Bled the rear brakes today and adjusted the rear a little tighter. Didnt seem to help much. I did notice the more I pumped the brakes the more the RPM fluctuated so I decided to replace the brake booster. For anyones information you can do it without disconnecting the lines from the Master Cylinder. Just have to be careful moving it out of the way. The nuts on the inside holding the brake booster (4) are a pain but can be done with a 3/8" drive 15mm deep socket and a universal. The lower right has to be a boxend wrench and 15mm shallow socket after the nut is out far enough. The hardest part was putting the nuts on the two top studs. Large hands dont help. Tape one of the nuts to the deep well socket. Just enough to prevent it falling off when you get it up there.

I dont think the master cylinder is bad there was no fluid in the booster I think I would have seen it my the shaft that pushes on the plunger in the master cylinder. It was rusty. No sign of fluid.

It helped some no fluctuation in rpm. Breaking a little better. I will bleed the front tomorrow. I was hoping it made a huge difference. I wish I knew what these were supposed to brake like.

 

From what I have read online, a woosh sound with everything else checking out would point to the booster.

How did you bleed the ABS system? You need a capable scan tool to bleed it properly.

 

I gravity bled and then bled at each wheel. Thinking about it when the line was removed it drained everything out of the rear line including the master cylinder on that side. I never bled the master cylinder. I spoke with a Chevy mechanic and asked him about bleeding and he said gravity bleed and then each wheel. There could be I suppose air still in the master. I will try that today.

 

Bled the front brakes today both 2 person and gravity. Brakes are much better. The brake booster made a big difference. For those people hearing a big hiss when applying the brakes for a 1/2 or 1 second. It appears that the booster is starting to go. Found a vacuum line that was softened by oil or brake fluid and replaced that. It was the one down to the trans. It now shifts better as well. Thanks to all those that replied. Hope this helps someone else along the way.

 

bet that was trans fluid in the vacuum line. indicating another problem

 

Newguy
Never thought about that. Where does it come from? To much pressure in the trans? I should check where the hose connects and see if its soft there. Your right though it was where the line turns horizontal and lays in the line.

 

It connects to a switch for the 4 wheel drive. If the rear seal on the trans is bad ,fluid will leak into the transfer case filling it up and forcing trans fluid up the vacuum lines. On the back of the transfer case there are 2, 3/8s rachet plugs, one higher than the othe other. that one is the full hole.( you fill it till it pours out that hole) take the plug out and if a lot fluid splills out your trans seal needs replacing

 

I remember the car was in an accident about 5 years ago and that seal was replaced because it had not had the problem before the accident and did afterwards. I will check though. Thanks.

 

Checked out the transmission fluid level and its right on. Could be that line wasnt replaced the last time I had the input shaft seal replaced. I didnt check the transfer case level thats for another day.

 

That's good news