M Brake issues

[Finn2500m14]

Hello,

Having issues after rebuilding the calipers (type 16pb) on my M with new seals and pistons

I'm fitting new discs, pads and braided lines.

The outer pad seems to be binding to the disc quite badly whereas the inner pad has about 2mm clearance from the disc.

Currently only fitted the drivers side but if the same issue presents itself on the passenger side i'm guessing the culprit is the disc ?

Just wondered if anyone has encountered this before and what they did to resolve it ?

Much appreciated, Finn

[Finn2500m14]

plasticpig72 said:

Hi Finn,
have you bled the Brakes yet and applied them to make the Pads touch the Discs.
When you assembled the Pistons and Seals did you use Brake Fluid to lubricate the Seals.
I see you have used Copperslip on the Pad retaining Pins and i hope you didn't put that on the new Seals
Alan

Hi Alan,

I have not yet bled the system as i am concerned that the pad is binding too much and the problem will not be solved. It almost seems like the mount needs to be faced or the inner surface of the disc bell needs machining down 1mm. By eye the pistons are all the way home but there is still the 2mm gap on the inboard side of the disc.

Yes, fresh fluid was used to lubricate the seals when the new pistons were inserted, not copper slip .

Many Thanks, Finn

[Finn2500m14]

plasticpig72 said:

Maybe just for the bleeding of the Brakes you could put an old Pad in to have clearance. At least you will know then that the Pistons move correctly. I think the Discs are Triumph TR6.
Have you measured the distance on an old Disc from the Braking Surface to locating surface to compare to a new Disc.
Have you changed the Wheel Bearing and Dust Shield which could change the position of the Hub to further out.
Alan

That's a fair point as that should eliminate any possible issue being caused by the caliper and narrow down the options.

I will be measuring the distance this evening as i now believe this could be the culprit. the wheel bearings have been re-packed but not replaced.

Cheers, Finn