Hydroboost pedal feel

[edfiero]

Should the brake pedal in the hydroboost cars be firm, as in any other kind of car?
My pedal is spongy under hard stops. Wondering if this is normal, or might I have some air in my system?
Thanks

 

[Chuck Leeper]

Sounds like air in the system.
We use a rubber hammer, to knock on the calipers, m/c, wheel cyls, while bleeding.
I prefer to "bench bleed" the m/c on the car. Even once the m/c is deemed to be bled, a couple more raps, there's another few bubbles pop up.
Some use a power bleeder. When working right, it does a good job. We don't have one. The one we tried was junk.

 

[captndave737]

The pedal will feel different from other systems but not feel spongy. You should also be able to lock up the wheels, not that you want to do that but you should be able to without very much brake. I tested mine after rebuilding the unit yesterday and I locked up with about 2/3 pedal and I've got some pretty hefty sneakers.

 

[1KWIKSIX]

try installing 2# residual pressure valve in front brake line for disc brake set up and 10# residual pressure valve in rear drum brake line.
These will eliminate excessive pedal travel. I have them installed in my set up & couldn't be happier with firm brakes and pedal travel.

Wilwood Disc Brakes - Proportioning Valves & Pressure Valves

Wilwood makes a wide assortment of small, lightweight master cylinders that are suitable for high performance street and racing applications and they are available in a variety of bore sizes. This page displays Proportioning Valves & Pressure Valves

www.wilwood.com

 

[Chuck Leeper]

try installing 2# residual pressure valve in front brake line for disc brake set up and 10# residual pressure valve in rear drum brake line.
These will eliminate excessive pedal travel. I have them installed in my set up & couldn't be happier with firm brakes and pedal travel.

Wilwood Disc Brakes - Proportioning Valves & Pressure Valves

Wilwood makes a wide assortment of small, lightweight master cylinders that are suitable for high performance street and racing applications and they are available in a variety of bore sizes. This page displays Proportioning Valves & Pressure Valves

www.wilwood.com

Good point. We use a 10# on all rear drum apps.
We use 2# on all rear disc apps.
It is installed as close to the m/c as practical.

 

[captndave737]

I never heard of those! I love the things i learn on this board. Guess i have to break out the wallet again.