break questions

[pedro_8149]

hey so today we replaced the master cylinder, bled it, bled the brakes in all 4 corners, pedal was nice and firm and no air. went for a test drive the pedal is still going almost to the floor and spongy kinda feeling what did i miss or what do i do next. break shoes and pads are in good condition and the drums and rotors are in good condition what step do i take next.

 

[sle2115]

About the biggest issue on these trucks with all good brake parts is adjustment. I adjust my rear shoes up so they just start to drag, and don't depend on the auto adjusters, every couple oil changes, manually adjust them again. If the rear shoes have to travel very far, it creates a spongy pedal with low engagement. If you REALLY want good brakes, find a hydroboost setup and don't look back, while you'll still need to keep things adjusted, the brake potential is phenomenal!

 

[riotwarrior]

Adjustment

ADJUSTMENT

ADJUSTMENT

is the key.....Seriously you have to make sure that the rears are spot on! One day I'll find the TSB again and it also indicated a larger bore MC to help with this issue. Moves more fluid pushing out further on wheel cylinders.

IIRC you can use the dually WC too but I just don't recall for certain.

Hydroboost is the HOT ticket item. and I'm sure if you check the yards up there you will find some floating around. Get it all...pedal, booster, master cyl, ps reservoir, and lines all three of em. Then once you got it all, go and do the swap you won't look back!


and as for me I'm quite picky when I have stuff that works, I'll go so far as to undo axles so I can get a super good feel for the drag when adjusting the rears too. Almost impossible to get that JUUUUUUSSSST Perfect feel with the axles in...but this is just me the OCD guy

Right now I cannot even get a brake drum off to remove my park brake cables DOH let alone do much else. They are RUST welded to hubs. NO amount of SMACK from BFH has been able to get em to budge. Just waiting to swap rear diffs! Means when I swap my rear diff I'll blow up my drums to get at the park brake cables.

Anyway

Did I mentions adjustment? Cause if not Adjust yer rear brakes!

Al

 

[icanfixall]

Try this... Apply just part of the parking brake. See if the brake peddle works higher up now. If it does then your rear shoes are way out of adjustement. the rear self adjusters don't work no matter what we do so manual adjusting is necessary. Otherwise you get a sinking soft peddle at stop lites and the fronts are doing all the brakeing. And thats not good. The rotors overheat and warp or crack like mine did. Not very safe.. A Midus brake shop showed me that trick and told me whats been going on. So I fixed it my manual adjusting and now with the hydroboost its never a problem because I use the 1 5/16 inch bore master cylinder. More fluid is pushed per inch of peddle travel.

 

['94IDITurbo7.3]

adjusting the pedal once a week sucks FYI.................just sayin lol


h-boost and rear disk FTW! i would love to do that someday.

 

[stumiister]

Ok heres a question that no one has asked.
Doe you hear a whistle noise or whoosh sound down at your feet when you push the brake pedal?
If you do replace the brake booster.
If it looks wet or like something is leaking between the brake master cylinder and the brake booster replace both parts becasuse the master cylinder leaked brake fluid into the brake booster and rotted out the diaphram in the booster.

 

['94IDITurbo7.3]

Doe you hear a whistle noise or whoosh sound down at your feet when you push the brake pedal?
If you do replace the brake booster.

THANK YOU!!! for a clear and to the point question and answer. what affect will the bad booster indicated by the whooshing noise have on breaking power? I have anything but a hard pedal.....

 

[stumiister]

You have the symptoms you are describing such as a soft sinking pedal all the way to the floor with poor braking performance.