readymix
3/4 ton status
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Brake pedal pushes back??????
- Thread starter K85 Octane
- Start date
Failed on Saturday again. Decided to get drunk, then play golf Sunday morning. Spent the rest of Sunday sun baked, overhanged, and migrained....sleeping all day. 
ReadyMix's MC wouldn't fit on my booster, the center hole on mine wasn't big enough. So I swapped out my brand new $110 booster for his used one that matches the MC. The prop valve I got from him has a rear line output bigger than my connection up front. So I wasn't able to use it. Re-bled all the lines real good and got no change in braking or pedal pressure.
I tried to bleed the rear brakes first, like I've been doing, and go hardly a trickle. So moved on to the fronts and they bled correctly. So moved back to the rears and they bled great. So that was interesting. I had ordered an aftermarket prop valve off SummitRacing the other day. It came up for our trucks and 4wdb conversions. So I went to try it after ReadyMix's wouldn't fit and wouldn't you know it.... wrong size rear output also. Fock
Here's the different boosters. The rods and size are the same, the center hole on mine was too small (even with rubber removed).
ReadyMix's MC wouldn't fit on my booster, the center hole on mine wasn't big enough. So I swapped out my brand new $110 booster for his used one that matches the MC. The prop valve I got from him has a rear line output bigger than my connection up front. So I wasn't able to use it. Re-bled all the lines real good and got no change in braking or pedal pressure.
I tried to bleed the rear brakes first, like I've been doing, and go hardly a trickle. So moved on to the fronts and they bled correctly. So moved back to the rears and they bled great. So that was interesting. I had ordered an aftermarket prop valve off SummitRacing the other day. It came up for our trucks and 4wdb conversions. So I went to try it after ReadyMix's wouldn't fit and wouldn't you know it.... wrong size rear output also. Fock
Here's the different boosters. The rods and size are the same, the center hole on mine was too small (even with rubber removed).
Also, to answer the question about pad spacing. When I pulled all the calipers off last time to sand down the rotors and pads, they were tight on the discs. So removal and replacement felt normal.
I did have the chance to replace my rear 56s while I had help on Saturday. That was nice. So the rear has new U-bolts (have to keep an eye on them now) and 56s. I set the newly acquired springs on the floor, center of arch pointing up. Put my current springs next to them. I had AT LEAST an 1" difference between their heights. I hope this improves the ride quality and bounce while climbing. That's as far as I'm willing to go ATM for the rear suspension.
Hoping to get pressure gauge today and check pressures tonight after work.
I did have the chance to replace my rear 56s while I had help on Saturday. That was nice. So the rear has new U-bolts (have to keep an eye on them now) and 56s. I set the newly acquired springs on the floor, center of arch pointing up. Put my current springs next to them. I had AT LEAST an 1" difference between their heights. I hope this improves the ride quality and bounce while climbing. That's as far as I'm willing to go ATM for the rear suspension.
Hoping to get pressure gauge today and check pressures tonight after work.
So now, with a week of time till BB, I have to ask myself the question.....
Spend $2,200 or so (renting truck, trailer, and gas @ $4gal getting 10mpg) transporting my truck to Moab and hope somehow to get the brakes working good enough to drive it.
OR
Spend ~$500 renting a tiny car that gets 40+ MPG and drive myself up to spend a week hoping to get as many rides as possible.
PS: I don't even know what else I can do aside from changing the pads, calipers, and frame hardlines just so I can call the entire system 100% different from before. I've spent more money just trying to FIX the brakes than I spent originally buying the whole system. Plus a locker. LOL. Heading to work, will try to reply with my phone.
Spend $2,200 or so (renting truck, trailer, and gas @ $4gal getting 10mpg) transporting my truck to Moab and hope somehow to get the brakes working good enough to drive it.
OR
Spend ~$500 renting a tiny car that gets 40+ MPG and drive myself up to spend a week hoping to get as many rides as possible.
PS: I don't even know what else I can do aside from changing the pads, calipers, and frame hardlines just so I can call the entire system 100% different from before. I've spent more money just trying to FIX the brakes than I spent originally buying the whole system. Plus a locker. LOL. Heading to work, will try to reply with my phone.
readymix
3/4 ton status
I might have the adapters you need for the rear lines. If so I'll get them in the mail asap.
Saturday my buddy spent the day working on an old f100 with an ongoing brake issue similar to yours. He had no rear brakes at all and sucky fronts, we were "sure" it had no air, but after a out 30 min of bleeding the rears we got a huge fart of air and great brakes. I'm not exaggerating when I say he used a 32 ounce bottle of brake fluid before the air came out. Still not sure how the bubble was stuck that long. Maybe you just need to run a crap load of fluid through the system. 
