ABS Issues?

Tiny
RGC01
  • MEMBER
  • 2010 CHEVROLET SILVERADO
  • 4.8L
  • V8
  • 4WD
  • AUTOMATIC
  • 63,000 MILES
I was doing what I thought was a routine brake job on my truck when finished I took a drive and there was a judder where the pedal pulsates and vibration can be felt in the steering wheel.
On the front end new rotors and new pads were installed, and on the rear only brake shoes as the drums did not look that worn.
In an attempt to correct it I replaced the rotors and pads again on the front with no change.
Later I tried using the e brake and it juddered that way so I thought due to the front brakes not being used it must be the rear brakes causing the problem. So, in attempt to correct that I installed new drums on the back with no change in the juddering condition.
A family member, whom is a mechanic told me to try to change the drums again and if that did not work that I might have a bent axle which is probably unlikely I hope since I have never hit anything that hard that I can recall and the truck it not used for plowing.
The pads are supposed to be OE equivalent premium grade from NAPA and the drums are from Autozone if it makes a difference.
Also, no fluid appears to be leaking from the cylinders in the rear, all the hardware seems good and moving freely.
Any ideas would be helpful.

Thanks
Do you
have the same problem?
Yes
No
Tuesday, September 8th, 2015 AT 11:09 PM

22 Replies

Tiny
CARADIODOC
  • EXPERT
First lets start with the basics. Be sure the rear shoes toward the front have the shorter linings and the rear shoes toward the rear have the longer linings. Next, if there was any grease or other contaminants on the linings or drums, that has to be washed off with brake parts cleaner before they go through the first heat cycle. Once the drums and linings get hot from normal braking, those contaminants seep into the linings and the drums or rotors, which are porous, and will never come out. That will cause chattering, and the only way to solve it at that point is to replace the linings and drums.

Check out this video to help get the codes

https://youtu.be/rTtAnsOlZU4

and

https://youtu.be/Pb6nXV-iamI

It sounds like your parking brake system is working okay, but nevertheless, look at the tops of all four shoe frames and be sure they're hitting the large anchor pins at the top of the backing plates. If they aren't touching that pin, the parking brake is partially applied due to a sticking cable. Next, use your thumb to push the parking brake strut bar forward against the pressure of the anti-rattle spring. That bar should have a good 1/8" of free play. If it is tight, the parking brake is stuck partially-applied. That will cause that brake to grab and possibly lock up under light brake pedal pressure.

New linings can be bonded slightly off-center relative to the old ones. That will cause them to ride on the ridge of rust near the outer edge of the drums or on the rust on the inner edge. We cut that rust off when we machine drums for reuse. You would assume that isn't a problem when you install new drums, but it's not uncommon for those to be warped a little. A light machining will take care of that. If they're egg-shaped, you'll get a pulsing brake pedal and a sensation of stopping, then not stopping, twice per wheel revolution. You won't feel that in the steering wheel.

You aren't going to bend a rear axle, but it's easy to get the same feeling if there's debris stuck between the flange and drum. This is common on front rotors that slide onto the bearing assembly. There are access holes in those flanges, and water sprays through them and forms rust spots on the backside of the rotors and drums. Those rust spots have to be scraped off before the part is mounted on the brake lathe, otherwise a warp will be machined into it. If the part isn't machined, it can be installed in a different orientation than it was before, and that puts that rust spot in between the flange and drum. You'll see that by watching the wheel as it rotates while you run the vehicle in gear and raised off the ground. We use a dial indicator to measure "lateral run out" at the wheel's lip where the weights go. .045" run out is excessive and is enough to cause a noticeable vibration, but if there's rust or other debris stuck on the mounting flange, you'll find a lot more run out than that.

Another common cause of warped parts is failure to use a click-type torque wrench when tightening the lug nuts. Guessing leaves the nuts tightened to different amounts with uneven clamping forces. One heat cycle or one splash of rain water on a hot rotor or drum will cause warping. This was never a problem up to the '70s, but it's real important on light front-wheel-drive cars and any other vehicles that have slide-on rotors.

