ABS Thoughts (1 Viewer)

[Uluabob]

Hey all,
So I am a year into my 80 series ownership and have dropped a lot into my 96 to get her roadworthy as I regularly drive my kids in it, and nearly all of my driving is on road currently. When acquired I had a mechanic overhaul a lot of the stuff including "rebuilding" the brakes which included new pads, rotors, calipers. They had some trouble bleeding the system with the LSPV, but got it working, at least seemingly working. Well I have never had confidence in the brakes on the truck despite all the new parts. The pedal was really soft, and when I have to stop fast, like panic stop, the harder I press does not make the truck stop any faster, almost like it is just going to stop when it is good and ready, there is no corresponding increase in stopping force with increased pedal pressure. I have adjusted my driving style and drive slow and try to avoid having to make fast stops as I don't have faith in its ability to stop for a crosswalk or stopped vehicle etc. Frankly it has freaked me out at times thinking about the what ifs! Well this morning driving the truck to work, i noticed that the pedal felt weirdly stiff, like I had to push through resistance to start getting slowing, but it was brief and not intense but like most of you I know every feel of driving this truck and any change in feel, sensation or noise I notice. I drove straight to the mechanic as I can't risk failing brakes. They just called and can't figure it out and think its likely that my ABS system is not engaging, why this was not noticed before I don't know, but the ABS light on the dash has never come on and there are no codes about it. I feel like an idiot not knowing more about how the system works and how to test it myself and figure it out. I haven't had time to read the FSM about the ABS system and I read a lot of the threads on here, but none seemed quite similar. ANy guidance on where to start would be greatly appreciated, my wife is pissed that the "old money pit" has yet another problem. Oh don't know if it is related but the center diff does not seem to engage when I try to excercise or engage the front and rear lockers, that is the next problem on my punch list. Thank you for my newbie stupidity and rambling, its been a freaking long day. Thanks and here she is, and I love her

 

[baldilocks]

Your biggest problem is your wife. If she isn’t on board you will have a difficult time.

Remove the ABS system and have better brakes. Some crazy guy on here went another step and converted to a hydro booster and bigger bore master cylinder. It cost quite a bit but he reports a high, firm brake pedal and a corresponding increase of brake power with increased input.

Your issue is very common and will require some effort on your end. There are a couple very good threads on deleting ABS. I’m willing to help, as I’m sure l, other members will.

 

[Tedward]

Might be 2 problems. Air in the system and a failing brake booster.

If it were me I'd bleed the brakes again and again. Find the correct pattern to follow for bleeding. Can be found here in Mud or in the FSM (factory service manual).

Then I'd also check the brake booster. The method to test that can be found here on mud or in the fsm too.

 

[desmocruiser]

I think you need to do some additional research and get another opinion to have someone (Toyota dealer or specialist) look at your master cylinder/ brake booster as well as the ABS system.

I have 2 80’s, I replaced the brake booster on one due to a improperly routed cable wore a hole in the metal booster.

That one stops noticeably better than the one with the original booster, not that the other is bad, just not as good.

As far a ABS goes, does the light come on when you turn on the key and then go off after it starts?

 

[95BBC]

I would take it to a gravel lot or dirt location and activate ABS. After you have activated it a couple of times gravity bleed (open bleed screw and let drip for 3-5 minutes) the system starting from the passenger rear, driver rear, passenger front and last driver front. While it’s gravity bleeding make sure the cap is off and the fluid is full. I have seen caps not let it gravity bleed. I have fixed a couple systems like this that independent shops couldn’t get right.

 

[Mrtwooooo]

Honestly doubt your ABS is the issue.

 

[baldilocks]

I would take it to a gravel lot or dirt location and activate ABS. After you have activated it a couple of times gravity bleed (open bleed screw and let drip for 3-5 minutes) the system starting from the passenger rear, driver rear, passenger front and last driver front. While it’s gravity bleeding make sure the cap is off and the fluid is full. I have seen caps not let it gravity bleed. I have fixed a couple systems like this that independent shops couldn’t get right.

Gravity bleeding is impossible with the abs system in place. Research this issue and you will find the answer.

 

[eastoak]

Check the position switches for your lockers, that’s an easy first step. My 96 had 3 bad position switches and replacing them revealed that the center and from locker worked but the rear locker actuator had to be replaced. I used Beck Arnley 201-1788 which is identical to the OEM switch but costs $15 or whatever it is.

