Installed Hydroboost into '97 Riv. The objective of improved braking power.
When I start vehicle the brake pedal instantly goes down about 1 1/4 to 1 1/2 and stops, with this movement the brakes are slightly engaged.
1. HB is plumbed correctly.
2. Using '97 MC with 1" bore. Had MC male or pilot portion machined down to fit properly into HB.
3. Stock '97 Power Steering pump.
4. Can drive car, PS works fine.
5. Vehicle front jacked up for proper HB bleed.
6. This is the second HB installed and doing same thing. First HB was reman and second is from '98 Astro, via junk yard.
7. Have fooled with push rod in between HB and MC. When I shorten push rod it just allows break pedal to travel even further down.
8. I can drive vehicle short distance, before calipers on front get very hot.
Have read many different forums and have not found this exact problem.
Would greatly appreciate and suggestions & help. Not sure if I have HB problem, or MC which is not correct with HB or PS pump issue??

 

Have your thoroughly bled the power steering system? Thats usually a problem associated with air in the lines.