Front brake lines

This is a job I’ve been putting off for a while because 308 brake lines are usually a bit of a nightmare.

The 308’s flexible lines run from small S-shape hard lines at the calipers to a coupling on the chassis close to the upper shock mount. At both ends the flared hard line has a threaded inverted sleeve that screws into the coupling of the flexible line, with a lock nut that screws over the top sleeve.

The first problem is access to the chassis coupling since normally it can only be accessed from the wheel arch and one is normally working blind. However, one of the first modifications I made to my car was to make the front glass fiber trunk liner removable in order to provide easy access to both the steering rack and brake lines for maintenance. Today that modification paid off handsomely. With the liner removed, access to the back of the chassis brake fitting is straightforward and the only tools needed are a 17mm wrench, a 24mm wrench and an 11mm flare wrench.

Ferrari 308 brake line
Chassis coupling between hard line (right) and flexible line (left).

The first task is to bend back the metal tab folded over the large lock nut. A flat screwdriver followed up with some persuasion from a 5 lb hammer did the trick.

Ferrari 308 brake line
Chassis tab lifted up showing threaded inner sleeve and outer lock nut

The inverted sleeve is unscrewed with an 11mm wrench and given that these flared tubes are somewhat fragile, it’s best to use a dedicated flare wrench which will grip the nut on five sides instead of the two of a regular wrench. Once the sleeve and its delicate contents are removed, the lock nut can be unscrewed and the flexible line completely removed.

Ferrari 308 brake line
Flexible line removed

My lock nuts came off fairly easily… in fact one was loose on the driver side. This is a little bizarre since the tab had been folded over but it seems before that someone only did the nut up finger tight and forgot to tighten it with a wrench.

At the hub end, the flexible line is connected with the same sort of nut and sleeve to the caliper S-fitting. This S-shaped line is even more fragile than the hard lines at the chassis. Again there are a couple of tabs that need bending to access the lock nut.

Ferrari 308 brake line
Flexible/hard line coupling at the hub

For some reason these fittings were signficantly harder to undo than the ones at the chassis side. I’m not sure if it was corrosion from the road that froze them tight or just a too-enthusiastic mechanic with excess muscle… but I had trouble.

Ferrari 308 brake line
Tabs bent back but both nuts are frozen solid

I couldn’t undo either the large lock nut or the smaller sleeve. I didn’t want to apply too much pressure because that S-shaped hard line is no longer available so if I broke it, I’d be in trouble. I doused the area in Liquid Wrench penetrating fluid and waited an hour.

Ferrari 308 brake line
Wrenching but nothing is moving

Even with the Liquid Wrench  applied I could not get the lock nut loose. So I gave up with the lock nut and turned my attention to the sleeve. This was also stuck tight but with some effort, it started to moved. It was immediately clear that I was going to have more luck removing the sleeve and carefully bending the hard-line away so I could remove the rest of the fitting from the hub as one piece. Once off the hub I could get the lock nut into the vice and reach for a much bigger wrench. Job done.

Ferrari 308 brake line
Some times you just need a big wrench and a big vice

The new brake lines are made by HEL, part number FER-4-005, and are braided stainless steel. I orderded black braid to avoid too much bling. Fitting is (almost) the reverse of removing the old lines, so first the new lock nut needs to go over the sleeve then then the tabbed pice of metal, then the new flexible line goes in and the sleeve is inserted. Although I took the sleeve out before the locking nut on disassembly, its better to put the sleeve in before the locking nut when reassembling. This way the coupling on the flexible line can be manhandled more easily to line up with the sleeve even though you are fighting significant tension from the S-shaped hard line.

Ferrari 308 brake line
Lining up the inner sleeve with the coupling of the new flexible line before fitting the lock nut

Depending on how much room you have to get the two parts lined-up, the sleeve might go in really easily as one of mine did or you may need to use the flare wrench to slowly force it in against its will.

Ferrari 308 brake line
Inner sleeve fully home with just the lock nut to fit

With the sleeve in and tightened, the lock nut can be put one, tightened and the tabs folded down again. And that’s one end of one line done.

Ferrari 308 brake line
Line fitted, just the tabs to fold down

At the chassis end, reassembly is the same but as with the disassembly, everything went together more easily due to the easy access.

Ferarri 308 brake line
Reassembling the couping at the chassis end

Tighten everything up, bend the tab back and we are done.

Ferrari 308 brake line
Brake line finished.

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