Jwild909

I'm hoping you guys could help me out.
A few months ago a few buddies and I replaced my master cylinder since my pedal would sink to the floor. That fixed that problem. Recently the pedal takes a lot of force to stop and has a lot of play until you can actually feel the brakes grab. Every now and then I have to drive the car around for a good 20 mins before I get the pressure back up. Well today the pedal actually sat right at the top and with the slightest pressure on the pedal the brakes would grab but that's the first time that has happened. Oh yea I also just had my booster replaced on Friday. Well it still has a lot of play in the brake pedal before it actually grabs so my question to you guys is, could my rear calipers be seized or any caliper for that matter? Could it be something with the hydraulic brake pressure? Any opinions would be great, this has me stumped!

Jwild909

Bump . Help please

getafewliv

Who recommended that you should change out your master cylinder in the first place? How sure are you that the master cylinder was your issue?

I am no expert on brake systems, but it sounds like you had/have air in the lines. Did you properly bleed the system completely?

Jwild909

My pedal would sink to the floor at a light or stop sign so it was a clear sign it was bad. I'm going to have the lines power bled today or tomorrow so hopefully that removes all the air once and for all if there is air in the lines still. I also ordered akebono pads for the front and rear so I will be checking for seized calipers as well.

getafewliv

If you had air in the lines that could have very well been your issue... I think you need to do some research on cars and brake systems before you start doing diagnosis yourself and before you start replacing more parts.

I don't think this sound seized caliper at all. A seized caliper would cause the pads to drag and not release properly, not cause a loss of brake pedal pressure.

The quick and dirty explanation of how brakes work is that you have brake lines filled with fluid that connect your brake pedal to your calipers. Brake fluid does not compress, therefore when you press the brake pedal, it forces the fluid against the calipers and ultimately pushes the pads against the rotors. Air on the other hand does compress. if you have air in the lines, that air will compress instead of pushing brake fluid. If there is a lot of air, this can easily cause the brake pedal to bottom out before any fluid actually pushes the pads.

It's relatively easy to bleed the brake system, but do some research first on how to do it without causing more issues or introducing more air into the system. You will need either a second person to help you, or a vacuum bleeder. Also, make sure that you keep the reservoir topped up as you bleed the brakes. If you don't you will suck in air through the master cylinder. You also want to start with the caliper that is furthest from the master cylinder and work your way closer.

Get yourself some clear tubing that fits snug onto the bleeder screw and run that into an old water bottle. I usually cut an X in the cap and shove the tube through. Then when I am finished, I swap the lid for an uncut lid to seal the old brake fluid in the bottle.

Don't over tighten or strip the bleeder screws. Make sure you use the proper size wrench.

Don't get brake fluid on anything, it is very corrosive.

Jwild909

hmm thanks for the info. It mainly happens in the morning when its cold or if they car hasn't moved in a few hours. If its warm or im constantly driving it, the brakes feel fine.

getafewliv

Once again, I am no expert, but it could depend on where the air bubble(s) are in the system.

Do some research, bleed the system, then take it from there. It will only cost you $10 in brake fluid.

getafewliv

Just saw this in another thread where someone had an issue with an aftermarket brake cylinder:

https://www.clublexus.com/forums/sus...ml#post9683772

Did you use an OEM part or aftermarket?

It is very well possible that the brake cylinder was the original culprit and that the replaced master cylinder is also causing issues. I know there have been reports of people's alternator's failing and the replacement aftermarket part being defective from day one.

But like I said, i am no expert.

The350Girl

Ebay parts and Aftermarket parts will give you headache, you'll get what you've paid for ! the cost is not much different, why not OEM ? i remembered back in the day, Ebay parts made me spent 500$ for no reason and the issue still there.