2001 GS430 Front Suspension Refresh
01-14-13, 03:42 PM
#46
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I decided, after much reading, to go after the motor mounts next. I have the ever so slight vibration at idle and found a few folks on the sc430 threads identified the motor mounts to be the culprit of the vibration and noise they thought was from the front end. I ordered the 2 engine mounts and tranny mount from Sewell. probably won't get to install for a few weeks though. Will keep you informed. FYI, 2002 sc430 with 77,000 miles.
01-14-13, 06:33 PM
#48
When I jack up or down my car from the front, using a floor jack, I can visibly see the motor moving with each pump of the jack (like the motor is in jellloten) this is how it is suppose to move (I have brand new motor mounts) if the motor does not move in this fashion I suspect your motor mounts are toast. Change the tranny mount while you are at it. By the way I gained acceleration (0 to 60 full throttle) with the new motor mounts, probably due to quicker and smoother shifting. Car will also feel like higher quality. But I never had a clunk and mine were sheared in half, completely sheared, but my tranny mount was good so that may be why no clunk
01-16-13, 04:32 PM
#49
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Just for reference, here is a torque diagram for the sway bar.
The potential sway bar sources of noise are: worn bushings, worn links, loose U-brackets that wrap around the bushings, and the one that nobody ever thinks of is the body mounts that aren't properly torqued down. I need to eliminate that as a possible source next...
And Sam, I'm not convinced that my problem is brake related. I notice that I hear the front end clunk at about the same magnitude whether I am on the brakes or not (when going over bumps at low speed).
I have heard that low speed clunking is often times sway bar related.
The potential sway bar sources of noise are: worn bushings, worn links, loose U-brackets that wrap around the bushings, and the one that nobody ever thinks of is the body mounts that aren't properly torqued down. I need to eliminate that as a possible source next...
And Sam, I'm not convinced that my problem is brake related. I notice that I hear the front end clunk at about the same magnitude whether I am on the brakes or not (when going over bumps at low speed).
I have heard that low speed clunking is often times sway bar related.
Last edited by BayAreaLex; 01-17-13 at 09:34 AM.
03-06-13, 07:17 PM
#50
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Ok guys, so today I had the sway bar bushings replaced even though the old ones looked perfect when removed in an effort to hunt for the source of the front end-clunk.
Both the Lexus dealer and my independent mechanic said my motor mounts looked fine and they didn't see anything obviously wrong with any particular front suspension components. I ordered OEM motor mounts from Sewell along with the OEM tranny mount and asked my mechanic to replace them anyway.
Upon removing the driver side motor mount, we found this:
Not only was this the cause of the groaning when braking, but it was also a major source of my front end clunking as the engine was allowed to hop up and down when hitting bumps.
In summary, if your car has a slight hesitation at idle, groans when braking, or has front end clunk when going over bumps and you can't seem to identify any sources coming from the suspension/brakes, look at the motor/tranny mounts (especially that driver side mount)!
Today is a good day :-)
Both the Lexus dealer and my independent mechanic said my motor mounts looked fine and they didn't see anything obviously wrong with any particular front suspension components. I ordered OEM motor mounts from Sewell along with the OEM tranny mount and asked my mechanic to replace them anyway.
Upon removing the driver side motor mount, we found this:
Not only was this the cause of the groaning when braking, but it was also a major source of my front end clunking as the engine was allowed to hop up and down when hitting bumps.
In summary, if your car has a slight hesitation at idle, groans when braking, or has front end clunk when going over bumps and you can't seem to identify any sources coming from the suspension/brakes, look at the motor/tranny mounts (especially that driver side mount)!
Today is a good day :-)
03-07-13, 07:32 AM
#51
Ok guys, so today I had the sway bar bushings replaced even though the old ones looked perfect when removed in an effort to hunt for the source of the front end-clunk.
Both the Lexus dealer and my independent mechanic said my motor mounts looked fine and they didn't see anything obviously wrong with any particular front suspension components. I ordered OEM motor mounts from Sewell along with the OEM tranny mount and asked my mechanic to replace them anyway.
Upon removing the driver side motor mount, we found this:
Not only was this the cause of the groaning when braking, but it was also a major source of my front end clunking as the engine was allowed to hop up and down when hitting bumps.
In summary, if your car has a slight hesitation at idle, groans when braking, or has front end clunk when going over bumps and you can't seem to identify any sources coming from the suspension/brakes, look at the motor/tranny mounts (especially that driver side mount)!
Today is a good day :-)
Both the Lexus dealer and my independent mechanic said my motor mounts looked fine and they didn't see anything obviously wrong with any particular front suspension components. I ordered OEM motor mounts from Sewell along with the OEM tranny mount and asked my mechanic to replace them anyway.
