harleydjce

Late last year (Early Dec), the brake feel on my RX literally went from great to spongy and needing more effort overnight. Fortunately, it was due for it's annula service. The dealer examined the system, couldn't find anything wrong and bled the brakes and the pedal feel and effort returned to normal.

Shortly afterward, while on a long trip at Christmas (1400 Miles round trip), the same thing happened again (after about 450 miles). Called into a local Lexus Dealer who examined the system also, couldn't find anything, bled the brakes and all returned to normal again for another 500 miles.

Once I returned home, I went to my usual Dealer who again, couldn't find anything wrong. As a precaution, they replaced all rotors, calipers etc and everything returned to normal for 1200 miles.

It's happened again but is now intermittent rather than a constant issue. Parked the car in my garage on Tuesday night everything OK. Started up Wednesday morning with spongy brakes etc.

Has anyone else had this problem? The guys at the Dealership have kept my car for the weekend and have given my another RX (brakes are great on this one).

Orzel

iTrader: (1)

Wasn't there a TSB for the brake booster? This sounds a bit like the power brake system loosing pressure. Suggest you ask your dealer to go through all the TSIB's for the RX.

RXSF

^^ no, that was only available to 2004-2005 models and not 2007

Orzel

iTrader: (1)

Hmm, OK, so the TSIB was for the 04/05 models. Well, still thinking brake booster though, it's a logical explanation, especially when coupled with the brake bleeding by the dealer which improved the feel, albeit temporarily. If the booster goes, one indication is spongy brake pedal, and possibly lower fluid level as booster is "sucking" some of that fluid in.

RXSF

in case you want to look at the tsb...

data.pdf

KeysRx300

Ive had my RX350 for a little over 13 months. About 6 months ago. I started to noticed when I pressed the brakes. It took more pressure to get the car to stop.

When I went in for the first oil change. I told the Sevice Rep about the brakes. And they checked them out. And said it was ok. He said Lexus had used a different material on the brake pads.

My RX300 had tight brakes. You just had to rest your foot on the pedal. And the car would start braking. He said Lexus changed the material because customers had complined about the brakes being to sensitive.

Since then. The brakes have been a little spongy. But have stayed the same.

harleydjce

Thanks everyone. I'll stick the TSIB under their noses and see what happens. Will let you know the outcome.

grouch

If the brakes get better every time they are bled, then air is getting into the system somehow. Either a caliper has a pin hole, a fitting is not tight or the M/C has a small leak. My guess is somewhere below the M/C, that's way the air bubbles rise and accumulate while it sits overnight.

Just my 2 cents.

harleydjce

The Dealer can't find the cause but is replacing the master cylinder as a precautionary measure. It's being airlifted from Tokyo and should be here Monday!

Losiho

Sorry to hear of your problems Dave. Hope the new master cylinder solves the problem.

Haven't had any issues with the brakes on my RX.