Brakes are breaking me down!

[blazd88]

So if it wasnt for seeing the new tires on I think I would have drove this thing off a cliff. After putting discs on the rear all I have ahd are problems. Bled, bled, and bled with stock MC and no rear brakes. New LARGE MC and reset the prop and now it seems like its bleeding air back into the MC. Ther are no leaks anywhere. If you pump it for long enough it will pressure up and you wont hear the air in the MC but let off for just a sec and its back. What gives. Did I get a bad MC? By the way it was bench bled and had no air when installed.

 

[blazd88]

Come on guys. No one?

 

[makovai]

Come on guys. No one?

I cant help you cause i have the same problem. After spending 3 months converting to 3/4 ton, cross steer, and rear disc brakes, the conversion is complete except i have no brakes. I have been fighting this for a couple weeks now. I have new m/c, new booster, new calipers, and no leaks.
Just for kicks and giggles this weekend i put an entire bottle of brake fluid in it and had 3 peeps going at it. 1 to pump the brakes, 1 to make sure the m/c never got below half empty (or half full ), and 1 to bleed.

I finished that and wow! i had brakes. I went for a 15 minute residential drive and when i got back my brakes were almost gone.

To me it acts like air is getting into the system, yet there is no leaks anywhere. I'm so frustrated that i dont even care about them anymore. Brakes are way over rated anyway......................all they do is slow you down.

 

[loafer]

Did you guys make sure to bench-bleed the MC? Most of the problems I've had with MC's have always been improperly bleedeing them. I can not stress enough how important it is to bleed that thing with the brake lines disconected to make sure there is NO air trapped in it.

 

[makovai]

i did bench bleed mine, it was my first time so i think i did it correctly. I know it shot brake fluid about 15 feet across my garage.

Lets supposed i did it incorrectly. Is there no way other than re-bench bleed it to get air out of the m/c? it wont work its way out through the lines?

 

[MuddinManny]

Hey Guys,

This seems to be a repeating issue and since I've done a disc swap, but yet to have it installed, I'm a little concerned. Here is the list of measures I have/will take:

1. All new hoses
2. All new calipers, rotors, pads
3. New MC. The largest I could find 1999 C3500 Van (See MuddyBuddy's post)
4. Motive Power brake bleeder

When I had my Toyota's, I had a Motive bleeder and it was awesome. No air anywhere in the system because the power bleeder forces fluid only, under constant pressure, into the MC and through the lines, one at a time. Air cannot be bypassed. It is always forced out! You'll physically get to see the air pushed out in the catch bottles attached to the bleeder screws. It's awesome.

Bleeding with constant pressure is something that the old fashioned method cannot do. By constantly pumping the brake pedal via the old method, the return stroke of the MC piston "draws" any deficiency back, whether bad fluid or air. Pressure isn't constant. That means you have to work harder to get the bad stuff out! Why work harder when you can work smarter??? That's why bleeding with a power bleeder is fool proof. You'd be amazed at the results.

If you didn't want to purchase a unit, I'd go and see if one can be rented anywhere. Give it a try. The Motive Bleeder for the Chevy is #0250.

I bought mine through www.trackhaus.com. The unit was $80.96 and the catch bottles, part MP-1810, was $14.95.

Total investment is less than $100.00 and you have it for life. Bleeding brakes every year is easy as 1-2-3! Trachaus is a very reputable company.

Click Here

Best of all, once properly hooked up and the process begun, it's literally HANDS FREE! NO JOKE!

I'm not going to insult you to ask what pattern you used to bleed the brakes. Just a friendly reminder that using the correct pattern is essential to properly bled brakes. MC, DR, PR, PF, DF. With the power bleeder, you can do all this within 30 minutes by yourself.

Double check all connections. Check caliper pistons for blow by. Also, what grade brake fluid are you using? I've heard DOT 4 or 5 can create pressure issues in older vehicles. A power bleed also forces out every bit of bad junk in the old lines. Brake fluid does go bad, and can loose its effectiveness.

