Hydroboost won't lock up wheels!

[tflyboy77]

Hi guys, I have a 77 Trans Am with 18" Rushforths, drilled and slotted rotors, ssbc upgrade aluminum calipers up front and 94 camero 12" brakes in back. I also have braided lines all around. I didn't have enough vacuum so I decided to switch to hydroboost but Hlike an idiot I chose the cheap universal fit unit instead of calling hydratech. My problem is that after the install I can't lock up the wheels on pavement. I can lock the front on gravel and I've tried adjusting the willwood proportioning valve all over the place. I'm also using a steel corvette style 1.25 master and proportioning valve. Any help would be great.

[gsxrken]

How much PSI are you getting at the caliper bleeder? Get a brake gauge and measure it.

[tflyboy77]

I'll try that. I've never checked brake pressures before. Do you have any tips on how to do it?

[MuscleRodz]

are you saying you don't have any hard brake lines or just braided flex instead of rubber.

[neki67]

I think it's due to the 94 Camero brakes.

Changing over to Camaro brakes will certainly help . . . . . . .

[tflyboy77]

Braided lines instead of rubber and typing with a 6 week old in your lap leads to bad spelling. It also leads to less garage time.

[neki67]

1.25 or 1.125 Master? Usually a 1.125 is recommended in combination with Hydroboost and those kind of calipers.

Could you lock up with the vacuum/old system and what kind of master were you using? Any other changes in the brake system compared to what you have now?

Sure there's no more air in the system?

[tommycomfort]

Are you running though the factory proportioning valve? I have found that things work better when you run reservoir for the fronts to a distribution block and the one for the rears direct with just an adjustable valve along the way. Might be something to look at.
Tom

[tflyboy77]

1.25" master the master and proportioning valve are the old corvette style that seems to be common in this setup. The rears go from the master through the proportioning valve to the adjustable valve then to the brakes. All of the parts are brand new.

[camaro427-69]

somehow it seems it´s a ssbc problem. i have the same setup front just no drilled rotors and a disc kit back but it seems the ssbc calipers are no good. i was able to lock up the fronts with my stock front discs without a problem, but since i swapped to the ssbc quick change a long brake journey started with several changes in mc,boosters,manual,......! now with the hydroboost it went way better and i have brakes again, but i need to heat those brakes to make them work. maybe it´s a brake pad problem but never changed them. when cold there´s no bite at all, when i applied brakes a couple times to warm them, they start to lockup. but for safety in mind it´s definitely not good when you have to hope that your brakes work. i´m gonna save some money to swap over to a willwood kit or something similar to get rid of the ssbc stuff.

[MCB Matt]

Does the valve have a switch on it with a wire hanging off? If so check contanuity from that center pin to ground. If the circuit is closed the prop is closing off pressure to front or rears. With that type of valve you need to presssure or vacuum bleed the system or the valve will sense low pressure front or rear and close off that circuit.

Switching to Wilwood or Baer is never a bad choice! They are both proven brands with BIG names to back them up. We hardly ever have issues with either!

Matt