K5 almost killed me brakes to the floor

[75gmck25]

If the linkage is all intact, my best (somewhat educated) guess is that the piston seal inside the master cylinder has torn or otherwise failed. However, the pedal will usually still return up, so check the external mechanical linkage and the rod first.

 

[Ricko1966]

I’m generally not looking to changes things for the sake of changing them BUT after yesterday I need to be confident that I have brakes I’ll buy gold brake lines if in my head they will help me stop

do you know what this is? It’s on the vaccume line before the booster check. Is kind of oily so maybe it’s in there to keep oil out of the booster?

I’m trying to decipher what the last guy did. Some things look solid others I’m suspect of. This one I don’t know

Those are original brake booster hose fitting and check valve,maybe,maybe not for your year and engine I don't have all memorized. But those will not create a problem for you.

 

[BryanS]

Those are original brake booster hose fitting and check valve,maybe,maybe not for your year and engine I don't have all memorized. But those will not create a problem for you.

Thanks. It just looked weird to me. I think I have a vacuum problem as the low idle is pretty loopy like it had a huge cam. Does Mean anything the black check valve was a little oily?

Got my new MC installed and going to bleed everything now

Really appreciate your help

 

[Ricko1966]

Thanks. It just looked weird to me. I think I have a vacuum problem as the low idle is pretty loopy like it had a huge cam. Does Mean anything the black check valve was a little oily?

Got my new MC installed and going to bleed everything now

Really appreciate your help

If you are 2 man bleeding it go real slow,don't pump the pedal, you may or may not blow the combination valve off center,watch your brake light. If it comes on the shuttle is off center and you probably will not be successful bleeding the brakes. Unless you have a bypass pin you can depress it,pull it,depending on year and model or a centering tool. Post back if you have problems. I can walk you through making the tools.

 

[BryanS]

If you are 2 man bleeding it go real slow,don't pump the pedal, you may or may not blow the combination valve off center,watch your brake light. If it comes on the shuttle is off center and you probably will not be successful bleeding the brakes. Unless you have a bypass pin you can depress it oull,depending on year and model or a centering tool. Post back if you have problems. I can walk you through making the tools.

Well….i was going to start bleeding and went to passenger rear and there is fluid leaking out of the drum. Did not see that yesterday.

 

[HotWheelsBurban]

Well….i was going to start bleeding and went to passenger rear and there is fluid leaking out of the drum. Did not see that yesterday.

Probably a bad wheel cylinder, had to get them replaced on my Crew Cab last fall. I could have done it but not in the timeframe we had before a gig, so I paid a shop to fix it while I was at work.

 

[idahovette]

Before I replaced anything, I would drain and flush the brake fluid. If it's black and looks oily, it may be. If it is , you run the risk of ruining all of your new parts. AND I would replace everything in the hydraulic end of your brake system.

 

[BryanS]

If the linkage is all intact, my best (somewhat educated) guess is that the piston seal inside the master cylinder has torn or otherwise failed. However, the pedal will usually still return up, so check the external mechanical linkage and the rod first.

The old master had bits of rubber coming out around the piston so I’m assuming it was No good. I think I have a blown wheel cylinder too b/c there is fluid leaking from a drum.

Probably a bad wheel cylinder, had to get them replaced on my Crew Cab last fall. I could have done it but not in the timeframe we had before a gig, so I paid a shop to fix it while I was at work.

Before I replaced anything, I would drain and flush the brake fluid. If it's black and looks oily, it may be. If it is , you run the risk of ruining all of your new parts. AND I would replace everything in the hydraulic end of your brake system.

Yeah I was going to bleed everything until it it ran clear.

 

[Girth]

Sounds like it's too late, you already swapped the master cylinder...... but don't be like me. I replaced the leaking master on the wife's Burb with a NAPA part. This was before I had heat in my shop, and I was in a rush. I took one look at it, cursed lousy replacement parts these days, and slapped her on there. It works, but that damn cap hasn't sealed since. I KNEW I should have dressed that sealing surface for the cap, since it was a lousy casting. I was in a rush, and lazy, and I've been mad at myself ever since. Sooooo I get to do that job again. Don't be like me. lol If you notice a leak from your cap though, welcome to the club.

Well.... that's assuming you have a cast master cylinder and not one of those plastic tanked jobs. Just dawned on me that her V2500 has the heavier brake package, so different master cylinder maybe.

 

[BadBowtie]

Make sure your e-brake is working properly. That is a fail-safe before wrecking it. You just have to use your left hand to hold the release handle out..

Odd that it has 1983-84 headlight bezels in a 1982?

Check your glove box brake code too, before ordering your new master cylinder.

 

[BryanS]

Make sure your e-brake is working properly. That is a fail-safe before wrecking it. You just have to use your left hand to hold the release handle out..

Odd that it has 1983-84 headlight bezels in a 1982?

Check your glove box brake code too, before ordering your new master cylinder.

E brake did not work….of course. That’s on my list of to do’s.

Replaced the master and like magic I have brakes

I don’t know the history of the truck but there is a newish core support so I’m thinking 83 parts went into the 82. I got it from a guy who got it from somebody else that was restoring it. I don’t think it was a frame off but the entire frame is clean and painted black. New paint even interior dash and what not so the truck looks nice and not a bit of rust anywhere. BUT I have no idea who did what when they swapped in 454. The vacuum is a messy mystery and there are a lot of wires that no longer go anywhere. Frankenstein exhausted.

I like 83 looks better so I’m happy.

 

[BryanS]

Sounds like it's too late, you already swapped the master cylinder...... but don't be like me. I replaced the leaking master on the wife's Burb with a NAPA part. This was before I had heat in my shop, and I was in a rush. I took one look at it, cursed lousy replacement parts these days, and slapped her on there. It works, but that damn cap hasn't sealed since. I KNEW I should have dressed that sealing surface for the cap, since it was a lousy casting. I was in a rush, and lazy, and I've been mad at myself ever since. Sooooo I get to do that job again. Don't be like me. lol If you notice a leak from your cap though, welcome to the club.

Well.... that's assuming you have a cast master cylinder and not one of those plastic tanked jobs. Just dawned on me that her V2500 has the heavier brake package, so different master cylinder maybe.

Yeah I had plastic. Was easy fix and the old one had bits of rubber coming out of the piston