So i have a little vent hole in the middle my front master cylinder. Does this serve a puprose other than to allow brake fluid to drip onto my gas tank? I would like to plug it or replace the master cylinder cover.... Thoughts?

 

It's a vent port and DO NOT BLOCK OR SEAL it off , if it's leaking you need a a new cover gasket and maybe a cover too . Seen a bunch of those warp for whatever reason , pull the cover off and lay it on something flat like glass and check the flatness and that has a thin paper gasket with what looks a condom sandwiched in there , easy to tear and leak it will .

 

That's what I figured. Thanks.

 

You can buy those gaskets in packs of 6.


Carl

 

Bumping an old thread here... but I'm having the same problem with mine. Have replaced the gasket three times, even tried a brand new cap. Still leaks, still will not hold pressure. I'm thinking I need a whole new master cylinder... any tips/thoughts?

 

yep its internal bypasing the fluid and if it is full to the top it will come out someplace - just get another one - they are only china today and its 50 50 if you get a good one

you could try a kit but we are talking about a master that is probly 35 years old soooo

we have had some luck with OH them - the master from MID USA is actually a good one for china

it only comes chrome and the number is 45208 is the one we use its 100 bucks retail

 

I would work for days on OE before I give Chiwan any $$ I don't have to!
A Shotgun bore brush and Cleaning swab holder..Chucked in a Handheld drill motor works wonders...Cups and O-rings are cheap at NAPA!
$0.02

 

that is an owner that can be that way - i keep 3 of those kits in stock at all times and weeks go i do not have one for a job we sold them all - its a money thing even at 50 bucks and hour and we are more than that, plus the kit --- and when it come back in 3 weeks not working what then - you its oh well it dident work - me i have a guy who spent the same or more money fixing a junk master AND who pays for the new one china or not

 

I'll give ya all that...Owned a Shop for years...don't now.
Most folk coming to a tech forum are attempting to DIY, not justify Shop Time.
For those who Have to have "New" at the cost of Quality... Well There is always Chiwanese ..."products". so yes there needs to be alternatives....

 

at the antique event swap meets a new old stock harley master fetches 300 bucks on a bad day raining all week end