LS - 3rd Gen (2001-2006) Discussion topics related to the flagship Lexus LS430

A fix, any fix for heavy '02 brake and accel pedal?

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Old 01-31-19 | 11:39 AM
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Default A fix, any fix for heavy '02 brake and accel pedal?

I have done enough forum searching to understand the LS430's heavy brake and accelerator pedals are part of its charm.

Why give a chauffeur a touchy European pedal just so he could spill your espresso while you sit in the back seat? Let him wear out his leg pushing the pedals around town to save you the headache of jerkiness.

Problem is, I don't have chauffeur, and it's my hip flexor taking the brunt of the heaviness in my city driving.

I'm curious if anyone has gotten any indie to do anything that might ameliorate the heaviness.

So far I've:

-Significantly straightened my chair to give my leg increased leverage over the pedals. Somewhat helpful.
-Worn squishier shoes so switching between brake and accelerator is easier. Less helpful.
-Employed the old two-foot braking and accelerating when my hip flexor is tired. Much more helpful than anything else so far.

Here it is. I bought seven months ago as my first car in over 10 years of city living. She's a great beast, I just wish it was a little less tiring to move her.

Old 01-31-19 | 11:44 AM
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Could this be relative, I find the LS' brakes soft? lol

And yes the action is "touchy" or "jumpy." I know when my wife and I first drove the LS it was jerky. Muscles involuntarily learn to smooth it out. I thought it was shot LCA bushings but no.

For example, my BMW brakes are very firm and linear. If one liked the LS they may not like it at all, or simply their muscles train themselves. When I would switch back and forth between BMW and Maxima, it was strange, my legs were all "confused." But then it became nothing at all. Maxima has an extremely hard clutch, and springy accelerator (it's a cable). BMW has a soft clutch, and an electronic pedal for the accelerator. Brakes on Maxima hard, but not linear either, take up at the beginning.
Old 01-31-19 | 11:51 AM
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Thanks but my legs aren't as confused as they are tired from all the pedal heaviness. I'd love to learn to smooth out the LS if they were touchier. But the pedals are just soft and heavy now. And maybe forever.
Old 02-05-19 | 10:03 AM
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Once a year or more, someone posts about the soft braking "problem". See this link for my summary of the problems and the conclusions: https://www.clublexus.com/forums/ls-...ml#post9850497
Old 02-05-19 | 10:45 AM
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i can attest to the link about greasing the shims. i always did it on other vehicles i had & never had a problem. found after i did the brakes on the LS, the pedal wasn't as hard/stiff has it was prior. after ready about this, i went back and cleaned off the grease on the front brakes as best i could and it made a huge difference. haven't cleaned off the rear yet. so i would think that it would just get better.
Old 02-05-19 | 12:16 PM
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Originally Posted by StanVanDam
Once a year or more, someone posts about the soft braking "problem". See this link for my summary of the problems and the conclusions: https://www.clublexus.com/forums/ls-...ml#post9850497
Thanks -- I hadn't come across that summary.
Old 02-06-19 | 11:18 AM
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In regards to the "heavy accelerator" pedal, have you tried switching to "Power" mode? I typically run in the default mode for a combined commute on clogged highways but if I don't have to worry about constant stop and go then I switch to power mode to get better throttle response. I have SI joints which commonly lock up and Power mode will decrease the amount of effort required to accelerate. If you haven't serviced your air filter and cleaned your throttle body those might help with acceleration.

Brakes have been covered in the other posts; but I would first flush and bleed the brakes (I use a air compressor and Mightvac unit to pull the fluid to the wheel cylinder bleeders) to see if that gets you a firm pedal. My brake pedal is firm and compared to other cars I have owned it is borderline touchy. I have found that other "vacuum" bleeding system tend to be susceptible to air bubbles; especially on large wheelbase vehicles and/or collector cars that have switched to silicone brake fluid.I have never had to "electronically cycle" the ABS using the Mightyvac as simply hard breaking takes care of any micro-bubbles. I have used the system on both Brembo 6 and 4 caliper brakes, diesel hydroboost systems and classic 70's GM.disc/drum systems. I did rupture a wheel cylinder on a classic GM station wagon where I run silicone brake fluid as there was a partial blockage in the crossover line feeding the right rear drum brake. Replacing the wheel cylinder was much more efficient than replacing the line.Bottom line, the brake fluid itself can cause problems with a soft pedal and getting it professionally flushed will potentially identify marginal piston seals if the psi is raised. A seal typically won't leak at low pressure but as you raise the pressure (for example from 20 to 40 psi) it might. The higher pressure will push the debris in the brake lines out whereas at lower pressure it may leave behind residue which effects your pedal firmness.
Old 02-06-19 | 11:30 AM
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Originally Posted by Catalina45
In regards to the "heavy accelerator" pedal, have you tried switching to "Power" mode? I typically run in the default mode for a combined commute on clogged highways but if I don't have to worry about constant stop and go then I switch to power mode to get better throttle response. I have SI joints which commonly lock up and Power mode will decrease the amount of effort required to accelerate. If you haven't serviced your air filter and cleaned your throttle body those might help with acceleration.

