Is there a way to trigger ABS actuator to combat spongy breakes? (1 Viewer)

[Bud_Dude]

So, I was just trying to diag a possible stuck/sticky caliper so I set the cruiser on four jack stands two on each axle. Each wheel only one maybe two inches off the ground. Had my helper shift it from park to drive. The wheels spooled up as they would. When he depressed the pedal to slow the wheels is activated the abs immediately. I tested it a couple more times and each time it activated the abs module.

I’m gonna replace my master and get to the bleeding using the abs activation method we stumbled upon. I’ll report back with an update.

I was recently doing the same thing on my '97 80 series LC up on four jack stands in an attempt to document the speed sensor pulses per mile output. Same thing happened, with the truck at idle I put it in gear and the wheels started spinning when I released the brake. When applying the brake to stop the wheels and place it back in Park the ABS went crazy and made wild growling sounds and vibrations. I reckon this happened because with the wheels in the air (therefore not locked to the ground) and with one or more wheels able to slow at a different rate than the others (probably due to variations in brake disk friction) when the ABS sensed different rates from different wheels it went into action. Actually, it seemed like a good test of the ABS system in terms of confirming it really worked in terms of detecting a wheels stopping at different rates.

Now, how to use all this info as part of the brake bleed process? I'm not so sure... Do you really want to be around a spinning wheel or tire and trying to open a bleeder valve? Seems like it's getting in the danger zone a bit there. Were you successful in doing this?

I'm fixing to install a set of Slee stainless steel brake hoses in a day or three here and have been considering how to do the best brake flush and bleed I can when done.

 

[cvenom96]

I don't think the idea is to bleed them while doing this. More along the lines of bleed, activate, bleed again, and check for spongy brakes.

 

[Bud_Dude]

I don't think the idea is to bleed them while doing this. More along the lines of bleed, activate, bleed again, and check for spongy brakes.

Got it... Thanks for the thoughts... with that in mind, perhaps I've already dislodged any air bubbles from the ABS and they'll find their way out when I flush and bleed.

 

[cvenom96]

Got it... Thanks for the thoughts... with that in mind, perhaps I've already dislodged any air bubbles from the ABS and they'll find their way out when I flush and bleed.

Maybe. I'm glad to know this works putting it up on 4 jackstands like that. I tried locking mine up in some gravel and then bleeding once I got back home but I feel like still are a little spongy. I've got all new hoses so now that it's warming up again I'll probably just go swap all of them and use this method to get every last bit out.

Side note: I was going to see if Pep Boys (really close to my office) would put the new hoses on. Keep in mind that I was providing the hoses, they simply were going to install them. I got quoted just a bit over $700 for what basically amounts to labor only. I figured it would be ridiculous but damn did they over achieve in going for the rip-off!

 

[cartercd]

I was able to activate my ABS using the procedure in post #19. It flushed a lot of old fluid out of the ABS unit - much more than locking up on gravel a few times.

 

[Bud_Dude]

Maybe. I'm glad to know this works putting it up on 4 jackstands like that. I tried locking mine up in some gravel and then bleeding once I got back home but I feel like still are a little spongy. I've got all new hoses so now that it's warming up again I'll probably just go swap all of them and use this method to get every last bit out.

Side note: I was going to see if Pep Boys (really close to my office) would put the new hoses on. Keep in mind that I was providing the hoses, they simply were going to install them. I got quoted just a bit over $700 for what basically amounts to labor only. I figured it would be ridiculous but damn did they over achieve in going for the rip-off!

Well - having just spent the entire day under the truck and three trips to NAPA for different tools and penetrating oils in attempts to crack the 23 year old hose nuts without damaging the steel tubing; perhaps $700 isn't terribly unrealistic from a business standpoint. The effort will begin again in tomorrow morning...

 

[JeepinPete]

Do yourself a favor, find a pair of these:

Pliers

They lock onto the flare nut and do not slip. Puts a flare nut wrench to shame.

 

[smritte]

Do yourself a favor, find a pair of these:

Pliers

They lock onto the flare nut and do not slip. Puts a flare nut wrench to shame.

OK those are cool. Thanks for the link. I ordered a pair for my tool box.

 

[Wyatt Pine]

I was able to activate my ABS using the procedure in post #19. It flushed a lot of old fluid out of the ABS unit - much more than locking up on gravel a few times.

Could you be a little more specific as to what you did? I am hoping to bleed the abs and brakes this weekend.

 

[cvenom96]

Do yourself a favor, find a pair of these:

Pliers

They lock onto the flare nut and do not slip. Puts a flare nut wrench to shame.

Thanks alot a-hole. Now there's another tool I just had to have. Ordered.t.

Seriously though, thanks for the link!

Well - having just spent the entire day under the truck and three trips to NAPA for different tools and penetrating oils in attempts to crack the 23 year old hose nuts without damaging the steel tubing; perhaps $700 isn't terribly unrealistic from a business standpoint. The effort will begin again in tomorrow morning...

Admittedly I was leaning that direction too. They had quoted me a little over $400 initially which I was ok with given exactly what you mentioned. Then called me an hour later and said it would be $700+. Yeah nah man. I'll suffer through it myself.

 

[Bud_Dude]

OK those are cool. Thanks for the link. I ordered a pair for my tool box.

Thanks for the suggestion!! Ordered as well!

 

[jjdeneen918]

Do yourself a favor, find a pair of these:

Pliers

They lock onto the flare nut and do not slip. Puts a flare nut wrench to shame.

ordered. Thank you.

 

[rolliges]

Along with the proper tool, a little heat helps disconnect the hard lines.

 

[Bud_Dude]

Cute tool received.... It's tiny ... I guess that means it'll fit into tight spaces....

...and they've shown themselves to work quite well on old rusted brake fittings and bleeder ports where conventional flare wrenches were failing - Good purchase!

 

[cartercd]

Wyatt Pine - sorry did not see your request in post #29 until today. Below is how I activated my ABS. I did this several times in short bursts (5 secs) and then bled.

 

[Wyatt Pine]

Thanks! I'll give it a shot!

 

[dsmud4u]

Wyatt Pine - sorry did not see your request in post #29 until today. Below is how I activated my ABS. I did this several times in short bursts (5 secs) and then bled.

View attachment 2234677

I’d like to do this as well to diagnose some issues myself. Just to clarify, can I do this on my 97’ as well without harm to the ABS unit?

 

[LandCruiserPhil]

Say no to ABS

 

[cartercd]

You can do this on your '97, but any override of the ABS system not done by certified Toyota tech using the proper tool is a risk.

 

[-Spike-]

You can do this on your '97, but any work on any Toyota not done by certified Toyota tech using the proper tool is a risk.

FIFY