Back with more questions!! sorry guys

[smartass12]

Info of what i have that might be needed to help answer...2001 5.3 ls motor with this http://www.summitracing.com/parts/rsd-j85315672 brake booster..

question 1..i have bled many brake lines in my day but never with ls motor (not that it should matter).. ive bled air out of lines for all 4 disk brakes..with truck not running pedal is firm but can still push to floor, if i start motor its not even firm just pushes to the floor with ease.. Any help with this?

question 2..on the brake booster above 1 assume the part the comes off prop valve is a brake switch but only has one wire, doesnt it need two to complete the circuit? if not a brake switch what could it be?

any help would be great

[clinebarger]

The wire is for the Brake Warning Lamp circuit, 8" dual diaphragm boosters are dangerous, They flat DO NOT WORK. Your better off with unassisted brakes than to use that booster.

If your running the booster push rod to the original hole in the pedal, That's 1/4 of the issue, Lower the hole as much as possible, This will give you greater travel, Albeit lower leverage.

[smartass12]

Originally Posted by clinebarger

The wire is for the Brake Warning Lamp circuit, 8" dual diaphragm boosters are dangerous, They flat DO NOT WORK. Your better off with unassisted brakes than to use that booster.

If your running the booster push rod to the original hole in the pedal, That's 1/4 of the issue, Lower the hole as much as possible, This will give you greater travel, Albeit lower leverage.

Not really what i wanted to here. So its pretty much a paper weight? What would you recommend i switch to? (based on what i have now so i dont have to switch to much)

[clinebarger]

Hydro Boost!! New GMT900 units can be had for $200. The expense is the install.
OEM vacuum booster work also....The bigger the better.

[crazy longhorn]

Stick a 3/4 or 1 ton vac booster on a 1/2 ton truck....you will have all the brake that you need! That said, if you are dropping the peddle to the floor, you may have a small leak in the system? Pump the peddle,does it come up/then drift to the floor? Pump it up again....is it solid, then floats to the floor? If so , you have a leak in the hyd system. No If's /ands, or butts....a bad master can play that game....but the 1st place that I would look, would be the banjo bolts, on the calipers? Best of fun...Longhorn

[paul mora]

Did you ever figure out your problems and get the brakes working?

[Blackpony]

If you can push the pedal to the floor, then either the master is bad, has air trapped in it or the calipers were not bled correctly.

[smartass12]

Originally Posted by paul mora

Did you ever figure out your problems and get the brakes working?

not yet, havent had time to mess with it. Going to adjust the rod to get more throw and try to bleed the system again (for the 100th time lol). We shall see. Thats all that is keeping me from shiftin her into drive.

[BR3W CITY]

IF they diagphrams on that booster are shot (or just suck) you'll never ever get pressure.

With the pedal on the floor, does there appear to be ANY braking, or just a loose pedal?

In most facets of my life....Hydro is just better.
FWIW, even when I've run vac-assist brakes, they created some pedal pressure even having never run the truck.

[crazy longhorn]

Just another thought on bleeding the rear calipers? Some of the rear disc kits do not clock the calipers (bleeder), to the very top, & state in the instructions to take that caliper loose from the bracket & clock the bleeder up while bleeding . This is to ensure that all of the air gets out. Just a thought....Longhorn

[littlevictories]

I gave up on power brakes long ago. I use the 1" bore manual master from early 70's corvettes and a wilwood adjustable prop valve on anything.

[smartass12]

Originally Posted by BR3W CITY

IF they diagphrams on that booster are shot (or just suck) you'll never ever get pressure.

With the pedal on the floor, does there appear to be ANY braking, or just a loose pedal?

In most facets of my life....Hydro is just better.
FWIW, even when I've run vac-assist brakes, they created some pedal pressure even having never run the truck.

There is some pedal pressure but i can still push it to the floor

Originally Posted by crazy longhorn

Just another thought on bleeding the rear calipers? Some of the rear disc kits do not clock the calipers (bleeder), to the very top, & state in the instructions to take that caliper loose from the bracket & clock the bleeder up while bleeding . This is to ensure that all of the air gets out. Just a thought....Longhorn

yes, my rears have bleeder on bottom but i did pull them and bled them upright.

[ls1nova71]

Originally Posted by clinebarger

8" dual diaphragm boosters are dangerous, They flat DO NOT WORK. Your better off with unassisted brakes than to use that booster.

I'll second that! The only thing worse is a 7" dual diaphragm. I put one on my car when I built it, but the brakes were just never right. They would stop the car, but if you got in a panic stop situation, it wasn't good enough at all. It was mounted under the floor, so no room for a bigger factory booster. I switched it to hydroboost and it was a night and day difference! It stops like a real car now, and I don't have that nagging thought in the back of my mind of "will I be able to stop in time if this guy in front of me stops suddenly without warning?" I had one close call on the freeway when a woman in front of the Astro van in front of me decided she didn't want to take that exit, and swerved back in front of the Astro van, he locks them up, and I tried, but ended up swerving to the left to miss him, luckily there was no one in that lane. Ironic part is the hydroboost I have now was off of an Astro!

But, back to the point, sounds like there's still air in the system. How are you bleeding it? Do you have a helper pushing the pedal for you?

[crazy longhorn]

Originally Posted by ls1nova71

I'll second that! The only thing worse is a 7" dual diaphragm. I put one on my car when I built it, but the brakes were just never right. They would stop the car, but if you got in a panic stop situation, it wasn't good enough at all. It was mounted under the floor, so no room for a bigger factory booster. I switched it to hydroboost and it was a night and day difference! It stops like a real car now, and I don't have that nagging thought in the back of my mind of "will I be able to stop in time if this guy in front of me stops suddenly without warning?" I had one close call on the freeway when a woman in front of the Astro van in front of me decided she didn't want to take that exit, and swerved back in front of the Astro van, he locks them up, and I tried, but ended up swerving to the left to miss him, luckily there was no one in that lane. Ironic part is the hydroboost I have now was off of an Astro!

But, back to the point, sounds like there's still air in the system. How are you bleeding it? Do you have a helper pushing the pedal for you?

Agree, it has air in the system....or possibly a small leak, that will give you the same feel? Check around all the fittings (banjos ,double check) I have seen, many times that the copper washers do not completely seal on the banjo fittings....because of a ruff casting/casting flashing on a rebuilt caliper & or, the replacement copper washers were not thick enough to compensate You can stack the copper washers , if you need to (not my 1st choice, but it does work)? Another couple of "messes" that I have seen , over the last 40 yrs, altho rare....a crack or pin hole in a rebuilt caliper, or a bleeder that was threaded crooked....check all you fittings/connections! It does not take a big puddle, to cause a big problem in the hydraulic system Best of fun, Longhorn

[paul mora]

This may sound odd but seeing the problem you had with the fuel are you sure you everything installed properly all the brake pads in place. When you bleed them the first time did you ever get a hard pedal if not in most cases without the engine running you should have a hard pedal.

[ls1nova71]

Did you bench bleed the master cylinder? If not, or not enough, you can bleed the calipers until the cows come home and you'll never get a good pedal. Just a thought...