ABS Actuator Replacement - DIY Questions

The issue with the ABS pump motor is that the carbon brushes need to be replaced. Since the hybrid uses the pump more often, that motor has to be properly repaired because if it isn't, it'll wear down really fast, overheat and cause a short.

The accumulator might be an easy fix where you just buy a replacement from a different make. But size difference might cause issues.

Originally the goal was to fix my car but I find it fun to figure out how these crucial parts can be made by an average person.

 

the brushes wear out because they keep on running due to the internal leak, I rarely see ABS pump motors on Prius fail. It is a known fact that during these years even the non-hybrid ones were suffering from ABS failures due to internal leak.

 

Its all an issue. The brushes will need to be replaced eventually. My estimation is at 230k miles. Yes my brushes were worn down due to running more than usual but it would still be at 3/4 of its life.

 

so you didn't fix the real issue then, got any codes prior to replacing? what scanner you're using?

 

We don't know what car he has ("other hybrid") and he believes the brake booster is simply a hydraulic pump and accumulator.

 

He has a Highlander Hybrid. See this 1.5 year old thread, https://priuschat.com/index.php?posts/3394873

 

I don't remember the exact code but it was a code for a leaking accumulator. The small abs pump kept running because the accumulator couldn't hold pressure. I didn't know it at the time so I tinkered around with the ABS motor and damaged it instead of just replacing the accumulator.

 

But a code about pressure not holding in the accumulator almost never indicates a leaking accumulator. It virtually always indicates that the accumulator pressure is not held because fluid is leaking elsewhere, through valves in the actuator, and returning to the reservoir. Replacing the accumulator won't fix that.

While an accumulator can become leaky (there was such a problem in early-production 2010s), that's a much more rare issue with symptoms that aren't identical. A leaky accumulator bellows will be releasing the high-pressure nitrogen gas into the brake fluid. It will cause the system to behave as if it has gas bubbles in the fluid and needs to be bled (because, well, it does).

 

Either way, the accumulator needs to be replaced once it leaks. There's no way around it. And then the system bled.

 

On the other hand, if the accumulator has never leaked, the accumulator has no need of being replaced. And that is the vastly most common case when failure to hold accumulator pressure is reported. The leakage is elsewhere.

 

Ah I see what you're saying. But if its an internal seal elsewhere that holds brake fluid, then one should be seeing fluid leak around the module. I don't recall seeing any major leaks or running low of brake fluid although it might've happened and I assumed it was the accumulator. If I had inspected it for a leak at the time it would've been easier but now the engine bay has been sitting and accumulating dirt for too long.

If its a module leak, is there a fix?

 

Almost never an actuator leak to the outside. Instead it is a leak between hydraulic passages internally. It could be a leaking solenoid or internal gasket or oring.

One thing is certain - it is a common fail and Toyota covered them for 10 years or 150,000 miles. It is not an easy job and diy'ers often have trouble bleeding and calibrating it.

There was a LA area company who thought they could rebuild Prius actuators for $550. You had to ship yours and wait for the repair and return. Last reports are they quit doing it.

Internal Leaks

 

An external leak is rare. With an internal leak no fluid leaves the system; it just returns through the passageways to the reservoir.

 

Well ok that does make things a bit more interesting. When I pulled the code, it said something about accumulator not holding pressure or something along that line, so I just assumed it was a bad accumulator since it has seals that wears out over time I would assume.

My strategy was to find a fix for the electric motor and then the accumulator but I guess I can focus on the abs block seals and the pump for now.

 

The brake system is a critical part of the car, and trying to repair its internals at the level of a home garage and risking your safety is a crazy idea.
It is better to install a new original spare part than to endanger yourself and other people on the road.
This is not an entertaining display.

 

I can understand your concerns, but personally I wouldn't do this if I wasn't confident in my abilities or in the car. Anything can cause an old car to break down on the highway and I'd rather put my faith into repair that's been carefully monitored than a car that hasn't been maintained.

Either way, the car is just sitting until its fixed. I'm not in any hurry to fix it.

 

You do a lot of assuming. The accumulator does not have internal seals. The accumulator has a bellows. Brake fluid is on one side of the bellows, and the high pressure nitrogen is on the other side of the bellows. Read post #28.

 

You have to understand, I'm not a manufacturer who makes ABS modules nor am I a master Toyota technician. I'm just one guy trying to fix a $2500 part for $200. Assuming and making mistakes is going to happen to get things going.

 

Ah the arrogance of youth and sometimes much older diy'ers. The Secretary of Defense during the Iraq war once said



Which is a version of Socrates from thousands of years ago who also recognized there are known unknowns and unknown unknowns.

This applies to nuclear defenses through repairing hybrids.

Risking innocents on the road is a high risk activity that is a known known by most.

The saving grace is a homemade hybrid brake booster or modification will never get out of the driveway even two years later.

 

I'm just trying my hand at the module to see if it is even repairable. If its not, I'll just scrap it and bite the bullet to purchase a new one. Please don't over think it.