Changing a rear brake hose...


Registered User
Need to change my offside rear brake hose for the MOT and was wondering if anyone had any tips? Can't find anything online and elsawin hasn't got much to say either.

I understand it's just a straight swap over making sure to keep an eye on brake fluid level and a proper bleed afterwards.

Will I need any special tools (line wrench?) and will the brake fluid rush out when I disconnect the old line?


spartacus 68

Registered User
No doubt it'll be corroded at the ends, so wire brush at caliper end and where it connects the fixed brake line. Spray Duck Oil penetrating release on it and leave for 30 mins. Tool wise, get yourself a decent brake line spanner. I've seen even this fail if the hex nut coupling is so corroded you can't get a decent grip on it. Prior to attempting the job, remove brake fluid cap and put a piece of cling film over aperture, then screw cap back on.

Remove brake hose. Have a tray or something to catch escaping fluid. If it slips or refuses to budge - you can cut the hose and use a deep socket that fits over the hex nut completely. Clean both ends prior to fitting new hose. You should have clips too. Use a little copper ease on the threads and tighten up.

Bleed caliper afterwards, etc.


Registered User
Cheers Spartacus.

I don't suppose you have any idea what size the banjo bolt is? I know it's M12 but no idea on the length needed.


Registered User
If you get a new hose it should come with the banjo bolt and seals all ready on the hose to fit, I know the genuine ones do as I fitted new rear hoses to my A4 a few weeks back.

I would say rear wheel off, arch liner out to get to the union on the metal brake pipe into the hose at the body side and also I took the upper of the caliper to carrier bolts to swing the carrier back so I could get a socket and ratchet onto the banjo bolt to undo it and a torque wrench on when doing it up.