ABS/Brake system warning/malfunction

Driving to work this am, doing approx 60mph on a significantly washboarded gravel road I got the "Check Brake System/ ABS" screens.. shortly down the road it went away momentarily, but then returned and has remained since... I assumed it was the a wheel speed sensor, but all 4 are registering in OBD fusion simultaneously and same speed..now I have no idea what to check or where..

Replaced front pads a month ago due to grinding sound that I assumed was due to low pads, didn't go away, seemed to be coming from the rear, truck has 205k miles so figured it was probably time for shoes/drum service in the rear, sound went away yesterday..

Any ideas? Thank you in advance.

 

I don’t know about your ABS problem, but I can tell you that there is a simple inspection procedure for brake pads that mostly consists of measuring their thickness. I would not rely on noises or miles driven.

 

First step is seeing what code(s) the ABS module has in it.

 

Is the check engine light on as well?

 

So i just got an alarm, lost most brake pressue and coasted into a loves truck stop (lucky)

Right rear drum is leaking brake fluid and has apparently beel slinging it around for a little bit. Resivoir is pretty much empty.

Can I refill and limp home or am I fucked and need a tow?

 

Need to scan the vehicle with a legitimate OBD reader

 

Filled the reservoir, limped 35mi home, pulled into garage and lost all brake pressure again. Got super lucky. Reservoir completely empty again.. time to research the mechanics of drum brakes I suppose.

BTW, No check engine light, not throwing any codes, all 4 wheel speed sensors functioning and communicating nominally. Absolutely leaking out the RR drum assembly.

 

If you are leaking brake fluid I don't think learning the mechanics of drum brakes is going to help you. You should instead inspect your brake hydraulic system: hydraulic lines, cylinders, and reservoirs. Your problem is likely going to be obvious after inspection.

I will also say that if you aren't an experienced amateur mechanic, I wouldn't mess with a safety sensitive system like brakes. I'd take it to someone more experienced.

 

sounds like rear brake cylinder is bad/leaking.....shoes will be ruined.....prob due to year of truck would be better to get 2 new cylinders instead of rebuilding them, new shoes, spray everything with brake kleen.....or have a shop repair it if you have never done it

 

Glad you got it home! I’m interested in what actually failed I have not seen a wheel cylinder blow out in a long time.
As for fixing it…..You’re going to need a lot of brake fluid. If the master went dry it needs to be bled first, then the rest of the system, lastly the ABS needs to be bled with a scan tool.
Plan on a set of shoes, wheel cylinders and a new hardware kit.
If you’re not a seasoned technician I suggest you take one side apart at a time, leaving the other as reference.

 

There has to be a code. OR's are brake by wire in the rear so likely it knew it wasn't able to build rear pressure. You'll need to get the whole system bled including the abs system after you repair the leak.

 

Like already stated its likely the rear wheel cylinder, replace both sides, new drums, shoes and springs if they were not already done. Inspecting the wheel cylinders for any leaks by pulling back the boot should be part of the rear service, or its generally a better idea to always just replace the cylinders as part of the rear brake service anyway bc you are already in there with everything cleared away and the rear brakes can be bled pretty quickly.

 

Did some research last night, made a parts list, ordered, paid for and picked up on the way home from work.. Hit the drums w some pb blaster then bolted them apart m8x1.25.. it was comical, buncha parts fell out. Old springs and pins and retainers. Shoes had approximately 0.0mm friction material remaining, I think I've found the source of the grinding sound lol..
Heaps of grease and dirt and FOD in all the crevices. The rubber gaskets? Boots? endpieces? of the wheel cylinder (why is it called that, its neither cylindrical nor wheely, more of a hydraulic actuator but IDK) were compromised and pissing fluid when depressed, so theres the source of the fluid leak.

Removed the wheel cylinder, and the drum components, cleaned all the gunk off all the parts, and called it for the day, 109F in the west facing garage at 1730 and my laptop just wasnt having it. Reassembly tomorrow. Yay.

 

Hopefully this gets you going soon!
And as far as the rear brakes? Another 205k miles!

 

made some progress today after work, got the other (non-exploded) side apart, WAY easier lol. There was actually friction material remaining on the shoes and everything wasnt covered in grease. So naturally I accidentally over-torqued and sheared off one of the 10mm mounting bolts for the wheel cylinder. Rookie shit. Additionally I realized that this component: the " parking brake shoe strut adjustment bolt" from the passenger (exploded) side is significantly bent.

Any recommendations on sourcing this part? I dont see a number on the diagram. Apologies if this is a dumb question, Im new to this.. researching concurrently but wanted to ask the hive mind. Good times..

 

Nevermind, figured it out. The bolt is 90080-1114 and the strut assembly is 04943-04010

 

Sourced components from toyotapartsdeal.com Fast enough and factory oem. The strut set came with both sides and the springs.
Put it all together, bled her out with assistance from a friend and his Autel device.
Not nearly as hard as I thought it would be, biggest PITA was connecting the large springs on the parking brake strut assembly with my subpar pliers.


Links that helped:
Team OilDrop, straight to the point, no fluff. Excellent
https://youtu.be/-dmUF5hbQEQ?si=LMZaoxizXoCcgfD4
CarCareNut, voice is challenging sometimes but seems to know his stuff.
https://youtu.be/qGeTOBWg3YE?si=JvNaM50FtVhft_eQ
Faye Hadley, long but very detailed
https://youtu.be/O-yN4LFlC6g?si=h_ze5S3AwwWuW73B