Brake job on 99 GS300
05-11-17, 04:22 AM
#1
Rookie
Thread Starter
Brake job on 99 GS300
Want to tackle the brakes and rotors on my 99 GS300. I've done brakes before on other vehicles, but need details. Can't seem to find step by step instructions using search function or on Youtube, they all seem to be for other model Lexus'. There's a sticky in the brakes section, but it says it's for an LS400. Do the GS & LS models have the same brakes ? Thanks in advance for any input !!
05-13-17, 06:15 AM
#3
Cbb- The brakes on 2nd gen gs are problematic. Imho Lexus designed the system for a general easy driver. The car over taxes the brakes mainly because of the car's weight and the spirited driving gs experience opposed to LS models and such. The system isn't anything special or unique. Here is the problems I have dealt with.
1. Frt brake bracket bolts stripping at removal - believe these are tq to yield bolts. Most mx reused with tread locker prone to stripping if not heated before removal.
2. 15 yo autos need new rubber brake hoses at all points. Old rubber migrates moisture and interior of hose degradation from brake fluid. Old hose become soft and ballon under pressure of braking. This will cause a soft pedal and/or pad release off rotor with accompanying overheating. I use OE rubber on my race car because of the counterfeit parts in circulation.
3.All caliper sliders require attention- smooth operation essential or overheating will occur. This happens quick and will demonstrate itself as vibration at braking and at cruise because of warped rotors.
4. Don't go cheap on brake system- No Hecho en China rotors or pads along with brake rubber lines.
5. Pay attention to all shims, clips at disassembly. The service manual is weak so take pictures and reassemble correctly.
6. Flush the fluid. Turn the car on after connecting bleeder hose. Don't start just on. Crack bleeder and press the brake. The ABS servo motor will pump the fluid. Drains resovoir at decent rate. Buy two large new brake fluids. Fronts from my experience you need to pump for flowage same process.
7.Dont break speed sensor wires or sensors. Expensive mistake while working on brakes or suspension.
There is a abundance of threads here concerning brakes. They are one assembly Lexus imho went cheap on the GS.
Here is a link concerning rotors. Take it to heart it applys to these cars.
https://www.hemmings.com/blog/2013/10/04/tech-101-how-to-choose-the-right-disc-brake-rotors/
Here is a guy who did a rotor pad exchange on 2006 left rear. It is the same for 2nd gen's.Note concerning this video if it was me.
1. Jack the car at the diff, prop jack stands under rear wishbone attach points but don't place load on jackstands keep load on floor jack.
2. Use gloves dealing with brake fluid. Keep it away from everything. If it melts paint what about your skin?
https://m.youtube.com/watch?v=91oIY96IAMs
Jack the front from the front subframe and backup support on both subframe members with jack stands.
The front process is essentially the same. The clips, pins and shims are important. I suggest buying new hardware kits for each corner of the brakes. If don't desire to replace pins, wirewheel the corrosion off. Everything has to slid smooth as you probably know.
1. Frt brake bracket bolts stripping at removal - believe these are tq to yield bolts. Most mx reused with tread locker prone to stripping if not heated before removal.
2. 15 yo autos need new rubber brake hoses at all points. Old rubber migrates moisture and interior of hose degradation from brake fluid. Old hose become soft and ballon under pressure of braking. This will cause a soft pedal and/or pad release off rotor with accompanying overheating. I use OE rubber on my race car because of the counterfeit parts in circulation.
3.All caliper sliders require attention- smooth operation essential or overheating will occur. This happens quick and will demonstrate itself as vibration at braking and at cruise because of warped rotors.
4. Don't go cheap on brake system- No Hecho en China rotors or pads along with brake rubber lines.
5. Pay attention to all shims, clips at disassembly. The service manual is weak so take pictures and reassemble correctly.
6. Flush the fluid. Turn the car on after connecting bleeder hose. Don't start just on. Crack bleeder and press the brake. The ABS servo motor will pump the fluid. Drains resovoir at decent rate. Buy two large new brake fluids. Fronts from my experience you need to pump for flowage same process.
7.Dont break speed sensor wires or sensors. Expensive mistake while working on brakes or suspension.
There is a abundance of threads here concerning brakes. They are one assembly Lexus imho went cheap on the GS.
Here is a link concerning rotors. Take it to heart it applys to these cars.
https://www.hemmings.com/blog/2013/10/04/tech-101-how-to-choose-the-right-disc-brake-rotors/
Here is a guy who did a rotor pad exchange on 2006 left rear. It is the same for 2nd gen's.Note concerning this video if it was me.
1. Jack the car at the diff, prop jack stands under rear wishbone attach points but don't place load on jackstands keep load on floor jack.
