MMM, did i miss something? (brake master troubles)

IwantMKIII

WVU MAEngineering
Jun 12, 2007
2,477
0
0
Perkasie, PA
Changed out my brake master as it had a steady slow bleed of pressure when constant pressure was applied. Changed it out with a reman. one and now i have no brakes and engine is stumbling :aigo:

All i did was swap resevoirs, and unbolt/rebolt the 4 nuts and brake lines. I attempted to 'bleed the system' at the master so that little bit of air wasn't there.

I notice i have no brakes, there is very very little pressure when the engine is on (stationary, did not take it for a spin obviously). Everytime i press the brake the Vacuum drops and engine stumbles....vacuum then remains low. For instance is vacuum is at -18 idle, hit the brake, goes to -10 and engine stumbles, release the brake and vacuum remains -10 inless i hit the gas??

im confused, given the previous symptoms of it just being the master.
 
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grimreaper

New Member
Jul 2, 2008
2,180
0
0
Dallas
is the brake vac supply valve hooked up in the correct direction?

sounds like the remaned needs to be remaned again.
 

Satan

Supramania Contributor
Mar 31, 2005
1,594
0
36
Tampa
Make sure you have good vacuum going to the booster.

If that's good, then bleed the WHOLE system from the rear-most caliper forward. You may not have bled the master enough and there may be air in the lines now. Since many of us NEVER change the brake fluid, this is a good oppty to use a big bottle and flush out as much of the old stuff as you can.

Once you have THOROUGHLY bled the system, things should be good. If they are not, then you may need to get another master and bench bleed again.
 

87tomanymods

87tomanymods
Oct 25, 2008
193
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0
lansdale
www.myspace.com
is your pedal hard or soft now .if its hard you prolly have a booster leak. did you replace the seal between the master and booster .also make shure your not sucking brake fluid into the booster . ive seen that happen before but not on a supra .and remember just cause its remanufactured dosnt mean its any better than the old one cheap is cheap.
 

IwantMKIII

WVU MAEngineering
Jun 12, 2007
2,477
0
0
Perkasie, PA
Problem solved. I rebled the system and it seems good now.

I'm still at a loss as to why Vacuum would drop so much and STAY down unless i pushed the throttle. Anyone explain this??
 

gelboy1015

Vroom Vroom!
Jan 1, 2007
234
0
16
Houston, TX
yea, the reman'd ones arent guaranteed. i was running 60 down the highway, and i went to press on my brakes cause a light was coming up, and there were no brakes. pulled the e-brake slowly and stopped it in time. tried bleeding it in a parking lot and at home, but still no pressure. i went and returned it and bought one elsewhere, and now the brakes are fine..
 

mirage83

Member
Mar 21, 2008
457
0
16
Georgia
Surprised the hell out of me, but the oem Toyota MC, new, was only about $180 from Champion. It was cheaper than the new (not remanned) aftermarket MC's I had found.