Hi all, new to the forum but not too wrenching. I've been a transmission mechanic for over 38-ish yrs and do all my own work and all my vehicles are 20+ years old. My wife has a 2001 RX300 with 100k miles, it's in great shape and this will be the first real repair other than maintenance. Her brake pedal started going to the floor sometimes, my first thought was a master cylinder but its been so long since I've done general line stuff I thought it would be better to ask the guys that know these particular SUVs/cars. I've read some older posts about this and before throwing parts/money at it I'd like to hear what you guys think.
Things I know....the brakes are in great shape, I did a brake job last year. There are no leaks or any viable signs of a problem outside of the pedal going to the floor. Once it's on the floor and you let up and pump it again it's fine"master right"?
Thanks Barry

 

Nothing special about RX hydraulic brakes.

When the foot pedal goes to the floor, either the brake fluid is not being pumped through the system or there is air in the system. If there are no leaks [fluid exiting and air being sucked in] or a recent brake job, then everything points to the master cylinder. Lexus/Toyota has a repair kit and the whole cylinder is also available. Since you know hydraulics, the kit may be the best option. Either way you will need to bleed the system.

Dealer has the set up to purge air through the ABS. Without it you can minimize/eliminate, by dripping the master cylinder.

Salim

 

Thanks, Salim, I'll probably buy a new one, do you have a suggestion? I can use the solus from the shop I retired from

 

So....I called the dealer,you always do because "I" (think their parts are best) sometimes the price isn't that much different. Anyway, the master is discontinued I asked the guy about the rebuild kit and he said that is also discontinued. I see the kit online, but I would rather deal with a person. So.... is there a place everyone suggests to buy the part? I'm never a fan of the cheap parts houses. I know this might sound foolish to ask, but sometimes other people know places we all don't. I see one on rock auto that's 60 bucks ,but it might be the same stuff I can get at the parts house.

I don't remember the last time I replaced a master on our vehicles. I replaced the clutch master/slave on my camaro two yrs ago with GM parts from the dealer, it's also a 2001.

Thanks guys
Barry

 

There's an Advics one on Rockauto. Advics or either Aisin makes the OEM master cylinders for our cars, so it may be an OEM part repackaged. I had a similar discovery when I bought Aisin ABS sensors. OEM part w/ OEM number on it. It had the correct copper terminals unlike all the no-name knockoffs which cost the same or more.

I did a cylinder on a 2004 Camry recently. Symptoms were like you described, no matter how many times I bled the calipers the pedal would go to the floor and you'd only get intermittent feel and power from the brakes after pumping them multiple times. The cylinder was leaking internally into itself, so no visible drips were seen.

 

Thanks, MattRX
Rockauto seems like the best price and it may or may not be the same-ish part. I went to the auto parts website and they're wanting 150-200 for a master.

 

I replaced one of these recently master was made by Aisin. Centric makes good brakes parts I've never had issues with them. Get 5% off at Rockauto
https://www.toyotanation.com/threads...360084/page-23

 

Potential source:
https://www.lexuspartsnow.com/oem-le...epair_kit.html

Most places will require core to be returned.

Best of luck.

Do your best not to pump air into the system. I would let the fluid dribble out at the master end .

Salim

 

Thanks, everyone, I'll check them out.

 

Top original, below new Aisin BMT-162.
Spot the differences.

 

JohanH, The only thing I see is the mounting location and overall casting is thicker, is there more?

I got the master installed and full of fluid.I tried to use a miti-vac and all it did was "I think" vacuum out all the brake fluid from the caliper. I tried to bleed the system the old-fashioned way by pump/hold, I didn't have a steady stream which doesn't make sense, I'm sure I need to use the scanner to open the anti-lock system.



thanks, Barry

 

They're exactly the same, apart from the 'Advics' stamp.
One might look thicker because of the photographing angle.
Put it here to show the OEM part.

 

Toyota/Lexus does not manufacture everything as they put their vehicles together. AISIN is the producer of the master cylinder. Bulk order for the parts is placed by Toyota/Lexus and boxed parts with Toyota Labels [beginning to see Lexus too] are shipped to assembly lines. AISIN can also sell to open market [if there is room in the agreement with Lexus/Toyota].
The problem creeps in due to copycats [which can even print out genuine looking Toyota boxes] and factory seconds and rejects if they are not destroyed. These products are now making their way to USA and to consumers through net sales.

I prefer purchasing parts through Lexus dealership. For members, I suggest they purchase through reputable sellers.

Salim

 

At the time that I needed this part, the price at the dealership (in NL) was approx. €600,-
At a reputable parts dealer the Aisin part was about €100,-
4 years later it is still working as intended

 

The part you purchased and one boxed and sold by Lexus could have been from the same batch and quality. I am just sharing what is regrettably getting to be a common situation. The fakes are making their way everywhere.

Salim