Brake ? for my 71

[az's1971C10]

Hello Everyone,

I have a brake question that maybe you guys can help me out with. I bought a 71 SWB with a 4 speed Saginaw for my daughters first vehicle and today was the first day we got a chance for her to drive it. She has only driven my Ram 2500 HD and our I35 which are both AT's in parking lots since she is only 15 and doesn't have her permit yet.

After a few minutes of showing her the pattern of the 4 speed, off we went and she did pretty well for her first time driving around in a parking lot. After 45 minutes of this I could tell both her and the C10 were getting frustrated with each other so I took over and drove home. Well as soon as I hit the road the "BRAKE" light came on and my brakes were squishy to say the least.

I took it home and checked the master cylinder and noticed that brake fluid appeared to have leaked out and I assume it boiled over. When I opened up the master cylinder it was only half full. I refilled with fluid and pumped it several times and got the brakes back to where they were before.

So to make a short story long, what are your thoughts on preventing this issue again?

Here are the Stats on her truck: 350 with PS, Front Disc, rear drum, Non-AC for now. If I can figure out how to post pics of it I will.

Any suggestions would be helpful.

Cheers

[litew8]

I don't think brake fluid can "boil" - best guess, you're leaking from somewhere. Check all wheels and dist. block. It's escaping from somewhere.

[mgchevyparts]

The "brake" light comes on when ever the shuttle valve inside the prop valve moves off center. It can do this when either the front or rear section of the brake system has a leak. The valve moves in the direction of the low pressure to shut off the flow of fluid in that side. When you refilled and pumped it you recentered the valve and the light went back off. Do you recall which section of the master was low? That is the side that has a leak or some other problem. Generally the front bowl is front disc brakes and the rear bowl is the rear drum brakes. Also notice that the larger bowl or reservoir is for the disc brakes and the smaller of the two is the rear drum brake side.

[az's1971C10]

Thanks for the info and both were low. I will be calling a mechanic friend of mine so we can find where the leak is.

cheers

[litew8]

You should be able to see where it's at yourself, if you able to look up underneath, behind each wheel. The lines connect to the backside of each wheel. It could also be due to rusty lines - creating pin sized holes in the line(s), in which - the leak(s) could be anywhere. If not the lines, try taking off the rear wheels+drum and check the cylinders - they could have gone south and need replaced.

[az's1971C10]

Thanks for the info. I will be doing a search for the problem hopefully sooner than later.

cheers