I have a brake (?) problem with my 2000 LX470, 168K miles. I have a squeal coming from the engine compartment, at/near to the master cylinder. It's gotten worse over the last 15+ months. The squeal happens during cooler/colder temps, never in the hot summer. It occurs for a short time (5-30 seconds) after first start, or if the car has sat for 5-8-10 hours, depending on how cold it is. (I'm in Dallas. Cold is relative.) The squeal is similar to the toilet tank filler process, if somehow the inlet water is restricted coming in. It finally ends, (5-30 seconds) later just like when the toilet tank lever stops/pinches off the water flow entirely. If I tap my brakes during this squeal, it suspends the noise momentarily, but then continues a second later. The squeal happens whether the car is in drive/motion or in park/idle. There are no leaks. There is plenty of fluid and has never really needed to be refilled. (I'm out of work, so I can't shotgun this repair.) Anyone else had this before? Any ideas? What "primes" in the braking system at start up??

Thanks for any responses.

 

I have the same problem with my LX470. Just so happens mine is at the dealer being diagnosed today. I will share findings, if any.

 

Mine's at Lexus today now too, for an electrical problem that won't let me even start the car. I tried someones suggestion in another thread about turning the car off to see if the brake goes mushy, to check if it's the power brake booster. 4-5 seconds later I turn the ignition back on with my foot hard on the brake and all cabin lights go on, then all lights OFF. No more nothing, except some relays clicking (ABS MTR1, (not the Starter relay)). Crazy.

Personally, I think my original squeal problem is the power brake booster pump. Unlike other threads I've read, it uses the brake fluid for it's hydraulics, and not air pressure from the engine. And the sound just sounds like a bad pump. Good luck. ( here's comes another $1000-$2000 bill I don't need)

 

OK Lexus service says I have two problemo's. 1st is that the rack and pinion is leaking. My steering has been fine, fluids fine and no leaks showing on the garage floor. They said it was leaking into the two "boots"? Don't know much about r&p steering, but this has nothing to do with my squeal. Quoted $1000 parts and labor to fix.

2nd, the Master brake cylinder (MBC) and ABS need to be replaced. Quoted $1300 P/L inc. Good price. Makes more sense, but does the MBC have a pump that would prime?? There's a RED line that comes from below the Accumulator, looks like the Brake Booster Pump, that travels under the MBC. I can’t see where it connects to. This Red line vibrates like a tattle tale that the problem is actually the booster pump. Does anyone know what makes up the Antilock Brake System (ABS)? Again, I’d hate to pay $1300 (or less at a non Lexus facility) to change the MBC when it’s either the power brake pump or whatever makes up the ABS.

 

Do you guys have any update to this problem? It sounds identical to the issue I'm having on my 01' 4Runner...
I took mine to the dealer as well but they were useless, especially since they only heard it once and it only lasted for 20-30 seconds. they don't care. my guess is the pump, but thought maybe you guys could confirm or share an easy fix?

Thanks for any help!

 

Mine is in the shop this week. Scheduled service of Master Brake Cylinder on Monday 12/22/10. Got there and they didn't have the part. The wrong part got received Tuesday. now, "Should be done tomorrow", Thursday. Will advise.

You are correct in that the sound/squeal only happens once, for varying length/seconds, depending on how long it's been sitting, how bad the, ' seal maybe? ' is worn out, and how cold it is. They just flushed/bled the brake system at first and thought that would do it, until I told them again, when it actually squeals.

 

No Good. It doesn't look to be the MBC. They replaced it. Next morning, same squeal !!!!!!!!!!!!!!! They had this car for 4 days !!!!! I'm not a happy camper. They want me to bring it in tonight and come back in the morning to hold their hands and show them the problem. What BS.

 

Shoot! Sorry dude. I know how ya feel. Did they replace the whole system including the pump and accumulator or just the MC?

 

Update Jan 5th.

Well, it seems that during the first visit they actually changed the Booster Pump Brake Assy (pn 47070-60010, includes the Brake booster pump and Accumulator) and not the MBC sub assy (pn 47025-60041, includes the master cylinder and brake fluid reservoir) The costs are similar, but the pump assy didn't fix it.

The changing of the MBC assy this last week FIXED IT !!!!! After day 2 in 30F overnight temp, there's no squeal in the morning. It's about frickn time.

They initially charged me $1659 for the first brake booster pump assy visit that didn't work. We had words so there was a No Charge/NC for the second try of replacing the MBC. Based on on-line pricing, the MBC is actually approx $150 cheaper than the Pump assy, ($1050 vs $1200) so they should owe me that back, or replace back my old brake booster pump assy. I'm torn as to whether I fight them on this. ($150 to pay for $1200+ worth of parts, pump/accumulator, that weren't(?) bad, but could be and were certainly 10 years old ??!!??)

For now anyway, I have a new brake hydraulic system that works and doesn't squeal. Good luck everyone.

 

Congrats! I would say if you get a new booster assy for 150 just let thatv go...
And low and behold my 4runner uses the exact same rediculously expensive hydraulic system. Same part numbers. Whhen I get around to it I will post up my results as well.

 

I am having this issue with my 2008 4Runner. Sounds like as soon as the pump is done charging back up, there is a valve that is not closing immediately. I only have 53,000 on my vehicle too... The comparison to a toilet valve shutting off is about the same sound... The dealer wont help me either on this... Anyone else have any ideas?

 

You can get the parts cheaper from http://shoptrd.com/, and have some local, non Toyota guy you trust, replace'm. I think Toyota charges $150/Hr labor.

 

what did they say it was from bc mine does the same and it’s driving me crazy

 

It was the Master Brake Cylinder. Not sure if it's repairable or not. I never looked into it, but it's probably better to have the dealer ( or a good shop) replace it. If you're handy, maybe try to buy a new/refurbished/junk yard part and try it yourself. Good Luck. I sold/traded in, my LX470 in 2017. It had 265K miles on it. It was still running good but the gas mileage was like 13-14 MPG and I was starting a job with a 60+ mile roundtrip.