Hi there!

So, my driver's side rear (drum) brakes have been locking up under heavy braking. I've been troubleshooting for the past month with no luck. I've replaced pretty much every part I can think of. Post here just in case anyone has ran into this before. At this point, I'm stumped.

This is what I've done so far.

• Changed ABS Module
• Changed Master Cylinder
• Changed Brake Booster
• Changed both rear ABS Sensors
• Changed both rear brakes AND drums
• Switched rubber brake line from right side to the left side.
• Ran a brand new brake line from the ABS module to the rear left brake (overkill, but still didn't fix it)
• Replaced YAW sensor.

No ABS lights / codes. Speed sensors rear correct speed on the OBD 2 computer.

Any ideas what could be causing this?

 

I cant contribute too much here (I'm unsure that I've touched drums on the fit,) but seeing your extensive list did you check brake adjustment on the left? I know drum brakes I've touched had manual adjustment screws. There'd be a little keyway in the drum through which you could fit a flathead and finangle a little sprocket, tightening the shoes against the drum. Think you have to take the cover off to loosen 'em.. given the extensive work you've done you prolly know that already. But you didn't mention comparing adjustment on the rear left to that on the rear right, and maybe counting threads on the non-locking side.

This is reaching, I know 😂 but maybe yanking the e-brake coulda cinched stuff tighter than it should be? An interaction like that could explain how, even after replacing so many parts, you're still winding up with binding. but heck, I dont know how those systems overlap

Excluding maladjustment this could be something electronic, and I'm not fancy enough for that.

 

Both wheel cylinders, too?
https://www.hondapartsnow.com/genuine/honda~cylinder~assy~43300-sna-a01.html

 

Ah yes, the cylinders too.

As a matter of fact, i had some extra brake line laying around, so I ran the left brake line to the right side and the right to the left side... then I also switched the speed sensor connections (L->R)

Now, the RIGHT wheel locks. LMAO so that leaves out the rear brake mechanism.. has to be before/or the ABS module... which I've replaced... at this point, IDEK

 

Damn, dude. Ghosts.

 

This looks like a job for the Electrical Wirer and Sensorer Man!
I'll tell yuh if I see him. He's a busy hero since his skill set is actually relevant.

But it sounds like you just isolated your fault as being one wheel speed sensor. said you switched it and the fault switched sides, yeah? I know gear heads swap to SS brake lines for a "more positive feel" but with my home plumbing/appliance/electrical experience I've had more success with non-braided/woven stuff across the board.. Once had a braided water heater line spring a leak and cut a hole in the wall 😂
The braid over the air hose for my tire pump separated and was causing a bulge. I cut the braid and the bulge is gone.
You can actually get a more positive feel out of brakes by changing to a fancier brake fluid. I've been using bel-ray super 4 for clutch and brakes and although it seems to fade a little faster it's definitely more positive.

Sorry, that last bit was all irrelevant. I meant I don't think the line change altered the fault

 

It's been sitting for half a year now and I think it's time I give it another go...

It was actually not the speed sensors that I switched, but the actual lines that connect to the ABS module.
So, I switched the RL and FR lines (connected FR brake line to the RL ABS solenoid) and vice versa...

This leads me to think that the one FR solenoid is the issue, BUT, I've already switched out 3 different ABS modules without any luck.

I think my starting point will be to get a new ABS module and FR speed sensor and go from there... If the problem is still there, I guess I'll dig into the wire harness

Has anyone ever ran into an issue like this?

 

Before replacing any more parts, try doing another inspection of the rear brakes with the drums removed. As Pyts suggested, the emergency brake mechanism could be binding on one side and pulling the cable on one side more than the other. With the emergency brake arm all the way down, there should be no pull on the brake cables. With the drums removed, pull each emergency brake cable at the shoes and see if each cable feels like the same tension and if each emergency brake arm at the brake shoe is at the same angle side to side. If one side is pulled more than the other, try to spray some lubricant down each cable under the console where the cables attach to the equalizer bar, and then pull the emergency brake handle repeatedly and then release it, working lubricant down the cables.

If both cables feel like they're working properly, I'd put both brake drums back on, **CAUTION: DO NOT STEP ON THE BRAKE PEDAL UNLESS BOTH DRUMS ARE ON. IF A BRAKE DRUM IS OFF, YOU WILL POP A WHEEL CYLiNDER PISTON OUT AND WILL LOSE FLUID AND HAVE TO RE-BLEED THE BRAKE SYSTEM!** With the drums on, hit one drum lightly with a dead blow hammer on the front of the drum and then the rear to center the shoes in the drum. Then try spinning the drum and adjust the amount of drag by adjusting the shoe adjuster until you get the same drag on each side. I would start with the shoes spinning more freely so you can balance their drag/ rotation. The automatic feature of the brake shoe adjusters will then tighten the adjustment up when you back up while applying the brakes. That automatic brake adjustment feature should adjust/ tighten both sides the same as long as there is no corrosion on the threads of the the expander bar.

I hope this info helps.

 

Dudes.. bros.. dudettes.... the previous owner installed the ABS lines in the incorrect order (the order that the service manual states) - I naturally installed them in the same order when I was installing the new abs module and digging through the service manual for everything ABS related.
Then, i noticed that the abs module has the order written in tiny letters. I bent the lines and installed them in the order written on the abs module and everything works now.

Always check the order on the abs module (not just the service manual).

 

That's positively bonkers, and I don't use that term lightly.
Messing up the order of ABS lines can cause lock-up of brakes. I don't know if this will be too relevant for future endeavors, but I want to hang on to it. I doubt I'd ever have guessed! Three cheers for you figuring it out!!!!

Hey, if you'd be willing, could you post up a pic of your abs module and maybe edit it by drawing on it to show how it was hooked up incorrectly? Just some colored dots showing that this line was there and that one was there. Maybe circling the bends in the lines, if there's any indication of non-oem bends.

How did you get your hands on 4 abs modules? Were you pulling 'em from junkyards and bench bleeding each one of them??

This is so cool. I'm psyched that you figured it out. That extra awareness of need to look at things more closely is definitely going to make you a better thing doer, and you get some serious bragging rights.

I'm nerding out over here.

Oh hold it! Are you saying the service manual has incorrect imagery for the ABS module line connections??

 

eBay listings with free returns 😂 how else?

And the abs module has the RR, RL, FR and FL written on it. The hard part is knowing which line goes to switch wheel.

Since I had everything off and was bleeding this stuff anyway, I just pushed fluid into the line and saw which wheel it came out of... Helps having 4 little tubes/bottles

Also, since the service manual and the abs module had a different order, I'm guessing different abs modules have different orders? So, not sure a picture will be helpful. Best to just look at the order written on the abs module itself.

 

@illyab2009 Glad to hear you figured this out. I'm a little vague on the ABS system. I do not understand how it would not be clear that an RR line goes to the RR wheel. I'll have to look at the service manual.

 

I would have to be past my limit to take an abs module and blow fluid through each line to see where it came out. 😂 That's gold.
I'll keep the ebay thing in mind, too. They took the modules back no problem, huh??

I understand where you're coming from. The whole lesson learned here is to look closer at the module. That's a tough but necessary pill to swallow.

I really appreciate your following up on this.