Problems bleeding brakes after LS400 install
06-05-09, 10:11 AM
#16
It sounds like you have the exact problem I've been dealing with for the past couple weeks. I simply replaced my front pad and rotors and my brake pedal became spongy. I tried bleeding the brakes and so did the dealer, twice. The final diagnosis is a bad hydraulic brake booster (master cylinder).
The Lexus service manual states to bleed the brakes with the ignition on and in this order: right & left front then right & left rear. Also, try bleeding the hydraulic brake booster (HBB) before you bleed the brakes again. Here's the brake bleeding procedure from the service manual (including bleeding the HBB if you have disassembled the HBB, disconnected a brake line from the HBB, or if the fluid reservoir becomes empty):
a) Ignition off. Pump brake pedal more than 40 times or until the pedal reaction force becomes heavy and stroke becomes shorter.
b) Turn ignition on. Check that the boost pump stops after 30 - 40 seconds. When the pump does not stop, repeat step (a) and (b).
c) With the ignition remaining on, pump the brake pedal more than 20 times.
d) Bleed the right and left front calipers.
e) Holding the brake pedal depressed, bleed the right and left rear calipers. You do not need to pump the brakes as fluid will continuously flow from the bleeders.
The Lexus service manual specifies using either the Lexus hand held tester or ABS tester to properly bleed the brakes. It looks like you need these tools to open each individual ABS port to properly bleed the entire brake system.
I'm interested in hearing what finally solves your spongy brake pedal problem and what you learn along the way. Please keep me updated!
Brian
The Lexus service manual states to bleed the brakes with the ignition on and in this order: right & left front then right & left rear. Also, try bleeding the hydraulic brake booster (HBB) before you bleed the brakes again. Here's the brake bleeding procedure from the service manual (including bleeding the HBB if you have disassembled the HBB, disconnected a brake line from the HBB, or if the fluid reservoir becomes empty):
a) Ignition off. Pump brake pedal more than 40 times or until the pedal reaction force becomes heavy and stroke becomes shorter.
b) Turn ignition on. Check that the boost pump stops after 30 - 40 seconds. When the pump does not stop, repeat step (a) and (b).
c) With the ignition remaining on, pump the brake pedal more than 20 times.
d) Bleed the right and left front calipers.
e) Holding the brake pedal depressed, bleed the right and left rear calipers. You do not need to pump the brakes as fluid will continuously flow from the bleeders.
The Lexus service manual specifies using either the Lexus hand held tester or ABS tester to properly bleed the brakes. It looks like you need these tools to open each individual ABS port to properly bleed the entire brake system.
I'm interested in hearing what finally solves your spongy brake pedal problem and what you learn along the way. Please keep me updated!
Brian
06-05-09, 11:19 AM
#17
do you have a pic of the brakes now?
in 240s with 300zx brakes conversions, sometimes people would install the caliper on the wrong side.
the bleeder screw should be facing up. this caused poor bleeding procedures.
might not apply to the ls400 calipers but its worth a look
in 240s with 300zx brakes conversions, sometimes people would install the caliper on the wrong side.
the bleeder screw should be facing up. this caused poor bleeding procedures.
might not apply to the ls400 calipers but its worth a look
06-05-09, 12:02 PM
#18
Brian, that's interesting. Did you replace the booster already? If so, problem solved? I'd find it odd if my booster/master cylinder happened to go out when I was working on the calipers but stranger things have happened! I'm gonna take a shot at the ghetto method suggested by Stoptech before I go to the dealer and have them try the tester. I'll update this thread when I figure something out.
Here's the Stoptech article if anybody is curious. http://www.stoptech.com/tech_info/wp_bleeding_abs.shtml
The bleeder's are on the top, thanks for the suggestion though. Sometimes it's the stupidest little thing that trips you up and you can't figure it out since it's below your thought process, I've been there before!