Again, I'm just trying to be a friend and help. If I were closer I'd come and help personally. Hope I didn't offend. Give it a try. Let us know how things work out.

Manny

 

[makovai]

It would take alot more than that to insult me. I'm to the point now where obviously i dont know what i'm doing and i am going to purchase a power bleeder. I really really appriciate the suggestions.

 

[MuddinManny]

It would take alot more than that to insult me. I'm to the point now where obviously i dont know what i'm doing and i am going to purchase a power bleeder. I really really appriciate the suggestions.

Hey Makovai,

Don't sell yourself short. If I came across that way, it's not what I meant. I was trying to express what I've already experienced. I know you'll see a big difference with a powerbleed.

Start over again. But this time, I recommend you leave the MC where it is. Power bleed with it mounted. The PB will push any trapped air through the system. I am here to assist you any way I can. I only want success for you!

Manny

 

[makovai]

very cool.
I thought i new brakes well. My last project was a vette that i tubbed and actually converted from 4 wheel disc to drum on the d60 in the rear. It all came out fine. So this is really frustrating me. I am going to take your advise and start over from the beginning. The only reason i get hesitant about bench bleeding on the rig is that brake fluid is extremely corosive and i just painted everything below it.

 

[MuddinManny]

very cool.
I thought i new brakes well. My last project was a vette that i tubbed and actually converted from 4 wheel disc to drum on the d60 in the rear. It all came out fine. So this is really frustrating me. I am going to take your advise and start over from the beginning. The only reason i get hesitant about bench bleeding on the rig is that brake fluid is extremely corosive and i just painted everything below it.

Dude that's what's great about the powerbleeder. Just follow the directions. Set it up and pressurize the system without fluid. You'll hear a "hiss" if you've got a leak. If you hear no air, and the system holds the pressure steady for 5-10 mins, you're golden! Release the air, fill the tank with brake fluid, pressurize, and start bleeding from the drivers rear back. It's so easy, you'll kick yourself for not doing it the easy way to begin with.

Like I said. I'm here to help! If you need me, PM or call me! I'll be there for ya! Gotta get that rig on the road to bury it in some nice gooey brown MUD!

Manny

 

[bp71k5]

One problem I had when I did my disc swap was the MC pushrod was a little too long (I changed from 1/2 ton to a 3/4 ton MC) and so when I pumped the brakes to bleed them, the piston in the MC would never fully return and so no fluid was being sucked back into the piston. Once I shortened it a bit it worked fine. I even drove it around Moab with no issues.

Actually, I found the best way for me to bleed the front is to just attach a tube onto the end of the bleeder valve and put the other end in a jar of fluid. The fronts will gravity bleed themselves.

The rears were way harder because of the prop valve. I had to do lots of pumping to get those close. They are pretty good now except I haven't hooked up the parking brake which is supposed to keep them adjusted. Maybe this weekend.

 

[MuddinManny]

One problem I had when I did my disc swap was the MC pushrod was a little too long (I changed from 1/2 ton to a 3/4 ton MC) and so when I pumped the brakes to bleed them, the piston in the MC would never fully return and so no fluid was being sucked back into the piston. Once I shortened it a bit it worked fine. I even drove it around Moab with no issues.

Actually, I found the best way for me to bleed the front is to just attach a tube onto the end of the bleeder valve and put the other end in a jar of fluid. The fronts will gravity bleed themselves.

The rears were way harder because of the prop valve. I had to do lots of pumping to get those close. They are pretty good now except I haven't hooked up the parking brake which is supposed to keep them adjusted. Maybe this weekend.