I like to put new drums and rotors on the brake lathe and give them a light cut. Every once in a while we run into a part that was handled roughly in shipping, but another issue to be aware of is with Chinese parts. There is nothing wrong with their quality, but when we make parts out of cast iron, we set them aside to age for 90 days before they get their final machining. The Chinese cast 'em, pack 'em, and ship 'em, then they age on your vehicle. It's common for them to warp a little after a few months. One light machining will take care of that when it occurs.

It's important to use high-temperature brake grease on the six "lands" on each backing plate that the shoes ride on. This is especially important on GM vehicles because they are one of the few that don't have little tabs bent over to form a sliding surface. They just let the edge of the shoe frames grind on those lands, and before long grooves form in them. Those grooves can cause a shoe to catch and not apply under light pedal pressure, and in some cases, not release immediately. That usually shows up when new shoes are installed since the linings are thicker than on those that were removed, so the shoes are readjusted to accommodate that. That sets the shoe frames in a different location relative to those grooves.
Was this
answer
helpful?
Yes
No
Wednesday, September 9th, 2015 AT 12:44 AM
Tiny
RGC01
  • MEMBER
I rechecked everything I did, and the items you had outlined. The only thing I did not do that you mentioned was to put grease on the lands which I did and that did not change anything much. So, today I had the drums resurfaced, readjusted the shoes, and put everything back on. Then I took it for a drive and everything seems to be fine now with no chattering/juddering. The shop I took the drums to, said that they are resurfacing new drums and rotors very often these days. From now on I guess when I get new rotors or drums I will just have them lightly resurfaced to save time. Although, the rotors are Bendix and the ended up being fine, but the drums were Duralast and they were the issue.

Thanks a lot
Was this
answer
helpful?
Yes
No
Friday, September 11th, 2015 AT 11:12 AM
Tiny
CARADIODOC
  • EXPERT
Dandy. Happy to hear it's solved. Remember that if a pulsation comes back in the next few months, don't replace the drums or rotors. Just have a light cut taken on them. You should only have to do that once.
Was this
answer
helpful?
Yes
No
Friday, September 11th, 2015 AT 6:52 PM
Tiny
JWHITT
  • MEMBER
  • 2006 CHEVROLET SILVERADO
  • 0.6L
  • V8
  • TURBO
  • 4WD
  • AUTOMATIC
  • 140,000 MILES
Code says master cylinder pressure sensor shorted I cannot find this sensor can you please help me?
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:02 PM (Merged)
Tiny
KEN
  • ADMIN
Hello,

The sensor is on the brake master cylinder here is a diagram to help you see where it is.

Check out the diagrams (Below)

Please let us know if you need anything else to get the problem fixed.

Cheers, Ken
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:02 PM (Merged)
Tiny
PEZ06
  • MEMBER
  • 2006 CHEVROLET SILVERADO
  • 59,000 MILES
Model is LT extended cab with V8 5.3 w/flex fuel. Front brakes are disc. Reason for question is my ABS light along with brake system warning light and chime came on. This happened a week after I had new front and rear brakes installed. I returned to Pepboys and they checked the error code. Error code states there is a malfunction with the left rear abs wheel speed sensor. However the Pepboys tech states there is no rear sensors on my vehicle. I need to take it to a Chevy dealer to trouble shoot the problem. I need to know if there are no rear speed sensors. Thank you for your assistance.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:02 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
There's different ABS systems. Some have only one sensor on top of the rear differential (plus the two at the front wheels), some have one at each rear wheel, and some on GM trucks are in the tail housing of the transmission.
Was this
answer
helpful?
Yes
No
+3
Tuesday, July 7th, 2020 AT 12:02 PM (Merged)
Tiny
KHLOW2008
  • EXPERT
Our database don't show any rear wheel sensors. What are the trouble codes you are getting?
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:02 PM (Merged)
Tiny
ESTABON 68
  • MEMBER
  • 2003 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 25,000 MILES
Stopping at low speed (under 10 mph) ABS engages. No service lights come on. I was told to clean my wheel speed sensors. What's that?
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:03 PM (Merged)
Tiny
BLACKOP555
  • EXPERT
Wheel speed sesnor are the sensors at each wheel. They are a magnet and they detect how fast the wheels are turning by measuring the gaps in a moving tone ring. That tells the computer how fast each wheel is turning and if one is locking up. They are easy to find. Look for the wires goign to each wheel what the attach to is the sensor
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:03 PM (Merged)
Tiny
BILLH42
  • MEMBER
  • 2004 CHEVROLET SILVERADO
  • 6.6L
  • V8
  • TURBO
  • 4WD
  • AUTOMATIC
  • 165,000 MILES
When the vehicle is started the ABS / Service Brakes lights come on along with a Service Brakes Soon message. The problem is intermittent and does not show up on every start. Shutting the engine off and restarting usually clears it. There are no active DTC codes associated with this problem so it would appear to be a false indication.

