I recently had a very mushy pedal in my LS430, usually reared its head after driving for a bit. I immediately thought bad master. Then I read and dug around and hear that these masters very rarely fail. So I order all new parts. New oem front and rear discs, new front and rear oem brake pads and shims. Front and rear caliper rebuild kits. And new stoptech stainless braided lines. I thought I could have a caliper hanging up or old fluid or deteriorating rubber lines or a bad master. If I held pressure on the pedal once it started getting really mushy it would continue to slowly drop which is why I thought master. I ended up installing the braided stoptech lines and bleeding the system real well to get fresh fluid throughout the system. I still had some life left on the pads and rotors that were on the car so I started with the line change and fluif flush and bleed. Ended up that fixed my mushy pedal. Car stops great now and I dont get that soft pedal after driving over a long period. Fluid that came out didnt look terrible but after letting it set in the container for a bit a LOT of crud settled at the bottom. It was very dirty and probably full of moisture so after changing the lines (which can deteriorate from the inside out) and the fluid it stops great! I'll get around to putting the new pads and rotors on but for now its fine and there was probably 50-60% pad life left on the aftermarket stuff that was put on there at some point.

 

The service manual specifically says to bleed the ABS actuator if the pedal is still soft after the regular bleed. In addition, this soft brake pedal problem has been covered many times in the past, see my post at https://www.clublexus.com/forums/ls-...ml#post9850497

Attached is the service manual for the brake bleed, which includes ABS actuator bleeding. It says "After bleeding the air from the brake system, if the height or feel of the brake pedal cannot be obtained, bleed the air from the ABS actuator with an intelligent tester (aka Techstream) by following the 4 stage process", where each of the 4 stages requires running the bleed operation on the tester multiple times per wheel, doing that for all 4 wheels, and doing that entire process for all 4 stages of the ABS bleed.

Sounds like a huge hassle to do the ABS bleed, I would consider paying Toyota/Lexus to do this.

 

I asked my local Lexus dealer to do the Techstream actuator bleed in addition to the normal fluid change, and if they actually bled the actuator, they sure didn't use Techstream (my dashcam would have switched to a non-parking mode if the key turned to ON or ACC). I did notice that the procedure for brake fluid bleed procedure for 2001-2003 differs from 2004-2006. Below are the instructions for 2001-2003 which uses the bleed screw on the ABS actuator body combined with applying pressure to the fluid reservoir (Motive 0101 kit should do the trick):


The PDF in my post immediately preceding this one shows the 2004-2006 Techstream process, which is a 16 step process (4 ABS system phases, and each wheel has to be bled during each phase).

Any brake system experts have possible explanations as to why Toyota stopped using the bleeder screw on the ABS actuator for 2004-2006?

 

Because it can be done electronically and saves cost vs having the extra bleeder

 

The 16-step process would take closer to an hour and requires utilizing a lift and is a 2-person job, whereas hooking up the pressurized tool and bleeding it for 10-60 seconds directly at the bleeder screw takes closer to 5 minutes and is easily done by 1 person without a lift or tester. I'm not sure cost savings is the correct rationale. Surely there is something more technical?

 

What is the cheaper part to order for the actual maker of the car, plus now you get to charge more for service. There are MANY things like this you see generation to newer generation within brands that leverage electronic tools/require them to be able to perform otherwise basic functions.

 

I think you meant to say revenue generating for the dealership, as opposed to cost savings? Lexus only charged me 1 hour of labor for the brake fluid change, Toyota wanted 2 hours at Lexus rates. Maybe Lexus would have charged me 2 hours if my car was an 04-06 requiring the Techstream process? However, I have a feeling Lexus didn't bleed my actuator at all.

I don't believe that any parts of the LS430 service manuals have been tweaked for increasing revenues at a Lexus service department - everything in the manuals seem to be fully engineering-driven.

The Techstream ABS bleed procedure makes you bleed the "regular" line for all 4 wheels, then the suction line for all 4, then the pressure reduction line for all 4, then regular again for all 4. I am guessing that bleeding the actuator unit itself using the screw on the back doesn't clear old fluid from the suction and pressure reduction lines.

Considering the massive labor involved if you do it by the book using Techstream, I think the best DIY option is to start with the 2001-2003 process by pressurizing the reservoir and using the bleeder screw, then close it all up, get up to speed in a snowy/icy parking lot and slam the brakes to engage the ABS system and to circulate the old fluid out of the suction and pressure reduction lines, then repeat the first step until you feel the system is full of new bubble-free fluid. Maybe I'll try this in the winter.

For future readers, the bleeder screws are operated by a standard 10mm box wrench (no need for a special angled bleeder wrench) and are accessible without removing the wheels if you have air suspension on high and/or can slide under the car without it lifted. This car is designed for super-easy serviceability. Drill the cap of a 500mL-2L soda bottle, insert clear tubing til it touches the bottom, pour in some fluid so the tube is well-dunked to prevent sucking in air, then bleed away.

 

I hate to bump such an old thread but I was hoping to provide some insight and dispel some myths. I work in engineering and can give you some context.

Lexus engineers are tasked with designing a product that meets cost expectations for materials and manufacturability, not service. The Lexus engineers are focused on making a product that meets the customers expectations while reducing the cost to purchase all the components and make it as easy/cost effective to assemble at the factory - after all the more they can cut costs out of the manufacturing process the lower they can price the vehicle for the customer. Removing the bleeder screw removes a costly (relatively speaking) component from the ABS module and makes assembly of the ABS module that much faster (one less component to install). That's also one less component on the bill of material, one less component that needs to be stocked in inventory, cataloged and moved through the factory. It eliminates a potential failure point if an assembler forgets to tighten it or install it. You get the gist. The ABS can still be bled by the technicians when needed (which is not often) so there are no downsides to designing it this way besides convenience for the technician. Lexus leadership has a list of priorities and fast/easy to service is not one that matters to the vast majority of their customers. The percentage of Lexus customers that actually work on their own cars beyond very basic DIY (changing wiper blades) maintenance is negligible and would never impact the product design.

This is all assuming that the bleeder screw is absent on the later models which I don't know if it is. If it isn't then most like the procedure change is an improvement to the bleeding process to increase the chances of clearing all the air bubbles, possibly due to a design change of the internals of the ABS module.