A Bit Nervous After Bleeding The Brakes This Weekend

[ED.]

Some of the guys at my other board said bleeding the system vis a vi the brake pedal is not recommened as damage to the master cylinder may occur.

I figured with 211,000 on the clock, the system really needed new fluid. The job did improve pedal feel but since it is not my everyday car (my sister normally drives it) I am worried she may hit the brakes and keep on moving forward. I guess now would be a good time to remind her of the emergency brake! 'Not saying it will happen, but if you ever hit the brakes and nothing happens, by chance mind you, you may want to use this..' lol.

Should I place a call to our mechanic in the morning? I had the brakes on my 7 done back in Nov 2006 and have had zero problems with them and who knows when they were bled last by the PO. I assume (downfall) the master cylinder is something that can take some force and new fluid?

Thanks,

[kc92hatch]

Well, I guess anything is possible....but......I've never heard of damage to the master cylinder by bleeding the brakes. All you are doing is pushing brake fluid down the lines when you bleed them. Since you have the bleeder screw open when you do this, you are actually pushing the fluid down that one brake line at a lower pressure than when the brakes are under normal operation.

I think you are OK. If they were working fine after you bled them and if the master cylinder was topped off with fluid, I'd say you did a great job and don't worry about it.

Good luck!

[IS400]

The logic may be that when bleeding brakes the master cylinder plunger is stroking longer than it normally does and further breaks down old seals/boots etc. by pushing the 'high water mark' of sludge or corroded shaft sections into the rubber bits. Same danger when replacing brake pads, moving the piston back into the housing seal poses a risk of damage if you have lots of built up and rust.

With a modern vacuum brake system the day to day stroke on a brake pedal is pretty short. When I bleed brakes I put it to the floor and let it come all the way back up, but I have always enjoyed long strokes anyhow! :P

[ED.]

Thanks, guys! You are making me feel better. When the one guy said I should prepare to use the emergency brake I thouht 'oh crap' but maybe he was a little farfetched. He said something about working on older Jags which will explode if you don't get into them properly! The Lexus is a MUCH better car. Perhaps he doesn't know that?

Either way I will rest better today and later on. Thanks again!