9 replies to this topic

[Calderwood]

As the title says, what size spanner do I need to do my bleed my brakes? They'e f***ed.

 

Its a '99 Mpi on standard discs at the front and drums at the back.

 

Cheers

[alex-95]

I'm pretty sure it's 11mm.

[Calderwood]

Thanks. I thought it was a standard across most brakes, but the local auto shop looked at me like I was mad when I didn't know the exact size today.

[Alex_B]

7/16 rather than metric, and I think the rears are 1/4 or 5/16 you will have to check. 

Bleed nipples are usually rusted solid and being hollow are prone to snapping or just rounding off so using the correct spanner can save hours of agony. 

To be honest a 11mm will likely do the job as there isnt much in it (0.005") but I like using the correct tool for the job and getting a full imperial spanner set will mean you always have the right spanner and other imperial sizes dont match up to metric tools. But with the rears the size difference between metric and imperial may mean you round off a nipple so imperial is recommended. Also brake pipe spanners with more sides are handy for very stuck nipples as they help distribute the torque around the nipple better.

Edited by Alex_B, 11 April 2016 - 06:59 PM.

[Steve220]

It is 11mm. I always start brake nipples with a 6 sided socket, just enough to get them turning before using the ring spanner. Mainly as i've seen these things round!

Edited by Steve220, 11 April 2016 - 06:58 PM.

[A-Cell]

Front caliper bleed screw needs a 7/16 in AF and the rear brake bleed screw needs a 5/16in AF.
They are not metric. An 11mm AF will fit the front as it is close to 7/16in

[Steve220]

My rear brakes use an 11 or 7/16in... Have I got different bleed nipples? They're the same as the brand new built up plates i have to go on too..

[Alex_B]

My rear brakes use an 11 or 7/16in... Have I got different bleed nipples? They're the same as the brand new built up plates i have to go on too..

My guess is it would depend on the rear wheel cylinder sizing, I remember using a 7mm on mine when I bled them last which could make it 1/4 or 5/16. Wouldn't surprise me that there are different options ;) good old BL

[59 Speed]

I always start brake nipples with a 6 sided socket, just enough to get them turning before using the ring spanner. Mainly as i've seen these things round!

Good point on the six sided socket to start off (and on other rusted up nuts and bolts too) 😉

[Calderwood]

Thanks for all the help. I have an Imperial spanner set, I found the fronts to be 7/16, while the rears were different on either side haha, but a bit smaller as has been suggested.

 

Cheers.