y5mgisi
1 ton status
Makes no sense to me. All seems pretty good. I think at this point, if it was my truck, I'd swap to soft pads, a k5 master, and have them power bled by a different shop.
CK5
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Brake pedal pushes back??????
- Thread starter K85 Octane
- Start date
This is the MC and prop valve from the 2003 (or '05, can't remember, vacuum booster Tahoe) This is what's in the first pictures of this thread. This was removed in favor of the 1985 K30 MC. These are flex lines, but factory braided flex lines. This has a 4wdb matched prop valve that I used before Chris came over. Doesn't work 
Brake fluid used
This is the booster I just bought. I looks identical to the one currently on the truck. Unless something breaks inside, normally they only go bad because of a leak, right?
These are the MC I have previously used. The bottom on is the Vette MC. Middle one is the Tahoe 4wdb MC. Top on is the 1999 CK30 4wdb MC mentioned in a couple threads in the garage.
This is the matching year MC they gave me for the booster pictured above. It is supposed to be for a K30 VACUUM but the pushrod depth is way different than the others. This one will go back to the store tomorrow.
Brake fluid used
This is the booster I just bought. I looks identical to the one currently on the truck. Unless something breaks inside, normally they only go bad because of a leak, right?
These are the MC I have previously used. The bottom on is the Vette MC. Middle one is the Tahoe 4wdb MC. Top on is the 1999 CK30 4wdb MC mentioned in a couple threads in the garage.
This is the matching year MC they gave me for the booster pictured above. It is supposed to be for a K30 VACUUM but the pushrod depth is way different than the others. This one will go back to the store tomorrow.
Holy crap! That's a lot of frickin parts! I know you are trying hard to fix this. I really hope you do.
This is for BB! Come to my house and you can borrow everything off my Burb! It's going anywhere for a month except for a tow to a shop. And I won't need brakes for that. You can borrow anything you want.
This is for BB! Come to my house and you can borrow everything off my Burb! It's going anywhere for a month except for a tow to a shop. And I won't need brakes for that. You can borrow anything you want.
You are bench bleeding correct?
They should only have about an 1/8" of travel by the time they are done bench bleeding.
They should only have about an 1/8" of travel by the time they are done bench bleeding.
The only one I don't know of was the Tahoe MC. I wasn't around when it was bled. The others were bench bled for sure. Took a long time to finally get all the bubbles out of the current one.
Question:
When Chris and I were bleeding the brakes, I was the one pumping. Every time I pumped, I could see a little gush of fluid come up in the reservoir. NOT bubbles and ONLY when pushing in...never when letting off. I would pump 3 times and hold, then Chris would crack the bleeder. We started gravity bleeding each one and giving it some time to come out. Then started the manually bleeding.
So far, the only constant "common denominator" is the booster. If it doesn't leak, could it still be bad? I can't see how. Isn't it a solid rod that goes from the pedal to the MC? Maybe the rod is bent inside? It did work fine when I bought the truck though.
I have bent the mc rod once.
Are your rubber lines in the back looping higher than the bleeder. You may have a small amount of air in the line.
Just one more thing it just doesn't sound like air in your lines. MC can leak internally
Are your rubber lines in the back looping higher than the bleeder. You may have a small amount of air in the line.
Just one more thing it just doesn't sound like air in your lines. MC can leak internally
I don't see how air could stay in the rubber line, but yes, the loop is 5-6" above the bleeder
Typical with bleeding brakes
AAAHHHHHHHHHHHHHHH
OMFG
I feel like I'm beating a dead horse.
Like all I can do is bitch bitch bitch and bitch some more to a crowd of people who aren't going to want to listen to me bitch any longer. Just the typical problem with diagnosing something over the internet. Sorry guys, I just feel helpless.
I even looked up how much it would be for a hydroboost conversion using a kit from some company. Then came to my senses after seeing ~$900 for just the "booster", MC, prop valve, and hoses. gezz
OMFG
I feel like I'm beating a dead horse.
Like all I can do is bitch bitch bitch and bitch some more to a crowd of people who aren't going to want to listen to me bitch any longer. Just the typical problem with diagnosing something over the internet. Sorry guys, I just feel helpless.
I even looked up how much it would be for a hydroboost conversion using a kit from some company. Then came to my senses after seeing ~$900 for just the "booster", MC, prop valve, and hoses. gezz
Thought of that too Eric, so I held the hose down while bleeding them.
Even I am just about out of ideas......
Couple more questions and comments and suggestions.
First, I honestly cannot tell from the pic of the caliper, is the bleeder above the line or below?
It looks below, but the pic might have been taken while the camera was upside down.
If its below, then odds are you have an air bubble in the caliper. If the calipers are not on the wrong sides, then the only way to get all the air out, is to remove the calipers from the axle, put a block of wood between the pads, and bleed them with the bleeder straight up.