NOTE: In Jan 2014 the instrument cluster was replaced for an inoperable speedometer

Thank You.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
HMAC300
  • EXPERT
Have it scanned by a pro to see what is wrong with abs system autoparts can't do this.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
BILLH42
  • MEMBER
Dealer did a scan last time I was in. Did not find anything.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
HMAC300
  • EXPERT
That's odd but if it's an intermittent it may be hard to find. One thing to do as I see this is a diesel is to check both batteries for condition including load test. Bad batteries with cause false codes otherwise wait until it becomes a hard or full time code. I know annoying you can also check connections as there may be a loose or maybe worn through wire. On my truck in winter I would have the same condition but it was usually snow getting on harness and pulling it down a little causing a similar problem
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
BILLH42
  • MEMBER
Both batteries were replaced in April before this problem started. Rechecked battery connections. Also have checked wheel sensor connectors and parking brake switch. Will check the ABS Controller connectors when I figure out where it's hidden. Hoping it will become a hard fault so I can fix it. It was raining the other day so I locked up the brakes in an empty parking lot and the ABS operated normally.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
HMAC300
  • EXPERT
Controller connectors are on the abs unit on frame drivers' side
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
TGIBOB
  • MEMBER
  • 2001 CHEVROLET SILVERADO
Both the ABS and Brake lights sometimes stay on after starting the truck. One mechanic tried to fix it but said I would need to replace a part. The part cost more than the value of the truck. A second mechanic had a go at it and the problem seemed solved but now it has come back. I can live with it but have safety concerns.

Any suggestions?

Thanks.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
The yellow ABS warning light will not cause the red Brake light to turn on, but the red Brake light will turn the yellow ABS light on. That's because the ABS Computer only knows something is wrong with the base brake system but it doesn't know what. That problem could result in an inability to run the anti-lock function properly.

That means you need to look at the red warning light, and there's only three switches at most that affect it. The first, if your truck has it, is a low-fluid level switch in the master cylinder. If the fluid is low, do not fill it. Add just enough to turn the light off. The fluid is low either because there's an external leak that must be addressed or the front disc brake pads are worn and need to be replaced. Replacing worn brake pads requires pressing the pistons back into the calipers, and that pushes all the brake fluid behind them back up into the reservoir. If a do-it-yourselfer or inexperienced mechanic has previously filled the brake fluid, it's going to overflow and run all over creating a mess, and damaging any painted surfaces.

The second switch is for the parking brake. Be sure the pedal is releasing fully. The last switch is the pressure-differential switch. That may be in the hydraulic controller for the ABS system, otherwise it is in the middle of the brass combination valve that sits on the frame rail right under the master cylinder. On vehicles without anti-lock brakes, you can follow the two steel lines from the master cylinder to that valve. Simply unplug that switch to see if the red warning light goes off. If it does, one of the two hydraulic systems didn't build pressure as fast as the other one. Typically that's due to a leak. That valve is spring-loaded on GM and Chrysler vehicles but sometimes it sticks. A quick hard jab on the brake pedal usually releases it.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
TGIBOB
  • MEMBER
Hi and thanks for the reply. Took me a while to find my records and this is what they show.
Replaced front brake pads and rotor.
Codes were scanned

If this did not work I was told I needed an Electronic Brake Control Module.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
The mechanic needs to list the specific fault codes, otherwise that's like your doctor telling you, "well, we ran some tests". Wouldn't you like to know the results of those tests?

Again, an ABS problem won't turn on the red "Brake" warning light. If that one is on, look at the three things I mentioned earlier. You can simply unplug each of those three switches to see which one makes the red light go off.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2020 AT 12:04 PM (Merged)

Please login or register to post a reply.

Sponsored links