Rear tire locking up while driving

[myotis1134]

Gentlemen...

The rear driver side tire locked up while I was driving home from work. The two previous driving sessions today were uneventful, the vehicle ran smoothly with nothing out of the usual.

The third driving session, from work to home, was not good. In hindsight, the brake must have been either locking up, or attempting to lock up from near the beginning of the drive, and I just didn't notice until I got up to speed on the highway.

I first felt a low shimmy that didn't go away, and assumed I had lost a rim weight. When the shimmy progressed to medium-bad I started thinking about my bearings in the back, and began planning the repair.

I discovered the locked up tire on my side road, because all the roads here are ice rinks at the moment, and the tire started skidding which nearly put me in the ditch twice. I heard it skidding, then confirmed visually. The passenger tire may have almost locked up once during the last 3 minutes of the drive, but the driver side was definitely not moving at all - even in reverse.

The locked tire unlocked for a couple seconds when I was almost to the house, then locked back up. I also got the ABS light once - the first time I stopped after hearing the tire drag, then it turned off.

Hopefully this is all from something stupid like a malfunctioning speed sensor, but that's not how my luck runs... This doesn't seem mechanical to me, but probably electrical. Everything worked fine then not - five minutes later.

Mechanical problems have always telegraphed that shit is getting ready to hit the fan (at least in hindsight), but electrical ******** can happen in the blink of an eye.

I'm going to start troubleshooting brake and ABS system. Can anyone recommend specific things for me to check please?

 

[yaycandy]

You can jumper the abs plug under the hood for codes like the engine diagnostics.

 

[Irish Pride]

95% chance you have a bad hose on that corner. They will deteriorate internally and won't allow fluid to flow backwards. Essentially adding more and more pressure every time you apply the brakes. Remove the hose from the caliper and see if you get any fluid coming out. If it isn't the hose then my next guess will be the parking brake cable. Good luck.

-Chad

 

[sperold]

^^^^^^This.

Your rim was probably hot, even though the temp was freezing.

My bet would be the flex line internal clog not allowing the caliper to return to the relaxed position.

 

[myotis1134]

OK nice, new hoses ordered from the source. In the meantime, not a one in town... Test the hose theory in the morning.

 

[sperold]

How did this go?
When you jack the car up and the wheel does not rotate; then crack the bleeder screw and brake fluid will shoot out.

 

[myotis1134]

OK, I finally got into it on Saturday, and what I have found is not adding up.

First of all, there was zero pressure in the caliper. I opened the bleed valve to see what would happen, and nothing happened whatsoever. I had to pick up a flare wrench to disconnect the hard-line, and it's sitting out there dripping, but there wasn't tons of pressure backed up anywhere.

The distribution block looks good, the calipers and pads look "good" for what they've obviously been through the past several years. The hard lines aren't damaged anywhere I can see, and the brake fluid isn't dirty. I even checked the bearings, but honestly I'm not sure what a bad bearing looks like exactly...





I was hoping to slap the new flex-hoses from SHO Source on and see if I can force some fluid out of the calipers, but I have now run into another problem with the hoses themselves...


As you can see, the configuration of the new hoses doesn't fit the brackets. Is this... normal? Do I need to find a different bracket or modify this one? I'm not going to abandon the brackets, the hard line will become garbage in no time, so what the **** is the solution?

Help!

 

[Irish Pride]

If you weren't getting anything out of the caliper when you opened the bleeder but are getting a steady drip from the hard line then the rubber hose was your problem. Over time from sitting the pressure will naturally back off, just not fast enough to keep the caliper from locking up like you were experiencing.

There are specific hoses to each corner of the car. FL, FR, RL, & RR. Make sure you are trying to fit the correct hose to the correct bracket.

-Chad

 

[myotis1134]

Thanks for the confirmation on the hose Chad.

The fitment issue I’m having is physical-dimension related. Apparently the bracket is designed to accommodate a round hose fitting, and the new hose is hexagonal.



The c-clips sandwich the bracket, and I’m going to have to file a bit of material to make that happen. I’m just curious if this is typical of this upgrade, since the hose kit is supposed to be an exact fit for the vehicle.

 

[Irish Pride]

Thanks for the confirmation on the hose Chad.

The fitment issue I’m having is physical-dimension related. Apparently the bracket is designed to accommodate a round hose fitting, and the new hose is hexagonal.

