So I was travelling northbound on I-95 at 10:30 am Saturday (moderate traffic) about 70 MPH when upon pressing the brake pedal was surprised by no action at all. The pedal went all the way down to the floor! Slowed the car down by downshifting and applying the handbrake and very fortunately was able to get off the interstate and park in a gas station. A bit scared to say the least.

Popped the hood and found the forward reservoir totally empty, the rear reservoir was full, the drivers side rear wheel (on the inside) covered in brake fluid. Once I removed the wheel I found scrapes and a tiny perforation on the solid brake line angle close to the junction to the braided stainless steel hose that leads to the caliper.

After analyzing the situation it seems that the most likely cause of the scrapes (almost looked like someone had filed down the brake line) was the SS line flexing up and down with the movement of the rear wheel and rubbing continuously on the hard line until it finally perforated when I strongly applied the brake pedal Saturday morning. I inspected the other side and found the same situation: scraped hard line at the same spot.

I thought this report might be useful to some who have done brake upgrades with SS hoses (I have an MSA rear disc upgrade and SS hoses) and thus avoid a similar scary situation.

I have now changed the two segments of damaged rear brake lines for new SS hard lines and twisted the flexible braided ss hoses so they won't come near the new lines when the suspension is compressed.

 

Wow!  That soundalike an exciting ride.  So do you think the braided line was rubbing during suspension travel?

A braided stainless line (any braided stainless line) is a file.  I will cut through anything - metal, plastic, rubber.  The lines must not rub one anything.  You are lucky.  Re-routed the braided line and replace the brake hard lines.

Buy a lottery ticket.  This clearly is your lucky day.  

Dennis

56 minutes ago, Montana Z said:

Wow!  That soundalike an exciting ride.  So do you think the braided line was rubbing during suspension travel?

That is exactly correct on both counts!

4 minutes ago, psdenno said:

Buy a lottery ticket.  This clearly is your lucky day.  

Dennis

LOL! Tried it but nothing!

I had this happen to two different cars I had. The lines had rusted through. Pedal went right to floor.

When they say "dual braking system", that's Bull.  If either end goes you have nothing!

11 minutes ago, Lumens said:

I had this happen to two different cars I had. The lines had rusted through. Pedal went right to floor.

When they say "dual braking system", that's Bull.  If either end goes you have nothing!

Yeah! I was thinking about that. Even though one of the brake fluid reservoirs was full I had no brakes at all. I would have thought that the proportioning valve would have kept some braking capacity for the front brakes. 

Scary! There should have been some brake action on the front system. Check for a problem in the front brakes while you are in there.

 

Wow. That's a real brown pants kind of moment.

I believe the theory on the dual braking system is that you WILL (or can) still have braking on the other side of the system, but here's the thing...  You have to bottom out the proportioning and/or warning switch mechanism first. And you may have to pump the brakes (maybe more than once?) in order to make that happen.

In other words, you have to fill up all of the hydraulic space behind the floating piston and force that piston all the way towards the failed side of the system before you can build pressure in the working side of the system. And that won't happen on the first push, but might happen on the second quick pump?

And that's all assuming you're cognitive enough to even pump the brakes... If I were in your position, I wouldn't be thinking that, I would be thinking "where am I gonna land this beast without hurting anything".

 

 

I actually did pump the brakes like crazy and the pedal still went to the floor every time. I'm thinking that perhaps with my brake upgrades (larger discs on the front, discs on the rear, larger MC, stock proportioning valve) my bias was heavily on the rear to begin with. 

Well that's extra special scary then. I don't know why pumping didn't work, but I'm just glad you got out of the whole ordeal with nothing more serious than a good adrenaline rush!