i just finished swapping out the Master Cylinder yesterday and bled the whole system according to the Honda Service Manual. I can't get a hold of this special adjustment tool to adjust the piston / booster gap. Everything is working fine except i hear a "bob" sound when step on the brake pedal.

Anyone who replaced the MC had that problem before? i suspect the "bob" sound came from not adjustting the gap ( maybe the gap is too much that when i step on the brake, the rod hit the piston of the master cylinder )?

Any suggestion and help is appreciated.

 

OK i am kind of new here but i wanted to know what is the master cyclinder and why does it have to with anything with the brakes because my brake pedal is getting pretty bad too i have to kind of keep pumping the pedal so that it stops coming off the freeway. i have a 91 accord lx how nuch am i looking at if i do it my self ir if i pay a mech. or even at the dealership?

 

Simply put, the MC is in charge of housing your brake fluid and distributing the fluid to your calipers, etc. Of course, it works with the brake booster which is all vacuum controlled.

 

Oh yeah... And I have brakes! Finally can stop. My pedal no longer goes to the floor and is solid again. Shew....

 

There is another thread somewhere here on the forum that mentions this piston issue and if I remember, something about an alternative thing to do if you didn't have that special tool. Maybe not, like I said I can't remember the details. But actually, I think it was maybe even another brake related thread I started a few weeks ago. Just do a search. Sounds like you mostly have the job finished anyway. It's always the small things that trip you up...

 

so the MC did the trick?

 

Yes. The MC was the only thing replaced. Of course they have to put in new fluid and bleed the lines too with that job.

 

I've replaced a master cylinder, without that measuring tool. When you take out the old MC, carefully compare the piston shaft with the new one. I lucked out... their lengths were exactly the same.

If they're not exactly the same, you have to adjust the push-rod at the brake pedal. Otherwise your brake booster isn't sitting in the right position. It could become an excessive vacuum leak, or it won't give enough boost, or something like that.

 

hi there, thx for the info. i searched high and low within the forum but couldn't find out a way to adjust the gap. But i took out the master cylinder out last nite and inspected it, couln't find a "cheap" way to adjust it.

I gave up and put everything back and thinking of taking it to the shop to have it adjusted.

Interestingly when i drove to work this morning, the sound is not there anymore.

i guess taking the MC out and reseating it might have solved the problem.

thx