Hey Bp,

I hear ya loud and clear, but I have to say that relying on gravity feed vs power is like comparing apples to oranges. The MC 1/2 ton to 3/4 issue according to everything I have read, centers around volume of fluid available to push the caliper pistons. 1/2 tonners do not have an adequate volume, as such, I can fully appreciate your argument concerning the piston travel. If volume doesn't exist, how can the piston be adequate enough to do the job. That's why many have upgraded to the 3/4 ton, but with minimum success. Also, it is key to bleed the proportioning valve. I say this knowing that the Toyota's have a bleed screw. I do not know if Chevy's have such a thing on their's. I'll have to look on my rig. Interesting!

MuddyBuddy's post concerning the search for the largest MC was excellent. The C3500 1999 MC is perfect! Excellent volume and the piston size is right on. The only issue is that the lines have to be reversed when hooking up to that particular MC because the chambers are reversed. This again, is according to the testimony of MuddyBuddy, who also, happens to work at an auto parts store.

Where I respectfully differ in opinion is allowing gravity to bleed the brakes. Why would you want to fool around with something as so sensitive as brakes, especially on the type of rigs we build? Brakes, axles, driveshafts, steering and lifts are NOT area's any shortcut or "take for granted" or "assume" stances build-ups. The $100.00 it costs to get a power bleeder and the solid brake pedal it will give you far outweigh any perceived monetary loss. Again, that is IMHO.

I'm not disputing what worked for you. I like to see all angles on how to solve a problem and hit with what works best. In this circumstance, everything these two particular K5er's have tried, has failed. It's time to bring out the big guns and get their rigs rollin' and stoppin' safely.

Happy New Year!

Manny

 

[sandawgk5]

You can build your own power bleeder for aboot $20. That is what I have in mine I just need to put it together. There is a post on here aboot making your own from parts from any hardware store.

Ira

 

[loafer]

One way that works well with the MC in the truck is to disconnect the brake lines at the MC and screw in plugs. With plugs in plase pump the MC with short 1/2-1in strokes until the pedal becomes hard and you can no longer pump it. This will work all the air out of the MC. Remove the plugs, reconnect the brake lines and then bleed the rest of the system.

Many of the reman. MC's now come with little plastic plugs specifically for bleeding the MC. The part stores are getting hundreds of perfectly good MCs returned because people think they are bad, when it is just a case of improper bleeding.

i did bench bleed mine, it was my first time so i think i did it correctly. I know it shot brake fluid about 15 feet across my garage.

Lets supposed i did it incorrectly. Is there no way other than re-bench bleed it to get air out of the m/c? it wont work its way out through the lines?

 

[makovai]

One way that works well with the MC in the truck is to disconnect the brake lines at the MC and screw in plugs. With plugs in plase pump the MC with short 1/2-1in strokes until the pedal becomes hard and you can no longer pump it. This will work all the air out of the MC. Remove the plugs, reconnect the brake lines and then bleed the rest of the system.

Many of the reman. MC's now come with little plastic plugs specifically for bleeding the MC. The part stores are getting hundreds of perfectly good MCs returned because people think they are bad, when it is just a case of improper bleeding.

I thought those lil plugs were so i could paint it without getting paint in the holes.

Actually I was wondering about that. I may do it that way when i start over. I am going to wait until i can afford a power bleeder as manny says. I want it to work this time. I cant stand brake fluid all over the place. Might as well poor paint stripper all over my frame .

 

[CDA 455]

Hey Guys,

This seems to be a repeating issue and since I've done a disc swap, but yet to have it installed, I'm a little concerned. Here is the list of measures I have/will take:

1. All new hoses
2. All new calipers, rotors, pads
3. New MC. The largest I could find 1999 C3500 Van (See MuddyBuddy's post)
4. Motive Power brake bleeder

When I had my Toyota's, I had a Motive bleeder and it was awesome. No air anywhere in the system because the power bleeder forces fluid only, under constant pressure, into the MC and through the lines, one at a time. Air cannot be bypassed. It is always forced out! You'll physically get to see the air pushed out in the catch bottles attached to the bleeder screws. It's awesome.

