Brake issues

[kevmic28]

My brakes are soft. I have to push way to hard to stop. If I pump them once they seem better but not for long. I have gravity bleed them and I have even bought a vaccuum pump brake bleeder but they still are not right. my next step is to replace the brake wheel cylinders. I cant find a leak but I know there has to be air in the system. I gravity bleed them to the point of flushing all the old fluid out of the system. What am I doing wrong here? I have never had such an issue with breaks before. Also its not power breaks, and I bench blead the master cylinder before I put it in. This is getting the better of me. Any suggestions would be greatly appreciated.
Maybe I am expecting too much out of my system as I am used to driving my 2008 car with power brakes.

[68gmsee]

It does take more effort to stop with non powered brakes especially if you are not used to them. Also a lot depends on the brake shoe material and adjustment. Can't use asbestos anymore.

If you bought new shoes and/or master cylinder they may be at fault. I've had trouble in the past with new master cylinders. I had to take one back 3 times and finally asked for my money back. I bought from a different auto store and didn't have anymore problems. Brake shoes the same way. Some of them just plain suck.

I have non powered brake drums on my 68 GMC and it does take a little more effort to stop than powered brakes but not that much. But, I also have the original brake shoes which I'm sure have asbestos in them.

[mr48chev]

To be honest, I never heard of "gravity" bleeding brakes until I got on the forums on the net. My personal background is that of having vocational auto mechanics training at the high school and trade school level, 10+ years as a working mechanic in dealership, independent and tire shops. 13 years as a vocational auto mechanics teacher at the high school level. Gravity bleeding seems to be a "hobbyist thing that may or may not work due to the application.
Due to not having a pressure bleeder at home. I usually use my mity-vac vacuum bleeder or have someone pump the brakes.

Doing the pump the brakes thing still seems to be the fastest and most positive way to get a good pedal if you don't have a pressure bleeder.

A couple of notes on doing the pump the brake bleeding thing.

The person pumping the brakes has to pump "very slowly" deliberately so as I have seen way too many helpers want to pump the pedal too fast.

Secondly, they have to hold the pedal down while you open the bleeder and keep it down until you close the bleeder and tell them "ok pump it again".

Last, make sure you never run out of fluid in the mc no matter what method you use or you get to start over.

There is an online article about making your own pressure bleeder out of a hardware store half gallon weed sprayer.
You would have to adapt your own cap for the master cylinder you have but putting a fitting on a used cap and trimming the gasket shouldn't be a big issue. OOPs, the article http://www.bmw-m.net/TechProc/bleeder.htm

[Elephanthead]

Are you sure your brakes are adjusted correctly? If it is taking two pumps, maybe your shoes are not tight enough. Other then that there must be air in the lines somewhere.

[jojo]

If you're sure you bleed everything properly and there are no leaks, you might want to get another master cylinder. I just went through a similar problem. I bleed that sucker so many times. In the end I just grabbed another mc for like $19. Brakes work great now.

[BIG69GMC]

Kev, its your master cylinder most likely unless you have a obvious leak at one of your wheel cylinders. problem is the master cylinder has a primary and secondary seals inside of it, and one of the two leaks internally (not showing a obvious leak)

[Tx Firefighter]

Adjust your brakes before you condemn any parts. When adjusted too loose, the excessive shoe to drum clearance requires more volume to apply than a single stroke of the master cylinder can give.

[kevmic28]

Ill check the adjustement first. Once it cools off it 105 right now in Nacanowhere Texas.
I have done the pump bleed system but my 9 year old was the one pumping and I dont think he was doing a good job.
Now that I think about it I would bet the adjusters are rusted and not moving.
I replaced the master cylinder to begin with because of the soft brakes and it didnt fix the problem. I have new wheel cylinders that I will change out too. I believe they are original, if not very old replacements. But I think yall are right about the adjusters.

[mclairmo]

On or more of your rubber brake hoses may be ballooning out when you push on the brakes. This would cause the condition you describe. Check for any bad hoses. Also, unbolt the master cylinder (but do not unbolt/remove the hard brake lines) and then tilt the front of it down with the cap off (so that the front of it is lower than the back of it), but not so much that fluid drips out. Then tap it with a screwdriver or small hammer and see if any air comes out. It's very hard to get all the air out of the master and even bench bleeding may not get it all out. Air can get trapped at the very front of the master cylinder bore since the piston may not go all the way to the front of the bore when you push on the pedal or even when becnh bleeding. Also, be sure the adjusters are clean and greased. Also, may be lousy quality brake pads/shoes that are causing excessive brake fade. Also, be sure there is no grease or brake fluid on the face of the pads/shoes. That will cause the brakes to simply not work. I had slightly leaking front calipers that soaked my pads and I could not stop the car at all. Was very scary. New calipers and pads fixed it. Also, if you have disc brakes, be sure the caliper bleeders are facing up and not down. Good luck.

[kevmic28]

Its drum brakes. Too hot today to work on it.

[mclairmo]

I have a 67 Camaro and it originally had manual drums all around and a 327. After installing a 396 big block with go fast goodies, the front drums could not stop the car even in easy around town driving. I would get massive brake fade after only a few stops. I had to swap to manual 11 inch discs in front and that solved the problem. If you added power to your motor or added any weight to your truck, the front drums may not be able to keep up now, especially if they are not 100%. However, I really think you have air in the system somewhere, there is grease/brake fluid on the shoes or the quality of the shoes is inferior.

[kevmic28]

No engine change yet. Its the original 350. Its just been sitting a while, or rather a farm truck. Im gonna change the wheel cyliders this weekend and inspect the adjuster bar and the hoses. I am also installing a set of headers and a new exhaust pipe too.

[kevmic28]

Well it figures It would rain today since I had big plans to work on my truck all day. Well maybe this evening.

[kevmic28]

Well I think I mat have figured out my brake issues. I went to install a new parking brake cable and realized that there are parts missing from my brake. The drum brake bar is missing from the left side rear brake. So after running to two different parts store and being told they cant get it, then realized all the salvage yards are closed today by me. So I ordered it from LMC. SO I have to wait another week to get my truck on the road.