I just finished putting LS400 brakes on my 2000 GS300 everything went great until I drove the car and have a very spongy feel. I have bleed my brake system 3 times finally gave up and took it to brakes plus even after having them bleed my brakes it still felt the same. I dont have and ABS or brake lighton it almost feels as if my GS300 brakes had better response any help you can provide would greatly be appreciated.

I "THINK" the reason why you get the very spongy feeling on your pedal is because the LS calipers (4 pot) takes up more brake fluid than your old set up. So you have to press the pedal farer down.

Now, I sold me lexus more than 4 years ago, so I don't have on to play with but on my race car, my push rod is adjustable. If the GS is adjustable, you can play with that. Push it out a little more so you don't have to press down the pedal as much. Another thing is to get a larger mastercylinder.

Good luck.

is your brake booster working?

It maybe time for some new fluid..

How can you check a brake booster? Also is their a possibility I could have a bad Master Cylinder? Is their a way to check? I just went for a short drive and noticed that the pedal gets firm the way it should be for a few seconds then it goes back to spoongie. Everything was purchased new LS400 calipers new slotted rotters brakes plus even did the fluid flush so it shouldent need new fluid.

I'm sure your brake booster is working. If your brake booster is not working, the pedal will be very stiff and yet you don't feel like the brakes are working. Also known as "Manual Brakes" VS "Power Brakes" Just to give you a clear idea of what it is like if your brake booster is not working. Try using your brakes when your car is off.

So once again, it's because the LS calipers has 4 pistons VS stock GS has 2 pistons and it takes more pressure/fluid to make those things work.

So just to be quick, the abs unit/master in these vehicles is VERY tricky to bleed the air out of correctly without the proper scan tool. I just put tt's on my 2gs a while back and it took me several attempts to get the air out of the unit, without damaging it i might add! A week later the abs motors, integral the abs unit, wouldn't stop running! Turned lights on, stored codes in the EBCM and everything. Still had some air in it somewhere. Keep workin at it you'll get it.

It's doable without a scan tool, but a little more labor intensive.

I'm going to keep working at it hopefully your right and I will eventually get it. Is their anybody out their who has LS400 calipers on their GS300 that can provide some input and let me know if they have a spoongy feel to their brake pedal?

what hoses do you use? stock 2gs or ls4?

edit: nm found out

same damn caliper the supra ones are half steel which is heavier but if you look at the specs thats pretty much it besides the 1000 extra you spend lol

i polished the lip on them and i plan on doing black with the polished strip to hard to polish the whole things bought the lexus stickers for them but they wont go on the ls calipers

braided stainless lines all four corners....

sorry, as we been talking about LS400's alot lately i figured i would post these,even though this post is old as dirt

lS400's will fit with a Sage RCA kit even on stock 16's with a 15mm Spacer

Figs is making a RCA also and i might test that to see if they fit also but they should with no issue, but for sure again with the Sage RCA kit they will fit with no grinding on any bolt

https://www.clublexus.com/forums/sus...o-rubbing.html

I havent done it myself, but the 98 ls400 we looked at buying insted of the gs only had 16" rims as standard.

PHML was able to do it with his 16" oem wheels with the SAGE RCA.