Rear brake bleeding struggles

[YakkoWarner]

You have a k20? 1974 would be a full float 14 bolt. 12/10 bolts came in half tons.

Inboard rotors/drums are not as convenient as if they were outboard, but not really a big deal overall.

Buy the correct socket for the axle/spindle nuts.

If drum needs to be removed to be changed or turned, it will require pounding all the lug studs out and reinstalling them (personally I’d replace them).

Technically, on a drum brake full floater, you don’t even have to take the wheel off to pull the hub/drum, if you were only needing to change a wheel cylinder and no work needed on drum itself. Pull axle shaft (make sure you have enough room to slide the shaft out), spindle nut(s) off and slide assembly off.

Not something most do on smaller trucks, but class 8 and medium duty’s that pretty normal to pull the hub, drum, wheels as an assembly.

Other than that they are not really any different than any other self adjusting drum brake setup.

Also, I’d replace the rubber soft lines, if they have not been replaced in your ownership or a known date of if/when they were replaced. One of those fairly cheap parts that get overlooked and can cause plenty of headaches.

Don't you have to remove something from inside the center section to enable the axle shaft to slide out???

 

[Ricko1966]

All fluid for rear brakes comes down 1 line,through 1 hose to a tee which branches left and right if you have fluid to 1 rear the problem is after the tee at the rearend.So,the steel line,or the wheel cylinder.

 

[Chris64]

Edit already covered. Should have read more posts

Yes it was covered but you made me think of another question. Where is this light? I didn't notice anything and it's possible the bulb may even be out but that would be really helpful to know.

 

[legopnuematic]

Don't you have to remove something from inside the center section to enable the axle shaft to slide out???

No, not on a full floater. Remove the bolts on the axle flange, have a drain pan ready, slide axle out.
(Dana 70u)

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Semi floater C clip type axles yes, like 14b SF, 10,12 bolts, the cross pin must be removed from the carrier to push axle in to remove c clips to remove axles. But all of those are outboard rotors/drums so no need to pull the axle to pull a drum/rotor.

Semi float axles can also be non c clip type, like the Ford 9", Mopar 8.75, and some others.

14b SF axles, if you note on the end there is a groove for the C clip

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[Ricko1966]

Yes it was covered but you made me think of another question. Where is this light? I didn't notice anything and it's possible the bulb may even be out but that would be really helpful to know.

I put up relevant info on post 18 after my edit. As for the light put on the emergency brake a light should come on in the dash,same light,same bulb.So that would be an easy first check.

 

[Chris64]

If and when you go back together with the hub....DO NOT drag the seal over the threads on the housing........you will be taking it back apart to fix the differential oil leak that's ruining your new parts inside the drum!!!

New fear unlocked.

 

[Rusty Nail]

Still ain't no pictures though

 

[YakkoWarner]

No, not on a full floater. Remove the bolts on the axle flange, have a drain pan ready, slide axle out.
(Dana 70u)

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Semi floater C clip type axles yes, like 14b SF, 10,12 bolts, the cross pin must be removed from the carrier to push axle in to remove c clips to remove axles. But all of those are outboard rotors/drums so no need to pull the axle to pull a drum/rotor.

Semi float axles can also be non c clip type, like the Ford 9", Mopar 8.75, and some others.

14b SF axles, if you note on the end there is a groove for the C clip

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Appreciate the detailed info - I'm hoping it will be a while before I have to even think about this, but having some idea of how it goes (and that video from Chevrolet) makes it less frightening.....

 

[Chris64]

I'm still fighting this.

I was thinking for sure the proportional valve (or whatever) was blocking the brake to the rear. Google told me to reset it by opening up the front and creating a fake front brake failure (shrug). I sorta did that and then re-bled the front. Also I checked the pin on the proportional valve to see if it's grounding (I don't think my dash light is working). I did this my putting a light meter on + and lifting the rubber boot and touching the part where the wire connects. It wasn't grounding so it doesn't "seem" to be blocking.

So I moved back to the rear splitter and tried to open the lines up there but all the threads are tighter than the fittings are strong. They're soaking in liquid wrench right now.

Anyway...still trying to figure this one out...more to come.

Side note: I do plan on replacing the rubber lines eventually but I want to get it semi functional first. They're not in terrible shape and I want to know exactly what I need to replace so I can do it all at once.

 

[Rusty Nail]

I'm still fighting this.

I was thinking for sure the proportional valve (or whatever) was blocking the brake to the rear. Google told me to reset it by opening up the front and creating a fake front brake failure (shrug). I sorta did that and then re-bled the front.

Bettin this is the ticket.

I also like the collapsed brake hose idea too tho and you can't see it by lookin.
Collapses on the inside.
Wanna get it "sort of functional? Brake hoses are cheap.What is your time worth?

 

[Rusty Nail]

One of our guys just went over similar not long ago - this year- it's pretty common (in 40 y/o trucks)
It's the pintle
Maybe you can search OR bucket knows his name lol
@bucket seems to know  everything - I'm amazed he aint fixed your truck yet.
Stand by

Remember that thread Cubo? What was that dude's name?

He knows. If he wont say it means he must not like you.

 

[Ricko1966]

If you are getting fluid at one bleeder but not the other,which is what I thought you wrote some where. It is not a hose,a combination valve or the master cylinder it is past the tee on the rear axle. If you are not getting fluid at either rear wheel cylinder most likely it is the combination valve off center,2nd would be rear brake hose.

 

[Rusty Nail]

If you getcha a pocket flathead and gently pry open the rubber boots (1 or both) of the wheel cylinder , there may be brake fluid present indicating the cylinder is faulty.

You're gonna wanna open the opposite side front bleeder and slam the pedal hard and fast to dislodge the pintle from it's rest. Might need a helper to close that screw ? Not sure.
There is a way like a button or some plunger deal on the prop valve i think u gotta pull out.
Never.ever.NEVER! underestimate the importance of pulling out.

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[Chris64]

OK, great responses, I should give some updates.

I WAS getting fluid bleeding the left rear. The right rear is when problems started.

In the process of trying to vacuum the right rear (got nothing) I then tried to have my daughter press the pedal (got nothing). So I went back to the left side eventually and now it's giving me nothing. So I'm getting nothing to the rear at this point.

I'm not even going to the cylinder at this point, I'm checking the brake lines going to the cylinder and getting nothing.

If it's the pintle I'm unclear how to reset it (for the rear, the front has a button). Also How do I bleed it without it doing this to me again?

 

[Ricko1966]

OK, great responses, I should give some updates.

I WAS getting fluid bleeding the left rear. The right rear is when problems started.

In the process of trying to vacuum the right rear (got nothing) I then tried to have my daughter press the pedal (got nothing). So I went back to the left side eventually and now it's giving me nothing. So I'm getting nothing to the rear at this point.

I'm not even going to the cylinder at this point, I'm checking the brake lines going to the cylinder and getting nothing.

If it's the pintle I'm unclear how to reset it (for the rear, the front has a button). Also How do I bleed it without it doing this to me again?

Yours shouldn't have a button. I'd buy a centering tool, unplug the harness from the brake warning light,unscrew the brake warning light. Look at the end of the warning light switch that little Plunger drops into a groove in the shuttle to turn the light off. You should be able to get the shuttle to center by pumping the brake pedal,then opening a front bleeder while holding pressure on the pedal,I've heard of people using a small screwdriver to move the shuttle to center. I've never tried. I believe the threads on the switch are 1/2 x 20 to improvise a centering tool I'd drill the end of a 1/2 x 20 bolt a stick a piece of a nail in the drilled hole. Look on line for a centering tool,a pic and it will make sense.