Hydroboost internal adjustment

[Mikel]

I believe inside the HB units there is a spring that controls how much hydraulic pressure is applied to the main piston for a given amount of pedal pressure.

I know I can change the pedal pivot point, but that would have an effect on pedal travel, which I would rather avoid. Has anyone heard about this internal adjustment?

Thanks.

 

[Gumbybronco]

I haven’t found any internal modification necessary, but I’m also not at the limit of the system.

Vanco was a place I remember hearing about them tailoring hydroboost for different applications. You might reach out to them.

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I have moved away from hydroboost for my next 2 brake upgrades and will be using an ibooseter. Very simple install.

 

[Tiha]

Never heard that. Curious to learn more.

Pedal travel is controlled mostly by master cylinder bore size.

Bigger bore, less pedal travel but more pedal effort.

Smaller bore, more pedal travel but less pedal effort.

 

[Mikel]

I have moved away from hydroboost for my next 2 brake upgrades and will be using an ibooseter. Very simple install.

Interesting! How reliable are those? I assume the pedal still transmits force to the M/C when the unit fails?

 

[Mikel]

Never heard that. Curious to learn more.

Pedal travel is controlled mostly by master cylinder bore size.

Bigger bore, less pedal travel but more pedal effort.

Smaller bore, more pedal travel but less pedal effort.

What I'm trying to do is early/easy pedal application with little pedal effort. By decreasing M/C piston diameter or changing pedal ratio (moving pivot up), I get lower effort, but at the expense of more pedal travel, which I don't like.

 

[Tiha]

What I'm trying to do is early/easy pedal application with little pedal effort. By decreasing M/C piston diameter or changing pedal ratio (moving pivot up), I get lower effort, but at the expense of more pedal travel, which I don't like.

I upgraded my PS pump and that made all the difference in the world for me.

First running a stock for pump. Read about guys upgrading to some series saginaw that helped a ton. Then I went with a pump off a 6.0 diesel from like 2005 and I think it was 1800 psi.

Had read somewhere that the hydroboost actually needs at least 1700 psi to work properly.

Should have kept all my notes, sorry. If you have ever driven a big truck with hydroboost, these little pickups feel so much different. Even compared to the older 6.2 gm stuff, those hydro boost systems worked much better and I think they were using the saginaw pump.

 

[Bebop]

What I'm trying to do is early/easy pedal application with little pedal effort. By decreasing M/C piston diameter or changing pedal ratio (moving pivot up), I get lower effort, but at the expense of more pedal travel, which I don't like.

increase steering pump pressure.

 

[Mikel]

I upgraded my PS pump and that made all the difference in the world for me.

First running a stock for pump. Read about guys upgrading to some series saginaw that helped a ton. Then I went with a pump off a 6.0 diesel from like 2005 and I think it was 1800 psi.

Had read somewhere that the hydroboost actually needs at least 1700 psi to work properly.

Should have kept all my notes, sorry. If you have ever driven a big truck with hydroboost, these little pickups feel so much different. Even compared to the older 6.2 gm stuff, those hydro boost systems worked much better and I think they were using the saginaw pump.

I shimmed the pressure relief valve to get a higher max pressure (I think it was 1500-1600 PSI vs the factory 1300 PSI). But I believe the higher ends of the pressure range only come into play at high braking loads, not during light braking.

 

[Tiha]

I shimmed the pressure relief valve to get a higher max pressure (I think it was 1500-1600 PSI vs the factory 1300 PSI). But I believe the higher ends of the pressure range only come into play at high braking loads, not during light braking.

Well my experience was different.

With stock PS pump I had to push on the pedal so hard during a panic stop that I thought I was going to go through the back of the seat.

Normal braking took a lot of pressure as well.

Swapping to the higher psi pump it stops and steers as nice as my 2014 super duty now. Takes little effort to lock up the tires if I wanted.

 

[Winchested]

From My experience you need a larger master with hydroboost than you do with vacuum assist.

I had to move up to a 1 7/16" bore master from the stock vacuum brake 1 1/8" master.

And I got exactly what you want.

I'm running a PSC 1450X pump though.