No rear brakes after rebuild wth??

I just replaced my wheel cylinders, rear brake shoes and had the drums turned. I also replaced the bell crank kits. We've bled the system. I adjusted the bellcranks so theres 1mm of play, adjusted the park brake cable to theres no slack. When the e brake cable is pushed down it clicks 8-10 times and the cable is really tight, e brake works.

YET when i push the brake pedal i have no rear brakes at all. With the drums off, we push the brake pedal and the wheel cylinders don't even expand at all. Very perplexing because we bled the system and have clean brake fluid at the rear cylinders. Truck on jack stands rear wheels just keep spinning while i have the pedal to the floor. What the heck??

 

First off, you should place something behind the brake pedal to protect the seals in the master cylinder if you are literally pushing the brake pedal to floor. A brick or small piece of wood should suffice.
Sounds like there is air in the system. Did you bleed the LSPV (above rear axle) in addition to the drums?

 

If you haven't already, I'd crawl underneath and take a look at your parking brake lever and see if theirs slop.

 

Two questions for ya, both have to do with the LSPV (Load Sensing Proportioning Valve):

Did you bleed the LSPV when bleeding the brakes?

Are the jack stands supporting the axle, or the frame?

If you’re not familiar with the LSPV, it is the contraption mounted to the frame above the axle, it has a rod going between it and the axle. It’s job is to increase rear brake pressure when hauling or towing heavy loads.

Bleeding it is an important step, as it is a high point in the system and will trap air bubbles. Also, if you have the truck supported by the frame, and the axle is at full droop, it might be cutting off fluid to the rear brakes.

 

thanks, I did bleed the LSPV . Maybe we'll do some more rounds of bleeding. We aren't pushing it right to the floor when bleeding. But I had to to get the wheels to stop spinning so i could put it back in P. Hope I didnt damage anything.

I did adjust the E brake cable adjuster underneath, there is no slack

What is the 8mm bleeder behind the master cylinder?

 

OK we'll bleed some more over here. Bleed the LSPV first this time.

the truck stands are under the axle in the rear.

crazy how theres no pressure going to the rear cylinders when the pedal is pushed.

 

I pedal bled for 20 years, I then bought a motive power bleeder. Made my own adapters for Toyota and gm a bodies. Mostly I just use the air pressure without fluid in the unit, but it’s so easy to fill the jug with Blake fluid and flush the entire system. Best to ya

 

Yeah, it is pretty crazy how little the rear brakes do with the truck fully unloaded. You can simulate load and increase the rear breaking power by adjusting the LSPV arm on the axle side. Moving it upwards towards the bed will increase pressure.

 

we just bled it again. getting nothing but fluid out of all bleeders including LSPV. the rear cylinders just aren't getting enough pressure. Can't even stop the drums spinning while in Drive. Dads been a mechanic for a couple decades and is perplexed.

 

We need pics, man. You'll need to remove the drums and get us pics to assist. Otherwise, we're all just going to guess and you'll be running around chasing your tail.

 

Are the star adjusters positioned correctly on the shoes? When the shoes are positioned correctly they rub the drums barely.

 

What the hell kind of bleeding operation are you doing? I have never once, nor heard of, putting the vehicle in drive while the engine is running to bleed brakes in over 40 years of wrenching on all kinds of vehicles.

 

I'd suggest reading through this: https://www.tundras.com/threads/rear-brake-adjustment-theory-and-practice.99575/

 

On vehicles with abs, I’ll often turn the key to acc and or start to bleed the the abs “block”.
I only run vehicles on stands if looking for problems with drivetrain or bearings. SUPER CAREFUL!!!! Triple check your stands, pray hard, do good deeds for karma.

 

Yes theyre adjusted to just barely rubbing.

haha the engine is not running nor powered up during the bleeding process. This is not my first rodeo. The wheels turning/brake testing was after the brakes were bled. I had the rear up on stands to replace all the brake components so raised the front up too because why the hell not. makes bleeding and adjusting the e brake cable easier.

Yeah the truck is on 4 - 3 ton jack stands, she solid. I might try bleeding with the ABS on if you think that'll help. Getting no air bubbles in the lines.