View attachment 16978

The c-clips sandwich the bracket, and I’m going to have to file a bit of material to make that happen. I’m just curious if this is typical of this upgrade, since the hose kit is supposed to be an exact fit for the vehicle.

No, you shouldn't have to modify anything. The hoses are supposed to be direct replacements. Don't do anything to the bracket before you verify that you have the correct parts.

 

[Irish Pride]

Are you on Facebook? Message Mike Stimson. He's the owner of SHOSource and is really good at replying. I message him all the time. Show him these pics and see what he says.

-Chad

 

[myotis1134]

Well shit. Too late lol. I got the hose fitting into the bracket already.



It only took a little file work, but the bitch is that when I was tightening up the passenger side fittings - getting ready to bleed the system - I twisted off the banjo bolt in the caliper... Everything WAS going a little too smoothly.

Plus, the labeling on the package indicates that it’s the correct parts.

 

[luigisho]

Yeah. Mistakes can also happen with packaging. I had a few mistakes when I ordered a bunch of Moog parts from Rock Auto years ago. Wrong parts in right box x 2-3 parts. Last time I do that for a daily driver. You should be fine so long as fitment with no rubbing/movement at the site.

 

[zoomlater]

russells need some modification

Earls or Russels Stainless Steel Brake lines? | SHO Forum

 

[Irish Pride]

russells need some modification

Earls or Russels Stainless Steel Brake lines? | SHO Forum

Interesting, I've had both and don't recall having to do that. I just recently replaced my Russell lines with the Earls.

 

[myotis1134]

Brake lines successfully installed a couple days ago. For anyone looking to upgrade hoses in the future - reuse the clips - you'll know what I mean when you get there.

Tore some threads out of a rear caliper while attempting to install new bleeder valves, had to wait 2 days for Napa to ship new calipers 250 miles, new calipers installed and system bled.

At this point the brakes have been bled twice until no air is pumped out, but the pedal still goes to the floor occasionally. I read a post claiming that an electronic tool is required to manually open and shut the ABS valves, so now I have to find one of them.

 

[RonPorter]

Brake lines successfully installed a couple days ago. For anyone looking to upgrade hoses in the future - reuse the clips - you'll know what I mean when you get there.

Tore some threads out of a rear caliper while attempting to install new bleeder valves, had to wait 2 days for Napa to ship new calipers 250 miles, new calipers installed and system bled.

At this point the brakes have been bled twice until no air is pumped out, but the pedal still goes to the floor occasionally. I read a post claiming that an electronic tool is required to manually open and shut the ABS valves, so now I have to find one of them.

Don't need the tool for the ABS. It doesn't come into play, unless the ABS is activated.

You can also engage the ABS in the wet, or on a dirt road, which does the same as the Thexton box, but that doesn't necessarily solve your problem.

Possibly a bad booster. But I suspect it isn't thoroughly flushed, with all the air gone.

The best tool for the job is a Motive pressure bleeder. Truly a one-man operation, and returns a hard pedal. Been the favorite of SHO folks for years.

https://www.motiveproducts.com/

 

[Irish Pride]

Make sure you are bleeding the rear brakes with the suspension compressed. If you are trying to do it with the car jacked up in the air you won't get a proper bleed. I back my car up on ramps and then get under it to bleed.

 

[RonPorter]

Or, unless you have disconnected and ziptied the bias valve lever in the closed (compressed) position, or have installed the bias valve plugs.

 

[myotis1134]

Oh I did the bias-plug mod a while ago. The valve and lever were just ugly, so I ditched them. Plus the idea of consistent brake pressure appeals to me for some reason...

So I still had air in the AB unit after the first round of bleeding. When I took it out for testing the brakes were all over the place. Between the mile of snow/ice covered side roads, and 5 miles of pavement, I must have locked it up 15 times. Bled it a second time, and it performs like a thoroughbred.

So in conclusion, the collapsed brake line was the most probable cause of my driver rear tire locking up. There is a very slim chance that the nasty old caliper might have contributed, but I guess it's possible. We'll never know for sure, since I didn't dissect the old brake line. My bad.

I want to give a shout out to @Irish Pride and @sperold - I can only imagine what you guys have been through to have acquired the knowledge you seem to possess. I always imagine you guys sighing, but looking anyways to see what I've ****** up this time...

Thanks to the rest of you who chipped in and saved my ass. I was seriously leaning in the "Oh shit it's a bearing" direction at the start.