Brake issues, sorry for the long read

[jpogue]

I've had problems with the right front caliper sticking off and on over the years. Have replaced it twice in the last 3 years, inboard pad always wears faster. About 4 months ago the ABS and the brake light would come on after I got up to about 20MPH. Both lights at the same time. So I took out the combination valve and blew it out and put back together and ran a lot of fluid through the system re bled and the brakes worked fine, which they pretty much did before besides the caliper sticking occasionally. However, the ABS and Brake light still came on after 20 MPH. So I've been meaning to replace steering box and get front end in shape and try to tackle the brake issue. Steelhead season is over so I have time now. First off new wheels and tires, wheel spacers no longer needed. Someone had told me about 3 years ago that the 2000 Dodge alloy rims fit my 1996 (long story will explain later if needed). Wrong! They looked a lot better than the old steel wheels so I found some spacers and used the wheels. This added to the steering and handling issues. So time for new tires got a wheel upgrade too. Driving home I noticed a bit of a wheel hop when coming to a stop. I didn't worry much about this I figured someone got some grease on the rotor, and I was having the ABS brake light issue looked at in 2 days. Next day dropped truck off for new steering box and synergy T steering upgrade kit. These were well worth the money went from 1/4 turn of play to none, almost as good as my wifes honda pilot. However still had the wheel hop. Next day drop off at shop to diagnose the ABS Brake light. Stored ABS fault code for air in the line. They reset the code said the pedal felt fine didn't see any problems. At this point I thought it was safe and ordered new rotors, calipers and pads and a pressure bleeder. The light stayed off for 5 days and the wheel hop not too bad. Yesterday the ABS and Brake came on while driving down the highway at about 40 MPH. Now the wheel hop is significantly worse. Got out the Gopro and a long selfie stick and had my daughter video the front wheel while braking. Then I did my side. I then took to a gravel lot and did some hard braking and the rears are locking up not the fronts. After reviewing the front wheel footage it doesn't look like it's coming from the front brakes. So after that and seeing the rears lock up in the gravel I've come to the conclusion that the issue is with the rear brakes, and somehow is more noticeable since I had the spacers removed. Any help would be greatly appreciated.
Thank you

 

[KATOOM]

Did you check the front rubber brake lines? They're known for breaking down internally and causing sticking.

 

[jpogue]

Should have mentioned that I have replaced the rubber lines with the braided ones from EGR. I think I mentioned everything but that. Thanks Katoom

 

[KATOOM]

Do you have rear drums? If yes then you have the proportioning valve above the rear axle. Not saying its acting up but you can disconnect the rod, tie it up, and see if it changes anything.

 

[jpogue]

Yes it has drums on the rear, but no proportioning valve in the back. It has the so called combination valve by the master cylinder. I think I made some good diagnostic work though. Cleaned off the front rotors just to see of that was the problem. While taking apart the driver side I noticed one of the caliper pins was kind of stuck. I thought for sure that was the problem. Put everything back together took it for a drive. Usually 1/2 way down the hill the ABS and brake light come on, no lights came on. Drove around town and a little wheel hop but not too bad, and no lights came on. So I wanted to check and see if the rears locked up again. So I smashed the brakes hard and could feel the ABS engage no lock up from any wheel. So drove around some more and wanted to do another lockup test. Pulled into an empty parking lot mashed on the pedal and the lights, ABS and brake, both came on and the rear wheels locked up, the fronts did not. Nice skid marks on the pavement from the rears and none in the front.

 

[KATOOM]

If you don't have the proportioning valve then you have the all wheel ABS...
Given what you're describing I'd say there's an issue with one of the three ABS sensors.
The rear sensor tends to get packed full of metallic dust from the differential gears. Easy to remove and clean though. And the fronts are susceptible to any excess movement in the front hub. And wire damage too.
But maybe you already checked those out since you seem to be pretty thorough.

 

[jpogue]

Thanks Katoom that was my next step to remove the rear sensor and take off the differential cover and do a fluid change. It's been a while since I only tow the drift boat and not a big toy hauler anymore.

