The Stovebolt Site Forums The Shop Area General Truck Talk Soft Brakes

I've bled the brakes several times on my '49 Chevy 1/2-ton, but they still seem soft. If I pump the pedal twice, it goes down about 1-inch farther on the first push than the second push. Is this normal, or is there air hiding in my system? Any advice for getting the same push every time? The master cylinder and brake lines are all new, and the wheel cylinders have been re-built. No leaks detected. Thanks!

49..the 2nd pump will be somewhat higher,,,if you have replace the shoes did you turn drums?? If shoes are new were they arced to fit drums,,most shops donot arc shoes anymore if that is the case you will have somewhat of a soft brake until shoes get wore to drum dia...doc

sound like you just need to adjust the shoes up a little. the first pump pushes the shoes out toward the drum, on the second stroke your just pushing them all the way out. Some thing like a ratchet affect.
Now soft is something different, that's hair fur sure. You should have a very hard pedal when they are properly bleed and adjusted.
Denny Graham
Sandwich, IL

I agree with Denny. Those brakes are tricky to adjust. Remember they are all right hand threads. Just visualize the wheel cyl.cup & turn it to tighten them up. Tighten each one till you get a heavy drag & back it off about 3-5 notches. You may have a little drag but thats OK. When these brakes are right the pedal will hardly go down you will just apply pressure. After a few hudred miles adjust them again.

Okay, let me clarify... "soft" probably wasn't the right description for my brakes. The pedal is firm on both pumps, but goes down 1.5-inches farther on the first stroke compared to the second. My drums and shoes are new in front. Shoes are new and drums are turned in back. After bleeding, I adjusted the wheel cylinders until each wheel just began to drag without pushing on the brake pedal.

It sounds like maybe I should stop worrying and just wait until the new shoes wear to fit the drums, adjusting them occasionally. Agree??

Thanks!

Yep, just do like George says tighten them up till they drag and back them off 3 or 4 turns. You've got a 1/2 ton right?? Doesn't that have Bendix brakes?
Denny G

I went through the same thing with mine. In my case I had converted to a dual master cylinder. They seemed soft and I would pump it a couple times and it would get firmer. I still had some air left in the system, but the shoes were not adjusted tight enough yet either. To make sure there was no more air, I would have someone pump about 10 times real fast and hold the pedal down at the end of the pumps. Then I would crack the bleeder screw with a hose and bottle attached. When there was no mroe bubbly fluid coming out, I knew the air was out. I started with the left rear, then right rear, then right front, then left front. Then I jacked up each corner of the truck and adjusted the shoes again. There is a really faint drag now when you turn the wheels. They are firm now and stop the truck. I took a bunch of pictures through the whole process and they are on the "brakes" section of my webshots. Hope this helps someone cause it sure drove me nuts for a week or two.

Hey, I have a similar problem on my 65 C10, but I don't know if I have different circumstances. I just completely renovated the entire brake system on my truck: converted the front to disc with a kit, installed a dual-resevoir M/C with a brake booster, all new lines with a porportioning valve for the rear, and new wheel cylinders, shoes, drums, and hardware in the back. I originally had a leaky line that I took care of, and the entire system is bled really well. I took it for a test run around the block today and, though she stops, the pedal is nearly to the floor -- much further travel than it was before I replaced everything. I thought that the brake booster was supposed to stiffen the brakes up a bunch, but that is kind of Greek to me. I don't know if it is just me being overly worried about the pedal travel since it has been over a year since the truck was able to stop itself or what. Any ideas out there?

Randy

sounds like its time to adjust your shoes, i'm waiting for it to get a little warmer before i do that to my 49

Sorry Randy, sounds like you covered it pretty good. But I would not trust it if your peddle is almost to the floor - does not sound right to me. Hopefully some one will know here pretty quick.

"I would have someone pump about 10 times real fast and hold the pedal down at the end of the pumps."
Hey justin,I've had a bit of experince with people pumping the brake's real fast and all it did was make the air bubbles smaller,foamy,harder to get out.When they do that I'd have to wait a day for the bubbles to reform to get em out.Anyway that's what happens when they do it to me.......Tom

Always check the toe board clearance first. If the pedal is too far away from the firewall, the cylinder can't refill completely from the reservoir.

Get a recently manufactured master cylinder repair kit, if you haven't already. Not NOS or something that sat on a shelf for years.

If the pedal is still soft and there are absolutely no leaks, including wheel cylinders, you need a new master cylinder or re-sleeve and hone the old one.

Also, Speed bleeders are cheap, safe and super easy to use.

A good brake system is and stays firm 100% all the time.
No need to pump to build pressure, at all.

Bleed the brake lines annually, if you drive much or little, to get the moisture out of it.

On the brakes,,,2nd push will be somewhat higher,,,as far as soft,,if you have all air removed and adj done look at shoes not matching drums,,if new shoes have them arced...They will wear to drums at some point and pedal will firm....doc