Other Hydroboost Problems

[kbronco]

Alright before anyone flames me for not doing a search, I've looked at pages of hydroboost posts. I have tried everything I know of and everything that I've read in previous posts to no avail. I have an astro hydroboost with a camaro m/c and newly installed chevy disc conversion. I've never driven with this unit so I don't know what it is supposed to be like other than hear-say. I started out by installing the hydroboost (the madgyver route), bench bled (twice) master cylinder. Jacked up the front end to bleed the hydroboost by steering turning lock to lock, did this 3 times with about 50 turns each time. Bled brakes at the wheels, starting at the passenger rear and progressing through until I got to the front drivers (repeated this process3 or 4 times). The pedal still goes to the floor after doing all of this and has a slow return. Is it the booster, the master cylinder, or what? HELP soon before I go completely INSANE!!!!!!?:? ?:? ?:? ?:?

Also I have a deadline to have this done for the LEBC Spring Roundup next weekend.

K

 

[Nobody]

Is the engine on or off when the peddle goes to the floor?

If off, the hydroboost is basically a mechanical pass through, so I'd toss that out of the equation if your peddle is going to the floor.

Check to make sure the bleeders are on the top of your calipers. One of the most common problems.

 

[bigmuddy]

As Nobody says, make sure your bleeders are facing in the right direction. I had a huge problem with this because my definition of up is different that what is really up. Anyway, two or three pass back and forth may not get the air out of the boost system. With the engine running can you see any air bubbles in the PS pump? A little isn't to bad. If it's really foamy then you probably have a leak or just haven't got enough air out of the system yet.

Ben

 

[DanWheeler]

ditto on the foamy and check the PS fluid level too. If the fluid level gets too low it will suck in air and bubbles and cause more bubbles making the problem worse. Fill it up to the top and keep it topped off and what the pump doesn't need it will squirt out the cap and make a mess.

and it seems to me if the pedal goes to the floor with the engine on OR off the problem is with the brakes or the master cylinder. The hydroboost is just "assisting" you in pressing the master cylinder.

 

[kbronco]

Is the engine on or off when the peddle goes to the floor?

If off, the hydroboost is basically a mechanical pass through, so I'd toss that out of the equation if your peddle is going to the floor.

Check to make sure the bleeders are on the top of your calipers. One of the most common problems.

All the bleeding has been done with the engine running. I have heard alot about the bleeders being on top, and as far as I know they are. They point straight up toward the fender wells.

The pedal is a little firmer with the engine off, but I think that's just the master cylinder. Am I correct here.

 

[kbronco]

As Nobody says, make sure your bleeders are facing in the right direction. I had a huge problem with this because my definition of up is different that what is really up. Anyway, two or three pass back and forth may not get the air out of the boost system. With the engine running can you see any air bubbles in the PS pump? A little isn't to bad. If it's really foamy then you probably have a leak or just haven't got enough air out of the system yet.

Ben

As in my reply to nobody, my bleeders are as up as I can get 'em. They point straight up toward the fender well. I did the ps bleeding sequence three times with about 50 back and forth each time for a total of about 150 lock to locks. The fluid has no bubbles to speak of and no foam. Also forgot to mention earlier that the ps pump is a brand new napa dual return pump. All hoses are brand new and I can't find any leaks anywhere.

Puzzled

 

[kbronco]

ditto on the foamy and check the PS fluid level too. If the fluid level gets too low it will suck in air and bubbles and cause more bubbles making the problem worse. Fill it up to the top and keep it topped off and what the pump doesn't need it will squirt out the cap and make a mess.

and it seems to me if the pedal goes to the floor with the engine on OR off the problem is with the brakes or the master cylinder. The hydroboost is just "assisting" you in pressing the master cylinder.

I was sort of suspicious of the master cylinder as well, but it is new from O'Reilly. I guess I can try to take it back and get a different one. What do you guys think before I go to this trouble again. Thanks for all the info guys, keep it coming.

Kaleb

 

[Nobody]

You say you used a camaro master. Are the lines hooked up correctly? Chevy is often opposite of ford, where the lines are front/front rear/rear. Is this a disc/drum master or disc/disc?

For best results, the power steering system should be bled with the engine off.

