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H3 brake bleeding issues.

CKHummer

Member
Messages
5
Location
Orlando, FL
I'm working on the wife's 07 H3X (170,000 miles). Both rear calipers were sticking causing uneven pad wear, so I decided to bite the bullet and do a full brake system upgrade. Ordered Crown Performance SS lines, Powerstop calipers, rotors and pads. Installed everything over the weekend and when replacing the right front brake line about 6-8 ozs of fluid came out of the line leaving the master cylinder reservoir EXTREMELY low. I started the car to turn the steering wheel to ensure the new lines would not bind at full lock. I then went to bleed the brakes, starting at right rear and was only getting a little fluid out, using a Mityvac brake bleeder. I assumed due to the brake line replacement this was normal. After quite some time trying nothing seemed to get better so I moved to the left front, thinking that I had the order wrong. I had a buddy pump the pedal and the front two brakes seemed to bleed as normal with good pedal feel. I made sure to keep the master cylinder full while doing this. I then moved back to the right rear and nothing comes out but air. Tried left rear with same result - no fluid only air. Dash gives error of "Brakes" when ignition turned on. I checked the forum and found some mentioning about the ignition having to be turned on to activate the EBCM. Can anyone provide help to troubleshoot this issue?

Thanks
 

scoreh3

Well-Known Member
Messages
1,024
Location
SoCal
I thought this sounded familiar, Here’s a post from DaveH3 early this year. I hope this is the problem with yours . Good luck.



So it turns out the reservoir wasn't full. The brake fluid was up to the neck of the reservoir. As you add more brake fluid, it ran into another chamber in the reservoir. Once that was filled, the brakes bled with no problems. With the new clear brake fluid, you couldn't see it on the outside of the reservoir at the full line. Brakes were bled, and everything is back to normal




 

jakesz28

Well-Known Member
Messages
1,041
Location
Cabool MO
I had my wife help me when I put new calipers on the the rear. I never pump the brakes when bleeding, regardless of everyone that tells you to. I turned the ignition on but did not start it. When first starting with a lot of air, loosen bleeder, push pedal down, tighten bleeder, and release pedal. Repeat until you get get fluid out both sides. After you have good fluid I change my sequence. Push pedal down, slowly crack bleeder, then tighten, release pedal.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Here's the Base Brake bleeding proceedure. System description - pg 156, Bleeding procedure - pg 120 (depending on which system):
https://schwarttzy.com/wp-content/uploads/2013/01/Hummer-H3-Hydraulic-Brakes-1-4-1.pdf

Then, according to the manual, you'll need to do the ABS bleeding procedure (using a scan tool with bleeding option). See pg 91 and beyond for ABS bleeding. You might want to start by reading the Description of the system to give you a better idea how things work - pg 127:
https://schwarttzy.com/wp-content/uploads/2013/01/Hummer-H3-Antilock-Brake-System-1-4-1.pdf
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
I turned the ignition on but did not start it. When first starting with a lot of air, loosen bleeder, push pedal down, tighten bleeder, and release pedal. Repeat until you get get fluid out both sides. After you have good fluid I change my sequence. Push pedal down, slowly crack bleeder, then tighten, release pedal.
Exactly. Do this and you'll bleed the brakes effectively, barring any other issues. Nice job capturing everything in five short sentences.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
..Do this and you'll bleed the brakes effectively, barring any other issues.

Very good chance you'll need to bleed out the ABS unit using a scan tool, ...but possibly not if yer *really* careful.
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
I've bled, or helped bleed, the brakes on three or four H3s in the past year doing exactly what jakesZ28 indicated. Pulled a full quart of fluid through each one. I've only seen a TechII needed when someone made a mistake and triggered ABS errors - and that was during brake work, but not during brake bleeding. This is not a complicated procedure requiring any tools more complicated than a box end wrench. The fact that the ignition needs to be on to do the rears does throw people off since it is typically unexpected.
 

CKHummer

Member
Messages
5
Location
Orlando, FL
Finally got around to bleeding the brakes and followed jakesz28 posting. The brakes appeared to bleed fine with no air bubbles in the lines and no warning lights on the dash. The only problem is when you first push the brake pedal it goes all the way to the floor and you have to pump it to get pressure. The brake fluid level is full. Should I rebleed the brakes again is or there something I missed
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
This first push to the floor - is this anytime after you restart your H3 or did it only happen once?

Sent from my SM-N976V using Tapatalk
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Hard to say w/o having been there. Here are my thoughts:

1) It's easier than many people think to introduce air into the brake system when the system was opened up as yours was. Even when a mechanic takes great care, new brake fluid is clear and it's easy to 'think' there's enough fluid in a cloudy or semi-dirty reservoir. And, often fluid doesn't immediately go to the back chamber of some vehicle's reservoir depending on the level. On top of that, the foot action needs to be somewhat slow and controlled, not pumping (not saying you did). Pumping can cause a jumping effect inside the reservoir and with low fluid it's possible (though not likely) air could get introduced that way. Which is why in the manual they indicate a gentle press and let up ..then a short rest period between each pump during the bleed process. Trust me, my wife would rather get back to her 'show' than bleed brakes, but tries to go as slow as possible. Again, not saying these happened during your process, but something seems to have gone awry.

