Higgins56
Well-known member
- Joined
- Jan 2, 2012
- Messages
- 196
- Reaction score
- 0
- Location
- Finland
- My Car
- 1971 Mach 1 Fastback now with 503 CID 4 bolt block with AFR Bullit heads , Edelbrock Performer RPM AirGap intake and ProSystems carburettor 1050.
4 sp Toploader with 9" Wavetrac rear.
Caltracs and shocks at the rear.
I have 71 Mach 1 with a modified 429 engine ( car originally with 302 engine).
Has original disc brakes front ( never checked the pads) and drums at the rear.
I renewed the bleeding master cylinder with the same original type but forgot to check the piston length ( assuming it does not need adjustment)
I tested the booster and it works ( pedal goes down when starting the engine).
The vacuum (with the new engine) taken from the intake manifold straight to the booster gives 20 inHg vacuum ...but
I would feel more comfortable if I could lock the brakes when needed ( to find more power) than it is now. Actually the car withe the old engine could lock the brakes when the brake booster was connected to the intake manifold...
What could I do next ?
Before measuring the vacuum from the intake I tought that the new cam is causing too little vacuum for sure but apparently as I know now it should be just fine ( altough on the minimum side = 20 inHG).
Therefore I decided to buy a Hella UP 30 vacuum pump . When measured - straight from the pump intake - it gives 24 inHG vacuum. I did not yet measure it through the whole pipeline at the booster with check valves and other stuff attached - but will do later to see if there is some loss of vacuum on the way. Anyway when the line was ready installed and I tried the car - braking was disappointing even worse than with the intake manifold
booster installation..... the pedal was stone hard ......so I am a bit confused.
The line is mostly 3/8 strengthened fuel rubber hose
Has original disc brakes front ( never checked the pads) and drums at the rear.
I renewed the bleeding master cylinder with the same original type but forgot to check the piston length ( assuming it does not need adjustment)
I tested the booster and it works ( pedal goes down when starting the engine).
The vacuum (with the new engine) taken from the intake manifold straight to the booster gives 20 inHg vacuum ...but
I would feel more comfortable if I could lock the brakes when needed ( to find more power) than it is now. Actually the car withe the old engine could lock the brakes when the brake booster was connected to the intake manifold...
What could I do next ?
Before measuring the vacuum from the intake I tought that the new cam is causing too little vacuum for sure but apparently as I know now it should be just fine ( altough on the minimum side = 20 inHG).
Therefore I decided to buy a Hella UP 30 vacuum pump . When measured - straight from the pump intake - it gives 24 inHG vacuum. I did not yet measure it through the whole pipeline at the booster with check valves and other stuff attached - but will do later to see if there is some loss of vacuum on the way. Anyway when the line was ready installed and I tried the car - braking was disappointing even worse than with the intake manifold
booster installation..... the pedal was stone hard ......so I am a bit confused.
The line is mostly 3/8 strengthened fuel rubber hose