brakes

sebaz8 · 01-05-2008, 03:15 PM

I have a 2003 GMC Sierra 4X4 and I have a brake probleme!!! It seems like I have no pressure in the pedal when I apply the brakes. The truck brakes but I have to press the pedal almost to the floor. I have new pads, rotors and calipers. I thought that changing these parts would fix the problem but it didn't. the lines have also been bled. The problem was there even before I changes all these parts. What is left to change?

mudseeker · 01-05-2008, 03:57 PM

your master cylinder could have an internal leak and the fluid is leaking past one of the seals.

gmctrucks · 01-06-2008, 12:34 AM

I second that.

sebaz8 · 01-06-2008, 04:29 PM

is a master cylinder hard to change?

sebaz8 · 01-06-2008, 04:34 PM

Also, I forgot to mention that I'm not losing any brake fluid. I guess that would confirm the internal leak?

mudseeker · 01-06-2008, 04:58 PM

just two bolts holding it to the vacuum booster and then the two brake lines. if you do end up replacing it, make sure you bench bled it first. it should come with everything to bleed it with. just mount it in a bench vise and push the piston in about a half inch or so multiple times with a large phillips screwdriver until you no longer see air bubbles going through the clear hose supplied.

crabtruck · 01-07-2008, 12:59 PM

Just a thought, check for brake hoses (3 or 5 depending on setup) that might be swelling under pressure.
Also I'd plug the outlet ports before buying a new master and see what your pedal does then.

sebaz8 · 01-07-2008, 05:35 PM

Could the brake booster have anything to do with this or am I just way out of line?

tjzz4 · 01-07-2008, 08:46 PM

Think MASTER CYLINDER

mudseeker · 01-07-2008, 09:23 PM

Quote:

Originally Posted by crabtruck

Just a thought, check for brake hoses (3 or 5 depending on setup) that might be swelling under pressure.
Also I'd plug the outlet ports before buying a new master and see what your pedal does then.

good point......

01-05-2008, 03:15 PM	#1
sebaz8 Junior Member Join Date: Jan 2008 Posts: 5	brakes I have a 2003 GMC Sierra 4X4 and I have a brake probleme!!! It seems like I have no pressure in the pedal when I apply the brakes. The truck brakes but I have to press the pedal almost to the floor. I have new pads, rotors and calipers. I thought that changing these parts would fix the problem but it didn't. the lines have also been bled. The problem was there even before I changes all these parts. What is left to change?

01-05-2008, 03:57 PM	#2
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,375	your master cylinder could have an internal leak and the fluid is leaking past one of the seals. __________________ i'd rather be hunting

01-06-2008, 04:58 PM	#6
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,375	just two bolts holding it to the vacuum booster and then the two brake lines. if you do end up replacing it, make sure you bench bled it first. it should come with everything to bleed it with. just mount it in a bench vise and push the piston in about a half inch or so multiple times with a large phillips screwdriver until you no longer see air bubbles going through the clear hose supplied. __________________ i'd rather be hunting

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01-06-2008, 12:34 AM	#3
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,035	I second that.

01-06-2008, 04:29 PM	#4
sebaz8 Junior Member Join Date: Jan 2008 Posts: 5	is a master cylinder hard to change?

01-06-2008, 04:34 PM	#5
sebaz8 Junior Member Join Date: Jan 2008 Posts: 5	Also, I forgot to mention that I'm not losing any brake fluid. I guess that would confirm the internal leak?

01-07-2008, 12:59 PM	#7
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,366	Just a thought, check for brake hoses (3 or 5 depending on setup) that might be swelling under pressure. Also I'd plug the outlet ports before buying a new master and see what your pedal does then.

01-07-2008, 05:35 PM	#8
sebaz8 Junior Member Join Date: Jan 2008 Posts: 5	Could the brake booster have anything to do with this or am I just way out of line?

01-07-2008, 08:46 PM	#9
tjzz4 Senior Member Join Date: Oct 2007 Posts: 277	Think MASTER CYLINDER