Major ABS Issue..?

[t4rFL]

just brought my 4runner home after spending almost a week in the shop....but still has the same problem..

for the past month i was trying to get my newly purchased 4runner ready for a long distance trip. just doing basic maintenance stuff etc...i drove it to work one day and it started pulling when i broke in the parking lot. I've had this happen before on another car, so didn't think it was a major deal. i figured it was a bad caliper. so i replaced the one side it was pulling to. had a friend mechanic come over to help me bleed the brakes afterwards.

next time i drove it, it was still pulling to that side. i was running out of time before my trip so i brought it to a reputable mechanic who specializes in Honda's and Toyota's. he told me he bets the problem is that it was bleed wrong, cause he explained to me these Toyota trucks need to be hooked up to a machine to be properly bleed.

he called me telling me he bled the brakes twice, but it still pulls and the abs pump noise it was making prior, has now stopped. he told me he isn't really sure what it could be now, but is thinking it's the abs pump. also told me in all his years of working on Toyota's he never had a problem like this. he looked up the replacement part and say it would be over $1k just for the part, and he couldn't find any used ones anywhere except for ebay (for a couple hundred), but rather not go that route cause they don't have warranties. i just told him i'd like to take it home for now, until i can figure out what to do.

when i went to pick it up, he was trying to explain to me that it was possible to replace the abs pump system with a booster.....i was trying to understand, but i'm not very mechanical so it was hard to understand, but i told him i'd do some research on it.

so this is where i need help....i want to trust the mechanic, but is there anything anyone can think of that could be the problem before i go ahead and spend a bunch of money on the ABS system thing. also i thought i read somewhere where people disable the abs on these 4runners....also, didn't they switch to the abs pump starting with the '01-'02's? if so is it hard to switch to the 2000 and older 4runner braking system?

 

[jeremyc74]

When it's pulling to one side, is the ABS kicking in and making a lot of noise?

If it is, that's a classic symptom of a bad wheel speed sensor. I had this happen to me when I replaced the LBJs and had the sensor out. When I put it back in it had a small piece of rust on the end cap where it senses the teeth on the hub. I bled the brakes several times, and finally was about to replace the wheel speed sensor. All I ended up having to do was clean it off.

There's no way I'd start replacing expensive parts without a complete diagnosis.

As for switching over to the earlier system, I'm sure it's possible but not really practical. There were significant changes to the trucks between '00 and '01, including the addition of electric throttle.

 

[t4rFL]

the ABS would randomly make noise, not specific to just braking, and do not think it did it when pulling. the noise seems to have gone away now.

even though i don't want to pay the stealership for work done unless i absolutely had to, should i bring it to them just for a 2nd opinion?

are wheel speed sensors easy/cheap enough to replace to see if it's the cause?

 

[TheDurk]

When it's pulling to one side, is the ABS kicking in and making a lot of noise?

If it is, that's a classic symptom of a bad wheel speed sensor. I had this happen to me when I replaced the LBJs and had the sensor out. When I put it back in it had a small piece of rust on the end cap where it senses the teeth on the hub. I bled the brakes several times, and finally was about to replace the wheel speed sensor. All I ended up having to do was clean it off.

There's no way I'd start replacing expensive parts without a complete diagnosis.

As for switching over to the earlier system, I'm sure it's possible but not really practical. There were significant changes to the trucks between '00 and '01, including the addition of electric throttle.

I agree with all this. The conversion would be not just the braking system, I'm pretty sure the old ABS would not integrate into the VSC/TRAC system, so you'd have to disable that, and it's all built into the '01-'02 ECU. I'd be really afraid of unintended consequences from trying to that, unless I had a detailed how-to from someone who had done it to a similar model with success.

When people disable the ABS, they just pull the fuse. Why don't you try that? If you still have the problem after that, then it's a good bet the ABS system is not at fault.