Upon removing the driver side motor mount, we found this:
Not only was this the cause of the groaning when braking, but it was also a major source of my front end clunking as the engine was allowed to hop up and down when hitting bumps.
In summary, if your car has a slight hesitation at idle, groans when braking, or has front end clunk when going over bumps and you can't seem to identify any sources coming from the suspension/brakes, look at the motor/tranny mounts (especially that driver side mount)!
Today is a good day :-)
03-07-13, 08:09 AM
#52
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BAL, I've got a question for you. Before you replaced your mounts, do you recall how shifting from reverse to drive, like say backing out of a garage or parking space, felt?
The reason I ask is that when I do it, when going into drive, the car bucks unusually hard. Did your car do this before the mounts? I've had mine replaced not too long ago. I think I need to talk to my mechanic and pull my service records, and see what the mileage was when they were replaced, I suppose they could be bad again already.
I think I'm chasing multiple issues..... I'm shimming my brakes, and putting in a new "fit" kit this weekend and lubing sway bar bushings, and lca #1 bushings, and see if that has any affect.
How hard is it to replace the mounts? DIYable??
The reason I ask is that when I do it, when going into drive, the car bucks unusually hard. Did your car do this before the mounts? I've had mine replaced not too long ago. I think I need to talk to my mechanic and pull my service records, and see what the mileage was when they were replaced, I suppose they could be bad again already.
I think I'm chasing multiple issues..... I'm shimming my brakes, and putting in a new "fit" kit this weekend and lubing sway bar bushings, and lca #1 bushings, and see if that has any affect.
How hard is it to replace the mounts? DIYable??
03-07-13, 09:30 AM
#53
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BayAreaLex – Nice. I just had my mounts done this weekend as well. Mine had not separated in two pieces yet but was definitely on their way by peeling apart. Made a big difference in idle, acceleration and overall engine feel but it did not solve my low speed noise over uneven surfaces. After spending time on the hoist we are fairly certain it is the right front strut top mount (also considering I have replaced everything but the struts and top mount ). I intend to live with it another month until I feel like spending another $260 for the front struts and top mounts and $50 on alignment to keep things in check. Anyone have good luck with top mounts other than OEM from Sewell or Carson? Maybe the KYB or MOOG.
03-07-13, 11:03 AM
#54
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Thanks for the encouragement guys as it's been a pretty long process diagnosing and addressing all the little annoyances of purchasing a 95K mile car.
Although I did it in another thread, I will include it again here just for documentation purposes...
Here is what I notice with the new mounts:
- The idle is silky smooth. I can hardly tell the car is on. With the split driver side mount, there was an unmistakable subtle vibe/hesitation at idle.
- With the broken mount I would get a jerk/thud from the rear differential when accelerating hard from a stop. That's gone. It must have had something to do with the motor torquing over and whipping back transferring that energy to the end of the driveline (back of car). I was sure some bushing in the rear was toast, but it was just the motor mount!
- Groaning when braking or when parked on steep hills is gone.
- The front end clunk when going over bumps is gone.
It's amazing what level of problems a split mount can create that all look like other things. Based on my bullet points above, you can see how easy it is to mistake the suspension/brakes as the culprit for some of these symptoms. And I'm convinced that some of unsolved front end clunking issues on this forum are/were motor mount related.
https://www.clublexus.com/forums/gs-...downhills.html
Blanco, when shifting from drive to reverse and vice versa, I never noticed anything unusual (well, except for when the brake clips were missing from the rear brakes causing a metal to metal "clink" when alternating from drive to reverse and vice versa, but that was a separate issue since the brake pads were allowed to shift without the clips).
However, if you look at my 2nd bullet point above, I was getting a very pronounced thud/jerk when hitting the throttle aggressively from a stop. I was convinced this was related to the rear diff bushings. However, it was completely cured with the new motor mounts. It had to have been a result of the engine physically shifting and transferring "2nd order" energy to the end of the driveline.
Although I did it in another thread, I will include it again here just for documentation purposes...
Here is what I notice with the new mounts:
- The idle is silky smooth. I can hardly tell the car is on. With the split driver side mount, there was an unmistakable subtle vibe/hesitation at idle.
- With the broken mount I would get a jerk/thud from the rear differential when accelerating hard from a stop. That's gone. It must have had something to do with the motor torquing over and whipping back transferring that energy to the end of the driveline (back of car). I was sure some bushing in the rear was toast, but it was just the motor mount!
- Groaning when braking or when parked on steep hills is gone.
- The front end clunk when going over bumps is gone.
