Master cyllinder warning switch leaking
Thread Starter
2nd Gear
Joined: Mar 2007
Posts: 2
Likes: 0
Master cyllinder warning switch leaking
Have a 86 vette and brake fluid is leaking out of the warning switch, which is screwed into the master cylinder. It leaks when brakes are applied from the hole between the two connector post. Have installed a new switch and it is worst than the original. Master cylinder seems to be ok as brakes are good and no warning lites.The switch has a plunger at the end of a spring which goes into the body of master cylinder, but there appears to be no fiber or rubber type of seat in the cast part of the master cylinder. Could this be the problem?
Thanks Gene
Thanks Gene
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
Master
your master cyl needs an overhaul. The plastic switch does not hold any pressure. the plastic piece has 2 purposes, 1. it holds the electrical contact, and 2. it holds the spring and internal piston in place.
No fluid should touch it.
if the fluid is coming out of it, your master cylinder big piston is seeping.
No fluid should touch it.
if the fluid is coming out of it, your master cylinder big piston is seeping.
Racer
Joined: Jan 2006
Posts: 473
Likes: 7
From: Houston Texas
The exact same thing happened to me.
I replaced the sensor thinking (hoping) at first it would fix my leak.
It did not fix it and I had to replace the MC as said above.
You can find a great deal on brand new GM/Delco from a seller by the name of thepartsladi on eBay. Just do an advanced search and search by seller name.
I paid $189 + 10 shipping for the one for my '88.
If you install it yourself don't forget to bench bleed the MC before you install it.
Good luck!
I replaced the sensor thinking (hoping) at first it would fix my leak.
It did not fix it and I had to replace the MC as said above.
You can find a great deal on brand new GM/Delco from a seller by the name of thepartsladi on eBay. Just do an advanced search and search by seller name.
I paid $189 + 10 shipping for the one for my '88.
If you install it yourself don't forget to bench bleed the MC before you install it.
Good luck!
