our deuces have 40 year old lines still in them that are operating nicely.

-Chuck

 

[MadHatter]

Sure thing Chuck! He's some backup for my statements:

Copper.org: Applications: Automotive - Hydraulic Brake Tube

Copper.org: Applications: Automotive - Copper-Nickel Automotive Vehicle Brake Tubing

http://www.fedhillusa.com/webnuts/burst.pdf

As steel gets older it oxidizes and weakens. Brake lines pit which causes a weak spot in the wall. There was a document that compared the two products in sea spray tests, but I can't locate it right now. Here in NH we use sea salt to treat our roads... brake lines will last 4-5 yrs if you're lucky.

 

[stumps]

Thank you Madhatter!

I think the testing in these articles is not indicative of normal use of automotive brake lines. In the first place, the salt water immersion testing for 60-120 days is very severe compared to what really happens in normal operation. In a real car, because of the relatively protected locations of the lines, the salt exposure is rather incidental. As is the road (gravel) damage they quoted. The lines are run through protected locations. The salt test was intended to act as a greatly accelerated test of the lines for corrosion.

The changes from terne dipping to zinc plating is pretty concerning. I haven't seen any such line in the US after market ... yet.

Brake line failures in the US are rare to unheard of in the first 5 years of use. In my limited experience, they crop up after 20+ years in vehicles that I operate routinely through Maryland's slushy winters. In NH, it is rare for a car to last 4 to 5 years period, from the extensive corrosion damage I have seen on cars from your area.

I can't help but worry about work hardening failures in the CuNiFe lines. The reason copper tubing is forbidden for any brake, or fuel line, use in DOT controlled cars is work hardening. Ordinary copper tubing of the usual sizes for hydraulic brakes could easily handle the pressures required, but they stress fatigue from the vibration that occurs whenever the line is left unsupported, such as happens around master cylinders, etc... Unlike steel, copper has no allowable amount of flexure before work hardening begins... In other words, there aren't going to be any copper springs (yes, I know about beryllium copper, and other alloys).

The articles, quite a lot to digest, don't seem to talk to this issue at all.... It might not be a problem.

Again thanks for the reference information.

-Chuck

 

[jesusgatos]

In-line Tube.com did an outstanding job for me. I sent him rubber lines to replicate in the stainless steel braided flavor. He called me on a Saturday with some questions about them. You just don't see that kind of dedication very often. They are good.

My rubber lines look pretty good, but I'm planning on replacing them with some nice stainless/kevlar-braided ones whenever I get around to it. Anybody know what size/type of fittings are on each end of those flexible rubber hoses? I should have taken some dimensions when I was working on my brakes...

 

[srodocker]

hrm got me to thinking i need to add that to the list of replacing

 

[mistaken1]

Copper.org pushing copper lines whoda thunk it....

Not attacking just pointing out that if steel lines were so dangerous the lawyers would have driven them out of automobiles in the US years ago. (maybe they are working on it and I just not aware of it)

Is the cunifer line a premium product? Probably but is it needed to ????

A single circuit braking system sucks no matter what the lines are made out of.......