My light bulb burnt out, please help with my HydroBoost.

[cheap bronco]

Hello All,

I want to thank everyone in advance for posting answers to my question. I have a 1988 Bronco w/7.3 IDI Turbo. I have converted over to hyrdoboost, I have used the hydroboost setup on the gas engine for 2 yrs before converting to diesel and no problems. Now when I finished the conversion I have issues. The rear axle is a 1993 10.25 sterling w/disk brakes from a 1999 E350 conversion. The hydroboost unit is a rebuilt Napa item from a 1988 F450 (2nd one), 1993 F350 Master Cylinder (2nd one), 1988 F450 Orielly's rebuilt powersteering pump (2nd one). Now for my dilemma, my brakes are Draggin, When I start the engine, I can see the pedal lower about 3/4-1", and when I shut the engine off I can see the pedal rise. The first hydroboost unit did the same thing that's why i exchanged it. My 02 F250 Superduty's brake pedal does not move when i start or shut the engine off. When i drive the vehicle and i apply the brakes it stops great, but when i take off it feels like its im towing a trailer and when i pull up on the pedal with my foot, it feels like it moves forward more freely. Also when i turn the steering wheel all the way to the left or right i can see the pedal rise. Now im suspecting it still might be the powersteering pump again. Hope someone with more knowledge at hydroboost can help me see the light. Thank you.

 

[icanfixall]

Sorry but thats a new one on me. Something sounds wrong thats for sure. Are the front brakes running hot or do you know. As for adding rear discs that shouldn't change things causing your issues. Why didn't you get the large bore master cylinder when you did the change. That 1 5/16 master cylinder bore really changes the brakes a lot.

 

[typ4]

dumb question, is it plumbed right, and at rest is there some free play in the pedal to hydro.?

 

[79jasper]

Sounds like the booster is failing.
But Russ's question is a great one.
Maybe a line(s) got hooked to the wrong spot(s).

When you turn full tilt, (IIRC) the gearbox will be taking all the pressure from the hydro.

 

[Ocelotl]

Did you install the steering pump cover with the two return inlets to plumb the returns individually, or did you tee them together before returning to the pump? I've seen a few mentions of dragging brakes due to teeing the returns. Or maybe the new to the truck rear calipers are sticking and need a rebuild?

 

[franklin2]

Like someone else mentioned, I would take the linkage off the pedal and see if the rod going to the booster has room, or is it being pushed a little bit all the time.

 

[riotwarrior]

Gotta ask, did you use the correct brake pedal for the Hydro boost or modify the stock brake pedal by moving the actuating pin up 3/4" on the arm?

I personally don't see how that would cause this but it's just one more piece of the puzzle really!

Will reserve thoughts till more 411 comes along....

Al

 

[cheap bronco]

well, i would like to thank everyone for their time trying to answer and knowledge. I fixed it, let me start by saying i sat in front of the bronco on a chair for an hour trying to think of what i did wrong. Then i realized i also installed a power steering cooler. So my problem is that i t-eed the return line from the hyrdo boost before the power steering cooler not after, which created a blockage. I was supposed to be t-eed into the return line after the cooler right before the pump. I cant believe i changed brake components twice and not realizing what i did wrong. Oh well, nothing like learning on your own skin. Everything works awsome. I love the rear disk brakes. So to everyone in the future converting to hydroboost brakes always connect the return line after the cooler right before the pump.

 

[icanfixall]

Thanks for posting what the problem was. It takes a big person to tell what they did wrong but its fixed now. time to enjoy it too...