Brake pedal is firm when engine is off. But goes to floor when it's on. It's a 65 dart upgraded the single pot MC to a dual. This car has no brake booster. When I go to bleed the brakes absolutely no air comes out just all brake fluid. Changed all the brakes and wheel cylinders when I did the conversion.
Brake pedal sinks to floor when engine is on
- Thread starter Valsig66
- Start date
-
valiantwagonguy
Well-Known Member
Did you bench bleed the master before installing it? There is no connection of the brakes to the engine if it's not power brakes so how can the two be related? Maybe a line in contact with the ex manifold causing boiling and vapor lock or something but I doubt that. It's got to be a master cylinder problem.
Yeah I bench bled the MC before I put it on. It's from a 69 dart with manual brakes.
valiantwagonguy
Well-Known Member
What about a metering block or residual pressure valves to the rear brakes ?
I bled all four sides a little while ago and no air came out from the bleeder valve. Only when it's put into drive the pedal goes to floor. I'm trying to upload a video to show you
I would guess something in the actual brakes at the wheels. Such as wrong or wrongly installed hardware. I think when you put it in drive, the pressure the engine puts on the rear axle trying to move the car then moves the brakes somewhat, and somehow changes things in the brake(s)
Did you recently have the brakes apart?
Did you recently have the brakes apart?
Yes, all new wheel cylinders and brake pads were changed to all 4 sides. It drove and stopped fine for about 2 weeks then this happened.
Professor Fate
Push the button, Max...
I'd put money on your brake adjusters being waaay out of adjustment.
Edit:
If it just happened after two weeks, then you may have the self-adjusters on the wrong sides- working in reverse.
Edit:
If it just happened after two weeks, then you may have the self-adjusters on the wrong sides- working in reverse.
Something worth checking out for sure. But why does it sink when it's put into drive?? And firm when isn't
Ok will check them out this weekend. Thanks for your feedback
Professor Fate
Push the button, Max...
When it gets way out of adjustment, and then twisting torque is applied, components in the brakes shift around and all kinds of weird funky stuff starts happening.
If the self-adjusters are in backwards, it will get progressively worse.
valiantwagonguy
Well-Known Member
There is something very wrong here and I think the only way to get to the bottom of it is to take the whole thing apart and look at everything. It's your brakes and they have to be right and you have to have confidence in them before you can go out on the road so going back to square ONE is probably the safest thing you can do.
-
Similar threads
