TOFIC!! Please help...

[jesus888]

I'm dying with this Lincoln hydroboost... Anyone know TOFIC's phone number?

 

[jesus888]

Ok here's the situation...
Engine off, and no matter how much I pump, the brake pedal doesn't get hard.
We've bench bled the MC. We've gravity bled AND pedal bled the brakes. There are no leaks.
The pedal basically returns from the floor about 2 inches...
The hydroboost and MC are from a 78 Lincoln Continental and the "accuator pin" was ground down to fit the MC since one didn't cone with the system (both were remans).
PS pump is a Saginaw dual return pump...
Possibly related, when the engine is on, Pierre steering works but it isn't 100% right... It kinda vibrates when you turn the wheel... It's just not smooth.
Also, we followed the lock to lock 20 times bleeding procedure prior to starting the engine...
SO frustrated because this is the only thing stopping (pardon the pun) us from going on the rigs first test drive!!!!!

 

[jesus888]

Any bronco hydroboost guru that'll share a phone number? We just don't know what to do next.............................. FACK!!!!

 

[73stallion]

have you tried with the engine running to see how high the pedal is? hydroboost will have a lower pedal with no engine power.

 

[jesus888]

When the engines on, there still very little pedal. Actually earlier in the day when we tried, there was none, but we bled the system again since then and did get a little more air out. Unfortunately can't start it back up til the morning... Got a baby and wife sleeping

 

[jesus888]

when bleeding the brakes (engine off) there are no air bubbles and plenty of fluid is pushing out; however the pedal never gets hard.........

 

[jesus888]

So we just pulled the MC to take a look at the "accuator" as we depress the brake pedal... when we push the pedal down, the accuator pushes out about 1 inch... and then when we let go of the brake pedal, the accuator pin also goes back... just 1 inch.

 

[jesus888]

And one more thing... before we pulled the MC, we jacked up the front end, hand-rolled the front tire and pushed on the brake pedal... the tire BARELY even slowed down. BUT if we bleed the brakes, the caliper gushes fluid... so there seems to be plenty of fluid in the system.

 

[72Sport]

The push rod in the hydro-boost should ALMOST touch the the bottom of the hole in the master cylinder piston when the master cylinder is bolted up to the hydro-boost. I set mine up with about 1/64 clearance when the master cylinder is bolted up to the hydro-boost. If the push rod in the hydro-boost is too short you will not have much braking if any.

Seems strange that you had to grind down the actuating pin on the hydro-boost if both the mc and hydro-boost were from the same vehicle.

 

[jesus888]

Since we didn't have a stock push rod... we actually shortened the one we had until it was as you said. When it's pushed ALL the way back towards the firewall, it will JUST touch the MC plunger at rest...

 

[72Sport]

I am not sure but I thought I had about 1 5/8" travel on my brake pedal. It has been a while. Make sure what ever you have for a push rod has enough travel and is not binding or hitting on something. Maybe the problem is in the linkage to the hydro-boost. ?? If you have your old MC handy push on the piston with a screwdriver and see how much travel it has. An inch doesn't sound like enough.

 

[jesus888]

At this point... we're thinking it may be the internals of the hydroboost... what pisses me off is it was a reman part... and my rig has never moved. Hence, somehow we jacked it up while hooking it up?? I will check the MC movement again in the morning...

 

[phred]

I've had quite a few reman'ed parts that were defective out of the box. Take it back and get another one.

 

[Mongonius]

Brake system Viagra?

 

[ET]

I've got the same issue with mine. However, the hb and pump are from p30 van and they're used. Not really an expert but it seems maybe the ps system is not fully bleed. We had success with some peddle with the engine running unfortunately the fuel pump quiet so we couldn't finish. Because of this, maybe the system is not completely bleed with just turning the wheel lock to lock on jack stands. And this is just a guess, but maybe cycling the steering wheel with the engine running and fluid being pump through to get all the air out. Still fixing the fuel pump so I can't try yet.

Eugene