Master cylinder or booster?
Thread Starter
|
Freshman User
Joined: Jun 2008
Posts: 26
Likes: 0
Master cylinder or booster?
Okay got the truck on the road. I have to pump up the brakes, then they work great. If I go a block they are gone. Just finished brakes except master cylinder. I found that the vaccum lines and check valve were bad. I replaced that and now the truck will die if I keep the brake pedal down, still no brakes. Which one do I need to replace or both? 
Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
You either still have alot of air in the master cylinder or it's bad.
Try this: bleed the master cylinder itself. When you buy a new master, it comes with the parts to do this. 2 plastic fitttings and nylon tubing. Fill the master cylinder, take the line from each fitting and put back into corresponding resevior(submerge in fluid). Pump the master til no air is seen in the lines. Hook back up to truck and then re-bleed the whole system. Don't push on pedal until lines are hooked up, as you'll then suck air into master again.
As for truck stalling with brakes applied? Sounds like possible vacuum leak in power booster? Unhook/plug the line so brake booster is not hooked up. Does it still stall? Then it's not brake booster.
Try this: bleed the master cylinder itself. When you buy a new master, it comes with the parts to do this. 2 plastic fitttings and nylon tubing. Fill the master cylinder, take the line from each fitting and put back into corresponding resevior(submerge in fluid). Pump the master til no air is seen in the lines. Hook back up to truck and then re-bleed the whole system. Don't push on pedal until lines are hooked up, as you'll then suck air into master again.
As for truck stalling with brakes applied? Sounds like possible vacuum leak in power booster? Unhook/plug the line so brake booster is not hooked up. Does it still stall? Then it's not brake booster.
Thread
Thread Starter
Forum
Replies
Last Post
WantFordF250
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
3
Oct 6, 2008 08:18 PM
Nightrain
1987 - 1996 F150 & Larger F-Series Trucks
5
Dec 4, 2005 11:01 PM
antitorque
1968-Present E-Series Van/Cutaway/Chassis
6
Jan 9, 2004 12:47 AM