Brakes have been covered in the other posts; but I would first flush and bleed the brakes (I use a air compressor and Mightvac unit to pull the fluid to the wheel cylinder bleeders) to see if that gets you a firm pedal. My brake pedal is firm and compared to other cars I have owned it is borderline touchy. I have found that other "vacuum" bleeding system tend to be susceptible to air bubbles; especially on large wheelbase vehicles and/or collector cars that have switched to silicone brake fluid.I have never had to "electronically cycle" the ABS using the Mightyvac as simply hard breaking takes care of any micro-bubbles. I have used the system on both Brembo 6 and 4 caliper brakes, diesel hydroboost systems and classic 70's GM.disc/drum systems. I did rupture a wheel cylinder on a classic GM station wagon where I run silicone brake fluid as there was a partial blockage in the crossover line feeding the right rear drum brake. Replacing the wheel cylinder was much more efficient than replacing the line.Bottom line, the brake fluid itself can cause problems with a soft pedal and getting it professionally flushed will potentially identify marginal piston seals if the psi is raised. A seal typically won't leak at low pressure but as you raise the pressure (for example from 20 to 40 psi) it might. The higher pressure will push the debris in the brake lines out whereas at lower pressure it may leave behind residue which effects your pedal firmness.
I have to admit I like the idea of Mityvac (never used one). I have the motive with 2 premium adapters for German and GM (billet aluminum), and then the Toyota one recommended here and purchased on amazon. It has three tiny levers which are supposed to secure it to the neck--not that good.

The only car that gets a good seal at all is the BMW. Very frustrating. Of course, the best is always the 2-man deal with the person in the car "NOT" pushing the pedal through the floorboard, just a press and then hold firm. The LS430 reservoir is very delicate, I think the cap can be simply pulled off without even unscrewing, scary...

p.s. I use the Motive to push air only, not fluid, so no cleanup. If I do that, why not do the mityvac right?
Old 02-06-19 | 11:43 AM
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Originally Posted by Johnhav430
I have to admit I like the idea of Mityvac (never used one). I have the motive with 2 premium adapters for German and GM (billet aluminum), and then the Toyota one recommended here and purchased on amazon. It has three tiny levers which are supposed to secure it to the neck--not that good.

The only car that gets a good seal at all is the BMW. Very frustrating. Of course, the best is always the 2-man deal with the person in the car "NOT" pushing the pedal through the floorboard, just a press and then hold firm. The LS430 reservoir is very delicate, I think the cap can be simply pulled off without even unscrewing, scary...

p.s. I use the Motive to push air only, not fluid, so no cleanup. If I do that, why not do the mityvac right?
A MightVac is a good investment. I have two Motive units and multiple adapters but just got frustrated not being able to get a good seal; especially when having to raise the PSI. After one mess (thank goodness it was Silicone fluid) I bought the MightVac and haven't looked back. Every friend that I have lent it to has ended up purchasing their own unit and shelved their Motive systems. Not that there isn't a place for the Motive in low psi applications but as the psi increases, sealing becomes an issue. I think you'll really enjoy a Mightyvac and it also doesn't make you reliant on finding a friend/spouse to help push bleed a system.
Old 02-06-19 | 12:11 PM
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Originally Posted by Catalina45
A MightVac is a good investment. I have two Motive units and multiple adapters but just got frustrated not being able to get a good seal; especially when having to raise the PSI. After one mess (thank goodness it was Silicone fluid) I bought the MightVac and haven't looked back. Every friend that I have lent it to has ended up purchasing their own unit and shelved their Motive systems. Not that there isn't a place for the Motive in low psi applications but as the psi increases, sealing becomes an issue. I think you'll really enjoy a Mightyvac and it also doesn't make you reliant on finding a friend/spouse to help push bleed a system.
Which Mityvac do you use again? I only had to activate the ABS on my BMW, which they call an automated bleed, as I had removed the ABS/DSC pump for repair. BMW claims it is not possible to remove the air bubbles any other way, but we are talking about the entire pump being removed (6 lines). They also state this is recommended when removing a caliper or hose, but I don't really see why. I've only done calipers on my Maxima and did not have to touch the ABS, so I would expect the LS to be no different, but of course reserve the right to wrong of course (haha)
Old 02-06-19 | 12:36 PM
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My Mityvac is at the shop but I believe it is MV6830. Follow the link and go to Page 20 of the Mityvac catalog..
https://www.skf.com/binary/301-31734...Catalog_v5.pdf

Here's a link to it on Amazon but there are multiple suppliers (Tooltopia; etc.).
Amazon Amazon

On the final bleed I typically reduce the pressure to the minimum to reduce any bubbles. I haven't had an ABS bleed problem yet but the more complicated the ABS system is the greater the chance that it will need to be cycled electronically (which may be the case on your BMW). I did a bleed on a GM diesel with Hydroboost and it worked fine. I was concerned about the ABS and had a buddy cycle it with his electronic tool but there was no difference. The way I look at it is that if I can bleed silicone based fluid without a problem (which will bubble very easily) then it will handle most ABS systems without a problem.
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Old 02-06-19 | 01:53 PM
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Originally Posted by Catalina45
My Mityvac is at the shop but I believe it is MV6830. Follow the link and go to Page 20 of the Mityvac catalog..
https://www.skf.com/binary/301-31734...Catalog_v5.pdf

Here's a link to it on Amazon but there are multiple suppliers (Tooltopia; etc.).
https://www.amazon.com/Mityvac-6830-.../dp/B000JFN9WC

On the final bleed I typically reduce the pressure to the minimum to reduce any bubbles. I haven't had an ABS bleed problem yet but the more complicated the ABS system is the greater the chance that it will need to be cycled electronically (which may be the case on your BMW). I did a bleed on a GM diesel with Hydroboost and it worked fine. I was concerned about the ABS and had a buddy cycle it with his electronic tool but there was no difference. The way I look at it is that if I can bleed silicone based fluid without a problem (which will bubble very easily) then it will handle most ABS systems without a problem.
Sweet thanks! I am on the fence but would like to try the pull method.....pushing at 10-15 psi is also rather slow and if the seal isn't good a bit frustrating...

edit: Looks like a compressor of this size would be needed

"at 90 psi consumes 4.3 scfm"

https://www.harborfreight.com/8-gal-...sor-68740.html

Last edited by Johnhav430; 02-06-19 at 01:58 PM.
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