I suppose you could gravity bleed them without the wood........
The MC with the deep hole, is what I was calling a manual type.
Also, I'm sure you have done this, but with all the changes I don't know what the results would be now.
First, with the engine off, hit the brakes a few times until all the boost is gone.
Let the truck sit a few seconds after that to let everything equalize.
Then press firmly on the brake. What happens? What should happen, is a small movement, then a hard pedal. You should be able to stand on it with almost no further movement.
I suspect yours is going to go way down.
May even be spongy.
If so, then that fluid is going somewhere. If its not inflating rubber lines, compressing marshmallow brake pads, or bypassing the pistons in the MC, then its compressing air.
You have gotten all the extraneous rubber out, I don't think even Chinese wood chip brake pads would compress that much, and you have put on way too many MCs for them to all be bypassing.
So, that leaves air.
Of course, if you do have small movement and then hard pedal, the brakes should work.
Then you are pretty much left with super slick brake pads, or way too big master cylinder, or both.
Also, while you are doing the pedal test, if you still have the steel top MC, then pop the top, press the brake pedal down hard, then let it snap up to see if you get a geyser from one side or the other.
On most trucks, you can see between the cowling and the edge of the hood when its up.
If not, and you are by yourself, maybe a mirror........
Oh, and I think I saw where one can order brake fluid in a 30 gallon drum one time............
Couple more questions and comments and suggestions.
First, I honestly cannot tell from the pic of the caliper, is the bleeder above the line or below?
It looks below, but the pic might have been taken while the camera was upside down.
If its below, then odds are you have an air bubble in the caliper. If the calipers are not on the wrong sides, then the only way to get all the air out, is to remove the calipers from the axle, put a block of wood between the pads, and bleed them with the bleeder straight up.
I suppose you could gravity bleed them without the wood........
The MC with the deep hole, is what I was calling a manual type.
Also, I'm sure you have done this, but with all the changes I don't know what the results would be now.
First, with the engine off, hit the brakes a few times until all the boost is gone.
Let the truck sit a few seconds after that to let everything equalize.
Then press firmly on the brake. What happens? What should happen, is a small movement, then a hard pedal. You should be able to stand on it with almost no further movement.
I suspect yours is going to go way down.
May even be spongy.
If so, then that fluid is going somewhere. If its not inflating rubber lines, compressing marshmallow brake pads, or bypassing the pistons in the MC, then its compressing air.
You have gotten all the extraneous rubber out, I don't think even Chinese wood chip brake pads would compress that much, and you have put on way too many MCs for them to all be bypassing.
So, that leaves air.
Of course, if you do have small movement and then hard pedal, the brakes should work.
Then you are pretty much left with super slick brake pads, or way too big master cylinder, or both.
Also, while you are doing the pedal test, if you still have the steel top MC, then pop the top, press the brake pedal down hard, then let it snap up to see if you get a geyser from one side or the other.
On most trucks, you can see between the cowling and the edge of the hood when its up.
If not, and you are by yourself, maybe a mirror........
Oh, and I think I saw where one can order brake fluid in a 30 gallon drum one time............
readymix
3/4 ton status
Are you missing a clip or something on the brake pedal?
I don't think so ReadyMix. There's a nut on the stud that goes through the booster linkage. Just can't see if behind that bracket thing. Well, I could be but I never messed with this area.
Off to run J's tests.....
Off to run J's tests.....
Looks correct
The rear caliper bleeders are straight up, couldn't be more straight up. The D60s are in the factory up position, which are damn near straight up.
I thin I'm going to change out the booster. It's the one thing I haven't touched on it. Probably wont do a damn thing but at least it's changed. I was wrong about the rod inside the booster too. It's in 3 pieces. The small rod that goes into the MC, a rod inside, and the rod that attaches to the pedal. I can wiggle the rod going to the pedal FAR TOO MUCH for it to be one straight piece. LMAO I dunno
Try taking the rear calipers off, put a c-clamp on the piston so it can't expand, then hang it up as high as you can on the frame and then bleed the brakes. It's fixed air in the rear lines for me before, the rear discs are a LONG way from the MC and the loop in your rear line may be trapping air no matter how long you bleed it as-is.
I'll try it
y5mgisi
1 ton status
The whole, "never gets hard" (leaving out dick jokes...) just screams air.
Also, it would seem that the k30 master would at least get the front brakes to hold like factory. So, if you put a k30 master on it, and you have k30 front calipers and you still can't lock the front, it's either air, or glazed pads.
Also, it would seem that the k30 master would at least get the front brakes to hold like factory. So, if you put a k30 master on it, and you have k30 front calipers and you still can't lock the front, it's either air, or glazed pads.
