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Weird Brake Noise! Any Help?!


99svtvenom
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Hey guys my girlfriend just purchased a really nice 1998 lexus 400 and it runs and drives great, but has what hopefully is a small problem. The brakes make no noise in forward motion whatsoever, but in reverse when you have some speed built up and press the brake firmly it sounds like a bad grind very similar as to when your pads go bad. The guy who had it before us said the car had been sitting through the winter and he just put a new battery, new tires, and new pads with re-surfaced rotors on less than a week ago. The confusing thing to me is that if it were just the grind it would seem like an easy diagnosis, but here is the strange part. When you get the grinding noise and keep your foot firmly on the brake I hear a humming or low drone coming from what sounds like under the center console or under the vehicle towards the middle even when the vehicle is completely stopped. You can hear it from the inside really well but the outside I can not hear it. Please guys any help would be greatly appreciated just want to get this really nice car running error free!

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Possibility is that the transmission mount is in need of replacement. They're a V type shape, and when you go forward, the torque put the pressure on one side, and when in reverse, the torque shifts over to the other side. If the other side is bad, the rubber insulation will fail and cause two metal parts of the mount to touch, which will allow noise and vibrations to come up through the frame. Since you say it feels as though it's right under the center of the car, maybe a little further back, I'd say check it out. The tranny mount is located in that specific area.

www.lexuspartsonline.com is one of many great resources to buy your oem parts online, and save some significant money. Buy the part, and take it to an indi mechanic for replacement, shouldn't take them more than 30 minutes to do it. Part is about $30-$40 bucks, i believe. It's under the "engine" section, and is called "the rear mount". Front mount is the engine mount, which require two.

Brakes..... Do you hear or feel a click noise when you first apply the brakes in the new direction? For example: put the car in reverse, start backing up and press the brakes...do you hear or feel a click from them? Same for forwards... Only happens the first time you apply the brakes. If so, it is doubtfull the previous owner put on oem pads, but rather instead used aftermarket pads. Some aftermarket pads don't sit completely perfect in the caliper, and will wiggle every now and then "click noise". Nothing wrong with it, but if you don't know what it is, it can spoke you. Additionally, the aftermarket pads, depending on what was used, can sometimes create a humming noise sensation, but will most likely fade away as they seat themselves on the newly surfaced rotor.

But my bet, since you can hear the noise inside, but not outside, and you hear it under the center of the car, is tranny mount. A very common repair at around the 100k mark. Go dealership route though, and you'll pay out the nose for it, as they know it's a common repair, and use it as a money maker. In all honesty, it shouldn't cost you more than $150 max if you buy online and take it to an indi. Or, if you're a DIY type, just do a search on here for transmission mount and learn how to do it yourself, as it is very easy to do! You do need a floor jack though to lift up the transmission a little, to get the old out and new in. Then, from there, it's two bolts, and done. :cheers:

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Possibility is that the transmission mount is in need of replacement. They're a V type shape, and when you go forward, the torque put the pressure on one side, and when in reverse, the torque shifts over to the other side. If the other side is bad, the rubber insulation will fail and cause two metal parts of the mount to touch, which will allow noise and vibrations to come up through the frame. Since you say it feels as though it's right under the center of the car, maybe a little further back, I'd say check it out. The tranny mount is located in that specific area.

www.lexuspartsonline.com is one of many great resources to buy your oem parts online, and save some significant money. Buy the part, and take it to an indi mechanic for replacement, shouldn't take them more than 30 minutes to do it. Part is about $30-$40 bucks, i believe. It's under the "engine" section, and is called "the rear mount". Front mount is the engine mount, which require two.

Brakes..... Do you hear or feel a click noise when you first apply the brakes in the new direction? For example: put the car in reverse, start backing up and press the brakes...do you hear or feel a click from them? Same for forwards... Only happens the first time you apply the brakes. If so, it is doubtfull the previous owner put on oem pads, but rather instead used aftermarket pads. Some aftermarket pads don't sit completely perfect in the caliper, and will wiggle every now and then "click noise". Nothing wrong with it, but if you don't know what it is, it can spoke you. Additionally, the aftermarket pads, depending on what was used, can sometimes create a humming noise sensation, but will most likely fade away as they seat themselves on the newly surfaced rotor.

But my bet, since you can hear the noise inside, but not outside, and you hear it under the center of the car, is tranny mount. A very common repair at around the 100k mark. Go dealership route though, and you'll pay out the nose for it, as they know it's a common repair, and use it as a money maker. In all honesty, it shouldn't cost you more than $150 max if you buy online and take it to an indi. Or, if you're a DIY type, just do a search on here for transmission mount and learn how to do it yourself, as it is very easy to do! You do need a floor jack though to lift up the transmission a little, to get the old out and new in. Then, from there, it's two bolts, and done. :cheers:

Awesome info man thank you!!! another piece of info that i can include is that the brakes feel like they are dragging when this happens. the only time the problem will occur is in reverse but when you go forward after the problem occurs it feels like the brakes are hanging up for about 40 feet then free up and will not occur again while going forward, it almost feels that a caliper is not releasing the rotor properly. the weirdest thing to me was how the humming noise from under the car still occured while not moving and lasted until i released my foot off of the brake pedal. again though man great info you gave me there. let me know if you have any more possibilities thanks again nc!!

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do you know if the previous owner had the pads and rotor resurfaced at the dealership?

It does sound like you've got a sticking caliper, as well as a tired transmission mount. The rear set up is floating. If you take the wheel off, look along the top and bottom of the caliper, along the inner side. You should see two, tiny, black boot covers. Inside of there are two slider pins, that must be cleaned and regreased when you take them apart. Otherwise, the calipers can stick together. Also, the brake piston, has a rubber seat and boot cover. Several LS owners have had to replaced these seats and covers. After a while, they wear out, and cause the piston to actually stick. That is not uncommon, but it does usually show up on the fronts, before the backs.

Another possibility, if the pads weren't done at the dealership, is that they're way too small, and they're very much out of line inside of the caliper seats, causing them to not just wiggle ever so slightly, but actually shift and pinch against the rotor. There are two kits for the pads that Toyota uses. One is called the Fitment Kit, which is a few clips and pins to hold the pads still. The other is the anti-squel kit, which are two, thin, pad clips that go over the back of the pads. One is black and covered in rubber that is greased and sandwiched between the pad, and the outter metal pad, which takes the pressure of the piston.

I think the key here, is to know where the brake job was done.

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the brake job was done at my buddies shop in michigan (very good shop for body and mechanical repair) and i saw the box for the pads sitting there on the rack when i checked the car out and they were federated auto parts which didnt really bother me because i had used those before on a few of my old cars and had no problems. i will try taking apart the rears and just redoing the brake job that has already been done and see if i can find anything out of the ordinary and grease all the pins and check the rubber boots. thanks again for your help and i will write up on here as soon as i get done doing it to give you an update! :cheers:

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I'm curious about your ebrake: how does the peddle feel in the car? Does it have to travel all the way down to engage the rear ebrake?

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I'm curious about your ebrake: how does the peddle feel in the car? Does it have to travel all the way down to engage the rear ebrake?

the ebrake is kind of hard to push and has to go down kind of far to engage. im not quite sure what is the norm for these cars as we have never owned one. if someone can give me a spec of how far it has to travel in inches i will go measure it.

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well fellas i have an update. I tore the rear brakes all apart inspecting them and checking everything out, and here is what i found. The passenger side rear rotor has a flaw on the drum part of the disc. there is a piece of metal that looks like it was not machined right when the rotor was made and you can see the evidence of it grinding. there are also 2 hot spots about 2 inches in length 180 degrees apart where the regular disc part mates to the drum part. I have pictures and I am going to post them up later so you guys can take a look and hopefully this may help someone in the future.

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well fellas i have an update. I tore the rear brakes all apart inspecting them and checking everything out, and here is what i found. The passenger side rear rotor has a flaw on the drum part of the disc. there is a piece of metal that looks like it was not machined right when the rotor was made and you can see the evidence of it grinding. there are also 2 hot spots about 2 inches in length 180 degrees apart where the regular disc part mates to the drum part. I have pictures and I am going to post them up later so you guys can take a look and hopefully this may help someone in the future.

When you removed the rotor, were there two small screws you had to remove to get the rotor off? If not, they're absolutely 110% NOT Lexus oem. If there were several holes that could be used for the two screws, they're not Lexus oem "although I believe there are two other holes, with black rubber caps?". Just two holes for the screws = Lexus OEM rotors.

Since you've got the rotor off, and if you wish to keep using them, then I'd run it up to your local Midas with a $20 bill and have them throw it on the lathe.

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well fellas i have an update. I tore the rear brakes all apart inspecting them and checking everything out, and here is what i found. The passenger side rear rotor has a flaw on the drum part of the disc. there is a piece of metal that looks like it was not machined right when the rotor was made and you can see the evidence of it grinding. there are also 2 hot spots about 2 inches in length 180 degrees apart where the regular disc part mates to the drum part. I have pictures and I am going to post them up later so you guys can take a look and hopefully this may help someone in the future.

When you removed the rotor, were there two small screws you had to remove to get the rotor off? If not, they're absolutely 110% NOT Lexus oem. If there were several holes that could be used for the two screws, they're not Lexus oem "although I believe there are two other holes, with black rubber caps?". Just two holes for the screws = Lexus OEM rotors.

Since you've got the rotor off, and if you wish to keep using them, then I'd run it up to your local Midas with a $20 bill and have them throw it on the lathe.

im not sure whether to just buy a new one or machine this one for $20 it just worries me with the 2 hot spots i just dont want it to crack or warp but i will have to weigh those options out.

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Hot spots: You mean pad stamps on the rotor itself? If so, mine use to do that too, until I learned a little trick, which I do now in all cars that I drive. When I come to a stop, I roll forward about an inch or two to allow the rotor spot under the pads to cool. If it's a really hard or long stop, I pop the car into "n" and take my foot off the brake, to allow air to slip under the pads and prevent the heat trasfer into the rotor. My 4runner had those pad stains on the rears a few months ago. I had them turned with no problems. If you measure the thickness of the rotor and post the results up here, I'm sure someone can tell you if you're within spec. Which is always good to know prior to going to Midas, as they'll almost certainly tell you it's not within spec and you should buy one of their "specials", even though it probably is within spec. has happened to me, twice. First time I feel for it, second time I barked like a junkyard dog, which resulted in a perfectly turned set of rotors... ;)

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First time I fell for it, second time I barked like a junkyard dog, which resulted in a perfectly turned set of rotors... ;)

We would all appreciate a demonstration of this technique, could you post it on Youtube? Thanks.

What, no dinner, motor talk, or keg of Budweiser first? What kind of Southern Hill-Billy do you take me for? :blushing::lol:

But, it goes something like "Look here at this Lexus issued TSB on specifications. Do you see those numbers? Do I need to notify my friends at the Better Business Burea, who undoubtably will file a report, that will be picked up by the SBA "Small Business Adminstration" during their quarterly review, and will ultimately contact you for being in default of your loan agreement, to not take part in such unethical business practice".

I was very mad that day, and I know a thing or two about small businesses, especially new ones. It also helps that I live in a "on-line" county, with direct access to the registry of deeds. The SBA records certain documents, that can be found...

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What, no dinner, motor talk, or keg of Budweiser first? What kind of Southern Hill-Billy do you take me for? :blushing::lol:

But, it goes something like "Look here at this Lexus issued TSB on specifications. Do you see those numbers? Do I need to notify my friends at the Better Business Burea, who undoubtably will file a report, that will be picked up by the SBA "Small Business Adminstration" during their quarterly review, and will ultimately contact you for being in default of your loan agreement, to not take part in such unethical business practice".

I was very mad that day, and I know a thing or two about small businesses, especially new ones. It also helps that I live in a "on-line" county, with direct access to the registry of deeds. The SBA records certain documents, that can be found...

Hehehe thought that might get a bite. Excellent use of the TLA (three letter acronym), I am awarding full points. Sorry about the keg of budweiser, its nearly all gone....

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I'm not sure if this could cause the issues you're having, but there are V shaped clips at the top and bottom of each set of pads that act as spreaders to keep the pads off of the rotors when you're not actually braking. They don't look very important, and they're easy to overlook on a brake job and twice as easy to lose - but new Lexus pads don't come with them included, so if he lost and/or damaged one they might have been deemed "unnecessary" and been omitted.

worth a quick check.

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I'm not sure if this could cause the issues you're having, but there are V shaped clips at the top and bottom of each set of pads that act as spreaders to keep the pads off of the rotors when you're not actually braking. They don't look very important, and they're easy to overlook on a brake job and twice as easy to lose - but new Lexus pads don't come with them included, so if he lost and/or damaged one they might have been deemed "unnecessary" and been omitted.

worth a quick check.

yeah there were not any v-shaped spring retainers. I just cant figure out how the hot spots are 180 degrees apart and no where else. That inside edge I pointed out in the first pick is the root of the problem. It has grinding evidence all over it so I think once I get a new rotor she should be good to go. But now we are having another issue with the car just clicking when we go to start it and then you turn the key again and it will keep clicking or it will decide to start. I will start another thread up with this issue as all the battery connections are tight and it is a bran new battery I have started looking into this issue and I might know the cause but am not sure we will cross this bridge when we come to it :).

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