1991 G30 7.4L V8. (Its in an RV). ~60,000mi.

The brakes have never felt right. The pedal mostly feels like it travels too far before it engages any power braking, and then it does't really feel like I am getting a lot of power assist - so I have to really stomp on the break pedal. Sometimes after pumping the brakes a few times, I do feel like the pedal is higher and get some more power assist. One BIG Note, during my repairs, I did once lose all power braking, so as bad as my brakes are now, there is some power assist going on.... just not great. As for repairs, I have had the following:

- Master Brake Cylinder replaced. (There was leak between the hydro boost and master cylinder)
- Hydro boost replaced - twice (guessing re-manufactured part.)
- Rubber brake lines replaced 2x in front, 1x in the rear.

Not yet done:
- Brake pads / rotors
- Power steering pump.
- Hydro boost lines.
- Proportioning valve.

Anybody have any guidance? Could it be the PowerSteering pump? Lame Hydro boost rebuild? Bad proportioning valve? Bad pads (there were probably done long ago by someone else.)

Thanks
Doug

 

I would get the brakes side squared away first then mess with the assist side.
Does the rear have gear oil leaking on the brakes? Are the self adjusters working? Are the wheel bearings too loose on the front? Are you using quality DOT4 brake fluid from a new sealed container? Have the brakes been bled to get clear fluid out of each corner?
Cheap pads have very poor friction coefficients! Get some good quality pads and shoes. Look at the edge codes. I don't know why they don't list them in the specifications. You need to look at the parts themselves. I normally consider FF my minimum.

https://www.hotrod.com/articles/disc...des-explained/

Then again I don't have any experience with diagnosing hydro boost systems.

 

Pads and shoes will make a difference in pedal travel.

Hydroboost may need to be bled.

 

Are the rotors bare metal on both sides of the disc or are they all crusty? Are the calipers seized and only applying on the inside of the rotors? Are the rear brakes adjusted with normal operation of the parking brake? How much does it weigh in its current state?