2. Use gloves dealing with brake fluid. Keep it away from everything. If it melts paint what about your skin?
https://m.youtube.com/watch?v=91oIY96IAMs
Jack the front from the front subframe and backup support on both subframe members with jack stands.
The front process is essentially the same. The clips, pins and shims are important. I suggest buying new hardware kits for each corner of the brakes. If don't desire to replace pins, wirewheel the corrosion off. Everything has to slid smooth as you probably know.
Last edited by HLamar; 05-13-17 at 07:31 AM. Reason: spelling
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Comage (03-22-24)
05-13-17, 06:34 AM
#4
Cbb- GS brakes are like 99% of auto disc brake systems. Non floating rotors with single piston calipers. No difference besides the points i made before which affects all brake systems. One point i neglected in prior post. Make sure if r/r rotors be sure and remove rust or anything which precludes proper rotor to hub and rotor to wheel mateing. It's easy to check runout of rotor with mag base dial indicator. If runout is outside tolorence and you cannot "clock the rotor, to hub and wheel combinations" . Most likely bent rim. You can check runout on rotor specifically without rim easily. If new rotor is outside tolorences take it back. You will be chasing vibration problems for a long time.
BTW- Brakes are a huge money maker for auto service and parts manufactures. Don't trust the bullsh#t. Do it yourself and save a ton of money. Just especially with this particular model of car don't buy cheap a## drilled/slotted/ super marketing rotors or pads. Solid OE rotors and OE pads or check via search function on Lexus forums what knowledgeable mx people have success with. OE from Lexus will cost more but will assure best combination if you don't desire to trust the internet jihadist/experts. Slotted/drilled rotors and Such is marketing on a street car. May have some use on a car your using for a day at the track. If your using these cars at the the track with the stock brakes the rotor pad combination will not matter anyway. The system is too small. The amount of understeer the cars produce will burn the fronts tires off as quick or quicker than boiling the brake fluid. It's a est. <3000 lb. brake size system on a >4000 lb. projectile.
BTW- Brakes are a huge money maker for auto service and parts manufactures. Don't trust the bullsh#t. Do it yourself and save a ton of money. Just especially with this particular model of car don't buy cheap a## drilled/slotted/ super marketing rotors or pads. Solid OE rotors and OE pads or check via search function on Lexus forums what knowledgeable mx people have success with. OE from Lexus will cost more but will assure best combination if you don't desire to trust the internet jihadist/experts. Slotted/drilled rotors and Such is marketing on a street car. May have some use on a car your using for a day at the track. If your using these cars at the the track with the stock brakes the rotor pad combination will not matter anyway. The system is too small. The amount of understeer the cars produce will burn the fronts tires off as quick or quicker than boiling the brake fluid. It's a est. <3000 lb. brake size system on a >4000 lb. projectile.
Last edited by HLamar; 05-13-17 at 07:35 AM. Reason: spelling
05-14-17, 07:03 AM
#7
This forum is not lame, it is incredibly useful. You want lame, go look at the MB GLK forum 
.
As for brakes, there is nothing unusual or complicated about Lexus brake pad replacement.
Front pads: Rear:
.As for brakes, there is nothing unusual or complicated about Lexus brake pad replacement.
Front pads:
3. LIFT UP CALIPER
(a) Hold the sliding pin on the bottom and loosen the installation bolt.
(b) Remove the installation bolt.
(c) Lift up the caliper and suspend it securely.
HINT:
Do not disconnect the flexible hose from the caliper.
The anti−squeal springs and support plates can be used again provided that they have sufficient rebound, no de- formation, cracks or wear, and have had all rust, dirt and foreign particles cleaned off.
When replacing worn pads, the anti−squeal shims must be replaced together with the pad.
(a) Install the 2 anti−squeal shims to each pad.
HINT:
Apply disc brake grease to both sides of the inner anti−squeal shims.
(b) Install the inner pad with the pad wear indicator plates fac- ing downward.
(c) Install the outer pad.
NOTICE:
There should be no oil or grease adhering to the friction surfaces of the pads or the disc.
(d) Install the 2 anti−squeal springs.
(a) Hold the sliding pin on the bottom and loosen the installation bolt.
(b) Remove the installation bolt.
(c) Lift up the caliper and suspend it securely.
HINT:
Do not disconnect the flexible hose from the caliper.
- REMOVE 2 ANTI− SQUEAL SPRINGS
- REMOVE 2 BRAKE PADS WITH 4 ANTI−SQUEAL SHIMS
- REMOVE 4 PAD SUPPORT PLATES
The anti−squeal springs and support plates can be used again provided that they have sufficient rebound, no de- formation, cracks or wear, and have had all rust, dirt and foreign particles cleaned off.
