OldIHC

Hey all! I've got some questions in regards to some brake issues I have on my R120. When I apply the brakes the petal goes to the floor. I checked the master and full of fluid. It Almost seems like.the break leaver is not attached the the master cylinder. Any thoughts on a repair option?

Thanks!

if you have no leaks anywhere, and master is full, it is an internal leak IE: the plunger rubber is worn and allowing fluid to pass,

usually this happens to one that has sat, or was low, plunger goes past regular wear area into crusty zone, fries em quick.

, you need to rebuild it or buy a new one,

my dad refused to believe in a internal leak, made me help him bleed his brakes 4 times before he finally admitted it was the master.

Have you bled at the brake shoes? Do you have someone to help and observe? Others will probably speak up with more advice.

Looks Like i will need to get a new Master... That Stinks... But better be safe than sorry! Thanks guys. Ill have to post pictures of my Findings. You all will Appreciate!

I have tried to bleed the breaks but no luck... There is no pressure to the cylinders.

The master cylinder is likely shot and needs to be replaced.
Bill

To save the question/time just in case...
Master cylinder
R 100,110,120 + 130 w/o hydro-vac
48638HA IH
MC1722 Raybestos
MC1722 Wagner
P1722 NAPA Proformer (reman)
M1722 NAPA Premium (new)

Kit
121402HB IH
MK25 Raybestos
MK3631 Wagner
UP25 NAPA

HE SAID:
Have you bled at the brake shoes?
Those bleeding brake shoes are the absolute worst. I have no suggestions. I'll bet that MAGIHC Mike would have a solution.

I tried to bleed the breaks and no luck... Is rebuilding the Masted Difficult?

If you have to ask, maybe you should consider buying a new one. I say this because it is reasonable to assume that you do not have the tools to hone the bore of the master cylinder. This is one of the most critical areas of the system. If you do not get the brakes correct, something will break when you can't stop. You are responsible to maintain and repair your brake system to the manufacturers original standards. Your insurance may become invalid if you have failed to do so and there is injury or property damage. This is not an area to hone your skills.
Don't be too surprised if you have to replace the whole system if it is original or not done in decades. The flexible hoses in the system will most likely be failing and the original steel brake lines should have significant corrosion on the inside. Brake fluid is hygroscopic by nature and will have absorbed moisture. This moisture will rust the lines through from the inside. The corrosion situation in the master cylinder has been mentioned and the same situation will be in the wheel cylinders.
I used silicon brake fluid in my R120 and after 20+ years and a quarter million miles the system was clear on the inside, but it rusted heavily on the outside of the steel lines.
Brakes are not for first timers.