Here's the Stoptech article if anybody is curious. http://www.stoptech.com/tech_info/wp_bleeding_abs.shtml
do you have a pic of the brakes now?
in 240s with 300zx brakes conversions, sometimes people would install the caliper on the wrong side.
the bleeder screw should be facing up. this caused poor bleeding procedures.
might not apply to the ls400 calipers but its worth a look
in 240s with 300zx brakes conversions, sometimes people would install the caliper on the wrong side.
the bleeder screw should be facing up. this caused poor bleeding procedures.
might not apply to the ls400 calipers but its worth a look
06-05-09, 03:26 PM
#20
Yes, I replaced the entire hydraulic brake booster assembly with a used one that I was fairly certain was good, however, I still have a spongy brake pedal. That could be for one of two reasons: 1) the used HBB is bad; 2) there's still air in the system because I don't have the Lexus electronic gizmos to follow the complete factory bleeding procedure. I can't decide if I want to pay another $150 to have the dealer bleed the brakes and I'm beginning to think that I can live with spongy brakes. I'm kinda particular about things like this and I'd really like to get to the bottom of what caused the failure. I shouldn't have to replace a $2000 part on my car when I change pads and rotors.
06-05-09, 11:44 PM
#21
man this sucks kyle.....u steering me away from the ls400 brakes though sir. i hope for safety reasons u get this fixed. im going to take more pain pills and off to bed... (im off work at both jobs till i see a specialist so, im sure i'll be even more active than normal if thats possible)
06-06-09, 01:12 PM
#22
man this sucks kyle.....u steering me away from the ls400 brakes though sir. i hope for safety reasons u get this fixed. im going to take more pain pills and off to bed... (im off work at both jobs till i see a specialist so, im sure i'll be even more active than normal if thats possible)
What happened that you're off work and on pain pills? Hope you're back up and going soon!
06-07-09, 12:33 PM
#23
Brian, I don't think this has anything to do with the LS400 brakes themselves. Looking at how many people here have done LS, TT, or front BBK's without any problems, I don't think the LS calipers are at fault. I drove the car quite a bit last night and it feels like an air issue to me, I had no problems stopping, the pedal's just softer than I expected. I'm gonna try to check the air-tightness of the brake booster and rebleed them and see if I can get anywhere.
What happened that you're off work and on pain pills? Hope you're back up and going soon!
What happened that you're off work and on pain pills? Hope you're back up and going soon!
lifter a box WAY to big for me and then next day a 15 foot fall...lol. so im facing possible hernia surgery and possible back surgery to repair some pinched/damaged nerves. pills are good though but man im already bored at home
06-07-09, 01:04 PM
#24
Yes, I replaced the entire hydraulic brake booster assembly with a used one that I was fairly certain was good, however, I still have a spongy brake pedal. That could be for one of two reasons: 1) the used HBB is bad; 2) there's still air in the system because I don't have the Lexus electronic gizmos to follow the complete factory bleeding procedure. I can't decide if I want to pay another $150 to have the dealer bleed the brakes and I'm beginning to think that I can live with spongy brakes. I'm kinda particular about things like this and I'd really like to get to the bottom of what caused the failure. I shouldn't have to replace a $2000 part on my car when I change pads and rotors.
true....alot of people are using them. could it just be u have a bad brake booster?
lifter a box WAY to big for me and then next day a 15 foot fall...lol. so im facing possible hernia surgery and possible back surgery to repair some pinched/damaged nerves. pills are good though but man im already bored at home
lifter a box WAY to big for me and then next day a 15 foot fall...lol. so im facing possible hernia surgery and possible back surgery to repair some pinched/damaged nerves. pills are good though but man im already bored at home
It's funny, I've been driving it for a couple days now and the brakes work well, I had to stop for a deer last night and they stopped like I needed them too. I think the pedal feel should be different, I'm gonna try shaving the caliper/tie rod bolt just a little more if the bleeding doesn't work; there's virtually no clearance and I've noticed the outside of the caliper is flexing a little bit when I hit the brakes; maybe I need a little more clearance on the inside. Let's see if I get off my lazy rear and work on it today.