It's amazing what level of problems a split mount can create that all look like other things. Based on my bullet points above, you can see how easy it is to mistake the suspension/brakes as the culprit for some of these symptoms. And I'm convinced that some of unsolved front end clunking issues on this forum are/were motor mount related.
https://www.clublexus.com/forums/gs-...downhills.html
BAL, I've got a question for you. Before you replaced your mounts, do you recall how shifting from reverse to drive, like say backing out of a garage or parking space, felt?
The reason I ask is that when I do it, when going into drive, the car bucks unusually hard.
How hard is it to replace the mounts? DIYable??
The reason I ask is that when I do it, when going into drive, the car bucks unusually hard.
How hard is it to replace the mounts? DIYable??
However, if you look at my 2nd bullet point above, I was getting a very pronounced thud/jerk when hitting the throttle aggressively from a stop. I was convinced this was related to the rear diff bushings. However, it was completely cured with the new motor mounts. It had to have been a result of the engine physically shifting and transferring "2nd order" energy to the end of the driveline.
03-07-13, 11:52 AM
#55
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Had my mechanic email me my service history. Looks like my mounts were last replaced at 165K, and I'm now at 208K. I suppose it's very possible that they've already begun to go bad.
I plan on diagnosing from cheapest to most expensive first. I just got done dropping a couple of Clevelands on a whole new steering system, so I think it might be a while before ponying up for new mounts. Hell, I need to replace my TB/WP (again) and assorted belts and pulleys, and a/c comp bearing first.
And I keep telling myself that it's cheaper to fix, than buy another car.......
I plan on diagnosing from cheapest to most expensive first. I just got done dropping a couple of Clevelands on a whole new steering system, so I think it might be a while before ponying up for new mounts. Hell, I need to replace my TB/WP (again) and assorted belts and pulleys, and a/c comp bearing first.
And I keep telling myself that it's cheaper to fix, than buy another car.......
03-07-13, 01:31 PM
#56
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Had my mechanic email me my service history. Looks like my mounts were last replaced at 165K, and I'm now at 208K. I suppose it's very possible that they've already begun to go bad.
I plan on diagnosing from cheapest to most expensive first. I just got done dropping a couple of Clevelands on a whole new steering system, so I think it might be a while before ponying up for new mounts. Hell, I need to replace my TB/WP (again) and assorted belts and pulleys, and a/c comp bearing first.
And I keep telling myself that it's cheaper to fix, than buy another car.......
I plan on diagnosing from cheapest to most expensive first. I just got done dropping a couple of Clevelands on a whole new steering system, so I think it might be a while before ponying up for new mounts. Hell, I need to replace my TB/WP (again) and assorted belts and pulleys, and a/c comp bearing first.
And I keep telling myself that it's cheaper to fix, than buy another car.......
03-07-13, 02:06 PM
#57
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Is the only definitive way to determine if they're bad is to remove them??
03-07-13, 02:27 PM
#58
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I did both of these tests and it wasn't obvious to me. Someone who works on these cars regularly *might* be able to use those methods to diagnose the mounts, but most of us have little point of reference and given how cluttered it is under there, removing them is the only 100% sure fire way to tell.
03-25-13, 07:16 PM
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So after a weekend spent at a DIY garage. I lubed the brake pads, installed the shim kit and fit kit for the front brakes, sprayed silicone lube on lca bushings, and swaybar bushings. Also noticed a few screws missing from plastic under engine cladding that protects the motor, so I replaced the missing screws.
Bottom line. It helped some, but I can still hear the noise. The more and more I hear it, I'm convinced it's suspension related. Next on the list is either new struts and mounts, which are about 60K miles old, or replacing the stock lcas with new bushings.
This mystery is REALLY PISSING ME OFF!!!!!
Bottom line. It helped some, but I can still hear the noise. The more and more I hear it, I'm convinced it's suspension related. Next on the list is either new struts and mounts, which are about 60K miles old, or replacing the stock lcas with new bushings.
This mystery is REALLY PISSING ME OFF!!!!!
03-26-13, 09:33 AM
#60
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I was also convinced that my problem was suspension related, which is why it took me so many months to solve (see pic of broken motor mount above, lol).
Blanco, I'm not completely clear on your symptoms. What are you experiencing exactly that's leading you to believe it's suspension related?
I'm still chasing my rear popcorn sound going over small bumps at low speed but just haven't found time to dig into it. Once that's solved, I should be good to go finally, lol.
Blanco, I'm not completely clear on your symptoms. What are you experiencing exactly that's leading you to believe it's suspension related?
I'm still chasing my rear popcorn sound going over small bumps at low speed but just haven't found time to dig into it. Once that's solved, I should be good to go finally, lol.