 

[pluton]

even though i don't want to pay the stealership for work done unless i absolutely had to, should i bring it to them just for a 2nd opinion?

Diagnosis from the dealer service dept. should cost $90-$100, and often the info they give you is correct. But sometimes it isn't.

 

[absalom]

Few random thoughts in no specific order:

• Have you checked caliper's ability to extend and retract when removed from the brake disc
• Have you completely bled all fluid from the system
• Have you tried swapping in new calipers from auto parts store? (can return for refund if no fix)
• Have you tried to poor man bleed the ABS pump by locking up all wheels while on a low traction surface, repeatedly
• Have you inspected the rotors/pads for uneven wear
• Have you checked the tires pressure to ensure same in each
• Have you followed FSM bleeding technique, complete with 40 pumps w/ key off to bleed booster
• Have you scheduled appt w/ Toyota to utilize their require SST as prescribed by FSM
• Has your truck recently been aligned factory specs
• Are all front end suspension components new as of last 100k miles? Including ALL bushings, joints, etc

 

[Doc2012]

As for switching over to the earlier system, I'm sure it's possible but not really practical. There were significant changes to the trucks between '00 and '01, including the addition of electric throttle.

I switched mine over to manual brakes. Took the ABS pump out, got a non-ABS MC.

I did have to run new lines, but it works better than before.

You need a t-fitting for the front lines, but you can ususally find them in a junkyard from non-ABD Tacomas and 4Runners.


IDK if it's an issue for you, but the ABS light will be on. Maybe something with the Speedo, but I switched to manual hubs, and a different axle in the back.
[MENTION=118207]midcoma[/MENTION] can tell you how to get it done with the ABS system. I used a Tacoma one in the t-case.

 

[jeremyc74]

I switched mine over to manual brakes. Took the ABS pump out, got a non-ABS MC.

I did have to run new lines, but it works better than before.

You need a t-fitting for the front lines, but you can ususally find them in a junkyard from non-ABD Tacomas and 4Runners.


IDK if it's an issue for you, but the ABS light will be on. Maybe something with the Speedo, but I switched to manual hubs, and a different axle in the back.

[MENTION=118207]midcoma[/MENTION] can tell you how to get it done with the ABS system. I used a Tacoma one in the t-case.

What year is your truck?

 

[Doc2012]

what year is your truck?

1999.

 

[jeremyc74]

1999.

Ok. The problem is there's a big difference between a '99 and an '01. They switched to drive by wire throttle, and added a full on stability control system, not just ABS.

I'm not saying it couldn't be switched over, but there's going to be more to it than just swapping the brake controller.

 

[gamefreakgc]

are wheel speed sensors easy/cheap enough to replace to see if it's the cause?

Yes, very easy to replace. You'll find them on the opposite side of the tire right on the hub for each wheel. They are held in by one 10 mm bolt (you may have to remove the wire with the sensor though). Like others said, you might just pull it out, find some metal or gunk on the magnet and clean it and pop it back in.

I switched mine over to manual brakes. Took the ABS pump out, got a non-ABS MC.

I did have to run new lines, but it works better than before.

You need a t-fitting for the front lines, but you can ususally find them in a junkyard from non-ABD Tacomas and 4Runners.


IDK if it's an issue for you, but the ABS light will be on. Maybe something with the Speedo, but I switched to manual hubs, and a different axle in the back.

[MENTION=118207]midcoma[/MENTION] can tell you how to get it done with the ABS system. I used a Tacoma one in the t-case.

I don't think the OP is capable of doing a swap though.

 

[t4rFL]

i brought it to a dealer today and said it is the brake booster...something about no PSI to the left side (pulls to the right, though)....is the booster and ABS pump the same thing on these trucks?

i think i'm just going to look for a used one to swap in.

 

[gamefreakgc]

No, I believe the booster and ABS are separate. My 91 had a brake booster but sure didn't have ABS!

It could very well be a bad brake booster. Check and make sure it's not just a vacuum leak!