Ouch!
That's no good! 
Last edited by Kyle Harty; 06-07-09 at 01:10 PM.
06-07-09, 01:35 PM
#25
So Kyle, I thought I'd chime in, although I've never worked on your specific issue. I'd say either you have air in your system still, or very possibly have a small point where the system is consistently bringing new air in when you attempt to bleed the brakes. i.e. any used part you used. The only problem with using used parts. You just never know. I would definitely follow the bleeding procedure from a previous post.
Although most cars can be bled without problems from right rear to left rear to right front to left front, every car has a specific bleed procedure. So following this procedure when you encounter a problem is a key first step in eliminating more problems. I would bet that the only other thing possible for bleeding is the factory scan tool to engage the ABS pump corrrectly.
I also would not engage the brakes with the calipers off! You can cause the pistons to overtravel and damage the fluid seal on the inside.
Just in case you haven't tried it, here's a trick I use with a problem air situation. Get a container to hold brake fluid in, like a water bottle or something. Make sure it's clear. attach a length of vacuum/wiper tubing to the bleeder, and stick the other end into the brake fluid in your clear container. Making sure it's completely submerged and stays submerged throughout this process. Open the bleeder for that caliper and have someone go down and up on the brake pedal. As he goes down on the pedal you will see air in the system as bubbles in the container as he lets up on the pedal it will suck brake fluid into the system. continue until you don't see anymore air bubbles coming out of the line.
my guess would be that you've got air in the ABS pump though...hope this helps
Although most cars can be bled without problems from right rear to left rear to right front to left front, every car has a specific bleed procedure. So following this procedure when you encounter a problem is a key first step in eliminating more problems. I would bet that the only other thing possible for bleeding is the factory scan tool to engage the ABS pump corrrectly.
I also would not engage the brakes with the calipers off! You can cause the pistons to overtravel and damage the fluid seal on the inside.
Just in case you haven't tried it, here's a trick I use with a problem air situation. Get a container to hold brake fluid in, like a water bottle or something. Make sure it's clear. attach a length of vacuum/wiper tubing to the bleeder, and stick the other end into the brake fluid in your clear container. Making sure it's completely submerged and stays submerged throughout this process. Open the bleeder for that caliper and have someone go down and up on the brake pedal. As he goes down on the pedal you will see air in the system as bubbles in the container as he lets up on the pedal it will suck brake fluid into the system. continue until you don't see anymore air bubbles coming out of the line.
my guess would be that you've got air in the ABS pump though...hope this helps
04-01-10, 10:18 PM
#26
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Kyle it would be nice to know if you ever got the spoongy pedal fixed? I just upgraded my brakes to LS400 brakes and have the same problem. I'm going crazy trying to figure it out I've tryied all the diffrent bleeding techniques mentioned here and nothing. I've havent even went to work for the last 2 days messing with this spoongy pedal im loosing my mind somebody please help! where are all the lexus master techs when you need them? If I take the vehicle to the lexus dealer will they bleed the brakes using the scan tool? I've read many posts claiming they only suck the fluid out of the reservoir and add new fluid can anybody confirm this? Also will they give me a bunch of mumbo jumbo about bleeding my breaks because I have LS400 calipers?
04-01-10, 10:30 PM
#27
I have the same experience when I put on the LS400 calipers on my SC400. I bled it all the way around about 4 times, no air bubbles coming out and the pedal was still soft/spongy. Took it for a test drive and seems ok. Still soft/spongy but it grabs.... Spoke with my cousin who has a GS400. He said that his car is the same way with mine and his is still all stock. i figured its a V8 thing or could just have been the ABS......
Put the car back together and take it for a test drive and see how it feels.
Put the car back together and take it for a test drive and see how it feels.