When you start the engine does the peddle go down by itself?

 

[kbronco]

You say you used a camaro master. Are the lines hooked up correctly? Chevy is often opposite of ford, where the lines are front/front rear/rear. Is this a disc/drum master or disc/disc?

For best results, the power steering system should be bled with the engine off.

When you start the engine does the peddle go down by itself?

Yes the lines are all hooked up correctly, and the master is disc/drum. I bled the power steering with the engine off as well last night and the results were no different. The pedal stays up unless you depress it, it doesn't go down by itself.

 

[bludorbronc]

I found this maybe it will help http://www.babcox.com/editorial/bf/bf030542.htm

 

[kbronco]

I found this maybe it will help http://www.babcox.com/editorial/bf/bf030542.htm

That gives me a couple of ideas to try tonight, but I still need suggestions. Where are TOFIC and Mad on this deal? If I don't get it tonight I'm liable to really lose my cool with this thing.

 

[Roadburner]

I went thru the same thing with my oldest sons 70 with 4 wheel disc. Pedal would go almost to the floor and had very weak brakes. We drove it a few days and the brakes finally came around on their own. Now if you hit the brakes hard it would put you thru the windshield. We are finishing up #2 son's 74 and have the same problem. Hoping the driving around will work again. Good Luck

 

[eds66bronco]

it hasn't been mentioned in this thread yet, but double check the clearance on the knuckles for the calipers. if they can't slide past the knuckle, you will never get good pedal.

 

[kbronco]

it hasn't been mentioned in this thread yet, but double check the clearance on the knuckles for the calipers. if they can't slide past the knuckle, you will never get good pedal.

I'll double check this. I ground them some, but how much is enough. This is one thing I hadn't really thought about.

Thanks

 

[kbronco]

I ground on the knuckles and calipers last night and now have about 3/16" gap between the two on both sides. I guess that should do the trick. I had other projects going too (needed a night away from brake bleeding) so I didn't get a chance to try them out, but tonight is the test. Wish me luck.

K

 

[eds66bronco]

I ground on the knuckles and calipers last night and now have about 3/16" gap between the two on both sides. I guess that should do the trick. I had other projects going too (needed a night away from brake bleeding) so I didn't get a chance to try them out, but tonight is the test. Wish me luck.

K

hope that does the trick for you..

 

[bigmuddy]

Hey man, can you post a picture of your calipers? According to your description you say the bleeders are pointing straight up to the fender wells. If this is so, I beleive you have them on the wrong side. Swap the calipers side to side and try again. You want the bleeder nipples to be at the highest point of the caliper and they should be pointing straight back to the rear tires. I fought this issue with bad brakes and a low pedal for way to long and finally discovered by accident that I had the calipers on the wrong side and there was just simply no way to get the air out of them. Took me about ten minutes and then bled them and I was in business.

Ben

 

[kbronco]

Okay so maybe they don't point exactly straight up. Not a pic of mine but this is how they look.

http://classicbroncos.com/img/chevybrakelines1.jpg

Things came up again this evening and didn't get a chance to work , but first thing in the morning I have a date with a hydroboost.

 

[bigmuddy]

Then you are probably OK? I forgot you are using the chevy stuff brakes on your rig. Mine are the ford calipers and when they are mounted correctly they shoot all most directly back toward the rear tires.

Ben

 

[BG's 68 Bronco]

Okay so maybe they don't point exactly straight up. Not a pic of mine but this is how they look.

http://classicbroncos.com/img/chevybrakelines1.jpg

Things came up again this evening and didn't get a chance to work , but first thing in the morning I have a date with a hydroboost.

It sounds like you have the calipers on correct. I never had my pedal fall to the floor, but I have and still fight with a bit of a soft pedal. If I find out my issue I will let you know, but for now lets see what we can do about yours.

The lines from the pump to the booster etc. are all hooked up correctly? This has probably been gone over a couple times, so forgive me asking it again.

Just thinking here, but when your pedal goes to the floor (I assume this only happens when the engine is running) are the brakes engaged during this time? Can you push the Bronco if you put it in neutral? I'm kind of thinking the booster could be bad if all else is good? No loss of Power steering fluid around the booster?