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So the other day my VSC/VSC off/ABS lights came on and I've been hearing this whining noise coming from what seems to be the brake booster. It sounds kind of like an alternator on it's way out. When I turn the car off, lights go off. The lights don't come back on unless I really get on it & the engine gets above 4500 rpms. Regardless of the lights being on the whining noise is still there and pretty annoying in park or stopped at a light.
* Pedal feels a bit soft until you go about 1/2 down then it's the way it should be and brakes fine
* Is there a chance it's just a dirty/bad connection/hose? I'm assuming that noise is the pump motor going bad, but not entirely sure
* Can you get just the brake booster or do you need the entire BMC/pump unit?
Any input on this from those with experience would be greatly appreciated.
Not really looking forward to spending $700 for a new BMC... idk where everybody is finding all the SC430 BMCs for $250, cheapest I found was $425. I love my GS though, so such is life sometimes.
I pulled the codes with a Maxidas scanner and here's what I got; Tried looking the codes up, but didn't find any useful information.
Also getting C1241, abnormally height battery positive voltage. Could this be causing everything else to act off or what?
Bmc's don't typically whine. Just open the hood and put your ear near the bmc. The only sounds you should hear is the pump motor and pressure tank cycling periodically. Excessive cycling or any other unusual sound(s) from the bmc is most likely a sign of a bmc on it's way out.
To answer your questions:
* Pedal feels a bit soft until you go about 1/2 down then it's the way it should be and brakes fine
-> That's how mine were before my newer bmc. It's common for the GS4 to have somewhat soft/spongy breaks.
* Is there a chance it's just a dirty/bad connection/hose? I'm assuming that noise is the pump motor going bad, but not entirely sure.
-> Possible but the only connection you'd have access to is the pump motor. Remove the bmc and you can take the cover off the pump motor to inspect it.
* Can you get just the brake booster or do you need the entire BMC/pump unit?
->You may be able to find a booster and pump separately but dont get your hopes up; most sell them as one unit together.
Not sure if your electrical/battery problem is a source or symptom of you other problems. But I agree all signs point to a failing alternator and/or battery. I'd start their first before moving on to the bmc.
Bmc's don't typically whine. Just open the hood and put your ear near the bmc. The only sounds you should hear is the pump motor and pressure tank cycling periodically. Excessive cycling or any other unusual sound(s) from the bmc is most likely a sign of a bmc on it's way out.
To answer your questions:
* Pedal feels a bit soft until you go about 1/2 down then it's the way it should be and brakes fine
-> That's how mine were before my newer bmc. It's common for the GS4 to have somewhat soft/spongy breaks.
* Is there a chance it's just a dirty/bad connection/hose? I'm assuming that noise is the pump motor going bad, but not entirely sure.
-> Possible but the only connection you'd have access to is the pump motor. Remove the bmc and you can take the cover off the pump motor to inspect it.
* Can you get just the brake booster or do you need the entire BMC/pump unit?
->You may be able to find a booster and pump separately but dont get your hopes up; most sell them as one unit together.
Not sure if your electrical/battery problem is a source or symptom of you other problems. But I agree all signs point to a failing alternator and/or battery. I'd start their first before moving on to the bmc.
Thanks, I'll get the electronics checked out first. I just replaced the alternator a couple months ago and got a full charge on my battery when it died. I've been driving around an awful lot for it to be the alternator (or at least I think so)
I've read about others having ABS problems and having that faint whining noise coming from under the hood. Anybody know more about this and the cause/effect?
I also have Supra TT front brakes. Would that be a factor possibly?
Sorry for starting a thread, I know how much everybody dislikes it, but I couldn't find any solutions by searching.
Also read about people having a similar issue with wheel sensors after having suspension/brake work done. I installed coilovers and did my rear brakes and a couple days later this started happening. What could explain the damn whining though? It's driving me nuts
Last edited by Danny365N; Oct 27, 2014 at 03:12 PM.
what does the whining sound like? Does it sound like babies screams? That's how some have described the sound.
Yes, that's the sound I've been hearing.
It's pretty faint and I can hear it best sitting in the car. Sounds like it's coming from right in front of me
I had that same problem with that annoying sound with my original BMC and also one bought from eBay after using it for like 2-3 years.
The sound is being created by the motor, cuz I mean what else would make that sound? I don't think the solenoid valves inside the modulator can create that sound.
If it's the pump motor (and sounds like it is) you can (if you're up to it and/or strapped for cash) remove the pump motor from the bmc unit and visually check it out. Of course you'd have to take the bmc off (there are basically just four bolts holding it on) but once you did you could just take the cover off the pump motor and visually inspect it. When I took mine off it was really dirty inside (kinda like wearing the same underwear for 16 years) but you could make sure the contact brushes aren't stuck and there isn't debris preventing the motor from turning/operating. Blow out all the junk using a can of compressed air, give it a good wipe down and put it back on to see if the wine goes away.
Best outcome: you get a few more (years?) of service from the bmc pump motor.
Worst outcome: you just confirmed that you need a new bmc.
It's a fair amount of work but if you have more time than money you've got nothing to loose - lol
It's annoying as u can imagine. I have since then replaced with a different used BMC.
Your best bet is to just find another used one or get the a new one from a SC430.
Mine sounds just like this, but it only does it every so often right after I tap the brakes. I assume it's on the way out. Luckily I found a 2001 BMC locally that I'll be picking up this weekend.
What's the shop called? Never heard of anyone rebuilding these.
"ABS" in Orange, California
They put ABS systems into old hot rods and such so I figure if they can handle fabricating all that, they can manage to rebuild it if they say they've done many before.
Went and picked it up today, putting it in tomorrow. I'll let you know my results
"ABS" in Orange, California
They put ABS systems into old hot rods and such so I figure if they can handle fabricating all that, they can manage to rebuild it if they say they've done many before.
Went and picked it up today, putting it in tomorrow. I'll let you know my results
Wow, that's great. I hope it goes well. Please let us know how it goes. I'm sure alot of people here would be willing to ship them their faulty brake masters to save a ton of cash.
I just pulled one out of a 2001 GS300 today and I noticed it had writing on the side, like from a salvage yard. At least it was only 200 bucks..
Put it in on Saturday, but had to wait til today to have it bled.
Runs good. If any of you have problems with your BMCs, hit up ABS Power Brake Inc.
233 N Lemon St
Orange, CA 92866
Phone number (714) 771-6549
Sorry if advertising this sort of stuff is against the rules, but I'm not doing it for profit just trying to help others get their BMCs rebuilt.
Rebuilds > Salvage yard parts
BMC going out?
