brake pedal to the floor

[chickentender]

i was driving my 60 BT7 the other day and all of a sudden i have no brakes with the pedal going to the floor. pump it again and i have brakes. it happened a couple of times on that drive and hasnt happened the next few drives. when it happened, i assumed it must be the master cylinder and was going to take it in for repair but it hasnt happened on the last two outings. the brake fluid cannister is full. any suggestions?

 

[elrey]

FIX IT OR DIE.

 

[tahoe healey]

Master cylinder is my guess. When you push the pedal, fluid is going around the rubber cup instead of being pushed to the wheel cylinders. Check for dripping on the cabin side of the fire wall under the carpet. If you still got lots of fluid in the reservoir, there isn't a leak. If you had a wheel cylinder leak you would see fluid on the inboard side of the tires and the fluid level would go down.
Not real difficult to replace. Moss got their act together with the master cylinders now. Caution when bleeding. I over tightened one of the bleeder valves and stripped the threading. Got effective but spongy brake until I discovered the failure (spotted the fluid in the tire). Very hard to find Castrol LMA these days. This is a good time to flush out all the fluids including the clutch. Clutch slave is a real bitch to get to but do able.
Definitely agree with Elrey!

 

[Keoke]

FIX IT OR DIE.

 

[Roger P. Main]

It could be the spring in the master cylinder that closes off the line to the fluid reservoir. If the spring is broken, as happened on the clutch master cylinder of my Triumph TR-3A, which uses the same Girling master cylinder as on your Healey, way back in 1963, fluid will be forced back into the reservoir, instead of to the brake calipers/wheel cylinders, when your step on the brakes. I was told back then to use two springs, which will guarantee that breakage of one of the springs will not cause problems. The spring is highly tempered and very brittle, and can break without warning. I had to drive all the way from New York City to Washington, D.C., with a clutch that would not disengage back then. I forced the gearbox into fourth gear and stalled the engine every time I stopped. I then restarted the engine with the gearbox in fourth gear and the good, old, tractor engine the Triumph had drove right off. Try that with any modern car with a manual transmission.

 

[why]

Same very intermittent work-not work with no loss of fluid in my Etype clutch, rebuilt master cylinder now just fine.
Jay
'65 3000

 

[Marvin Gruber]

Sounds like the M/C is bypassing when you push the brake the first time but does still hold after pumping. A rebuild is in order.

Marv