Brake Problem

[nubuilder]

Got in the ZR2 and took it for a spin this evening and heard a "whoosh" sound when I pushed the brake pedal. It went pretty far down and pretty easily. This truck had a much better pedal than my Z71 ever had so I noticed this pretty quick.

Checked the fluid level and the front half of the reservoir is almost empty or completely empty. I have noticed the level going down, but not this fast. I can't tell if I have a leak at a caliper or not (4-wheel discs; probably going to pull the wheels off this weekend if I have time). The truck has 141k on it.

I think this means one of the following:
1) brake booster is leaking internally and will only get worse
2) have air in the line (which at this point is completely possible)
3) master cylinder is bad

Doing a quick search, some said the pedal would get harder if the booster was bad. Other said that the "whoosh" sound meant the booster was bad.


Can anyone help me out more on this?
If I have to replace the booster and/or the master, anyone have a good brand to go with?

 

[daddy]

Park it, start it up, pump the hell out of the brakes and hold pressure if there is any. If not, keep pumping. Then, go check at the inside base of the tires. If you find a puddle, you have a leak at the caliper. If not, move on to diagnosing the other options.

 

[nubuilder]

Park it, start it up, pump the hell out of the brakes and hold pressure if there is any. If not, keep pumping. Then, go check at the inside base of the tires. If you find a puddle, you have a leak at the caliper. If not, move on to diagnosing the other options.

Will do. Good thing I have 2qts of brake fluid sitting around!

 

[drperry]

Pull the vacuum line from the brake booster... If it's leaking on the pedal side, you should probably be able to see some traces of fluid in it... Especially after doing the pedal mashing to find out if it's an external leak or not.

If the pedal is easy to press without the booster connected... I'm pretty sure that's bad

 

[ScottyBoy]

Same thing happened to me before on a car I had. Turned out that one of the rubber brake hoses split wide open. $20 and about an hour or so of work and it was back on the road.

 

[Black02Silverado]

Make sure you fill the master cylinder back up so it isn't sucking air before you start pumping. If there isn't any leaks and when you put pressure on it and the pedal goes slowly all the way down to the floor then the master cylinder is bad most likely. That is what happened on my 91 jetta.

 

[nubuilder]

Pull the vacuum line from the brake booster... If it's leaking on the pedal side, you should probably be able to see some traces of fluid in it... Especially after doing the pedal mashing to find out if it's an external leak or not.

If the pedal is easy to press without the booster connected... I'm pretty sure that's bad

I'll check that too. (the vacuum line)

Same thing happened to me before on a car I had. Turned out that one of the rubber brake hoses split wide open. $20 and about an hour or so of work and it was back on the road.

I haven't had to replace one of those in a while, but anything is better than replacing the master or booster!

Make sure you fill the master cylinder back up so it isn't sucking air before you start pumping. If there isn't any leaks and when you put pressure on it and the pedal goes slowly all the way down to the floor then the master cylinder is bad most likely. That is what happened on my 91 jetta.

Already filled it up. Planning on looking at it either tomorrow or the next day.


Thanks for all the tips guys!!

 

[nubuilder]

Some troubleshooting.....

Filled the reservoir.
Started the truck.
Pumped the hell out of the brakes for at least 30sec.
Pedal got a little firmer, but not by much.
Vacuum line is bone dry.

When I shut it off, the pedal firms up almost instantly. (not sure if that helps at all)

It appears I may have a leak at the back left wheel.


Any more thoughts? Could this be a bad caliper or just a flex line?

An even better question: Is is safe to drive in this condition?
I really don't think it is as there's no pedal to it at all and a panic stop would be impossible.

 

[Texas Jim]

Some troubleshooting.....

Filled the reservoir.
Started the truck.
Pumped the hell out of the brakes for at least 30sec.
Pedal got a little firmer, but not by much.
Vacuum line is bone dry.

When I shut it off, the pedal firms up almost instantly. (not sure if that helps at all)

It appears I may have a leak at the back left wheel.


Any more thoughts? Could this be a bad caliper or just a flex line?

An even better question: Is is safe to drive in this condition?
I really don't think it is as there's no pedal to it at all and a panic stop would be impossible.

That should answer your question right there...

 

[daddy]

No. Driving with known bad brakes is a horrible idea under any circumstances.

The only way to know whether it's a caliper or a line is to look. I'd suggest just climbing under and taking a look.