- CHECK DISC THICKNESS AND RUNOUT
- INSTALL 4 PAD SUPPORT PLATES
- INSTALL NEW PADS
When replacing worn pads, the anti−squeal shims must be replaced together with the pad.
(a) Install the 2 anti−squeal shims to each pad.
HINT:
Apply disc brake grease to both sides of the inner anti−squeal shims.
(b) Install the inner pad with the pad wear indicator plates fac- ing downward.
(c) Install the outer pad.
NOTICE:
There should be no oil or grease adhering to the friction surfaces of the pads or the disc.
(d) Install the 2 anti−squeal springs.
10. INSTALL CALIPER
(a) Draw out a small amount of brake fluid from the reservoir.
(b) Press in the pistons with a hammer handle or similar implement.
HINT: If the pistons are difficult to push in, loosen the bleeder plug and push in the pistons while letting some brake fluid escape.
(c) Install the caliper.
(d) Hold the sliding pin and torque the installation bolt. Torque: 34 N·m (350 kgf·cm, 25 ft·lbf)
(a) Draw out a small amount of brake fluid from the reservoir.
(b) Press in the pistons with a hammer handle or similar implement.
HINT: If the pistons are difficult to push in, loosen the bleeder plug and push in the pistons while letting some brake fluid escape.
(c) Install the caliper.
(d) Hold the sliding pin and torque the installation bolt. Torque: 34 N·m (350 kgf·cm, 25 ft·lbf)
- INSTALL FRONT WHEEL Torque: 103 N·m (1,050 kgf·cm, 76 ft·lbf)
- DEPRESS BRAKE PEDAL SEVERAL TIMES
- CHECK THAT FLUID LEVEL IS AT MAX LINE
1. REMOVE REAR WHEEL
Remove the rear wheel and temporarily fasten the disc with the 3 hub nuts.
2. INSPECT PAD LINING THICKNESS Check the pad thickness through the caliper inspection hole and replace pads if the thickness is not within the specification. Minimum thickness: 1.0 mm (0.039 in.)
3. REMOVE ANTI−SQUEAL SPRING AND PAD GUIDE PIN
(a) Raise the ”B” portion with hand, push up the ”A” portion and disengage the anti−squeal spring from brake caliper.
(b) Remove the anti−squeal spring.
NOTICE:
Do not deform the clip and anti−squeal spring.
The clip and anti−squeal spring can be used again provided that they have sufficient rebound, no−deformation, cracks or wear, and have had all rust, dirt and foreign particles cleaned off.
(c) Remove the clip and pad guide pin.
4. REMOVE PADS AND ANTI−SQUEAL SHIMS
(a) Remove the 2 pads.
(b) Remove the 4 anti−squeal shims from each pad.
When replacing worn pads, the anti−squeal shims must be replaced together with the pads.
(a) Apply disc brake grease to both sides of inner anti−squeal shims .
Remove the rear wheel and temporarily fasten the disc with the 3 hub nuts.
2. INSPECT PAD LINING THICKNESS Check the pad thickness through the caliper inspection hole and replace pads if the thickness is not within the specification. Minimum thickness: 1.0 mm (0.039 in.)
3. REMOVE ANTI−SQUEAL SPRING AND PAD GUIDE PIN
(a) Raise the ”B” portion with hand, push up the ”A” portion and disengage the anti−squeal spring from brake caliper.
(b) Remove the anti−squeal spring.
NOTICE:
Do not deform the clip and anti−squeal spring.
The clip and anti−squeal spring can be used again provided that they have sufficient rebound, no−deformation, cracks or wear, and have had all rust, dirt and foreign particles cleaned off.
(c) Remove the clip and pad guide pin.
4. REMOVE PADS AND ANTI−SQUEAL SHIMS
(a) Remove the 2 pads.
(b) Remove the 4 anti−squeal shims from each pad.
- CHECK DISC THICKNESS AND RUNOUT
- INSTALL NEW PADS
When replacing worn pads, the anti−squeal shims must be replaced together with the pads.
(a) Apply disc brake grease to both sides of inner anti−squeal shims .
(b) Install the 2 anti−squeal shims on each pad.
HINT:
Make sure the arrows on the inner anti−squeal shims facing to the direction of disc rotation as shown in the illustration.
(c) Draw out a small amount of brake fluid from the reservoir.
(d) Press in the pistons with a monkey wrench handle or equivalent.
HINT:
Tape the monkey wrench handle before use.
If the piston is difficult to push in, loosen the bleeder plug and push in the piston while letting some brake fluid escape.
(e) Install the 2 pads.
7. INSTALL PAD GUIDE PIN AND ANTI−SQUEAL SPRING
(a) Install the pad guide pin and clip.