Bleeding with constant pressure is something that the old fashioned method cannot do. By constantly pumping the brake pedal via the old method, the return stroke of the MC piston "draws" any deficiency back, whether bad fluid or air. Pressure isn't constant. That means you have to work harder to get the bad stuff out! Why work harder when you can work smarter??? That's why bleeding with a power bleeder is fool proof. You'd be amazed at the results.

If you didn't want to purchase a unit, I'd go and see if one can be rented anywhere. Give it a try. The Motive Bleeder for the Chevy is #0250.

I bought mine through www.trackhaus.com. The unit was $80.96 and the catch bottles, part MP-1810, was $14.95.

Total investment is less than $100.00 and you have it for life. Bleeding brakes every year is easy as 1-2-3! Trachaus is a very reputable company.

Click Here

Best of all, once properly hooked up and the process begun, it's literally HANDS FREE! NO JOKE!

I'm not going to insult you to ask what pattern you used to bleed the brakes. Just a friendly reminder that using the correct pattern is essential to properly bled brakes. MC, DR, PR, PF, DF. With the power bleeder, you can do all this within 30 minutes by yourself.

Double check all connections. Check caliper pistons for blow by. Also, what grade brake fluid are you using? I've heard DOT 4 or 5 can create pressure issues in older vehicles. A power bleed also forces out every bit of bad junk in the old lines. Brake fluid does go bad, and can loose its effectiveness.

Again, I'm just trying to be a friend and help. If I were closer I'd come and help personally. Hope I didn't offend. Give it a try. Let us know how things work out.

Manny

Excellent tip !!

 

[NEK5]

Quick question, I`m going to be picking up a 1 ton 14bff with disc conversion. What am I going to have to do to make the brakes work right? I`m guession swap out the 1/2 MC?

 

[bp71k5]

Maybe I didn't explain quite right what I meant. I'm not the kind of person to skimp on the important stuff like brakes. If you want to go get a power bleeder, go for it and it'll probably work well.

I'm just suggesting that if bleeding the front half of the brakes is really difficult and you have bled the MC and PV already, then there might be something else going on that's causing it. That's what I ran into with the pushrod. I actually misstated what I did. I swapped the booster, not the MC.

The gravity bleeding is just an example of how easy it's supposed to work. As long as there is no PV and the bleeder screws are pointing in the right direction, gravity bleeding works just as good as power bleeding...on the front only.

For reference, my PV did have a bleeder screw, but I got a new PV for dual disc brakes and it doesn't have one. I'm going to try and find one that fits sometime.

Edit: I think I get where the confusion was. When I swapped my booster, the pushrod for the MC was too long and preventing the MC piston from returning all the way back. So when I bench bled it, it worked fine, but when I bolted it back up, it wouldn't push any fluid through the system at all. That made it pretty hard to bleed even with a vaccum bleeder I bought. Once I fixed that, it would bleed very easily. This is all with 1/2 ton gear. If you're upgrading to 3/4+ then it may still be good advice, but there will be more issues.

 

[MuddinManny]

Quick question, I`m going to be picking up a 1 ton 14bff with disc conversion. What am I going to have to do to make the brakes work right? I`m guession swap out the 1/2 MC?

Hey BIGBLAZE,

I have read that swappin MC and installing a new proportioning valve does the trick. The latest Bling Bling seems to be installing diesel hydroboost. That's a stretch for me. Other than the MC/Prop, everything I've read says your good to go. The MC is a definite!

Manny

 

[Tabb]

I helped a friend of mine do a rear disc swap on his 91 sub, we had the same problem, after checking everything out he started messin' with the proportioning valve. He told me he was backing out the bleeder screw and then it suddenly popped out, he was in his front yard so he searched through the grass a long time until he finally found the screw but the spring that was behind it could not be found, I think it had a little ball bearing in there too.
I told him it's time to get a new prop valve but he told me he put the screw back in just to see what would happen and guess what? rear brakes are working great! Just thought I would share that, I would'nt recommend doing this, in fact thats what I told my friend. His front and rear brakes are 50/50 now, and he says he has had no problems.