07 Sierra brake booster problem

[Chuck Youngblood]

1 hour ago, txab said:

I would pay more attention to this suggestion.

 

Of course see what the manufacturer has to say. I've only ever had one booster go bad in all my years and never exhibiting itself in the manner you've described. 

 

You bought this truck used? Did the issue present itself in the same time frame that these boosters have failed?  I would make sure, if you haven't already, that I was getting the correct part #. IIRC, 3 different part #s for the new body style 2007 and don't forget about the 2007 "classic". As noted on a vacuum booster, engine oil would not be drawn into it, If there is fluid it would be brake fluid.

 

When this appears, does it do it every time your out for a drive? Does it when fluidi is cold or hot?

There is nothing in that suggestion that is valid in this case, sorry not being an ass but if ny of that was the problem it would be worse cold (?) and the problem would not go away when I remove the vacuum line. I am 70 and I have never had a bad booster and I have had many cars. I did buy it used but no problems for at least 5-6 months. It does do it every time I drive it unless it is a very short trip so yes, the fluid would be warm at least.

[Chuck Youngblood]

UPDATE:

I just got my brake issue taken care of, it was not the booster this time, it was the front brake chamber that was not letting fluid flow back in so once I drove it for more than a few minutes the brakes were dragging. This was a real pain getting it figured out and I was blaming the booster because it was doing almost the same thing it was doing with the bad booster. Thanks to all who replied, I appreciate it.

[Jsdirt]

??? Is that in the ABS module? Never heard of a "front brake chamber", and I've been doing this a long time ...

 

Glad you got it fixed, anyway. 

[Doug_Scott]

14 minutes ago, Jsdirt said:

??? Is that in the ABS module? Never heard of a "front brake chamber", and I've been doing this a long time ...

 

Glad you got it fixed, anyway. 

He means the compensating port was covered and not allowing the brake fluid back into the master. Usually occurs when brake boosters are replaced and the adjustment is not made correctly.   Don't know for sure, but I think it was one of the suggestions made earlier.

[Jsdirt]

Ahh, gotcha. Thanks, Doug.

[txab]

2 hours ago, Chuck Youngblood said:

UPDATE:

I just got my brake issue taken care of, it was not the booster this time, it was the front brake chamber that was not letting fluid flow back in so once I drove it for more than a few minutes the brakes were dragging. This was a real pain getting it figured out and I was blaming the booster because it was doing almost the same thing it was doing with the bad booster. Thanks to all who replied, I appreciate it.

So what was your fix? Replace MC or adjust booster travel?

[Chuck Youngblood]

Replace mc

[Chuck Youngblood]

6 hours ago, Jsdirt said:

??? Is that in the ABS module? Never heard of a "front brake chamber", and I've been doing this a long time ...

 

Glad you got it fixed, anyway. 

Sorry, I didn't know what else to call it.

[Jsdirt]

No worries - I thought you were reading off your receipt. Was worried there for a second!  

[Big Bear99]

I got the same on my 2007 gmc sierra classic 2500.just pulled the booster, no leak.  Sometimes it happens regularly, other times day go by with no issue.  I actually carry a wrench and bleed pressure at the master.... can feel the truck roll free and I'm off again. Brakes come on with cruze on flat ground. Any new things I can look at.