Master Cylinder Question ?

[Duke]

I have the corvette master cylinder with S-10 drum brakes in the rear and GM disc on the front. I swapped the front line to the back port and rear line to the front port. My brakes are now working great, but today I noticed some drag on the disc in the front. Does the corvette master have a residual valves in the master cylinder ports. I sure didn't see anything, but there almost has to be one. Any ideas ?

 

[donsrods]

I think it must have, because we used the same one on my Kids T and the front brakes still drag a little even though we gutted the inline residual valve and turned it into an empty fitting. Not sure where it is in the m/c though.

Don

 

[Todd]

Do you have a return spring on your pedal? I had this problem on a '31 Model A. It had GM disc up front, firebird drums in the rear and I drag until a spring was used to help release the pedal. There was just enough weight from the pedal to do it.

 

[Duke]

I don't have a return spring, I am pretty sure the pedal is returning all the way but I will check that to be sure. You are right it wouldn't take much to make them drag. Today I going to open the bleeder and see if there is pressure in the caliper. That should give me a hint of whats going on. The rotor does get hot, not so hot you can't touch it but hot enough that you wouldn't want to touch it for more that a second or two.

 

[Duke]

Well, now I am confused. Fired up the bucket and applied the brakes a few times. Opened a bleeder on one of the front calipers and there was zero pressure. That tells me there is no residual valve in the Master Cylinder. Jacked up the front and spun the wheels, no drag. I see no problem now, maybe I don't have one after all. One thing I thought about was if there was a little air left in the caliper, when the air got hot from braking the air would expand and apply press inside the caliper. But, my bleeders are on the very top where they should be and I have no air in system. I guess I can't fix it, if it isn't broke. As far as the rotor being hot, it would be hot after braking, I only found it because I often do a walk around looking for problems. I have found over the years it cost less and is a lot easier to fix small problems instead of waiting for it to turn into a big problem, safer also. But, sometimes I find problems that are not really there.

 

[Todd]

When you come home from a drive, couple of miles or so, jack of the front end right away. Then try to turn the tire by hand. You'll know right there if you have a brake that drags.

 

[Duke]

Good point, Will do soon as I can, if the weather holds. thanks

 

[butch27]

Duke: I'm glad your weather is still holding up.Michigan is crap.

 

[Duke]

That was yesterday, today is Pooh Pooh fast turning to crap. suppose to be kaka by weekend. Time to put the bucket to bed till Spring. :lol: