brake thud (1 Viewer)

[pemarsh]

2004 lx 470

when beginning to let off the brake from a stopped position, i feel a small "thud" noise/feel from the back. It only happens after coming to a complete stop. It will not recur after the first time---in otherwords, after the thud, if i brake again immediately (from just a crawling speed after already letting off the brake), it does not happen.


This usually happens about 75% of my braking. I have taken it to dealer 3 times....they keep saying its fixed, but its not.

Lately, I experience sometimes two thuds very close together when letting off the brake.

Does anyone at all have a clue about this???

 

[hoser]

Here we go again... I'll give you the link to a thread that will give you the link to an FAQ that will give you the solution to your problem.

https://forum.ih8mud.com/showthread.php?t=78660

Btw, Welcome

 

[pemarsh]

sarcasm...have to love it.

anyways

i read that thread prior to my original post, and my problem is not at all described there.
Thanks anyways

 

[hoser]

Try #8 of that thread. Let us know how it goes.

8. Lubing in the drive shaft zirc arguably still does not lube the splines that allow the shaft to slide in and out but too much lube in there can cause unacceptable loading and damage to the t-case or diffs. Instead, drop the drive shafts from the diff ends and separate the drive shafts into two parts at the spline (be sure to make match marks before you separate). clean the spline and receiver area for spline (there may be a lot of built up hardened grease in there) and then lube the spline and reassemble. This is a ½ banana job requiring you to undo 8 bolts (although you have to remember to loosen from the bolt side, not the nut, because the nuts are friction locking and can wear out)

 

[a990dna]

The thunk is a common problem for some reason. My LC only has 3500 miles on it and I already notice a small thunk ever now and then. I've never tried this, but ran across a fix using Loctite silver grade anti-seize on the splines.

Maybe someone can elaborate on the use of this stuff...

 

[hoser]

People also have had good things to say about Green Grease.

http://www.greengrease.net/

 

[pemarsh]

to keep people up to date about my thud problem

It has now became worse. It can happen multiple times (in just that short 1-2 secont time span of when the car begins to move when letting off the brake). I have taken the car back to the dealer, for the third time, for this problem.

They had me drive with one of their senior staff members, who was very easily able to reproduce the problem in no time at all. His words..."this is just horrible". I was told by the service mgr that they are aware of this problem, but do not have a fix for it. Is this true???? I really can not believe that anyone spending $70,000 would put up with this at all. I tend to believe this was just some smoke and mirrors ploy.
Later the next day, I was told they were going to replace the drive shaft, and see what happens next. I am expecting to hear somethign back today---the drive shaft arrived thursday or friday of last week.

What are your thoughts about this repair?? Does anyone have a similar problem and has not been able to get this repaired?

 

[Mark SR.]

Pemarsh,
I had these exact symptoms and they went away when I put in new OEM rear brake pads (for the rear discs, not the drum P. brake shoes). I have not touched my driveshafts in just over 40,000 miles BTW. On a truck as new as yours they may not think to check this. It might be worth a look. I guess my results could be a coincidence, but it is rare that problems fix themselves.
Good luck,
-Mark

 

[hoser]

Pemarsh, try putting your suspension into "HI" mode, does it still give the thud sound?

 

[pemarsh]

finally fixed!!

took it to lexus for the 3rd time. everyone's suggestions had already been tried by the dealer...i even pritnted a few threads for them to look at.

They replaced the rear drive shaft (whatever that is or does)...and the problem is 100% resolved!!!!! I am one happy guy!!

 

[pemarsh]

by the way...forgot to reply in my post aboe about this...i had a complete brake job done without any resolution of this problem a few months ago. ALso, the problem was there regardless of the suspension option selected.

 

[hoser]

Glad to hear your thud problem is finally fixed. Must be much more enjoyable to drive w/o the noise. Did your mechanic happen to say exactly what was wrong with your old driveshaft?

 

[pemarsh]

dealer said they had no idea what was wrong with it (??? maybe a spline???)...it was a shot in the dark replacing it they said!!

 

[Jim_Chow]

dealer said they had no idea what was wrong with it (??? maybe a spline???)...it was a shot in the dark replacing it they said!!

Maybe because the GX's have been plagued by that same thud problem w/ no real fix yet after 3 yrs? (including trying a new driveshaft using a different metal for the splines and polishing the splines) Funny thing is, I never got any clunking from my old 4runner's driveshaft, and it can't at all be that different. I wonder if a custom, 3rd party shaft like one w/ spicer ends would make the same clunk. Would be an interesting experiment. If it did, it would suggest it wasn't the d-shaft.

BTW, did the clunk occur when light braking, heavy braking, or it didn't matter? I wonder if the type of grease one uses on the splines (MP dino vs synthetic MP vs. synthetic moly) makes any difference. Yes, I know the FSM specs MP non-moly for the d-shafts. On my 4runner, I've used by synthetic moly (Valvoline) and synthetic MP (Amsoil red). No clunking there, but again, it has 200K mi, and I wheeled it hard for a year in WA state while I was unemployed (i.e., almost every day). I also wonder if lots of offroad driving (e.g., NF dirt roads) would help break the driveshaft splines in faster on a new vehicle? Any thoughts?

 

[pemarsh]

It did not matter what kind of braking it was. It occured with any and all types of braking.

 

[hrc0105]

My '99 LC does the same thing, especially when stopping while in Reverse. My question is.......... is this really that big of a problem? I've not noticed a decrease in braking efficiency, and it's not like embarassingly loud or anything. Basically, since I'm out of warranty, should I just turn my head the other way (so to speak)?

 

[pemarsh]

Interesting you should say it gets worse in reverse.....the tech tested this with my lx...it did not get worse in reverse. However, it being worse in reverse DID mean something specific...cant really remember what, but i do remember he said it was not serious.

My specific problem was getting worse and worse as time went on. It had nothing to do with brakes. I wish they could have told me exactly what was wrong. But one thing is for sure, ever since they replaced the rear drive shaft....ive been 100% of the thud from he**.

 

[SWUtah]

Maybe because the GX's have been plagued by that same thud problem w/ no real fix yet after 3 yrs? (including trying a new driveshaft using a different metal for the splines and polishing the splines) Funny thing is, I never got any clunking from my old 4runner's driveshaft, and it can't at all be that different. I wonder if a custom, 3rd party shaft like one w/ spicer ends would make the same clunk. Would be an interesting experiment. If it did, it would suggest it wasn't the d-shaft.

BTW, did the clunk occur when light braking, heavy braking, or it didn't matter? I wonder if the type of grease one uses on the splines (MP dino vs synthetic MP vs. synthetic moly) makes any difference. Yes, I know the FSM specs MP non-moly for the d-shafts. On my 4runner, I've used by synthetic moly (Valvoline) and synthetic MP (Amsoil red). No clunking there, but again, it has 200K mi, and I wheeled it hard for a year in WA state while I was unemployed (i.e., almost every day). I also wonder if lots of offroad driving (e.g., NF dirt roads) would help break the driveshaft splines in faster on a new vehicle? Any thoughts?

I had the thud on my 95 80 series, 2004 4runner and 99 100 series. It's not a problem. Just need to grease the drivetrain. There is some sloop in this type of drivetrains. Every once in awhile my 80 would thud and I would grease it and it would go away for awhile. On my 4runner it did it when new 1st 15K miles, I kept it greased and it doesn't do it anymore, when it is greased every 5K miles, it now has 35K miles. My 100 series does it every once in awhile but I grease it every 5K miles and it goes away. Some are looser then others, my 80 had 135K miles on it when I traded it and some thud but no mechanical problems. I would not worry about it, just grease it every oil/filter change and just drive it.

 

[a990dna]

My specific problem was getting worse and worse as time went on. It had nothing to do with brakes. I wish they could have told me exactly what was wrong. But one thing is for sure, ever since they replaced the rear drive shaft....ive been 100% of the thud from he**.

I read somewhere on a Lexus Forum (last year) that Lexus coated the new driveshaft splines with teflon... it would be nice to know this was the actual fix. You can ask the parts manager if the PNs changed... and compare with your service report and that will tell you if they replaced it with the same drive shaft or a redesigned d-shaft.

It will also give you an idea if the driveline thud or thunk will return in time.

I believe the thunk is inherant to "truck-type" driveline angles, suspension dynamics and the d-shaft "slip-yoke" or "slip-shaft" splines binding (maybe due to trapped air or suction) while applying /releasing the brakes as the suspension settles.

Complex problem..

 

[Tinkerer]

Another thudding '99 LX here.

Been doing it for at least the last few years. Sounds kinda like the rear wheels strike a small pavement bump, immediately after starting to accelerate from a stop.

Lubing makes no difference. My rear shaft slip seal allows a little grease leakage, which I interpret as a good thing (after reading other posts on the lube topic.)

I wonder if it is driveshaft flatulence? (As noted by others - momentary pressure buildup & release somewhere in the slip assembly, maybe a seal holds then releases pressure with a thud.)

My solution:

*Gentle* acceleration, from a stop. This prevents the thud altogether. (And also has the added benefit of helping to maximize life of the drivetrain.)

The only drawback to this solution is that the drivers behind me mistake this slow & gentle start as a sign that I am a weak, infirm, defective or somehow retarded individual, and they conclude that this makes it OK to tailgate me and generally drive like assh*les in passing me too closely.

(See earlier post about needing a "super-Slee" bumper, with retractable spikes, rear-facing oil spray nozzles, and other tailgater-discouraging devices.)