Volvo 850 DIY: Front Flexible Brake Line Replacement

[oragex]

A few years back I was driving my Passat on the highway. The car in front on me braked slightly so I braked too slightly. I heard a "bam!" under the hood and all of a sudden completely lose all brake power. Luckily enough, the hand brake did work properly so I could slow down and take an exit (was close to home).

One of the flexible hose was blown. The other one had a crack exactly at the same place. What surprised me the most, is that there were no brakes at all. I thought that when a brake line fails, the other half of the brake circuit takes over, but no.

The car had about 100k miles on the clock.



As for the DIY, it's very nice. I would add, use a water hose and clean all the brake line connections with water under pressure to make sure there's no dust or dirt particles at all. Prepare some small pieces of eraser to block the lines once opened - this helps a lot reducing the fluid loss and giving you plenty of time to work without any stress. I found screwing back the lines to be very hard, as the filets hardly catch on, especially at the caliper. Better to have everything perfectly clean and have plenty of time to work without pressure. Definitely reconnect the new line first at the caliper, then pay attention to the way the line twists when screwed - you don't want it to remain twisted, so perhaps twist it a little in the opposite direction before starting to screw it.

[cartagena]

This now in the Volvo Repair Database. Thanks Jason!

Love it. Should add a fist full of cash saved for another icon/and a Brinks truck icon for the stealership.

[xHeart]

A post in support of Jason's pressurized/vacuum "solo method".

using Mityvac - vacuum pump

[regent]

I really appreciate the decent write-up with detailed pictures made by jreed.

My question is about tightening the flare fittings in the hydraulics (brakes, power steering, etc.):
VIDA specifies torque values for all hoses, pipes, and even for caliper bleed nipples (8 Nm, IIRC).
Since I do not possess the 'feel', I always reach for my torque wrenches.
Now it looks like I am gonna have to buy some crow's foot extensions for the brake lines' fittings.

So, the real question is: How critical are those torque values?
(Please don't laugh at me now...)
Thanks

[kahl]

Using line wrenches get them as tight as possible.

[oragex]

Not too tight, maybe as hard as you can tighten the key with two fingers. Careful not to bend supports or asjacent fluid lines. Prepare plenty of fresh fluid and a large rug in case reconnecting the lines takes a while which, of course, will cause quite some spill.

[regent]

...as hard as you can tighten the key with two fingers...

That's exactly what I was afraid of doing... My two fingers seem to be too strong for this approach (long is the list of threaded fasteners they have put to death... oops)

[dosbricks]

regent, these lines are originally very tight from the Swedish assembly elves, even if they are not corroded. Your two fingers should be fine, and you might have to employ a third after driving the car and checking for leaks. Consider the psi inside one of these lines during a hard stop.

[oragex]

Think of it as to be able to un-tighten it without having to pull hard on the line. As mentioned above, a leak inspection is imperative. The bolt must not be able to come loose by itself. It has to be tight-secure. I think the flange must crush a little bit.

[regent]

Thanks everyone - I feel a lot more confident now.