So clearly its not a master cylinder or booster problem... You might have answered this before, but are your calipers not seating the pads correctly? That would cause them to use an excess amount of fluid to apply the brakes. If you pump the brakes does the pedal then become firm? If you raise a wheel up and spin it, do you hear the pads just brushing against the rotors?
Chevy305:
All pads are worn evenly across the surface.
I can't say I remember if the pads make noise while or not. I only remember what it was like pulling the calipers off, which were tight to the rotors.
All three boosters I've put on have had the brake pedal rods seated all the way on the rods. I could unthread the connector rod some, preloading the MC some until it affects free-spin.
Dunno
All pads are worn evenly across the surface.
I can't say I remember if the pads make noise while or not. I only remember what it was like pulling the calipers off, which were tight to the rotors.
All three boosters I've put on have had the brake pedal rods seated all the way on the rods. I could unthread the connector rod some, preloading the MC some until it affects free-spin.
Dunno
y5mgisi
1 ton status
Fock! At this point I would just about take the truck to moab just to have other people lay eyeson it! Have a wrenching party between trails! At tthe worst I would take it and if you can't get thebrakes fixed, jjust do the really easy trails. At least then you can see it and say you have been.
What's the possibility you could drop it off at a shop?
Really? And they haven't found the problem?
1) My driveline shop originally put it together for me. Different setup but same outcome. Running factory prop valve (I don't blame him, he does everything else great)
2) My rollcage builder took a whack at it and didn't get any better. Ran factory prop valve with adjustable valve to the rear
3) Then a brake specialty shop, dealing with only brake systems and had custom cars in their work bays, worked on it next. Braking improved the tiniest amount with the use of check valves and a Vette master. Lost factory prop valve (these guys should have gotten it right, but said this was the best I'll ever get without going hydroboost, or course they sell hydroboost kits)
4) Rollcage guy tried again with the 2003 Suburban MC and matching prop valve. Got worse outcome, like back before #3 worked on it.
5) I put a previously tried MC back on and a new booster and bled bled bled the brakes. Nothing
6) Chris and I tried valiantly to get things better. Nothing
7) Put on ReadyMix's MC and booster on, a set up that comes directly from his own truck. I wanted to install the prop valve but the rear line was wrong size. Go no difference.
So that's 4 or 5 different masters
2 used boosters and 1 new one
check valves
sanded pads and rotors
calipers with 3k miles on them, I bought "re-manufactured"
two different brands of pads front and rear
SS braided drops with same mileage
short 10" pieces of rubber at rear calipers with same mileage
If there was a shop that would work on it with the guarantee that it would get better or the work is free, I'd take it to them. I guess I could start taking it to random shops over the next 4 days. One shop per day LOL
2) My rollcage builder took a whack at it and didn't get any better. Ran factory prop valve with adjustable valve to the rear
3) Then a brake specialty shop, dealing with only brake systems and had custom cars in their work bays, worked on it next. Braking improved the tiniest amount with the use of check valves and a Vette master. Lost factory prop valve (these guys should have gotten it right, but said this was the best I'll ever get without going hydroboost, or course they sell hydroboost kits)
4) Rollcage guy tried again with the 2003 Suburban MC and matching prop valve. Got worse outcome, like back before #3 worked on it.
5) I put a previously tried MC back on and a new booster and bled bled bled the brakes. Nothing
6) Chris and I tried valiantly to get things better. Nothing
7) Put on ReadyMix's MC and booster on, a set up that comes directly from his own truck. I wanted to install the prop valve but the rear line was wrong size. Go no difference.
So that's 4 or 5 different masters
2 used boosters and 1 new one
check valves
sanded pads and rotors
calipers with 3k miles on them, I bought "re-manufactured"
two different brands of pads front and rear
SS braided drops with same mileage
short 10" pieces of rubber at rear calipers with same mileage
If there was a shop that would work on it with the guarantee that it would get better or the work is free, I'd take it to them. I guess I could start taking it to random shops over the next 4 days. One shop per day LOL
I've got an idea............get a plug and plug off the rear brake port at the master cylinder. Then work with the front brakes only. Once they are functioning correctly, hook up the rear lines again and trouble shoot them. As of right now we aren't possitive which circuit is causing the issue.
Good idea ^^^
Anyone know the size of the rear port? 9/16-18?
Anyone know the size of the rear port on the prop valve? I have a local shop that's really good for adapters and such. I can bring in the valve and they'll probably have an adapter but I don't know what size my line is Then I can try the prop valve.
Then I can try the prop valve.
readymix
3/4 ton status
No idea.
I just looked and I don't have the adapters either...
I just looked and I don't have the adapters either...
I believe the factory rear line is a 1/4". The front lines are 3/16".
The rear outlet fitting on the prop valve is 9/16".
The rear outlet fitting on the prop valve is 9/16".
