# Different length brake lines okay?



## d*rock (Oct 24, 2003)

I was told braking won't change if the brake hard-lines are different lengths on vehicles with ABS. My question is this:
Will the length of the short hard-line that runs along the rear passenger side swing-arm affect the braking on that wheel?
I had to replace the that particular hard-line on my 1997 Jetta GLX VR6 (with Teves 20 GI ABS/EDL unit) and the new line is longer by about 4 inches. I used a pre-cut and flared line that I bent to shape.
My logic says if the lines aren't the same length from the master cylinder then you'll get uneven brake pressure. However, the lines are coming out of the ABS unit, and I don't have technical knowledge to know how this changes the physics of the system.
Any knowledge on this matter is appreciated.


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## spitpilot (Feb 14, 2000)

*Re: Different length brake lines okay? (d*rock)*

While its true that flow would decrease pressure available at various distances from the source for things like water systems..the "flow" in a brake system is nil so the distances, number of elbows etc have no effect...pressure will equalize throughout the system..so don't worry about slight differences in line length affecting your system performance.


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## d*rock (Oct 24, 2003)

*Re: Different length brake lines okay? (spitpilot)*

spitpilot: I'm glad to hear that. That's the type of answer I want to hear. http://****************.com/smile/emthup.gif
Anyone else agree or disagree?
Also, this is off the original topic but related... are there any tips or tricks for removing all air bubbles in the calipers after doing a complete rebuild? I've heard of tapping them with a mallet when bleeding the system but it wouldn't seem to be very effective to get the deep dark areas inside the piston and such. Should I fill the calipers up with fluid when re-assembling?
Thanks. I love this forum.


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## pnw_dubz (Jul 9, 2008)

*Re: Different length brake lines okay? (d*rock)*

Concur with spitpilot. Chances are that the brake line lengths are not even anyway. At least the front left and right lines are almost never even from the factory since the ABS controller is on one side of the engine bay. (Some brake lines have extra turns & loops in them - but I don't think those are to equalize length. Ususally they just add flexibility so that engine vibration and whatnot does not stress the line and cause cracks over time. Besides, any turns in a line affect fluid flow rate since it takes extra energy for the fluid to change direction. As splitpilot said, the actual flow is minimal, so this is not a concern)
With regards to bleeding the brakes, don't use a pressure source to force the fluid through as this may actually disssolve a lot of air into the liquid. Instead, either use vacuum at the caliper end or just do the manual bleed method by pushing the brake pedal:
http://www.stoptech.com/tech_i...shtml
For the OEM-style calipers, tapping a mallet works well. But as long as the caliper is installed in the same orientation as the OEM intended, there should not be a problem with air pockets. Some caliper styles that have 2 bleeders might require a more specific bleeding procedure.



_Modified by pnw_dubz at 11:54 AM 3-5-2010_


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## d*rock (Oct 24, 2003)

*Re: Different length brake lines okay? (pnw_dubz)*

Great! Thanks for the responses, guys. What's funny is I have that StopTech article bookmarked but forgot about it.








Glad the mallet tapping will work good. I was a bit unsure it'd be effective.


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## GTijoejoe (Oct 6, 2001)

*Re: Different length brake lines okay? (pnw_dubz)*


_Quote, originally posted by *pnw_dubz* »_Chances are that the brake line lengths are not even anyway. 

Chances...I will guarantee 100% they are not http://****************.com/smile/emthup.gif


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## mechsoldier (Aug 14, 2004)

*Re: Different length brake lines okay? (GTijoejoe)*


_Quote, originally posted by *GTijoejoe* »_
Chances...I will guarantee 100% they are not http://****************.com/smile/emthup.gif 

On any car ever http://****************.com/smile/emthup.gif


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## THP8VGTI (Dec 29, 2002)

*Re: Different length brake lines okay? (mechsoldier)*

i agree also. the only thing will be extra fluid in the system to take up extra length.


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