nicedive4u

Hi Guys,

Need help with this problem:

Conversed my 68 from manual drum to power drum. Have bought the midland drum booster, new pedal for power brakes, new brake light switch for power brakes, new cylinders, drums and so on, all is new!

Drums are appointed, and the braking action is perfect. No air in the brake-system.

BUT the brake pedal is too soft, AND the rod from the booster seems to be too soft therefore the brake light switch turns on very very late if engine is running
If engine is off, than the light switch turns on in time after pressing the pedal a short way.

Thought the vacuum is to strong and have installed a reducer in the hose from the brake-booster to the carborator - no change...

So what is the problem there? It's very dangerous to drive, because cars behind me are seeing my brake lights very late

Hope somebody has an idea. Regards
Thomas

2+2GT

Vacuum too strong for power boost? Not hardly. Not enough vacuum is the only power boost problem I've seen.

Did you use the power brake switch?

Do you have the calipers on the correct side? Not as easy as you think, ask me how I know.

nicedive4u

Yes, I bought as well the power brake switch - hope they've sent me the right one, maybe this is the problem with the late switching? Have to check tomorrow. What is the different between the switch for manual brakes and for power brakes - is the spring harder or softer?

I think I have installed the callipers on the right side as described on the box of the calipers, but that could be maybe explain the too soft pedal.
Please tell me 2+2GT how to do it right.

Thanks
Thomas

2+2GT

Look at the angle of the bleed valves in the photo, and look at you car.

JMD

I am going with air in the system theory as well....

nicedive4u

The photo shows calipers for disc brakes, the drum calipers looks different and they are horizontal.

Have read somewhere else that: ...Adjusting the brake booster pushrod: the pushrod has an adjustment screw to maintain the correct relationship between the booster control value plunger and the master cylinder piston...
Could it be this?

Also have read to adjust the rear shoes until you can just barely turn it...
Is that good?

2+2GT

Crap. Drum-to-drum. I blame lack of coffee when I posted.

Nicedive is onto something. The headspace needs be adjusted whenever a master cylinder is installed. The setting is 0-.012

This special tool helps a LOT:

nicedive4u

So, yesterday I disconnected the master cylinder from the booster and adjusted the bolt, yes there were to much space between them. But why? I bought both together as a set master cylinder and booster from CJPonyParts... Must be adjusted already or not?

Anyway, now it's a littlet bit better, but the brake light switches still late. Maybe the switch is bent a little bit? Or I will replace the spring in the switch with a very soft one, that the brake lights are shining when I step a little bit on the brake pedal.

Will tell more the next days.

nicedive4u

O.k. changed the spring and here we go
Now it's finde the light are on when I just press the pedal a very very short way.

I think they sold me the wrong switch :-(

Thanks
Thomas