 

[jpogue]

Well of course it wasn't the easy sensor (the rear one). I thought for sure that was the issue. I tested with an ohm meter and the old one was at 1.38 and the new one was at 1.97, took it for a drive after replacing and was good until I came to a quick stop. Then all lights came back on. However, now that you mention sensors Katoom I also had the front axle u joints replaced when I replaced the tires and wheels. They had been rattling for quite some time.

 

[Ozymandias]

To properly bleed the ABS unit you need a workshop computer to set the unit into bleeding mode.
That is needed as soon as some air entered the unit itself.

 

[jpogue]

Ozymandias when I was going through the manual tonight it mentioned making sure that the front brake metering valve will have to be held open to bleed the front brakes. What is the difference from pumping (by foot) and using a power bleeder? And honestly the more I think about it it has to be one or both of the front abs wheel sensors. The lights, abs and brakes, had been on constantly for a few months. The brakes were still working fine and it was steelhead season so I kept fishing. The only things that changed were new tires and wheels and the front axle u joints being replaced before the wheel hop happened. I took to shop the next day for the brakes and they cleared the code all lights were off and the brake hop was diminished greatly and they said pedal felt fine. 5 days later the brake hop gets significantly worse after the lights come back on again. I'm going to talk to the local brake guru here tomorrow. I would have taken to him first but his appointments are 3-4 weeks out. However if you catch him around lunch he's pretty chatty and willing to help DIY people since he's so backed up. Which is amazing since he does no advertising at all.

 

[Ozymandias]

With the proper software you can watch all the parameters live while driving and see what is really triggering your lights.
There is more behind then just a "code".
If your shop can not do this - go to one that has the ability.
Btw, locking rear wheels are an absolute no-go, with or without ABS.
There is something badly wrong with the system if that happens.
Normally the ABS is fail safe, if anything is out of order or specs it should switch itself off and tell that to the driver, remaining a standard brake - but that would mean locked front wheels and rear ones turning.
What you have now is very dangerous and needs to be properly diagnosed.
And that can only be done from a capable mechanic at the truck itself, not through the internet.

 

[jpogue]

Thank you Ozymandias. Accept for test drives for checking the work I've done I've been riding the motorcycle.

 

[Ozymandias]

On a test drive he can monitor all three Wheel sensors at the same time and see differences in the signals if there is a problem with a sensor under certain circumstances.
It can also be a faulty ABS unit itself, i had that on my Gen3 and needed a new one after a proper diagnosis.

 

[jpogue]

OK the hop is coming from the rear. Weeks ago one of my friends said "Do you have the old wheels and tires?" I said yes. Then he said "Well why don't you try putting the old wheels and tires back on and see if it still does it?" I thought well they're brand new tires and wheels what could be wrong with new stuff. I put the old tires and wheels on today and no brake hop stopped somewhat smooth. There's still an ABS issue the lights are still on and the rear wheels will lock up if I stomp on the brakes. So at least the mysterious hop has been figured out. Spoke to the wheel shop and they said to bring by the tires and wheels. I have an appointment with the brake guru next Friday and he'll figure out my ABS issue for sure.

 

[DavidC]

Just because things are new doesn't mean it's good. Learned that quite a few years ago.

 

[Ozymandias]

Sounds good, one point ruled out.

Now you really need to figure out why your rears are locking up. (Before the front ones)
Like said, they should NEVER do that, with or without ABS.
Locking rear wheels sends you directly into the ditch, thats why we had first rear wheel ABS before the all wheel ABS.
Point your friend onto this issue!

 

[jpogue]

OK new twist to the brake issue. I've been running a 2 inch spacer on the rear wheels due to someone talking me into getting a set of 2000 aluminum wheels which don't fit these trucks. The hop has something to do with the spacer. The tire shop spun the wheels a different way using lug nuts instead of the center attachment. They weren't out of balance or out of round. So I tried leaving the spacer on and taking off the old wheels and tires and putting on the new wheels and tires with the spacer. No wheel hop. So for now I'll run the spacer until I get the ABS issue figured out.