View Full Version : 1950 3100 brakes not holding
bluechevelless
10-23-2006, 10:13 PM
Got a 1950 Chevy 3100 truck that the brakes arent holding on. They just lose pressure and the petal will go to the floor, The fluid is going some where and its not fun to drive when the brakes stop working.
Some times you can pump them up and then go for a drive but they get weak agian.
We rebuilt the master cylinder then went and both a new master cylinder but neither helped and I cant find a leak anywhere.
Philip
10-23-2006, 11:30 PM
Danny it sounds like the master cyl is leaking internally. The fluid may be bypassing the rubber cups allowing the pressure loss. A sure sign of this is after pumping up pressure the pedal will slowly sink with your foot on it. Was the replacement master cyl new or rebuilt? Sometimes if the rebuilder doesn't bore and sleeve the cyl it is out of spec once it is honed to clean the bore.
bluechevelless
10-24-2006, 12:40 AM
I really dont know Im gonna say rebuilt but im not sure. We also rebuilt the old one and it did the same thing
bluechevelless
06-12-2007, 02:11 AM
Ok this isnt a chevelle but hey brakes are the same on most.
1950 chevy 3600 Truck
Brakes are non-power single piston m/c
Rebuilt Wheel Cylinders
New M/C
New Brake lines hard and rubber
Problem is the pedal will go to the floor but if you pump it a few times its firm and holds until you let off then in about 5 seconds and you press the pedal agian its all the way to the floor and you can pump it up and its firm. Would this be a faulty master cylinder?
HELP Need to get this going by the weekend.
THANKS!
Philip
06-12-2007, 04:39 PM
sounds like the shoes are not adjusted properly.
When there is to much clearance between the shoe and drum the wheel cylinder can not push the shoes far enough in one stroke to make good contact, but as you pump the pedal the wheel cylinder can expand more with the additional fluid each pump sends thru the lines. When you let up for a few seconds the return springs pull the shoes back and you have to start the process ll over again. Tighten the shoes against the drums and then back off a few clicks to get a litle clearance. You should be able to hear the shoes rubbing a little on the drums when the adjustment is correct. This procedure will need to be done about once a month if the truck is driven on a daily basis because they are not self adjusting.