Re: Compression Fittings On Brake Lines

From: jon@dakota-truck.net
Date: Fri May 13 2005 - 10:20:24 EDT


david.clement@verizon.net wrote:

: Absoultly wrong! A compression fitting is every bit as safe as a flare. Reason
: the manufacturers don't use them is there are more parts and require more
: manual labor to install them. The tubing will fail long before a compression
: fitting will seperate.

: Years ago I worked in the lab of a company that made pressure transmitters. We
: used to setup test fixtures for pressure testing to 10,000 psi with compression
: fittings.

    Compression fittings can be used on high pressure systems
(including hydraulics), but the fittings are usually steel or
stainless steel and the ferrule design is different. Trying to
use common brass hardware store type compression fittings on brake
lines is begging for trouble; they have a max pressure rating of 100
to 400 psi, depending on the tubing size which is (best case scenario)
something like 5 times less that what you need in a brake system.
If you use the "self aligning" compression fitings which basically
have a sleeve built into the nut, you can get up to 1400-1900psi
in the standard brake line tubing sizes, but that's not acceptable
either. There are "high pressure" brass fittings which can get
you into the 1600-2300psi range, but even at 2300psi, I still
wouldn't use them on a vehicle - I'd like a larger safety margin
than that.

-- 
                                          -Jon-

.-- Jon Steiger ---- jon@dakota-truck.net or jon@jonsteiger.com --. | 1970 Barracuda - 1990 Dakota 'vert - 1992 Ram 4x4 - 1996 Dakota | | 1996 Intruder 1400 - 1996 Kolb FireFly - 2001 Ram QC 3500 CTD | `------------------------------------ http://www.jonsteiger.com --'



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