2) If air is introduced at the M/C, you'd be lucky to 'not' need to perform the ABS bleed process. A few air bubbles can get trapped and, although you pump the pedal, it chugs forward a certain amt of fluid then stops, then forward again. Sometimes air can get trapped at a certain location and difficult to remove. A buddy of mine with a Ford Dually made several trips to the Ford dealer to remove air from the ABS. They had to draw it out with a pump to finally get it (not a hand pump).

3) The ABS bleed process is a normal part of proper brake bleeding on 'modern' cars. That's why it's in the manual. Sure you can skip it, but where vehicles use fluid in a ABS reservoir, that should be flushed out. I'm not sure what gets replaced through normal pedal bleeding on the H3. (I just haven't studied it closely all honesty). But in the manual they do show an ABS fluid reservoir for certain models.

If you know someone with a good scan tool, like a Snap-on, Bosch, Tech II, Launch, etc, that has the brake bleed feature for your year vehicle, ask them over for a beverage and go through the ABS bleed procedure. My hunch is it will remove trapped air and restore your pedal feel. You'll still have to re-bleed the air out of the pipes again as per normal.

Best of luck. Let us know what the solution turned out to be...
 
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CKHummer

Member
Messages
5
Location
Orlando, FL
Sorry for the slow update but here goes:

Tried to re-bleed the entire system following the same process as above, but still ended up with same result.

Wife wanted her truck back, so I had H3 towed into the Chevy Dealership near the house to have them check my work. Was told everything appeared ok and they used the computer in conjunction with the pressure bleeder to bleed the brakes. Cost was $150.

Picked H3 up two weeks ago and the second day of driving home from work my wife called, advising the Traction control and Brake warning icons on the dash came on. She said the brake pedal felt fine and made it home safe. The lights reset after turning the truck off, waiting a few minutes and then turning it back on. I took the H3 back to the dealership and they ran the codes, which indicated low brake fluid. They added very little fluid and said everything was in order.

The H3 ran great for about 10 days until yesterday. While she was driving home, the traction control icon and brake icon came on again, and this time the readout said "Traction", then "Brakes", then "Fluid" and then "Failed". These stayed on for about 2 minutes and then they all reset and went off, this time without having to turn the car off, then on again. She again said the brake pedal felt fine so she drove home.

Making another trip back to the dealership tomorrow 11/22, but wondering what could be causing the warning light issues.

Any thoughts?
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Here are a couple ideas, not sure how close it parallels but I'll throw them out:

1) They may need to go through the re-bleed procedure again. Could be residual air in the ABS they didn't get out. Sometimes it takes a few times to get all the air out (that's a general statement regarding bleeding the ABS via a scan tool on a variety of vehicles). As I mentioned above, I've been through it a few times in the past. But it sounds like the dealer was pretty thorough. $150 for what they did sounds fair. It takes time to dig out the scan tool, go through all the menus, consider the 'maybe' and dig out the pressure bleeder and get on with the bleed process. You know how long it takes to do a thorough bleed job. [Now when a dealer charges $125 to program two key fobs like they did me, THAT'S when you can really complain!]

2) Brake switch: I went through a traction control issue with my pickup a few months ago. It acted as you described with multiple brake lights, ABS light and TC, ...except the brake fluid light didn't come on (but i don't know if there is a fluid light on my ram). In fact it also happened about a month after a complete fluid change where we did a lot of pedal pumping (I also had to do the ABS bleed proceedure). On my pu, the lights would come on, not right away, but after 5 miles, sometimes 20 miles of driving ...the truck would even 'lurch' during acceleration after coming on. After shutting the vehicle off, the warning lights would not come on upon restart, just like yours. Scanner indicated all wheel sensors were working fine, brake switch was fine. (this was on a Ram truck)

The issue ended up being an *intermittent* failing brake switch which was unrelated to the bleeding. Its pretty common situation on the Ram forums and many modern vehicles. Once I assumed it 'might' be the switch, if I lifted the pedal with my foot, or 'bliped' the brake pedal with my foot, it must have overcome the intermittent issue and the lurching would stop (I believe the lights may have stayed on until restart). So perhaps give that a try when the lights come on. For me, a new $30 ebay mopar switch, and a 10 min install resolved the problem. The switches on modern vehicles are nearly weightless (no kidding!), there can't be a lot of metal in them like the old days. Not sure how this parallels your issues, but its an idea to chew on. Could be all that pedal-pumping during the bleeding process pushed an already-old switch into the outer edges of the twilight zone where 80% of the time it's good, but sometimes it isn't. If your rig has a lot of miles, you may consider replacing the switch anyway with a new Delco switch. If it doesn't do the trick, you only replaced a presumed-aged part, and maybe back to the dealer she goes (??) for another look-see.

Good luck. Thanks for the update ....let us know how it goes.
 
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SlcHummer

Well-Known Member
Messages
368
Location
Salt Lake City, UT
Doesn't sound like the same issue but figured I'd post in case it's related, https://www.hummer4x4offroad.com/forum/showthread.php/13673-Can-Not-Bleed-Brakes-HELP

"So it turns out the reservoir wasn't full. The brake fluid was up to the neck of the reservoir. As you add more brake fluid, it ran into another chamber in the reservoir. Once that was filled, the brakes bled with no problems. With the new clear brake fluid, you couldn't see it on the outside of the reservoir at the full line. Brakes were bled, and everything is back to normal."
 
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