Help no brakes

[BAD5oh]

So I found a couple of very rusty brake lines in my 84 and decided to do everything or else one will naturally blow at midnight during a snowstorm. Everything was working fine before I replaced parts.

In the spring I replaced all of the rear lines and wheel cylinders and hardware and so far everything ok. Last weekend I replaced both front lines from the prop valve to the calipers. Also put in new rubber lines, remanned calipers. At first I heard the rear brakes working while bleeding then they stopped. All I had comming out was constant fluid with bubbles and the pedal was all the way to the floor engine running or not. I figure the MC needs to be bench bled. For $28 I bought a remanned one. Bench bled it correctly and looked good. Put it in and started bleeding. Fluid shoots out like a gyser on all 4 corners. When we bled the first couple of pumps were to the floor then the pedal became full and hard. When we started the truck the pedal was lost again. Also while bleeding this time I was able to hear the rear brakes come on but not that much. The rears are adjusted properly. The PS pump is full and steering is fine (hydrobooster)

Again everything worked fine till I replaced parts. I bled almost 2 big bottles of DOT3 just in the rears and I never let the res. go empty

[ccatlett1984]

what is the AOD in your sig mean?

i'd suspect that your hydrobooster has gone south.

[BAD5oh]

what is the AOD in your sig mean?

i'd suspect that your hydrobooster has gone south.

AOD - automatic overdrive :D

Hydrobooster gone south???? Aww thats a bummer. I don't know much about them but is there something i could have done to cause this so I don't do it again??? Also doesn't it assist with the power steering? because even now you can turn the wheel with one finger easily while parked

[Robyn]

The power steering fluid pressure runs though the hydroboost and then to the steering box and on back to the reservior.

The boosters can and do go away. You should still be able to get a hard pedal though even with the booster gone.
Be real sure you dont have any air.

Have an assistant work with you, pump the pedal up like your jacking the thing up and then hold and while holding pressure pop the bleeder screws.
One little small air pocket will kill the system.


Robyn

[BAD5oh]

Have an assistant work with you, pump the pedal up like your jacking the thing up and then hold and while holding pressure pop the bleeder screws.
One little small air pocket will kill the system.


Robyn


We have been doing this method with a couple of hours into it with no results. Most of the time is spent at the rears starting with the right rear and I'm getting a solid stream of fluid with a very hard pedal and when I pop the bleeder and close it, the first 2 pumps are to the floor before getting hard again

[DmaxMaverick]

If you have a "soft" pedal that goes to the floor, then pumps up hard, only to happen again later, it is not the hydroboost. When the hydroboost fails, it will not cause a soft pedal. They leak, cause the pump to growl, make for jerky steering, prevent boosted braking (too hard pedal, even with engine running), or lose reserve braking, but will not allow the pedal to go soft to the floor. Even a good working hydroboost system will allow you to push the pedal to the floor with enough force, but there will be much hydraulic hissing, pump growl, pedal vibration, and increased engine load.

If you system is properly bled, your master cylinder is shot. If it isn't properly bled before connecting the brake lines, it can have a soft pedal for a while, but will eventually bleed itself and improve over time, not get worse. It is not uncommon to get a bad MC right out of the box (very common with Cardone MC's). I posted a simple "no tools" procedure for testing the system in another thread. I'll try to find it. For the time being, you can "bench" bleed the MC on the truck (actually easier if you are by yourself). Remove the brake lines from the MC and install the bleed kit that came with the MC. Fill the reservoir(s) and arrange the bleed lines to stay deep in the reservoir unattended. Slowly pump the pedal (engine off) all the way to the floor about 5 times and recheck the fluid level. If the level drops at all, there was air in it. Repeat at least 5 times. Once done, reconnect the lines and bleed top-down (on pedal, open bleeders at wheels, close bleeders, off pedal). Or you can use a vacuum bleeder that sucks the fluid through the bleeder with a pump. Don't let the reservoir dry up with either method, or you'll be starting all over.

[DmaxMaverick]

Found the thread HERE (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=28516). It's for a problem with a later model truck, but the procedure is the same for all brake systems on any vehicle.

[BAD5oh]

Time for an update

Still scratching my head here and also many others. This is the first time I have had this type of problem bleeding a brake system. I tried 2 remanned MC and a now have a brand new one on. I tried gravity bleeding overnight, tried a air powered vaccuum bleeder and still nanda. The vaccuum pulls air and fluid. Manually bleeding into a bottle using a clear tube shows soild fluid. Most of the bleeding is done in the rear. All MC were bench bled on the truck. I noticed that if I press the pedal without a cap on the MC the front res will shoot up a bit but nothing in the rear res. All 3 MC did this so I don't know if its normal.

