brake master cylinder replacement

[faiyaz]

So my brake master cylinder is leaking badly and i cant find the exact one locally, its a 13/16 master cylinder, bought new seals and fitted them but its not pressurizing , i managed to find a 1" bore master cylinder with the same hole pattern as the 13/16, my question is will the bigger master cylinder cause my brakes to leak over time or will the pedal travel just be less??

[Mud Dog]

It should be fine. The bore is not that much bigger that you will notice any significant difference besides a bit better braking power.

[faiyaz]

ok thats great, yup the pedal really goes down at the moment theres alot of play, should i adjust the push rod ? if so how to adjust it correctly ?

[Mud Dog]

No don't adjust it (don't think you can anyway) .... your braking will start a little higher up than before but6 that's also OK and in fact I personally prefer that.

[faiyaz]

ok cool thanks for the help !!! will get back to you if any issues.

[Mud Dog]

[faiyaz]

So i fitted the new master cylinder but before i did that i removed the front tires to make it easier to bleed the brakes, when i did that i notice one side of the caliper was leaking and I had fitted brand new caliper seals about 2 weeks back!! so removed the caliper and found one of the seals had got a grove in it, not sure if it occurred whilst i was fitting it or the quality of the seals is bad, mind you on the RHS i fitted the same seals and no signs of leakage, the pistons are all in good shape along with the bores. Anyways got a new seal and a few for spare, and fitted it, you can see what the one i removed looked like. After this i fitted the new master cylinder and bled the system then checked for any leaks, so far everything seems fine but will monitor that caliper. On the plus side the brake pedal has come right up !! before it used to be only 3-4 cm off the floor now that distance has doubled!! Luckily there's still some free play and no sign of binding on any of the brakes.

[Mud Dog]

Great stuff!

[Mars]

Glad to hear you got it sorted.

[faiyaz]

yup! but the following day the clutch slave cylinder gave up!! it was the seal inside luckily i was close by home, so just drove it in second!! managed to get a replacement kit and honed the cylinder to clean it up, also opened the master cylinder to inspect the seals, they were in good condition, bled the system and the clutch pedal is solid now !! think i used cheap brake fluid and it dissolved the seals ( within a year) because the brake fluid was really black, this time i used FUCHS dot 3 brake fluid so should be ok.