Excess footbrake travel LM mk 2

The travel on my Lemans Mk 11’s brake pedal may mean a MoT fail, two months hence.
The pads are hardly worn, I’ve changed the fluid, twiddled a grub screw on the master cylinder and screwed up the adjustment on the operating rod, as far as it will go.
Good job the hand-operated brake works!

Then the master cyl needs refurbishing tis the only answer

Or there is air in the system. Does it firm up if you pump the pedal up and down a few times?

Or the pedal is not coming up far enough to allow the master cylinder to work properly

Maybe I’ll try re-bleeding the system, before checking the master cylinder. The brakes seem to work alright, it’s just the excessive travel before they do.

Not sure on the lemon BUT on the other Guzzis there is a small grub type screw that spaces the lever to take up the slack it goes through the part where the gear lever meets the frame, you haven’t lost the adjusting screw have you?

pg128 haynes manual fig 6.5 item 12 it fits onto the side of the brake pedal…??? guzzibear2014-02-26 12:26:30

The mounting bolt for the pivot is on a eccentric cam. You can adjust the point where the pivot pushes on the piston, hence the amount of lever travel. I assume you have tried this when you said about twiddling a grub screw on the master cylinder.

Could be piston is sticking and not coming out fully. I’ve had this happen. Pedal should not bottom out at the end of its travel. Reasons for sticky piston have included rusted spring and even swarf in a new unit! I’m with GB M/C may need stripping and overhauling, maybe new piston and seals. LM2 rear brake is same as all the other Tonti models AFAIK. As an experiment, slacken pedal linkage right off then see if you can grip end of piston with long-nosed pliers and pull it out any further, + twisting will help. I suspect it’s not fully retracted. If so one or both of the fluid feed holes in the bottom of the reservoir is not open. Normally the end of the piston the pedal crank pushes on should be easily visible. HTH

I’d spend a bit of time re-bleeding it …and definitely unbolt the calipers and have them at the highest spot in the system…the linked brakes are nearly always a b…ger to bleed , especially if you don’t do this.

If there is air in the system, it tends to firm up if you pump the pedal up and down a few times. Does this happen?
Have you tried adjusting the eccentric cam on the arm pivot point?

Over to ‘rumbled’ …

After chatting to a mate the other night, I filled a 2 litre juice bottle with water and hung it on the brake lever for a couple of days. It’s reduced the travel by a good 60%. Just got to try it out on the road next and report back.

Yup, taken out the travel and sharpened the braking. It worked on the other front brake too, after strapping up the lever overnight.