 

[95BBC]

Gravity bleeding is impossible with the abs system in place. Research this issue and you will find the answer.

Really? Why? It worked on mine.

 

[baldilocks]

Really? Why? It worked on mine.

The factory system incorporates plumbing that feeds fluid back toward the MC. Gravity bleeding up hill does not work.

 

[95BBC]

The factory system incorporates plumbing that feeds fluid back toward the MC. Gravity bleeding up hill does not work.

I’ll pull the new car feature book out tomorrow at work for our model, if we still have it in the library that is. Many models like the Prius and highlander have the fluid feed back to the MC res, They all gravity bleed.

 

[baldilocks]

I’ll pull the new car feature book out tomorrow at work for our model, if we still have it in the library that is. Many models like the Prius and highlander have the fluid feed back to the MC res, They all gravity bleed.

What?

 

[95BBC]

What?

Ncf (new car features) is what tells us how all the new crap they put on a new model works. Like the abs system is new for the fj80 and it will give a functional diagram and description. So if we have a Ncf for the land cruiser it will talk about the ABS system in more detail then the manual. I guarantee the Abs return hose will not interfere with the mc bleed hole. Remember the abs system has to relieve the brake pressure somehow when it’s trying to unlock a wheel. That is why activating the system helps in the bleeding process. On the newer system we can use techstream but that takes too long so I find a gravel lot.

 

[shocktower]

Gravity bleeding is impossible with the abs system in place. Research this issue and you will find the answer.

Go pressure bleed it is the only way

 

[shocktower]

I’ll pull the new car feature book out tomorrow at work for our model, if we still have it in the library that is. Many models like the Prius and highlander have the fluid feed back to the MC res, They all gravity bleed.

Why fight it go pressure bleed that is how I do them

 

[jonheld]

Gravity bleeding is impossible with the abs system in place. Research this issue and you will find the answer.

I've never had an issue gravity bleeding my LX450. My ABS is in place and fully functional.
If I open a bleed valve on one caliper, the master will drain down through that...eventually. That's how I fill calipers after a rebuild and how I passively flush the system yearly.

Back to the OP, IMO, you should find another mechanic. There are ways to test ABS in the FSM, and if your ABS system was not working, the brakes would still work without ABS.
A hard pedal is associated with a failing vacuum booster. There are many threads regarding this, along with what to use for replacements.

I am extremely anal retentive regarding the brakes on my truck. It's a daily driver that sees extended road trips and gets wheeled when I have time. I only use OEM parts and the system gets inspected yearly. I have no trouble locking up 35" tires and kicking in ABS.

Vehicle brakes are a "system", not just a bunch of parts. Your emissions system/vacuum will also interact with the brake system.

 

[Heckraiser]

Your mechanic never properly bled the brakes. That's why it's felt like a turd since you got it. These are notoriously hard to bleed. Basically bleed it until you think you're done (you would be done with any other car) and then repeat the process about 4 times. My best bleeding setup to date is actually a vaccuum bleeder. If they were lazy or just working quick, they may have never bled the LSPV as well.

Once fully bled, it stops like a boss on 315 tires.

 

[ScubaSteve80]

I am having the same issue and am in the process of replacing rotors, pads, and calipers to rule them out. If you do find the solution to the problem I would love to know. I have come to the conclusion its the ABS as well but want to rule these other parts out before I go down that road. Good luck and keep us posted on what you find/try to fix the problem.

 

[95BBC]

I am having the same issue and am in the process of replacing rotors, pads, and calipers to rule them out. If you do find the solution to the problem I would love to know. I have come to the conclusion its the ABS as well but want to rule these other parts out before I go down that road. Good luck and keep us posted on what you find/try to fix the problem.

Before you replace anything, activate the abs system (hard stop) and see if it makes a difference. Imagine a system being used once in awhile.......

 

[ScubaSteve80]

Before you replace anything, activate the abs system (hard stop) and see if it makes a difference. Imagine a system being used once in awhile.......

My problem is I can't hard stop. When driving around 50 mph, if I slam on my brakes it takes me about 2 seconds to come to a stop. I need new pads, rotors and calipers anyway (already bought them). I had a shop try to bleed the ABS with no luck. This all started after I unhooked my break line coils in order to get in the alternator upgrade. I have bled my breaks, a shop has bled my brakes and still no luck. At this point, in my opinion, it has to be calipers, master cylinder, or ABS.

Maybe I need to find some gravel and try slamming on the brakes then re-bleed the system.