Keppie

I had the brake fluid changed at Lexus today. I asked the service advisor to make sure the tech was careful not to scratch the wheels. When I picked up the car the service advisor said he spoke with the mechainc, and the mechainc told him the service could be done without removing the wheels. The dealership has been great and I have no reason not to believe them, but I have to ask. Can you replace brake fluid without removing the wheels?

The pedal feels softer after the service, but the brakes work fine. Can this service change the brake pedal feel?

Thanks

streetx

iTrader: (4)

They would use a machine to pump it from the master cylinder if you went to the dealership

ISFPOWER

iTrader: (20)

yep, you sure can. its not a complete flush though but its most of the fluid.

laobo979

iTrader: (5)

Why not I've done it by going from the inside when you jack it up. But use a break bleeder to catch the fluids.

panda08

iTrader: (1)

yeah, you can bleed the brakes without removing the wheels. its just not as much space to move around

brake pedal should feel the same as it did before. if it feels softer theres the possibility of some air in the brake lines.

Keppie

would I need to go back to check for air or does it work itself out?

appreciate the feedback from all

skottydznt

iTrader: (11)

you can get to the bleeder valve without removing the wheels but it is more efficient and easier if you can take the wheel off. My car is lowered so it makes it harder but Im pretty sure a stock height is would be fairly easy to take care of.

panda08

iTrader: (1)

I don't think it'd just work itself out. If you can live with a softer brake pedal then you don't need to worry about it, but if you like the firm pedal feel then definitely go back and have them re do or inspect it. I replaced the brake fluid in my brothers RSX (yes I'm aware its another make/ model) and the pedal was soft for the first 2 pedal strokes. By the time your car, and brake pedal, got back to you it should've been firm.

Lestrade

Yep to both.

The bleeder screws that are used to drain and bleed the hydraulic fluid from the brake system are located on the inside of the calipers and are accessible if the vehicle is on a lift (I haven't done this on an IS so I can't say how much room there is though):


(The bleeder screw is the small screw at the bottom-right of the caliper with the black rubber cap on it).

When you step on the brake pedal, it pushes the piston of the master cylider which forces hydraulic fluid through the brake lines to the calipers at each wheel to push their pistons against their brake pads, which squeeze against the brake rotors (disks) to slow down and stop the turning of the wheels.

When you change the brake fluid, you're just pumping new hydraulic fluid into the lines/reservoir while draining out the old fluid. To finish it off, you have to bleed each caliper to remove any air from the system.

This is necessary because the hydraulic brake fluid is incompressible: the force exerted by the master cylinder equals the forces exerted on the brake pistons in the calipers (vacuum boosting ignored). If it were compressible, such as if there was air in the lines, then you would get some travel in the brake pedal before any (significant) force is exerted on the pistons, which is usually perceived as a soft pedal feel. This can also occur if there is water in the brake fluid as the result of a bad seal that is allowing moisture into the system (this is probably unlikely in your case, however, since the change came after this maintenance and simply replacing fluid shouldn't damage seals).

In other words: take it back and have them re-bleed your brakes.

Keppie

I called today and the service advisor asked me to promptly bring it in. Top mechainc took a quick drive and agreed the pedal feel was off. The top mechainc did a full old school drain, versus using a pump and the brakes are back to normal.

Thank you for the advice and information.

KillaIS250

iTrader: (1)

Glad you took it in and got it resolved.
Brakes are one of those areas where its always better to be safe then sorry

tlynch41

Speaking of brakes, my 2007 LS460 has this annoying clicking/thumping sound whenever I push hard on the pedal. It is also evident when I am carrying a heavy load and go down hill.