r100 project question.

[Voyager]

: I have put the air nozzle in and no sign of any movement.

What air pressure were you running ??

I have blown stuck pistons out using 150 PSI. Its best to wrap the caliper in a towel or something to restrain the bits

It makes a hell of a bang when they pop out

(This was an ATE caliper from a friend's 1980/81 R100RT).

Bob.

 

[(RIP) Proff]

Easiest way I find is to put plusgas or similar in caliper, let soak and then PUSH the piston in a little bit....
Then soak the outside where the little bastard was stuck soften the old shit/ rust seal and then after leaving overnight [ put bleed nipple back in to stop plus gas leaking....] lying piston up and marinading..


Then blow the fucker out in the morning

 

[fayeslane]

Using a grease gun eases them out as the pressure is gradual. Plenty of lubricant overnight, as mentioned above, helps. If using high air pressure be bloody careful, it's easy to damage parts or parts of you.

 

[wreck diver]

Many thanks for that,an overnight submerged soak and a gentle tap inwards made them move a tad,so pistons out now.new seals next week.
Is it possible to get seals only for the master cylinder? I have only found piston and seal kit,or is this the best way to go.
Just need to stop petrol pissing out of the one carb,its coming from the overflow under float bowl and the hole half way up the carb body
She starts quite well now and ticks over,all be it a bit lumpy.

 

[(RIP) Proff]

Many thanks for that,an overnight submerged soak and a gentle tap inwards made them move a tad,so pistons out now.new seals next week.



Is it possible to get seals only for the master cylinder? I have only found piston and seal kit,or is this the best way to go.
I use piston and seal
Just need to stop petrol pissing out of the one carb,its coming from the overflow under float bowl and the hole half way up the carb body
They all do that sir, it's called "airhead boot" easy fix, carb kit BUT MAKE SURE the floatboal gasket is trur, some ain't
She starts quite well now and ticks over,all be it a bit lumpy.

The lumpiness is probably the carb flooding, turn the fecking fuel off and let her run till it evens up...

 

[vmx1200]

Hi all

Hope you don’t mind me jumping into this thread
I have a 1978 R100RS which I have had since 1980, 5 years ago I rebuild both front callipers (new seals plus pads), at the time I wasn’t too happy with the brakes, it may have been imagination but they did didn’t feel as if the were releasing properly, however if I stopped and put the bike on its stand the front wheel turned ok.
Anyway the bike has been laid up until now and if the front brakes are applied the only way to release them is to undo the bleed nipples thus releasing the pressure.
My question is could this be a problem with the master cylinder not allowing the fluid back to the reservoir, the front pistons must be moving to lock the wheel. Having never had the master cylinder apart I have no idea if it is possible for it not to release pressure
Any ideas?
PS I was going to go for the Brembo conversion and master cylinder on the handlebars but I could not believe how expensive this conversion is now, the ATE’s did ok for 80k so I will stick with them
Thanks