Visit The Dirt Forum for More Information

Author Topic:   Plastic brake lines
Dman
Dirt Freak

Total posts: 270
posted December 03, 2004 08:56 AM  
My post on brake pads has brought up another issue.Don't use plastic brake lines!
We have sold a number of these kits and some of our customers have complained of poor braking and a spongy pedal.These kits use nut and farrell connectors.When you tighten these the farrell ball is crushed against the line to seal it and this reduces the size of the brake line at that point causing flow problems and can cut into the line making them weak or just plain plugging it off.This may be why your brake system is poor.Brakes are also a major major(did I stress major?) contributor to a cars handling.Plastic lines are heat sensitive and will require more frequent bleeding.They are not UV resistant and become brittle after long exposure to sunlight(I know it will take a long time)or exhaust.I have been around racing for over 20 years and have seen some stupid things done to save a little weight or time. Run steel lines even if it is more difficult.The weight savings is negligible if it affects the handling and safety of you or others you are racing against.I know some of you will say"I have never had a problem with plastic lines" but,do you really know? Is it worth the risk?

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted December 03, 2004 11:07 AM  
Over 3/4 of the car's i've worked on or raced have had plastic lines... and never one problem, yes we broke one but that was on the rear when the driver stomped the brake and it spun the bracket. The metal lines are more of a hassle to put on for most people. If your racing with your brakes that much there is a problem... the only time i think brakes are helpful is if the track is super slick and you need to get the car into the corner straight.

zeroracing
Dirt Forum Champ
Total posts: 1875
posted December 03, 2004 12:11 PM  
Plastic expands it is not as rigid as the steel so it does not hold the pressure as well. I have also seen a car melt the lines and loose a few thousand dollar spot over it. i would not run them and risk tearing up a car, but that is my take on it.

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted December 03, 2004 12:24 PM  
It just must be you westerners DMAN
lol just giving you a hard time

Dman
Dirt Freak

Total posts: 270
posted December 03, 2004 01:53 PM  
Yes Xtreme12x,
Just us westerners.I did also state that someone would say" They've never had a problem" and you are the winner. It was intended to be a warning not a scolding.It will bite you some day. I hope its not when you need them the most.Most chassis builders will put steel lines on at a minimal cost so you don't have to.I hate doing steel lines also.The clip you save may be your own.(or some one else's)
Dman

Wildside17
Dirt Maniac

Total posts: 119
posted December 03, 2004 04:04 PM  
DMan, to each their own, before long IMCA will outlaw plastic lines. Personally thats all I run and mine don't use the farrells.

Racer111
Dirt Freak

Total posts: 259
posted December 04, 2004 10:24 AM  
All i can say is FIRE !!!

joetaylor
Dirt Forum Champ
Total posts: 640
posted December 04, 2004 07:20 PM  
if you have a fire then you have BIGGER problems
I do use steel line myself.

------------------
if every thing is under control your not fast enough

Ego Racing
Dirt Forum Champ
Total posts: 724
posted December 07, 2004 06:12 AM  
I have used both and like the plastic. You just have to use your head when running it in the chassis. I have used a 1/2 inch conduit the length of the chassis and run the rear line in firesleve inside the conduit. I will admit that there are some problems with it but there are also problems with steel. I have ran over a small peice of someones car at an asphault track (I did not hit it but centered it in the car) going into the corner on a 5/8th mile track, hit the brakes to get into the corner and had no rear brakes due to the line being pinched by the debris. I have a peice of plastic from my car where a peice hit it and smashed it and it popped back out and just leaked.
We have run into the sponge like feel and found if you vacume bleed the lines it goes away.
One thing we have found is that the plastic seems to hold air easier in high spots, now when we are going to use it on a car we mount the master cylinders as high as we can and run the lines on the upper bars of the chassis.
The bottom line is if you run plastic PROTECT THE LINES!!!!! and if you run steel PROTECT THE LINES!!!!! either can bite you if done wrong!

rrrrick
Dirt Maniac

Total posts: 192
posted December 08, 2004 10:40 AM  
If you look under the steel braid on your brake lines you will find the same plastic line that most quality kits come with.


dirtywrench13
Dirt Freak

Total posts: 324
posted December 08, 2004 11:52 AM  
THE PLASTIC LINES ARE O K WHEN THEY ARE NEW, BUT THE FIRST TIME THE CAR TOOK A HIT, WE COULDN'T GET THE SYSTEM TO BLEED OUT. WE PUT STEEL LINES ON AND THE PROBLEM WENT AWAY.

zeroracing
Dirt Forum Champ
Total posts: 1875
posted December 08, 2004 03:25 PM  
rrrrick- "If you look under the steel braid on your brake lines you will find the same plastic line that most quality kits come with."
And that is why I hate the braided lines and have 2 sets usually in the trailer. I blew one front right one off sitting in the staging lanes setting my brake bias. and seen alot of them break.
i go steel as far as i can then braided and replace them often.

Back to the Archives