HINT:
Make sure the arrows on the inner anti−squeal shims facing to the direction of disc rotation as shown in the illustration.
(c) Draw out a small amount of brake fluid from the reservoir.
(d) Press in the pistons with a monkey wrench handle or equivalent.
HINT:
Tape the monkey wrench handle before use.
If the piston is difficult to push in, loosen the bleeder plug and push in the piston while letting some brake fluid escape.
(e) Install the 2 pads.
7. INSTALL PAD GUIDE PIN AND ANTI−SQUEAL SPRING
(a) Install the pad guide pin and clip.
(b) Install the anti−squeal spring.
HINT: Ensure that the claw of the anti−squeal spring is raised up on the caliper securely. Ensure that there is no gap between the pad guide pin and anti−squeal spring. Ensure that ”A” and ”B” portions of anti−squeal spring are attached to the pad.
HINT: Ensure that the claw of the anti−squeal spring is raised up on the caliper securely. Ensure that there is no gap between the pad guide pin and anti−squeal spring. Ensure that ”A” and ”B” portions of anti−squeal spring are attached to the pad.
- INSTALL REAR WHEEL
Torque: 103 N·m (1,050 kgf·cm, 76 ft·lbf) - DEPRESS BRAKE PEDAL SEVERAL TIMES
- CHECK THAT FLUID LEVEL IS AT MAX LINE
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05-14-17, 08:16 AM
#8
Rookie
Thread Starter
So you think that all brake procedures are the same ? Same parts, clips, torque specs etc ?? These forums are to help each other out with advice and minor details from experiences working on our cars, which is what I was asking. Thanks to everyone else for the helpful tips and details.
05-14-17, 06:45 PM
#9
So you think that all brake procedures are the same ? Same parts, clips, torque specs etc ?? These forums are to help each other out with advice and minor details from experiences working on our cars, which is what I was asking. Thanks to everyone else for the helpful tips and details.
05-15-17, 05:45 AM
#10
Definitely NOT what you were asking? Thats what you are asking now, cause you got your Skirt pulled up, now you feel like u need to make it right and not look like a douche... Wasn't your quote " This forum is kinda lame " Now all of a sudden your Mr. Forum goodie two shoes... GTFO here.....
We got no engines do we Ted?!
05-15-17, 05:53 AM
#11
So you think that all brake procedures are the same ? Same parts, clips, torque specs etc ?? These forums are to help each other out with advice and minor details from experiences working on our cars, which is what I was asking. Thanks to everyone else for the helpful tips and details.
FWIW - I will advise that you don't get into bleeding the fluid in the calipers until you fully understand how the GS Nitrogen Booster/ABS system works. In which there are a few threads about it if reading the FSM is too involved or you can't find it.
Last edited by 99 GS3; 05-15-17 at 06:05 AM.
05-15-17, 07:13 AM
#12
Rookie
Thread Starter
Definitely NOT what you were asking? Thats what you are asking now, cause you got your Skirt pulled up, now you feel like u need to make it right and not look like a douche... Wasn't your quote " This forum is kinda lame " Now all of a sudden your Mr. Forum goodie two shoes... GTFO here.....
05-15-17, 07:16 AM
#13
Rookie
Thread Starter
You'll never get decent help *****ing about the speed of getting help. 75 views isn't much, as well as most of the traffic in the GS section now is just honda kids that have bought a $1500 GS and so the quality has diminished dramatically. All the info for the basics like brakes are located in 18 years worth of threads, the FSM has everything you would ever need, or otherwise available utilizing google. It doesn't necessarily make it lame, but you may be expecting to much instant personal hand holding from such an aging forum.
Well changing the pads/rotors is just as straight forward as any other run of the mill brake job, there are Chilton's available for you at the parts stores if google isn't turning up good links for the FSM.
FWIW - I will advise that you don't get into bleeding the fluid in the calipers until you fully understand how the GS Nitrogen Booster/ABS system works. In which there are a few threads about it if reading the FSM is too involved or you can't find it.
Well changing the pads/rotors is just as straight forward as any other run of the mill brake job, there are Chilton's available for you at the parts stores if google isn't turning up good links for the FSM.
FWIW - I will advise that you don't get into bleeding the fluid in the calipers until you fully understand how the GS Nitrogen Booster/ABS system works. In which there are a few threads about it if reading the FSM is too involved or you can't find it.
05-15-17, 08:06 AM
#15
Rookie
Thread Starter
Yes, I agree there is a lot of good info here but sometimes when you search you get nothing specific. I'm not new to forums, am actually on quite a few of them. I always make an effort to give someone a quick answer if they're new and looking for some info I can help with.