2003 SR5 - ABS Hydraulic Unit going out…

TLDR: IS IT FEASIBLE TO FIX THE ABS HYDRAULIC UNIT MYSELF???


Hello, I’ve just created an account here to ask about my 2003 SR5 V6 RWD. Yesterday morning I started up my car and was met with 1) A continuous alarm tone 2) ABS, TRACT, and parking brake lights are on. It stopped after a minute or so, so I drove to school and planned to take it to the shop after school. Less than 5 mins later the same thing happened, but I still had complete control of the car and the brakes didn’t feel any different.

I took it to the shop later that day, and they’ve just told me that the ABS Hydraulic Unit is going out and gave me a quote of $3500, which is about half as much as I paid for the car in the first place.

I assume this is going to be a “no,” but is it feasible to save money fixing the thing myself? I figure that since it’s already broken, if I fail I can take it to the shop and just pay the money.

Thank you!

 

Has anything been changed such as a lift? Recent brake service? You say that ABS, TRAC and Parking lights are on, what about the CEL? Codes?

You could possibly try performing a zero point calibration?

 

I don't think there's a lift, but there could be: I'm not the first owner so maybe. No recent brake service but it's probably getting close to time for new ones, though no squeaking yet. No CEL light. I don't have a scanner so I'm not sure about any codes.

I called the shop yesterday and they said that my car is good to drive, but I just won't have ABS. They said the exact broken part (moreso an assembly) was the ABS Modulator Valve. I'm going to have to ask them to show me exactly what it seems to be and I'll have to figure something out from there. I'll update when I find out more.

Another question here: My brakes have always been softer than other cars I've driven. I've only driven cars that have been made in the last 5 years (I'm a pretty new driver) and those feel much more responsive than my car. Is this a typical difference between older and newer cars or have my brakes gone spongy?

Here's an interesting thread I found on the issue:

 

I am far from being a brake guy. VERY far.
Having said that, as far as I know, and I am sure there's plenty of other reasons, but generally, spongy/soft brakes are either air in the lines, or bad brake fluid. Brake fluid absorbs moisture over time, and enough moisture in the fluid will make it go bad. Especially if the moisture close to the brake actuators gets hot enough to boil the water. You boil the water, air in the lines.
It will also rust many of the parts, like the hard lines, and actuators. Makes enough new brake fluid to flush it every few years a very small investment with big returns.

It might be the entire solution to bleed the brakes out completely. IOW, making certain there's plenty of new, clean, fluid in the MC at all times, bleed each brake until the fluid coming out is the new, clean, fluid. Any air coming out, keep bleeding until there's not.
It may well take a fair amount of fluid, depending on the system your truck uses. Make sure you have more than enough to keep the MC full. Check it often!

Make sure to bleed them in the order, and using the method, specified by the FSM.

You really should replace the fluid in the entire system every few years. I believe most professional brake guys recommend no longer than every 5 years, but it might be every 3. I can't recall right now.

Good luck!
Pat☺

 

Keeping the above posters info in mind, absolutely go through the routine of doing a fluid swap and brake bleed. Thatll either show you have potential leaks, get air out of the system, or show that its neither of that and is indeed an issue with the MC or ABS valve. Roam around eBay. you can definitely find parts for cheaper than new OEM, but do your due diligence on vetting the parts best you can. If not, you may well be out that much, a new module is $2-3000 depending on the dealer you buy from.

Speaking of, try asking different shops, they may well say different

 

Thanks for the advice y’all. My dad was able to find a guy who had a couple master brake assemblies for the 04 4Runner (this whole time I thought my car was an 03, it was an 04 ) and he’s selling them for $400 each. Only issue is that they’re pulled from wrecked cars so I’m worried they might be messed as well. Do you guys have any suggestions or tips for when we meet the dude and check the thing out? Also since I’ll be replacing the entire assembly I assume they’re going to have to put new fluid in and bleed it but I’ll ask the shop just in case. Once I get back to me car I’ll also drop the error codes the shop scanned for anyone who stumbles upon this thread with the same codes. Thanks again!

 

I'm not sure about your year truck, but as a general rule, you need to "bench bleed" the MC before you connect it to the rest of the brake system. IOW: Get all the air out of the MC's piston before you connect it to the rest of the system. It ensures that it's not soft when pressing the pedal due to air within the MC's piston. Keeps it from pumping said air into the rest of the system, too.

The more modern and advanced the MC, the more complex the bleeding procedure for it. Make sure to check the FSM for your year truck on how-to bleed the MC.

Once it's installed, bleed out the rest of the system, making sure you use new, clean fluid, and keep the reservoir full as you go to prevent air getting sucked into the MC's piston, or the rest of the system. Bleed each brake until you get new, clean fluid out. Don't reuse old fluid anywhere. Dispose of it at an auto parts store.

Make sure you record any currently stored codes, then clear all the codes out, either by pulling one of the battery terminals, which is what I do, as it's easiest for me, or the EFI fuse, for 1 minute at least. Good opportunity to clean the battery terminals, and the cables that connect to them.
Bear in mind the SRS (air bag system) has a 90 second "memory" to it. IOW, it can go off up to 90 seconds after all electricity is removed from the truck, like by pulling the battery terminals to clear the codes. Be VERY cautious about reconnecting before the 90 seconds is expired.
Then see if you can get the codes to pop up again. Remember, the ECU has what's called a "two-trip" logic to it. It needs to get the codes during 2 separate, distinct trips before it sets the CEL, and stores the code.

Good luck!
Pat☺

 

I’m just gonna hand it over to the shop to deal with. I don’t trust myself messing with stuff I really don’t know much about

The codes they scanned were c1223, c1246, and c1252.