I'm reaching at this point but could it have anything to do with the parts I put in?? The auto pars store gave me a chioce of 2 calipers. Both looked similar but had different diameter pistons. My old ones i took off had the smaller and required the clips on the pads. Napa asked me rear brake size (13 1/2") for the MC which I got brand new from them. Also my truck uses a load control valve. It was leaking and was told I could bypass it. At first i did not and had this problem. Today I bypassed it and the problem still occurs. I don't know which brake system I have but I did match the parts i took out

Any more thoughts???

[Robyn]

Hmmmmm

A no pedal condition equals one of two things, not enough fluid to fill the capacity of the brake cyl (disc calipers and wheel cylinders) or air in the system.

If the MC is too small of a diameter this could cause it, but you should be able to pump the system up with sucessive pedal strokes to get a firm pedal.

Without being on site to mess with it, I am at a loss here ?????????/

If you replaced the parts removed with like parts then it should work as before.

keep looking, the gremlin has to be there somewhere close at hand.

Hmmm Let me ask a stupid question, have you adjusted the rear brake shoes up properly?

If the shoes are not adjusted out to the proper running position you could get a very low pedal??????????

Robyn

[BAD5oh]

I did check to make sure the rears were adjusted during the process but I found out what the problem was.

Of all the years working on brakes on all types of vehicles and equipment I made a rookie mistake here and was completely blind to it for days. The problem was literally at my face and I was blind to recognize it. My co worker Jerry figured it out while driving home last night. He asked me to crack the bleeders on the front calipers and noticed I was crawling under the truck to do it. We chatted this morning and he told me to forget the rear brakes for a second and think about the parts I replaced (front lines, hoses, calipers) Then he asked me where are the bleeders supposed to be? I told him "they are on top of the caliper facing up" Then he told me to check them. I put the calipers on backwards with the bleeders facing down!!!!!!!!!!!!!! After I scolded myself I swapped them and even before bleeding this time I had a harder pedal. We bled them and now I have the best pedal I ever had in the truck.

It amazed me how I overlooked this. I'd like to know where my head was for the past week

Thanks people for the responses. I really appreciate it but now its time for me to give myself an a$$ whoopin:o

[Robyn]

Hmmmm yup that would definately do it.
I was not aware that the calipers could be put on wrong to be honest.
Glad all is well now. :) I thought they were indexed to fit RH and LH only

Robyn

[BAD5oh]

Hmmmm yup that would definately do it.
I was not aware that the calipers could be put on wrong to be honest.
Glad all is well now. :) I thought they were indexed to fit RH and LH only

Robyn

lol ya know everyone I told said the same thing but when I put them on the wrong side they bolted right up no problem

[rustyk]

Cans of WhupAss can be bought from Robyn for a modest cost :D

[BAD5oh]

Cans of WhupAss can be bought from Robyn for a modest cost :D

please send PM with details and cost;)

[Subzilla]

Life is good when you can safely recover from a "duh" moment. We've all had them.

[Low_Bridge]

Maybe we should change the name of this thread to:

The " Number goes Here" most common mistakes / oversites for brake R&R.

My 82 is giving me fits ! Darn thing used to stop like my old vettes (well almost)

I'm going to go check a few more things before I reveal my laziness!

[rustyk]

Could be a lot of things - the GM HydroBoost system depends on the power steering pump being quite studly.

The brake pads/linings may be glazed.

Or you may have been weakened physically in the past few weeks, and no longer are Manly Enough to make the brakes work right. :D

The master cylinder may also be suspect.

Anyway, let's have some more details about your issue...

[Low_Bridge]

You want my trucks issues: (I have more bagage than Greyhound)

Left wheel cylinder replaced due to slow drippage
Master cylinder replaced due to the same
Heck, just kinda didn't stop very well any more.Last night I tried to "bench bleed" on the truck & the rears wouldn't squirt a drop!

I put another Master cylinder on today or Tuesday!

PS the first time I went to bench bleed the Master cylinder on the truck something popped about half way down whilst pushing the pedal?

I actually drove around on just front brakes- But things just got worse & I couldn't get the rears to bleed-

I though I'd better fix my problem when I saw a pickup run a very red light yesterday at every bit of 50mph It's a miracle nobody was in the wrong place- I was waiting to turn right & well out of harms way. But a guy on a Dresser is surley selling bike today!

[rustyk]

Not getting burbles out of the rears (or any) cylinders is NOT a Good Sign. Replacing the master may cure the issue, but if ot, a vigorous flushing of the system is in order - the symptom is that crud has built up, and crud is rarely a trifling issue.

[Low_Bridge]

All is well- faulty new master-cylinder

The Mobile Command Post needs a Mastercylinder next -

The resivoir leaked out all the rear fluid-

[rustyk]

Yeah, do the whuppin'; NONE of us have EVER done something like that...:D