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| | | | Joined: Aug 2005 Posts: 1,186 Shop Shark | | Shop Shark Joined: Aug 2005 Posts: 1,186 | 55 1st 6400. All new rear cylinders, hard lines, rubber line and shoes. I have them properly adjusted. I think my current problem is in adjusting the pedal travel. According to the shop manual, 13/16 fron the top of the pedal shaft to the toe board. I must be really dense because with all the adjusting I've done, it never moves away from the toe board. I had some problems getting the rear drum on and for a lack of smarts, I adjusted the master cylinder thinking it wasn't letting fluid back in so the shoe could get on (this wasn't the problem, I figured out why it was not going on shortly after). I took it out after putting the new shoes on the truck but forgot to bleed the rear brakes. Drove great, stopped great with three pumps of the pedal and the rear drums were the right temperature. Came home bled the brakes and went on another test drive and still had a soft pedal. Bled them again and after I filled the master cylinder, I pumped the brakes to make sure everything was flowing back in. I could see the piston moving in the big hole and fluid gushed back into the master cylinder from the small hole. What's weird is after I quit pumping the brake, the fluid coming back into the master cylinder was like Old Faithful (squirting) out the master cylinder! I re-adjusted the master cylinder rod to about where it was before. Had good pedal pressure which held. Went for another test drive. It stopped great and everything seemed fine. Felt the brake drums and it was deja vu all over again. They were smoking hot after a very short drive. I NEED HELP FROM SOMEBODY SMARTER THAN ME!!!!!
Bruce
Last edited by cletis; 06/07/2012 3:55 AM. Reason: Language
| | | | | Joined: Mar 2004 Posts: 3,068 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 3,068 | the fluid flowing back is normal, it has to return somewhere after pressurizing the system. As for the hot rear drums, just back off the adjustment a few clicks per shoe, per side until they run normal. When the fluid heats up and the shoes heat up, everything expands and starts the shoes to rub, creating even more heat. It happens, I had one start applying to the point they almost locked on,
Scott | | | | | Joined: Sep 2001 Posts: 29,270 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,270 |
Bruce,
Scott is correct about the back pressure. I also was surprised to see the Old-Faithful-like gyser flow. It's normal.
Did you follow Shop Manual instructions about tightening the brake shoes until drag, and then backing off until no drag (at least 7 "notches")?
Also, I have to ask, did you adjust the hydrovac first and then the wheel cylinders?
| | | | | Joined: Aug 2005 Posts: 1,186 Shop Shark | | Shop Shark Joined: Aug 2005 Posts: 1,186 | Yep have the shoes adjusted properly. I never went farther forward than the rear rubber line so I didn't mess with the hydrovac. Am I making to much about adjusting the master cylinder rod? Where do you start with it. The manual says to turn the knurled section with you fingers....right, how about vise grips!
Bruce | | | | | Joined: Feb 2000 Posts: 5,233 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 5,233 | The master cylinder should be adjusted so the pedal in its relaxed position is not pressing on the pistons in the master cylinder. You should have free travel between the pedal and pushrod. When its to close, the master cylinder is always applying pressure to the brake shoes. The wheel adjustment should dictate how close the pedal comes to the floor.
7 to 9 clicks or star points is where I back brakes off to. Its close enough to stop ok and still not heat up the drums.
Joe | | | | | Joined: Dec 2009 Posts: 66 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2009 Posts: 66 | I have an after market pedal/MC and booster. I don't know if this applies to your situation. I could not get the rears bled because it was not getting full travel on the pedal. After readjusting the pedal to get a full stroke I was able to bleed the rears. Check out my brake bleeding toot under Hypo. proportioning valve. Keep patient! You'll get it.
Al V. | | | | | Joined: Aug 2005 Posts: 1,186 Shop Shark | | Shop Shark Joined: Aug 2005 Posts: 1,186 | Feeling like I'm part of the NASCAR big bolt truck tire team, I had the rear tires off for what seems like the 1000'th time. I noticed on the drivers side the front or uppermost cylinder does not seem to retract. I opened the bleeder and fluid squirted out but no movement on the pistons inside. I really don't want to remove the cylinder again. Any ideas what's causing this?
Bruce | | | | | Joined: Mar 2005 Posts: 1,636 'Bolter | | 'Bolter Joined: Mar 2005 Posts: 1,636 | Is the wheel cylinder new? Old stock? Sounds like the pistons inside the wheel cylinder may be stuck. When the brakes are released, the springs on the shoes should pull the shoes back into the cylinder. Even letting the pressure off at the bleeder should make the shoes push the piston back into the cylinders. | | | | | Joined: Aug 2005 Posts: 1,186 Shop Shark | | Shop Shark Joined: Aug 2005 Posts: 1,186 | The cylinders are spankin new. I think a contributing factor might be semi weak springs however they seem to pull all the other shoes back.
Bruce | | | | | Joined: Oct 2006 Posts: 1,847 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 1,847 | just because your cylinders are new doesn't mean they aren't stuck. I have gotten plenty of NEW things that don't work. | | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | Do the emerg. brake cables work? If they are adjusted too tight or sticking it can hold the shoes off the stops.
The "geyser" in the master cyl. should be short & quick. If it last over a second you need adjustment of the shoes or have air in the system.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Aug 2005 Posts: 1,186 Shop Shark | | Shop Shark Joined: Aug 2005 Posts: 1,186 | Wow, my geyser lasted way longer then a second. Hopefully were getting close to solving this. The parking brake is the driveshaft type.
Bruce | | |
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