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2005 GMC Envoy 4.2 4X4 97K


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MarineGrunt
Enthusiast
MarineGrunt profile image

Mar 18, 2014, 7:15 AM

Post #1 of 5 (1683 views)
2005 GMC Envoy 4.2 4X4 97K Sign In

Yesterday I replaced the front brake pads since they were getting down there. I also went ahead and replaced the rotors. The rear disc brakes were replaced about 15K ago and are still in good shape. The brakes stop on a dime. You only have to push the pedal down about 1/3 of the way. I have no complaints with stopping at all. The issue I'm concerned about is once you do stop you can continue pushing the pedal down pretty much all the way to the floor. It's like it's spongy. You don't have to push it all the way down once you get stopped. The vehicle holds steady when the pedal is about 1/3 of the way. It's just that you can continue pushing the pedal.


I did some research and it seems like most have the same issue with the Envoy/Trailblazer and most shops say that it's normal. It just doesn't seem normal to me. Every other GM vehicle I have owned has never down this. You always get to point where the pedal won't go down any further. There was even one guy where the dealership replaced the master cylinder 3 times before 45K and he still had the same issue. I couldn't find anyone that ever figured out if there was a problem. Seems like you can usually come across a fix online being that so many have the same complaint if there is a fix.


I don't think the abs is engaging either which may have something to do with the spongy brake pedal? I'm not getting any kind of "service abs" on the DIC. When I had a hub go bad the "service abs system" flashed across the DIC.


I have a pretty good understanding how the brake system works but have never had to do much service on the system besides pads, rotors, drums, etc. I did replaced a master cylinder years back. I'm thinking the first step is to flush, replace fluid, and bleed the brakes? I've heard old brake fluid can get too much condensation in it and cause some issues. I figure that would be the easiest thing to try first.


I'm not sure if the brake pedal has always been spongy like this. The spongy pedal isn't causing any stopping issues at all. It's just that it doesn't seem right. I have never checked in the past because I didn't really need to. It has always stopped just fine. I just finally noticed it because I replaced pads and rotors.


Have any of you ever came across this issue with the Envoy/Trailblazer? Is it normal?


Thanks guys.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 18, 2014, 7:21 AM

Post #2 of 5 (1682 views)
Re: 2005 GMC Envoy 4.2 4X4 97K Sign In

I didn't have to read past your first paragraph. That is a typical GM pedal that is completely normal and has likely always been that way. You just never noticed before.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 18, 2014, 8:45 AM

Post #3 of 5 (1665 views)
Re: 2005 GMC Envoy 4.2 4X4 97K Sign In

MG, if many or all are known for this but behave a WAG is flex hoses are a slight maybe that a whole lot (meaning maker's specs) of them for GM just had a tad of flex and unseen bloat a bit more than some.


DOT 3, 4 fluids are hygroscopic and just a small % of moisture lose the high boiling point. I doubt that changes feel unless boiling which would be a problem of course. I think DOT 5 is really silicone based not hygroscopic. Never used it so no first hand know of the feel difference if any?


15,000 on rears right? Have you measured pad wear even if safe I find the more pad the better feel with less of piston extended and even fluid has some squish feel and there's lots more with pistons out of bore more OR worn rotors that never give enough metal to begin with IMO to work with.


You could probably spend a bunch of bucks on attempts for little gain or worse nothing. I don't like much pedal travel good brakes or not but think you'll have to live with it on this?? Tom



MarineGrunt
Enthusiast
MarineGrunt profile image

Mar 18, 2014, 10:09 AM

Post #4 of 5 (1655 views)
Re: 2005 GMC Envoy 4.2 4X4 97K Sign In

I've never had a GM vehicle with such a spongy brake so didn't know for sure. It stops just fine. I am going to go ahead and flush the brake fluid though. When we got the vehicle I just sucked the old fluid out of the reservoir. I didn't completely flush it so I figure it couldn't hurt to replace it.
I need to rotate the tires so will check out the rear brakes too just to be safe.
Thanks!


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 18, 2014, 11:22 AM

Post #5 of 5 (1648 views)
Re: 2005 GMC Envoy 4.2 4X4 97K Sign In

Be careful, you're going to need a bidirectional scan tool if you get air in the ABS.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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