dieselcarpenter

Haven't been here for a while,

but as luck would have it I was driving to work about 2 weeks ago, jumped on the breaks while approaching a red light and straight to the floor, needless to say it was startling, luckily i got the rears to lock up and and down shifted and brought to a stop, pumping worked and I was able to make it in and back home.

Back story,

My brake, and anti lock lights have always been on, about a year ago I got a lot of hissing from under the dash and the pedal got hard, (booster failure) being of larger stature it wasn't a problem to stomp the pedal and being strapped for cash it didn't bother me to wait for repair. If I could keep the engine wound up it still kinda worked. but as time wore on it faded completely.

Now when I inspected, the primary reservoir was empty, air in the system no doubt. checked all lines and brake units, no leaks, slight residue on master - booster interface but not huge.

due to no leaks I chose to replace the entire set. Kragen/O'Reiley had it for 130 out the door for both with lifetime warranty.

Yesterday I changed it out, bleed all lines and flushed with fresh fluid. fired it up, lights went off, booster came alive but pedal still feels like it goes to floor almost. has good braking response even thought the pedal is soooo light. I did an emergency stop and felt the anti lock feathering the pedal.

I really bled the entire thing twice per wheel and even the proportioning valve in the rear frame rail. but the sucker is so light, it even feels like the brakes keep grabbing harder for split second after I let go of the pedal sometimes. Is it just really good because of the new components and I have been used to terrible non boosted brakes for so long??

What is normal??

dieselJon

Bypass the RWAL.

I also had to bleed the front 3 times and the rears 4 times after I diagnosed and replaced all the rear lines.

wannadiesel

I would check the rear brake adjustment. Could also be that the pushrod on the booster is too short.

I thought my truck had OK brakes until I changed the booster - then the pedal got light and it stopped great. Pedal did not drop though.

dzl_damon

I have the same problem on my D250. Had the same symptoms and changed out the booster and the master but purchased seperate (not loaded). I've bled mine over and over and have great brakes, but they are a little soggy. One pump and they are RIGHT there. My suspicions have been the length of the booster pushrod as well since that's the only thing I was trying to adjust.

Hope to hear what you get done, cause I got to do it too!

RollinCoalSmoke

Something I just learned is the master cylinder plunger ia made two ways. One has a deep hole where the rod from the booster goes in the other is shallow. The one you need is the swallow one. The first 3 I bought had the deep hole and doesnt work very well, poor brakes. I just bought new loaded booster, front rotors, front loaded calipers, rear drums, rear shoes, rear wheel cylinders, and spring kits. Haven't had time to install yet but tired of poor brakes. Spent more than I wanted too but tired of the poor brakes.

jimlj

I 2nd the rear brake adjustment. Make sure they are adjusted before you do anything else.

jimbo486

i talked to my friend at the brake, suspension and steering shop in long beach and he told me that the rears being out of adjustment would cause a spongy pedal. i adjusted and bled them over this weekend. i got a bit of air from the right rear but other than that, they bled fine and adjusted easily. the pedal seems to be a little stiffer than it was before. i think the next time the drums come off, i'll throw in the 30mm GM wheel cylinders.

Rampage1967

If your rear brakes are adjusted right & there is no air in the system then try this test. Open the hood, remove the master cylinder cover. Now slowly depress the brake pedal and take note of when the spurt of fluid back into the resivor occurs. If this spurt does not occur at 3/8 to 1/2 inch of pedal travel then adjust the booster pushrod until it does.
This may take several rounds of removing the master cylinder and adjusting the pushrod.

Do not over do this adjustment or you will end up with self applying brakes!!

This did wonders on my own truck that I had bled & bled the brakes on because of a low pedal.

Rick 12v CTD

Yeah, check the adjustment on the rear brakes before anything else. If the self adjuster isn't working properly you'll have spongy brakes. It's happened quite a few times to me.

dieselcarpenter

We adjusted the rears same day thinking that it might be the problem as well, LR had slight drag as it should, and RR was a bit further away but we ran it up to its proper space. No change.

Pedal travels a long ways really soft still but it breaks nice and solid at the end. I am tending to think the shaft may be an issue.

How is it adjutsed? I assume its the master cylinder rod not the booster rod?

Also, there is a spring clicking noise in the back when pressure is applied or relaesed and seems to coinside with pedal movment, is this the ABS ? is it ok?

Bottom line, if I leave it soft with long travel but good power will I die or kill somedbody else? is it just a comfort issue?

What is looming if I take no action?????

jimbo486

the pushrod you're looking for that was mentioned is a booster pushrod. did you bleed the brakes as well after adjusting them?

wannadiesel

I would adjust the pushrod like Rampage1967 posted. With the pedal low, you have no capacity to pump up the brakes should a caliper, wheel cylinder, or brake line spring a leak.

grandpa ralph

Diesel Carpenter,
Just to make sure - you bled the RWAL module 1st?
Then RR,LR,RF,LF

dieselcarpenter

Bashfully no, A freind helped me with more expirience in brakes and he discussed the pattern but said it doesnt make that much of a difference, we didnt notice the RWAL module until the end of the process, no air escaped only clean solid fluid, and Yes I did bleed after adjusteing the rear shoes.

how is the push rod adjusted? is it threaded? lock collar?

grandpa ralph

Bleeding the rwal first is important. Mine bled clean until I tapped it a couple times with the wrench, then it spit bubbles.
Take the mc off, the pushrod is threaded. Mark where it is now and use a wrench to adjust it.