i have a 79 150 with 3/4 ton running gear. the brakes are reakky soft. i went to bleed them and broke 3 of the 4 bleeders off. so now i have the wheels and calipers off to fix bleeders. im wondering what u guys have found with soft brakes. the caliper pistons look good and dry. it has newer rotors and pads on it... is there something i need to look for around the master cylinder brake booster area?? when applying the brakes the petal goes way down with little resistance then gets firmer and slowly stops the truck..... also im wondering of there is a tutorial for replacing the wheel bearings with warn hubs.. thanks mitch

 

I'd say just fix the bleeder screws and finish bleeding the brakes. You need to rule out air in the line. Since the truck is new to you, I would go ahead and flush all the old fluid. Does it have drum or disc on the back?

 

It has drums in the back. Can I just drain the old fluid and chase it with new?

 

Yes, you chase the old with the new. Just don't let the master cylinder go dry. There are many youtube videos that demonstrate how to do it without a helper. Typically you start farthest away from the master cylinder and work your way around.

If that doesn't fix the problem, you may want to pull the drums and check the condition of the rear brakes. Also look for any signs of leakage. New master cylinders must be bench bled. If yours looks fairly new, the PO may not have done that correctly.

 

so i was able to replace a couple bleeders on the front calipers and just finished flushing out the lines. the brakes are quite a bit better..... they wont lock up but id say probably 50% increase in stopping power. the other thing i was thinking is this truck sat for a year prior to last wednesday, so as i drive i think the corrosion on drums and rotors will wear off and ill gain some stopping power.... a question,, is the cover for the mastercylinder supposed to be a sealed unit. im seeing a bit of fluid excape from the front of the cover. i pulled the gasket out and tuned up the contact surface....thanks for the previous advise. its sweet to be out in the garage wrenching and hear emails of advise come in......!!!

 

Shouldn't leak and there should be a diaphragm in the lid that flexes with the fluid level. Should also be a small hole in the cap above the diaphragm. You may just have it a little too full.