LS1 four wheel disc...poor pedal

[Lance-W]

I have the entire brake system from a 2002 SLP Camaro SS on my 69 Camaro. Well everything that is except the antilock unit. The pedal doesn't ever feel very hard. It finally gets some braking at about 1 inch off the floor. It will not lock up the tires it just mushes down to the floor. I've bled the brakes thoroughly about 6 times. I have vacuum to the booster. The pedal actually feels better with the car turned off. Anybody have any ideas?

[GetMore]

I am not sure, but I think you might need a scan tool to make the ABS unit bleed itself. I don't think the usual bleeding method will work if you got air in there.

[Lance-W]

I am not sure, but I think you might need a scan tool to make the ABS unit bleed itself. I don't think the usual bleeding method will work if you got air in there.

I didn't use the ABS. That's the only part of the system I didn't use.

[Apogee]

What are you using in the rear? If you have staggered shocks, are we to assume that you're using 2X LH calipers or are you running LH/RH somehow? Are all of the bleed screws at the tops of the calipers?

Tobin
KORE3

[Lance-W]

What are you using in the rear? If you have staggered shocks, are we to assume that you're using 2X LH calipers or are you running LH/RH somehow? Are all of the bleed screws at the tops of the calipers?

Tobin
KORE3

All the bleed screws are at the top. I mini-tubbed it so the shocks are inboard of the springs so I was able to use the calipers exactly like they came off the donor car. Let me look and see if I have a picture.


This is the best picture I could find. It's when I was mocking things up before I made them pretty.

[buddyholly]

Which master cylinder are you using? Is it a new one?
Soft pedal is almost always air somewhere. New master cylinders can be a pain to bleed and doing it with new calipers can take some time to get it all out.

[Lance-W]

Which master cylinder are you using? Is it a new one?
Soft pedal is almost always air somewhere. New master cylinders can be a pain to bleed and doing it with new calipers can take some time to get it all out.

The one that came from the donor car. It was a running car. My first thought also was air somewhere.... It bleeds nice and clean with no bubbles at this point. That's why I'm stumped.

[68sixspeed]

x2 if you don't have air in the system, it's usually the bench bleed on the master cyl.

[Lance-W]

I bench bled the master this morning. I bled the brakes after re-installing the master. It's a little better but it still has a soft mushy pedal most of the ways towards the bottom. Anybody have any other ideas?

[LSXfan]

still sounds like air, especially if it got better after the last bleed session...may have to look into power bleeding it or may have a bad master cylinder...

[BonzoHansen]

[Hammered]

I had the same problem with my LS1 conversion. Power bled everything five times over. I finally figured out that the piston boots were retracting the pistons too far causing excessive pedal travel. A slow drive around the block with some moderate brake application fixed it.

[Lance-W]

I had the same problem with my LS1 conversion. Power bled everything five times over. I finally figured out that the piston boots were retracting the pistons too far causing excessive pedal travel. A slow drive around the block with some moderate brake application fixed it.

I don't understand your fix? I've driven the car quite a bit now and it's the same. Did you limit the travel then drive it? Please elaborate

[MrQuick]

I think what he is saying is:
Drive stopping ability is actually less that if you were applying the pedal at a rest. Have you driven the car yet?

Also you might have wiped out the master cylinder seals when bleeding it. This happens often with used masters.

[Lance-W]

Yes I have driven it. The car has about 100 miles on it at this point. The car will stop but if you try and stop hard it will just mush to the floor. It will not lock up the wheels as a result.

[Hammered]

Sorry, I thought you were testing while still on the jack stands.

Maybe you got a bad master since you've bled everything thoroughly.

[MrQuick]

But what is funny is that his pedal is fine with no assist.

Can you give us details on the lines, prop/combo valve and rear tee used.

[Lance-W]

But what is funny is that his pedal is fine with no assist.

Or maybe the master just isn't bad anough to leak without the additional power of the booster. I'm really starting to lean towards a new master.