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Discussion Starter #1 (Edited)
Figured Out My Brake Pedal Issue (Video) - Updated!!

I was having trouble at the track the other day, the issue was twofold.

1) Bleeding the master cylinder lines took the spongy feel away. Bleeding at the calipers wasn't doing anything.

2) The inconsistent pedal I and maybe others have experienced was not a failing booster, it was that the brake booster line was collapsed from the header heat nearby.

See the video below for documentation of the issue.
http://home.indy.rr.com/bwgoodwi/Brake Booster Hose.wmv

**UPDATE!**
As noted in the video, the melted brake booster was the reason for my poor brake pedal. This likely happened after only 20-30 minutes of track time per the symptom onset, so I'm sure that others may have this issue underlying a brake issue they are blaming on other causes. After replacing the booster yesterday I now have strong brakes again. Just in time for a PCA event this weekend!!

The scary part after removing the old hose was that not only was the portion in the video damaged, btu the section behind the intake manifold was also collapsed, as noted in the photo. To illustrate, I could barely move any air through the tube by blowing in one end...this was definitely the cause of my chronic brake problem.

 

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that's interesting.the same thing happened to my old lumina Z/34.it was partially buried under the intake plenum where you couldn't see it.new hose was only 2.xx from the dealer.found out it is a common problem for several gm cars.
 

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Nice video! That was amazing how the like collapsed when the engine started. Thanks for the good follow-up.
 

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UstaB-GS549 said:
Nice video! That was amazing how the like collapsed when the engine started. Thanks for the good follow-up.
How did you fix it then? If the heat from the header is collapsing the booster line, won't it just happen again if you replace the line?

Sal
 

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Discussion Starter #5
New OEM line with some additional heat shielding is the plan.

Thought it might help to show this since it's not obvious at all without the help of a friend, and I'd bet the dealer has just pulled the whole booster out on many an occasion.
 

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BQuicksilver said:
New OEM line with some additional heat shielding is the plan.

Thought it might help to show this since it's not obvious at all without the help of a friend, and I'd bet the dealer has just pulled the whole booster out on many an occasion.

You could bend an aluminum tube to match the oem one and use short hose ends to connect.
Sabot
 

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Very Interesting :eyes:
 

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BQuicksilver said:
I was having trouble at the track the other day, the issue was twofold.

1) Bleeding the master cylinder lines took the spongy feel away. Bleeding at the calipers wasn't doing anything.

2) The inconsistent pedal I and maybe others have experienced was not a failing booster, it was that the brake booster line was collapsed from the header heat nearby.

See the video below for documentation of the issue.
http://home.indy.rr.com/bwgoodwi/Brake Booster Hose.wmv
How do you bleed the master cylinder lines vs calipers? Is there an additional set of bleeder valves somewhere?
 

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Discussion Starter #14
A friend who's a tech took some flare nut wrenches to the lines coming into the bottom of the master cylinder. He just shot me orders on when to get on the pedal, so I can't give full details. I could hea some air escape and he noted it as well. He didn't make much mess, but lay down towels when doing this.
 

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WhosUrDaddy said:
How do you bleed the master cylinder lines vs calipers? Is there an additional set of bleeder valves somewhere?
Ideally, you can bench bleed it, but I've done it on the car. Just put a towel or rag under the fittings, have someone pump the brakes, then crack the fittings a little bit. Make sure they don't release until you've tightened them up.
 

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Discussion Starter #20
A better hose is definitely in order, but the routing is pretty tricky in that you wouldn't want to use anything that could kink off easily at all.

I've only had the shielding on 2 days, but I will do a 2 day PCA event this weekend in 90+ degree weather....so we'll know for sure after that.
 
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