traxxi2003

Okay, I need assistance indentifying this part, my truck developed a brake fuild leak, I discovered this part below leaking fluid. I've looked on several online toyota parts dealers, and so far I've found two parts that could be the replacement for the part on the pictures below. I found what toyota calls, an "ABS control module" priced at $335.00, the other part I found is a "ABS Modulator" priced at $1200.00. My confusion comes with the fact that on ebay and on this site, the part on the picture below is refred as an "ABS Actuator" Has anybody on this forum had this parts gone bad? Is it safe to install a used one of this? A friend tells me that this part should only be purchase new at the dealer. Any suggestions?? Thanks!

Jomoka

'Should be'. Possibly. But thousands of us are driving around with ABS actuators that have 150/250/350K miles, and they're still working fine. I'd say look for one from a junkyard. A brand new one would probably be *best*, but one that works would be 'good'. As long as it's a lot cheaper of course.

Actuator/Modulator pretty much mean the same thing here, it's the gizmo with the little valves that bleed hydraulic pressure from a specific brake circuit to un-clamp a specific brake. Also pumps fluid back into the 'upstream' side of the valves when it does that to prevent the pedal from sinking down due to it bleeding pressure off. The ECU is a separate electronic control module that watches the speeds of all 4 wheels and decides when to start releasing one or more of them (when it starts to turn more slowly than the rest).

traxxi2003

Thanks Jomoka for the clarification. Do you know if there is a way to bleed the actuator once replaced without having to take it to the stealership? I was told by a friend that most if not all abs systems can only be properly bled by connecting the abs system to a computer that can actuate the selenoids inside the ABS actuator during the system bleeding process. Can someone please explain?

Jomoka

I think they can use a tool to activate the bleed/pump action and sort of self bleed the system, but you can still bleed the system normally. The valves in the modulator ware wide open unless ABS is activated, fluid will move through it normally. It's probably worthwhile bench bleeding it (filling it with fluid once it's installed on the truck and won't inadvertently pour back out, just fill with fluid where the brake lines go before you install them).

Just treat it like a junction block in a non-ABS vehicle.

traxxi2003

Okay I just got finished inspecting the ABS actuator and I discovered the origin of the leak. The actuator will only leak when the ABS is activated. I've included a picture pointing at the leak.



Has anybody ever taken one of this apart? A new unit cost $1300.00+-, Is anybody here had to replace this component on their trucks with a used one? Any information will be greatly appreciated.

FogRunner

I've replaced on a 98 4runner before and they are not hard to find on junk yard 4runners and Tacoma's.

The main reason for failures of the actuators along with master cylinders and if your have 01-02 4runner the whole brake actuator/vsc/master cylinder unit is because of poor maintenance.

Brake fluid needs to be changed/flushed every year or two or else it will cause brake system failure. The fluid holds water and allows corrosion to occur inside of the actuator like yours.

When you go looking around a junkyard for one look at the color of the brake fluid. If its not a light amber color then keep looking because the darker it is the more moisture is it which means there is going to be corrosion in the actuator.


FOG

traxxi2003

Thanks for the info. FogRunner, I actually already found one for $50.00 and yes the color of hte fluid was good when I removed the actuator from the donor truck. Now, my question is, Is it possible to correctly bleed the air out of the actuator without going to the stealership? I read a thread from a guy that drove his truck in order to engage the ABS system, then followed normal brake bleeding procedures with good results. My local dealer wants $200.00 just to do the computer bleed.

FogRunner

No nothing special required. Just hook it back in the way the other one was and bleed the brakes as you normally would.

traxxi2003

FogRunner, you were correct, I was able to install and bleed the system without the need to a visit to the dealership. In additon to just bleeding the brakes, after installing the new actuator, I also drove the truck in a dirt road in order to activate the ABS system several times. Then I bled the system a few more times just to ensure there was no air in the lines. So yes, you can replace the ABS actuator and successfully bleed the air out of the system without having to pay the stealership $200+ to have your brakes bled.

Jomoka

I think there were a few early ABS systems that had internal reservoirs or something, they did need a special bleed routine. That's left a lingering FUD (Fear, Uncertainty, Doubt) cloud around ABS systems ever since.

ABS or not, flushing new fluid through the system every 3 or 4 years is a really good idea. As fluid absorbs moisture it's boiling point goes down, in addition to it eventually becoming corrosive. Low boiling point could mean boiled fluid in a caliper under heavy use, and since you were using them heavily, you're likely going to miss them when they boil and stop working.