The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Brake question - no fluid to front left bleeder

1964 GMC 1500 305v6
So my brake pedal would fade to the floor at stoplights, so I just rebuilt my master cylinder. It was very nasty in there, lots of gunk. So I decided I'd flush the entire brake system just in case.

Instead of using brake fluid, I used denatured alcohol. Right rear, left rear, right front were all fine. Left front - nothing. Removed the bleeder valve completely - nothing. So my guess is that my line is blocked somewhere. Unfortunately, someone previously decided it was a good idea to use vice grips to put the lines on, and they are chewed up. I couldn't get them off. But before I do that, does my assessment sound correct that it's blocked? The hard line comes down from the MC to a tee fitting, which goes to the right and left fronts. Since the right gets fluid I think it has to be that line to the left. Anyone have any insight or previous experience? Any input would be appreciated. I'd rather not have to mess with those lines if I don't have to.

You've most likely got a blocked hose. Could also be a plugged up wheel cylinder, especially given the description of what was in the master cylinder. Without knowing what the PO has done to the brake system, it would be a good idea to replace all of the hoses, fittings on the lines as needed, and rebuild/replace the wheel cylinders.

OK, thanks. Sounds like I need to get that line off. If it's just blocked, flushing it might get me back on the road at least. But with the age of some of the parts it's not likely they'll be reusable after. Anyone have a source for individual lines? All I've seen are the full kits or the front kits. I'd like to get away spending as little as possible since I just spent a chunk on paint.

You should be able to get them from your local parts store. They may have to order in the rubber lines, which is where I would start. You usually won't see blockage issues with the steel lines, unless they are rusted badly, in which case they usually leak. As far the fittings, those are standard items from any parts store, you will need a tubing cutter, a flaring tool, and a good file to replace them. If you want to replace the whole line instead, bulk steel line is also available at the parts sotres much cheaper than pre-bent, but you will need to bend them to shape yourself. It's not too difficult to do. That also gives you the option of just dong the lines required, rather than doing a whole line replacement.

To get that chewed flair nut off use a 4" pipe wrench (Sears sells them). You may need to slide a pipe over the handle to get the extra torque.

For replacing the lines check out poly armour lines. They are coated and you can bend them without kinking them. It actually takes some doing to get a kink in one. Makes running new tubing real easy. The down side is they don't flare real well so you have to measure your length and buy accordingly.

OK, I was able to loosen the chewed nut with my big vice grips... as soon as it broke loose, fluid started running out of it. So I tightened it back up. Then I loosened the end of the flexible line from the wheel side ... fluid started running from there too. So this seems to indicate that there must be something in the braking system preventing the fluid from getting to the bleeder valve. I'm new to these braking systems, so how much of a job is it to get in there and find out? Any ideas or likely culprits? Longbox55, you mentioned the wheel cylinder.

http://captaincheeto.com/pictures/64-gmc/brakes/IMG_8847_1024x768.jpg

Since you have fluid at the lines, it does point to the wheel cylinder. Could be full of gunk, perhaps a bad cup or other trash. Getting to it isn't too difficult. Once you pull the drum off, you can remove the shoes to allow access to the wheel cylinder. If your front drums still have the rivets holding them to the hub, you'll need to pull the bearing apart to remove them. Not too difficult, just pop the cap, remove the cotter pin (replace with new), and loosen the nut. Make sure not to let the outer bearing fall out. Rebuilding the wheel cylinder isn't too much different that the mater cylinder.

So I got into the brakes in the front left.
The wheel cylinder was a little nasty to say the least. I didn't have a rebuild kit, so I figured it would be good enough to clean it out. Got it all put back together and bled the whole system. The brakes work much better and don't fade to the floor when stopped.

But a couple of questions:
1. When should the brakes engage and start stopping? The really don't do that until the pedal is about 8" from the floor.
2. It now pulls to the right when braking. That's odd, considering it didn't do that before and the left front wasn't getting any fluid. Do I maybe need to adjust the shoes?

Here are some pics for your enjoyment:
http://captaincheeto.com/pictures/64-gmc/brakes/index.html

you can set it up till you have 3/4-1" of free play at the top of the pedal
by the way if one cyl has that crap the rest also have it more than likely.
you may now be getting fluid to that cyl but that doesn't mean that it is working
adj may help
you could have a cyl leak on the other side and the brake is grabbing when applied
ron

I wondered about the others being that badly gunked, but since the drivers front is almost directly below the MC, I thought it was more likely to have more. And it didn't pull to the right before rebuilding the MC.
But it's probably a good idea to check the other front one at some point.

I could have some air since I flushed the whole system.... I may drive it for a while, then re-bleed.

Don't take any short cuts on the brakes, only one MC chamber on these trucks for the complete system, any problem and no brakes, that means the new paint might get messed up, or someone hurt, both are bad on your insurance.