Hello,
I bought 1998 GS300 like 4months ago and after fixing starter problems and door actuators not working a found another problem. When I want to stop just around 10 - 5 Miles per hour the braking pedal just go to the floor and I feel something like ABS kicking into the pedal. I also hear a buzzing noise when this happens. No ABS or VSC light are on.

 

Your abs unit sounds like it's going out, also check to see if the pistons in the caliper are seizing. Check fluid level too

 

I checked the fluid level and it is ok. I thought if it was an ABS it would throw a ABS light. Next thing is that ABS should not be active in those speed from what i know.

 

NoobExe.

I can tell you exactly what the issue is. It is your ABS rings. You have one on each of the rear hubs.

Each toothed ring fits around the rear hub and is visible if you remove the wheel. Each is coupled to a sensor and the brake ECU determines if the rear wheel are rotating at different speeds to control the braking force. The teeth do wear down or get clogged with dirt on an old GS300.

I recall that Lexus do not sell this as a separate part but don't despair! New ones are sold on e-Bay (certainly e-Bay UK). The old ones can be prised off and replaced. as I have done.

 

Thank you very much,
I checked them and they are all dirty and rusty. I will replace them and we will see.

 

I wouldn't try replacing them, if its the tone ring they're usually not serviceable. There is a lip that will prevent it from actually coming out. My advice is just to get a new axle that comes with a tone ring(some don't have it), I have the same exact issue and someone didn't put my rear axle in right when I had bought the car so its easier to just replace the whole thing.

 

Each to their own. e-Bay UK has 19 sellers for the ring including the following who has sold 390 of these

www.ebay.co.uk/itm/REAR-ABS-RELUCTOR-Ring-for-LEXUS-GS300-LS400-SC300-SC400-SC430-GS430-IS200/191129228721?hash=item2c803095b1:g:MTIAAOxyaTxTQt8k#shpCntId

The worn-out ring can be prised or sawn out without too much difficulty. Has to be easier and safer than fitting a reclaimed hub.