Break the Brakes?

[gerviswaddell]

Hey there,
continuing on my ongoing quest for Tercel greatness, am having an issue with the brakes, (forgive me if im a total nube at this sort of thing, I understand that brake systems are quite similar amongst most cars...) when I apply the bakes, the pedal needs to travel quite far down its run before I get any reasonable 'feedback', if I pump the pedal, it seems to build up some pressure in the system, making braking more effective. Upon searching this problem I came across this post http://www.tercel4wd.com/forums/viewtop ... fix#p30340 and feel that it may be the master cylinder that is 'going'.

I have a week and a half until my big voyage, what would be a timely and effective fix for this issue? should I replace the unit (this comes with possible consequences within the brake system, because everything is rusty as hell in there), is there a good way to fix this cylinder without pulling apart all of the fittings on the brake manifold?

thanks again for all of your help,

Dave.

[Petros]

IT sounds like the master cylinder to me. Two fixes: either buy a new or re manufactured master, or rebuild it (if you can get a kit for it). The master comes off easy enough, with a rebuilt one you just swap it out, and than bleed the brakes where the line meets the master. With an assistant it is not too difficult. A bit messy, so make sure you wash off all of the spilled brake fluid with carb cleaner, and than soap and water. It is corrosive and will rust what ever it touches if left.

I rebuilt mine using used parts (it was late sunday night when mine went out and I had to drive it the next day). I dismantled the one in my car, and the spare used one I had, and polished the inside with 400 grit wet-and-dry sand paper, cleaned it up with brake parts cleaner, and put in all the best rubber parts from the two I had. To my surprised it worked great, and I am still driving on it 2 years later. It took me less than an hour all together.

I will replace it with a smaller dia. one from an MR2 eventually (smaller dia. master gives more braking power, improves the braking ratio between master and wheel pistons), when I upgrade all my brakes later this summer.

Good luck.

[Neu]

I would also do a quick and simple bleed of the system before you do the master cylinder. I had some air in my lines, and they took a pump to get pressure.

[takza]

Could also be an issue of rear brake shoes that aren't being auto-adjusted. Pull the rear drums and check?

[splatterdog]

When masters are starting to go, You can usually get a good pedal with one quick stab at the pedal. Tis sudden burst of pressure can temporariliy make a weak seal push harder against the bore. When released even slightly the pedal will then usually do it's drop.

Check for leaks/bleed before you shotgun parts at it. 80's toy wheel cylinders are notorious for leaking. Good thing they are real cheap....

[ARCHINSTL]

Dittor splatterdog's remark on rear cylinders.
Tom M.