Thanks for this tip, I adjusted the arm, moved the locknut/sensor hose up about 3/4". Im thinking Willwood prop valve.

As it stands now, just drove the truck around, it brakes how it always has but its not great. Was hoping all these new parts and adjusting the bell cranks and cylinders might improve the performance. Going to look into the Willwood manual prop valve conversion to get these rear drums doing a little more.

 

Gonna look at getting one of these,

 

Thought mine weren't doing anything recently but after scuffing rotors and doing hard braking to bed in pads, I can see by fresh marks on rotors that rears are working now. At least working enough to bed pads anyway.

Have you tried something like that to visually tell if rear is doing anything during real use?
Also i assume you added fresh grease on slide pins/bolts for rear calipers? All 4 of my rear pins were totally dried and slightly gummed up when I took them out. Kinda sticky rather than slick.

 

This is 1st Gen forum. These trucks have rear drums.

 

Wow. I though they were disc.
Been a looong time since i worked on drums. Odd that both sides do same thing. Maybe a you made an error positioning cylinder and error repeated both sides?
Parking brake working makes me think has to be fluid not moving (either obstruction or stubborn air pocket) or cylinders not connecting right.
Can you tell if cylinder is moving at all?
Do you have a diagram to confirm the strut, leveler, lever, and all springs and other bits in there are correct, didnt hook one in wrong spot?

 

Homemade adapters, the round one for Toyota mc and the aluminum is for gm A bodies. Brakes and clutches are soooooo easy, almost fun.

 

That’s awesome! Thanks. No more bugging the wife to pump the brakes haha

 

You and I are like brothers from a different mother. I've had my Motiv for 20 years too, bought it when I had Euro brands with screw-on reservoir caps. I made the same adapter with the rubber plumbing fitting for my Toyota vehicles. Also like you, I just use it as a pressure vessel, and refill the brake reservoir. I used it once with fluid in the can, and it just made a mess -- never again.

 

Nice!


I'm in the opposite camp. I bought the power probe adapter (cnc aluminum with o-ring) and DIY'ed the pressure vessel using a garden sprayer.

 

My DIY Toyota adapter never made a perfect seal. It would hold pressure well enough to almost bleed one wheel completely before it lost pressure. When I saw the aluminum one that locks on and has an o-ring (saw it linked here on the forum) I bought one. But I haven’t used it yet. I have 3 Toyotas in the family that are due for a brake flush this spring.

 

@Teutonics posted this some months ago which seemed like a decent option:

$27 CMTOOL 43mm Brake Bleeder Adapter Compatible with Toyota and Lexus, Aluminum 43mm Master Cylinder Adapter, Works with Brake Bleeder Kit

https://www.amazon.com/dp/B0CPL15QLS

Seems a little less cumbersome than the one you can buy, I think from Motiv, with the stupid hooks and stuff that you need to align perfectly to get the cap to sit straight. (@Darkness truck, not mine. Miss that dude.)

​

 

https://www.tundras.com/threads/rea...-doesnt-make-sense.156650/page-2#post-3892012


And brake fluid is contained, so the wife doesnt freak out that the local squirrels dont get poisoned.

 

Yeah, that Scamazon cap is the one I have, but haven't used yet.

 

These are all awesome setups! I gotta get one soon.
I notice after using the eBrake now, I go under and the main cable is slack (goes to the PS rear wheel) and the DS is tight like a piano wire. That middle arm that the 2 cables connect on is solid, should that be free to pivot? Anybody replaced it or is it something you can just take apart and clean?

 

FYI for any diy brake bleeder builders. Use a ball valve, then nipple into a pvc bushing, adapter 1.5 pvc, then a rubber sleeve 1.5 with clamps. No glue. This is works for Toyota mcs’ . Cost less than $10, because we all have 1/4” ball valves around.

 

Are you just recommending this because the ball valve maintains pressure while you unscrew the fernco adapter to refill the reservoir? If you have em' all it does make sense (shit, I probably do if I search) but the cap is pretty slick for a no frills quick disconnect that costs only slightly more then the sum of parts listed.

I've almost pulled trigger on motive several times in the past. What's so messy with using the actual vessel with fluid in it rather than continually refilling the master cylinder?