what part is not working?

[BigSur]

So over the last few weeks every once and awhile my brakes will be hard as rocks and so i thought it was the calipers so today i installed new ones today and bled the system but while bleeding i would pump the brake pedal and it wasn't pushing fluid through the calipers in order to bleed. I just did the trick where you put your foot on the pedal and start the truck and the pedal should give a little and then get firm. Well nothing happened. Even with the truck on i pumped the pedal and it new got firm. Would this be a Booster issue, MC issue or both? I assume this is the original booster. i am going to tru and bleed again in the morning. I am hoping its just air in the lines but i doubt that is the problem.

Jason

 

[FF LC FREAK]

To me, it sounds like this could be more than one thing. Your booster could be bad from what you describe, but you still should be able to pump fluid through your lines without it. If you aren't getting fluid through, you either have a bad master cylinder or you have a kink or obstruction in your line somewhere.

First off, figure out why you are not pushing fluid. I would check all your lines first (i.e. the cheapest thing first). Then, if everything checks out, look at your master cylinder.

Next, figure out your booster. With your motor off, push on your brake pedal. Then, start the engine. Your pedal should drop a little. All the booster does is decrease the amount of force required on the brake pedal to actuate the brakes. In essence, it takes less force to apply the brakes when the engine is running.

Good luck!

 

[amaurer]

So over the last few weeks every once and awhile my brakes will be hard as rocks and so i thought it was the calipers so today i installed new ones today and bled the system but while bleeding i would pump the brake pedal and it wasn't pushing fluid through the calipers in order to bleed. I just did the trick where you put your foot on the pedal and start the truck and the pedal should give a little and then get firm. Well nothing happened. Even with the truck on i pumped the pedal and it new got firm. Would this be a Booster issue, MC issue or both? I assume this is the original booster. i am going to tru and bleed again in the morning. I am hoping its just air in the lines but i doubt that is the problem.

Jason

Sounds to me like you need to "bench" bleed master the cylinder. Did you run it dry?

 

[BigSur]

well i did notice i could push fluid through the passenger side caliper but it was having issues on the drivers side. Can i just disconnect some of the brake lines and push compressed air though it? for some reason i am picturing a messy job..

 

[D'Animal]

Why would you do that?

well i did notice i could push fluid through the passenger side caliper but it was having issues on the drivers side. Can i just disconnect some of the brake lines and push compressed air though it? for some reason i am picturing a messy job..

Crack you bleeder screws, fill your resivoir and walk away. The fluid will eventually find its way down the line. I do this and generally let it sit over night. The next morning it is super easy to bleed the system. Don't forget to tighten all the bleeder screw before you begin bleeding the brakes.

 

[splitshot]

Also make sure your bleeders are not plugged with something. Where I live there is a little wasp that builds a mud nest in any open orfice.

 

[Blue77FJ40]

Or you can make up a self bleeder bottle. Get a plastic bottle, run a plastic hose through the lid (seal it well), and add in a cheap one-way valve from DIY at a parts store inline. Then hook up to the bleeder and pump away. Just watch the master's fluid level as you pump. The one way valve will hold pressure.

Works like a charm. I also have a fancy phoenix hand vac for the brakes, and wind up using this simple approach instead.

 

[BigSur]

Well i ended up replacing the brake MC and that seemed to have helped alot but now when i push the brakes i have to really push hard. Brake Booster?

 

[bsevans]

Well i ended up replacing the brake MC and that seemed to have helped alot but now when i push the brakes i have to really push hard. Brake Booster?

When you removed the MC did you see any leakage where the push rod goes? If the MC was leaking then there is a very good possibility that brake fluid got into the Booster. Brake fluid on the Booster seals will cause them to eventually fail which will affect the required pressure on the brake pedal.

 

[BigSur]

no i didn't get anything on the booster. I noticed last night while bleeding the system it started to get really firm. There is no leakage around where the booster meets the MC. I did notice some leakage around where the smaller reservoir meets the MC. Would this cause some issues?

 

[steverb]

sounds like your rubber brake lines have internally collapsed. you cant see it from the out side.

 

[BigSur]

What do you mean internally collapsed?

 

[natvet]

rubber lines

if the rubber lines are old they can collapse on the inside and prevent proper movement of brake fluid. Seems like my brother in law had same problem and would not release pressure on the brakes(after pumping the pedal) w/o bleeding thru the bleed screw. Clear as mud now

 

[steverb]

the rubber deteriorates internally like when you suck soda threw a piece of liquorish.

 

[BigSur]

would all that cause my pedal to be hard to push in? Aren't there like 6 rubber lines that need to be replaced?

 

[steverb]

yes it could cause that. the rubber lines that where talking about are the one from the frame to the caliper and there is on from the frame to the rear axle so that make 3.

 

[BigSur]

question...wouldn't bad rubber lines cause the pedal to be more mushy instead of firm? Proportion Valve?

 

[steverb]

not sure but i would like to know the same thing because my rear cylinders seem to empty them selves so it have to double pump .yes they are adjusted right, no i don't have trapped air , there new, the brake lines are new and so is the master cylinder.

 

[BigSur]

i talked to toyota and they mentioned the gasket that goes between the MC and the booster and if i don't have one then there can be air leaking which would cause the firm pedal.

 

[Poser]

i talked to toyota and they mentioned the gasket that goes between the MC and the booster and if i don't have one then there can be air leaking which would cause the firm pedal.