Brake Fluid Hose vs Fuel Hose

[83_Silberpfeil]

I have my MC out for replacement. Looking into replacing the brake fluid lines from reservoir to MC. The Genuine Porsche is extremely costly. Wondering if the Cohline fuel hose could be an equal replacement.

Thanks!

Genuine Porsche Hydraulic Fluid Hose - 7.5 x 12.5 mm
https://www.pelicanparts.com/More_Info/99918102150.htm?pn=999-181-021-50-M100&SVSVSI=577&DID=4697

Cohline Fuel Hose - 7.5 x 12.5 mm
- Working Pressure: 7 bar ~ 100 psi
https://www.pelicanparts.com/More_Info/21220600.htm?pn=2122-0600-M20&bc=c&SVSVSI=

[nickelplated5s]

Go to a local hydraulic hose shop and have them made. Take the old ones to match the fittings. Last ones I had done were for a Komatsu dozer. Japanese fittings but they had them.

[HarryD]

Don’t do it. Fuel line is not compatible with brake fluid.

[EC900]

Definitely different and not interchangeable as Harry states above.

I’m sure a an import repair shop will have the few inches you need. These aren't vehicle specific other than perhaps the blue cloth braid.

Be aware of auto parts clerks if buying hose from them. They couldn’t or didn’t want to decipher my vacuum hose from gas hose…I watched as they looked for an O.D. match up rather than the type of product. I had to ask to go back behind the counter to read the label on the spool they were unwinding.

[930cabman]

Fuel hose is low pressure

Brake hose is high pressure

[917_Langheck]

There is very little pressure in the supply line between the reservoir and the master cylinder. There are no fittings to be made; just reuse the simple spring clamp at the base junction.

[stownsen914]

Look up Tilton or Wilwood brake reservoir hose if you want a cheaper option. As stated, don't use fuel hose. Not because of the pressure rating (m/c supply line isn't pressurized), but brake fluid will dissolve fuel hose and either cause it to fail or gel your brake fluid. Brake failure and/or a big mess would ensue.

[porschyard]

Originally Posted by nickelplated5s

Go to a local hydraulic hose shop and have them made. Take the old ones to match the fittings. Last ones I had done were for a Komatsu dozer. Japanese fittings but they had them.

Apparently you are not familiar with the hoses the OP is referring to.

[83_Silberpfeil]

Thank you everyone for chiming in and addressing my Q.
Definitely good to know that fuel vs brake fluid application are different, and the hose materials will react differently.

I looked at Tilton and Wilwood options. Thanks to stownsen914 for mentioning those. Very economical option, but size wise not exact match fit to the Genuine Porsche specs. Also looked at Bell Metric --- they have VW and BMW versions with ID =7 mm instead of 7.5 mm. That's a difference of ~ 13% in the cross section area. Install into the existing fittings might be an issue, and less flow also?

May be just keeping the existing lines would be good enough for now.

Thanks again everyone!

[PeteKz]

I'm trying to think if I ever replaced the supply lines. The OE stuff seems to last forever.

[stownsen914]

If you decide to replace, 7 vs. 7.5 mm is a trivial difference. There's almost no flow in the m/c feed hose. It would be fine.

[83_Silberpfeil]

Originally Posted by stownsen914

If you decide to replace, 7 vs. 7.5 mm is a trivial difference. There's almost no flow in the m/c feed hose. It would be fine.

Thank you for continuing to engage on this discussion stownsend914, and providing your insights.

I will proceed with old/original tubing/hoses. If later I decide to try the 7 mm BMW/VW versions, it will still be easily reachable and simple swap.

[PeteKz]

If you decide to replace it later, you won't have to bleed the brakes, because it's all uphill above the MC and any air bubbles will migrate up to the reservoir. Easy replacement.

[porschedude996]

Woops, late to the party!

Belmetric has brake fluid compatible hose.

12.5mm ID x 7mm ID $8.54 a foot.

https://belmetric.com/oem-brake-hose/?sku=RH7BLACK