2005 GS430 Brake actuator.

[Ian12]

Hello all.

 

Apologies if this question has been asked before for this car in particular, but I have one or two queries.

 

My friend has bought a new(ish) 450H, and is willing to give me his 05 GS430. However, the brake actuator recently went faulty (he had it at Lexus and they confirmed this). I was looking to have it replaced but can’t currently justify the £1300 price that the main dealer has quoted.

 

I have two questions, if anyone can help.

 

1: Is this unit the same as on the GS300? I spoke to service at Lexus a few days back, and he said they were the same, but he didn’t sound 100% sure if I’m honest. I ask this as that’d make it easier to track a used one down with the 300 being more common.

 

2: Upon replacement, do they have to be programmed in to the car it’s on, or is there anything else special that’s required that’d make it an unsuitable job for a general mechanic?

 

Thanks in advance.

[Ian12]

Sorry, just noticed that there are sub forums for brakes etc, if a mod wants to move this?

[Lwerewolf]

1) 3rd gen GS430/450h/460(?) (and 4th gen 450h) share brake actuators (LHD/RHD-specific... somewhat). The GS300 and GS350 (not sold outside in Europe) share a vacuum-based system. The rest use EBD (electronic brake force distribution i.e. brake by wire) - the actuator has a DC motor to make pressure, a hydraulic accumulator pre-pressurized with nitrogen to store pressure and the solenoid block to control pressure release to/from the individual calipers. Failsafe lines directly from the brake master cylinder go to the two front calipers - without any power assist whatsoever, so don't get any funny ideas 😛
2) Theoretically possible to bleed the system afterwards without techstream:

Practically - depends. Whether the pedal dance will be the same on hybrids and non-hybrids and on earlier/later generations - I don't know. You also need to bleed the line between the brake fluid reservoir and the actuator - usually done with a pressure cap adapter on the reservoir and opening an auxiliary/service port near the actuator's inlet (so that air/fluid can exit out of it as you pump up the pressure in the reservoir). There's also the actual master cylinder to bleed as well... etc, etc - you can find the service information online, pretty much all cars with EBD are the same.

[Ian12]

1 hour ago, Lwerewolf said:

1) 3rd gen GS430/450h/460(?) (and 4th gen 450h) share brake actuators (LHD/RHD-specific... somewhat). The GS300 and GS350 (not sold outside in Europe) share a vacuum-based system. The rest use EBD (electronic brake force distribution i.e. brake by wire) - the actuator has a DC motor to make pressure, a hydraulic accumulator pre-pressurized with nitrogen to store pressure and the solenoid block to control pressure release to/from the individual calipers. Failsafe lines directly from the brake master cylinder go to the two front calipers - without any power assist whatsoever, so don't get any funny ideas 😛
2) Theoretically possible to bleed the system afterwards without techstream:

Practically - depends. Whether the pedal dance will be the same on hybrids and non-hybrids and on earlier/later generations - I don't know. You also need to bleed the line between the brake fluid reservoir and the actuator - usually done with a pressure cap adapter on the reservoir and opening an auxiliary/service port near the actuator's inlet (so that air/fluid can exit out of it as you pump up the pressure in the reservoir). There's also the actual master cylinder to bleed as well... etc, etc - you can find the service information online, pretty much all cars with EBD are the same.

Thank you for the reply, and I think that almost decides it for me.

 

I’d wanted this car once he came to sell it for a while now, but this job sounds like it could end up being a right pain, and I don’t seem to be able to find anyone near me (Manchester) that I could rely on or, more importantly, that specializes on Lexus, aside from a dealer.

 

It needs two back tyres and the batteries have gone on the tyre pressure sensors too, so having to spend up to a couple of thousand right before Christmas isn’t ideal. It’s a shame, as the car is lovely otherwise, and it’s possibly even worth spending that sort of money, next to what it’d be worth once the work is carried out.

 

Anyway, thanks again for the information.  

[Lwerewolf]

TPMS... I'm running hamaton sensors now (just the cheapest that I found) that I'm too lazy to replace the batteries on the OEM ones (involves spot-welding, can do it with normal solder too but meh). You will need techstream to program them in regardless... and something to read the aftermarket sensors' IDs if they aren't printed on them (rtl-433 works wonderously).

IMO if you can find the actuator, the rest isn't that hard - you should have techstream (with a proper adapter) while owning such a car regardless.

Whether it's worth it or not - up to you. These cars aren't the cheapest to run, even though they are pretty much at the top of the reliability ladder as far as luxury rwd sedans are concerned.